Source: UNIVERSITY OF CALIFORNIA, RIVERSIDE submitted to
MANAGEMENT AND CONTROL OF GLASSY-WINGED SHARPSHOOTER: PREPARING FOR FUTURE INVASIVE INSECTS ON NURSERY AND FLORICULTURE CROPS
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
TERMINATED
Funding Source
Reporting Frequency
Annual
Accession No.
0193894
Grant No.
(N/A)
Project No.
CA-R-ENT-7062-H
Proposal No.
(N/A)
Multistate No.
(N/A)
Program Code
(N/A)
Project Start Date
Oct 1, 2012
Project End Date
Sep 30, 2017
Grant Year
(N/A)
Project Director
Redak, R. A.
Recipient Organization
UNIVERSITY OF CALIFORNIA, RIVERSIDE
(N/A)
RIVERSIDE,CA 92521
Performing Department
Entomology, Riverside
Non Technical Summary
The invasive glassy-winged sharpshooter has been associated (as a vector) with serious outbreaks of oleander leaf scorch and Pierce's disease of grapes in southern and central California. Within the state, exactly where this species can survive and reproduce is unknown. No predictive modeling based on actual insect life history requirements has been performed to determine the geographical and environmental limits for this insect. The development of such a model will allow a concentration of limited resources for management and control to those areas most likely at risk of infestation. The agricultural sector most heavily impacted by this insect has been the commercial nursery industry. This is due to the extremely costly intra- and inter-state quarantine measures restricting movement of nursery products from the sharpshooter-infested southern portions of the state where much of California's ornamental nursery production is located. As of this date, research from this project has led to an approved state-wide approved treatment program that allows transport of nursery shipments without inspections. Unfortunately this program is entirely reliant on two chemical insecticides, one of which is likely to be phased out in the next few years. Thus a main objective of this research is to continue to seek approaches and treatments to dis-infest nursery shipments of all stages of the glassy-winged sharpshooter.
Animal Health Component
(N/A)
Research Effort Categories
Basic
20%
Applied
80%
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
2163110113080%
2113110107020%
Goals / Objectives
This project will continue to focus on three areas related to GWSS management and control First, I will continue to develop, evaluate and deploy techniques to minimize sharpshooter densities within commercial landscape nurseries and prevent their movement to un-infested areas of the state and country. This latter area of research has been the main focus of this project for the last five years as developing a shipping protocol that allowed nursery shipments to go forth without costly inspections was the most pressing need. Second, I will complete the construction of degree-day developmental models and developmental threshold data to be used for the creation of environmental and niche-based predictive models estimating where in California that GWSS can and cannot survive should it be introduced to those areas. Even with climate and weather-based models, it is not known with any degree of accuracy to where GWSS will spread and potentially thrive with certainty within California, nor are there long-term suitable GWSS/PD management strategies available to reliably and consistently prevent the spread of this insect by movement of nursery products. Thus, completion of these two broad goals will advance significantly our ability to identify areas within the state that are most likely to successfully support populations of GWSS should they become established (and thus allow a concentration of those financial and human resources that are available for vector suppression), while simultaneously providing approaches to limit the spread of this insect to those areas of the state and country that are at risk for outbreaks of Xylella diseases. Finally, with the results and, more importantly, the methods and approaches in hand used here, I will initiate similar research directed toward managing the still-quarantined, but rapidly expanding, populations of Asian citrus psyllid as there spread through the state will also occur with nursery transport and movement of people. The specific objectives are: (1)Finalize stage-specific degree-day developmental models for GWSS (year 1); (2)Determine the lower lethal thermal thresholds for GWSS (year 1); (3) Using data from (1) and (2) develop a climate-niche models, that accurately predicts where GWSS populations can/cannot successfully thrive under a variety of current and future climate scenarios (years 2-3); (4) Continue to develop and evaluate various techniques to minimize GWSS density within Southern California's commercial ornamental nurseries and to minimize the movement of the insect from these nurseries to un-infested areas of the state (on going). This includes not only treatment of infested and potentially infested material, but improving monitoring methods as well; and (5)Transfer results and knowledge gained from 1-4, into initiating a similar research program with similar goals for Asian citrus psyllid (years 4-5).
Project Methods
For each life stage (five nymphal stages and the adult stage), approximately, 50 female and 50 male GWSS will be subjected to slowly decreasing temperatures. To determine the lower lethal-temperature (that at which ice formation occurs), isolated individual insects are placed in a polyethylene bath in which the temperature is slowly lowered to -25oC. Thermocouple probes are used to monitor both the temperature of the bath, the atmosphere around the animal, and the insect itself. At the point of ice formation (death), a small amount of heat is released from the insect which is then detected through the probe. This data will provide the lower critical temperatures which are immediately fatal to GWSS and will provide rough climatic limits to their occurrence in the state. Coupling the degree-day developmental model and data for lower thermal lethal limits with commercially available climate, land use, and land cover databases (1 km2 resolution) for California, will the creation of a a GIS-climate-based predictive model of possible GWSS habitat within the state. My primary efforts will continue to be directed toward phased series of pesticide efficacy experiments. Phase I experiments involve testing various experimental and traditional insecticides against all stages of the insect. Standardized experiments will be conducted under highly controlled environments. Separate replicate trials will be performed for each stage of the insect for both spring and summer generations. Only compounds that achieve at least 90% initial mortality and 75% residual mortality (20-day) against any particular stage will be considered as viable treatments for evaluation under subsequent phases. Phase II experiments will involve performing field-based trials located on commercial nursery properties under actual cropping conditions. Efficacy of each compound will be evaluated for a variety of nursery crops, under a variety of environmental conditions to assess the impact of cropping system, crop type and season on compound efficacy. Only those compounds that exhibit greater than 95% initial mortality and 95% residual mortality under all conditions will be advanced. Under Phase III testing, the results of Phase II experiments will be incorporated into the current management and monitoring practices of cooperating commercial grower operations and actual movement of all stages of the insect will then be monitored. At each nursery location selected, experiments will be performed to determine the overall efficacy of monitoring and treatment methods on preventing shipment of all viable stages of GWSS. Replicate plants within a crop type will be inspected at the point of shipping origin for all stages of the GWSS. Plants will be treated and then shipped using standard commercial nursery practices to nursery properties located in the northern and central portions of the state. Upon arrival at the point of destination, plants will again be inspected for all viable stages of GWSS. The efficacy of all treatments in all trials will be assessed using standard statistical techniques.

Progress 10/01/12 to 09/30/17

Outputs
Target Audience:The target audience for these efforts include the nursery and ornamental plant industry of Calfornia with a focus on Southern California. This includes large commercial nursery operations as well as retail outlets for these products. It also includes those industries and businesses responsible for pest control in the nursery and ornamental production areas and in the urban environment in general. Additional audiences include the commerical grape and citrus growing industries of the State and the California Department of Food and Agriculture. Changes/Problems:There have been two major problems encountered. One referred to earlier in the accessiblityu of critical GIS layers suitable to model the predicted distribution of glassy-winged sharpshooters. We endeavor to locate and properly use these data layers. The second problem has been the spotty availability of post-doctoral associates with the necessary training to perform some of the modlecular based work required for the resistance work. What opportunities for training and professional development has the project provided?The project has provided and continues to provide significant training and professional develoopment for all students involved (undergfraduate through post-doctoral scientist). Students have learned advanced techniques in constructing either developmental models for arthropods, or have developed the molecular tools for genetic analysis. The graduate student has gained considerable experience in writing and presenting results to both scientific and grower-based audience. As a result of these efforts, the student was awarded a USDA-NIFA Graduate Fellowship (in 2015). The undergraduates that have been associated with this project over its entire duration hava all gone on to gradaute school or professional schools. How have the results been disseminated to communities of interest?Results continue to be disseminated through internal reports, symposia proceedings to the California Department of Food and Agriculture, and through oral and poster presentations at a wide venue of statewide meetings of the California Association of Nurseries and Garden Centers, the Nursery Growers Association, and University of California Cooperative Extension. Results have also been presented at the regional and national meetings of the Entomological Society of America. What do you plan to do during the next reporting period to accomplish the goals?As this is a final report, techincally there will not be a next reporting period. For my next project, I will continue to include the insecticide resistance and modelling componenets of this project.

Impacts
What was accomplished under these goals? Under this reporting perio d(last of 5 years), my lab continues to focus on the control and management of the Glassy-winged sharpshooter (HOMALODISCA VITRIPENNIS) in California's commercial nurseries. Additionally our work with this insect pest also continues in the vineyards and citrus orchards of Southern and Central California. We also maintain our cooperation with the California Department of Food and Agriculture to refine and update the existing standardized quarantine treatment protocols for shipping nursery material throughout the state such that all stages of the glassy-wing sharpshooters are eliminated from nursery stock.This later work will likely become critical given the recent court-ordered ban on materials used to manage the spread of this insect. As in years' past, our efforts this year consisted of additional revisions of best practices for eliminating glassywinged sharpshooter from nursery shipments originating in Southern California. As part of these efforts we (and CDFA) continue to collect data regarding the efficacy of the quarantine program. Currently, almost all of Southern California commercial nurseries that export product to the north are participating in this program. As iin past years, our analysis continues to demonstrate that since inception (2010), the quarantine treatment program has been 100% effective in preventing the commercial spread of this insect. In 2016 we expanded this research this research to include evaluations of insecticide resistance within the sharpshooter within nurseries, vineyards, and urban environments. We can confirm that glassy-winged sharpshooters in the California's Southern Central Valley are now relatively resistant to both neonitotinoids and pyrethrins. For neonicotinoids, resistance levels have increases over 3000 times; for pyrethrins resistance elvels have increased up to seven times. In the Temecula Valley area, reistance to neonicotinoids has incresed five times while no detectable increase in pyrethroid reistance ahs occurred as of now. Over all, this level of increased resistance is of critical concern and threatens our ability to manage populations of this serious vector. In addition to the bioassay work we also used biochemical and molecular techniques to investigate putative resistance mechanisms to these (neonicotinoid and pyrethroid) and other (organophosphate; OP) insecticide classes. Thus far we have not identified any acetylcholinesterase insensitivity; esterase levels in susceptible and resistant populations remain very homogeneous. Based on the study of the aphid Myzus persicae, the mutation (R81T) in the loop D region of the nicotinic acetylcholine receptor beta subunit is associated with resistance to neonicotinoid insecticides. The arginine residue is important for binding of the insecticide to the receptor, and any change at this residue decreases the binding capacity of ligands, including insecticides. We identified one nicotinic acetylcholine receptor beta-like gene from the GWSS, with a single open reading frame of 1587 bp that encodes a protein of 529 amino acids, a 5' untranslated region (UTR) located 337 bp upstream of the putative start codon (ATG) and a 3' UTR of 314 nucleotides that ended in a poly (A) tail. DNA was extracted from Tulare 2016, HWY65 2016 and GBR 2016 GWSS. Sequence analysis revealed four synonymous mutations and one non-synonymous mutation in individuals expressing different imidacloprid resistance levels. However, the R to T mutation was not detected in GWSS, indicating that target site modifications are unlikely to confer resistance to imidacloprid in GWSS. We identified several cytochrome P450, glutathione S-transferase and ABC transporter genes based on the genome database of GWSS. In order to facilitate a more comprehensive analysis of their potential involvement in conferring resistance to imidacloprid and fenpropathrin, we are conducting RNA-seq analysis to compare individuals sampled from the Riverside, Tulare and Kern County locations where differences in toxicological response to the insecticides were measured. In addition, we are including in our RNA-seq analyses, survivors from the topical application bioassays, as these individuals are more likely to express resistance-causing genes. Metabolism by cytochrome P450 (Cyt P450) enzymes is of particular interest because these enzymes are known to confer resistance to imidacloprid in several insect species. Selection experiments can contribute to investigations of a potential role for these enzymes in resistance.to T mutation was not detected in GWSS, indicating that target site modifications are unlikely to confer resistance to imidacloprid in GWSS. To complement the RNA-seq analysis, we will also evaluate the efficacy of imidacloprid in bioassays that incorporate a pre-treatment with the synergist piperonyl butoxide. Initially, we will need to determine the toxicological effects of PB on GWSS, to ensure that the dose chosen is not toxic to GWSS. PB is a known inhibitor of Cyt P450 activity, so if we can identify a dose that does not kill GWSS, but enhances the efficacy of imidacloprid, then we will be closer to establishing a causal link between Cyt P450 activity and imidacloprid resistance. In addition to the synergist bioassay, we will also modify existing biochemical assays for quantifying cyt P450 activity. Assays with individual insect homogenates were unsuccessful when 7-ethoxy coumarin was used as substrate. High background fluorescence (from NADPH), together with possible inhibition of enzyme activity through the release of endogenous inhibitors during homogenization are possible stumbling blocks to using individual insect preps to measure activity. It will be necessary to generate microsomal preparations from mass homogenates of GWSS and then compare cyt P450 activity between insects from both susceptible (Tulare organic site) and resistant (General Beale Road conventional site) populations. While this approach may still suffer from the release of inhibitors, microsomal preps from insect abdomens (as are used in housefly work) may overcome this problem. In what continues to be a significant challenge, is our inability to complete modelling efforts aimed at predicting where this insect can survive and successfully reproduce in Western North America. Two factors frustratingly continue to limit our ability here: a determination of upper lethal temperature thresholds of the insect and acquisition of the necessary GIS layers (agricultural use, urban use, natural ecosystem, transportation corridors, etc.). Development of the statistical predictive models is essentially complete--that is, we have developed the tools and models to for predictive modelling, but we continue to lack all of the necessary GIS layers. Some advancement here continues to be made in that some of the GIS layers (agricultural use and environmental data) have been secured. We are committed to developing this models.

Publications

  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Schoeller, E. N. M. Yassin, and R. A. Redak. 2018. Host-produced wax affects the searching behavior and efficacy of parasitoids of the giant whitefly Aleurodicus dugesii (Hemiptera: Aleyrodidae). Biological Control: 121:74-79.
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: DR VanOverbeke, SN Thompson, RA Redak. 2017. Dietary self?selection and rules of compromise by fifth?instar Vanessa cardui. Entomologia Experimentalis et Applicata 163 (2), 209-219
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: JD Allison, RA Redak. 2017. The impact of trap type and design features on survey and detection of bark and woodboring beetles and their associates: a review and meta-analysis. Annual review of entomology 62, 127-146.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Redak, R.A., B. White, and F. Byrne. 2017. Management of Insecticide Resistance in glassy-winged sharpshooter populations using toxicological, biochemical and genomic tools. Proceedings of the Pierce's Disease Research Symposium. Sacramento, CA. pp. 163-169


Progress 10/01/15 to 09/30/16

Outputs
Target Audience:The target audience for these efforts include the nursery and ornamental plant industry of Calfornia with a focus on Southern California. This includes large commercial nursery operations as well as retail outlets for these products. It also includes those industries and businesses responsible for pest control in the nursery and ornamental production areas and in the urban environment in general. Additional audiences include the commerical grape growing industries of the State and the California Department of Food and Agriculture. Changes/Problems:As with last year, the continuing major, and only, challenge remaining in order to complete the original objectives is the acquistion of the necessary GIS data layers. This has been a long standing challenge; however, we have been able to secrure several, but not all, of the necessary data layers. Challenges with respect to the insecticide resistance work are minor, and progress continues in this area at an acceptable pace. What opportunities for training and professional development has the project provided?The project continues to provide significant training and professional develoopment for both the post-doctoral scientist and the graduate student. Both have learned advanced techniques in constructing either developmental models for arthropods, or have developed the molecular tools for genetic analysis. The graduate student has gained considerable experience in writing and presenting results to both scientific and grower-based audience. As a result of these efforts, the student was awarded a USDA-NIFA Graduate Fellowship. How have the results been disseminated to communities of interest?Results continue to be disseminated through internal reports, symposia proceedings to the California Department of Food and Agriculture, and through oral and poster presentations at a wide venue of statewide meetings of the California Association of Nurseries and Garden Centers, the Nursery Growers Association, and University of California Cooperative Extension. Results have also been presented at the regional and national meetings of the Entomological Society of America. What do you plan to do during the next reporting period to accomplish the goals?With regard to the modelling efforst, I would sincerly hope, that the requistite GIS data layers required for the niche modelling of glassy-winged sharpshooters can be obtained. Virtually all of the data layers required have been obtained, however several critical layers remain "elusive". Secondarily we will continue to determine the levels of insecticide resistances (and the genetic basis for that resistance) throughout the areas of the state impacted by this insect. For this year we will be targeting commercial nurseries and vineyards of Southern California

Impacts
What was accomplished under these goals? Under this reporting period, my lab continues to focus on the control and management of the Glassy-winged sharpshooter (HOMALODISCA VITRIPENNIS) in California's commercial nurseries. We have now expanded these studies to vineyards of Southern California as well as the Central Valley. Specifically, as in years past, we continue our efforts, in cooperation with the California Department of Food and Agriculture to refine the existing standardized quarantine treatment protocols for shipping nursery material throughout the state such that all stages of the glassy-wing sharpshooters are eliminated from nursery stock. As in years' past, our efforts this year consisted of additional revisions of best practices for eliminating glassy-winged sharpshooter from nursery shipments originating in Southern California. As part of these efforts we (and CDFA) continue to collect data regarding the efficacy of the quarantine program. Currently, almost all of Southern California commercial nurseries that export product to the north are participating in this program. As with 2014, Our analysis continues to demonstrate that since inception (2010), the quarantine treatment program has been 100% effective in preventing the commercial spread of this insect. We have explanded this research to include evaluations of insecticide resistance within the sharpshooter both within nurseries and vineyards. We can confirm that glassy-winged sharpshooters in the General Beale Road citrus-growing area of the Central Valley are exhibiting high levels of imidacloprid resistance based on data generated from topical application bioassays. In addition, we have also detected shifts in pyrethroid susceptibility. During the summer of 2016 we bioassayed adult insects collected from citrus groves in Kern (conventional and organic), Tulare (organic), and Riverside (organic) counties and compared the responses with toxicology data that were generated in 2003 for populations in Riverside County. In addition to the bioassay work we also used biochemical and molecular techniques to investigate putative resistance mechanisms to these (neonicotinoid and pyrethroid) and other (organophosphate; OP) insecticide classes. Thus far we have not identified any acetylcholinesterase insensitivity, indicating that there is no target site resistance to OPs. Esterase levels in susceptible and resistant populations are also very homogeneous, confirming that elevated esterase levels are unlikely to play a significant role in conferring pyrethroid resistance. We are using genomics tools to elucidate possible roles of cytochrome P450 enzymes in conferring imidacloprid and fenpropathrin resistance, as the biochemical assays have not been optimized for measuring these enzyme systems in these insects. We are currently comparing cDNA sequence data for sodium channel (pyrethroid target site) and nicotinic acetylcholine receptor (neonicotinoid) genes in insects from the different populations to determine whether mutations known to confer insecticide resistance in other arthropod species occur in glassy-winged sharpshooter. In what frustratingly continues to be a significant challenge, is our ability to complete modelling efforts aimed at predicting where this insect can survive and successfully reproduce in Western North America. Two factors frustratingly continue to limit our ability here: a determination of upper lethal temperature thresholds of the insect and acquisition of the necessary GIS layers (agricultural use, urban use, natural ecosystem, transportation corridors, etc.). Development of the statistical predictive models is essentially complete--that is, we have developed the tools and models to for predictive modelling, but we continue to lack all of the necessary GIS layers. Some advancement here continues to be made in that some of the GIS layers (agricultural use and environmental data) have been secured. We are endeavoring to obtain all other necessary layers.

Publications

  • Type: Journal Articles Status: Published Year Published: 2016 Citation: Waterworth, R. A., L. J. Robinson, R. A. Redak, and J.M. Morse. 2016. Evaluating the performance and preference of Aphytis melinus (Hymenoptera: Aphelinidae) on an exotic species, Acutaspis albopicta (Hemiptera: Diaspididae) and Aonidiella aurantii (Hemiptera: Diaspididae). Enviorn. Entomol. 45:83-93.
  • Type: Journal Articles Status: Published Year Published: 2016 Citation: Briggs, C. M. and R. A. Redak. 2016. See selection by the harvester ant, Pogonomyrmex rugosus (Hymenoptera: Formicidae) in Coastal Sage Scrub: interactions with invasive plant species. Environ. Entomol. 45: 983-990.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2016 Citation: Redak, R.A., B. J. White, and F. Byrne. 2016. Management of insecticide resistance in glassy-winged sharpshooter populations using toxicological, bichemical, and genomic tools. In: Proceedings of the Pierce's Disease Research Symposium. California Department of Food and Agriculture. pp.230-236


Progress 10/01/14 to 09/30/15

Outputs
Target Audience:The target audience for these efforts include the nursery and ornamental plant industry of California with a focus on Southern California. This includes large commercial nursery operations as well as retail outlets for these products. It also include those industries and businesses responsible for pest control in the nursery and ornamental productions areas and in the urban enviornment in general. Finally, an important target audience of this work is the California Department of Food and Agriculture Changes/Problems:The continuing major, and only, challenge remaining in order to complete the original objectives is the acquistion of the necessary GIS data layers. This has been a long standing challenge; however, this last year have been able to secrure several, but not all, of the necessary data layers. Challenges with respect to the insecticide resistance work are minor, and progress in that area continues to advance at an acceptable pace. What opportunities for training and professional development has the project provided?The project continues to provide significant training and professional develoopment for both the post-doctoral scientist and the graduate student. Both have learned advanced techniques in constructing developmental models for arthropods, and both have gained considerable experience in presenting results to both scientific and grower-based audience. How have the results been disseminated to communities of interest?Results have been disseminated through internal reports, symposia proceedings to the California Department of Food and Agriculture, and through oral and poster presentations at a wide venue of statewide meetings of the California Association of Nurseries and Garden Centers, the Nursery Growers Association, and University of California Cooperative Extension. What do you plan to do during the next reporting period to accomplish the goals?I would sincerly hope, that the requistite GIS data layers required for the niche modelling of glassy-winged sharpshooters can be obtained, and thus allow us to complete our modelling efforts. Secondarily we will continue to determine the levels of potential insecticide resistances (and the genetic basis for that resistance) throughout the areas of the state impacted by this insect.

Impacts
What was accomplished under these goals? Under this reporting period, my lab continues to focus on the control and management of the Glassy-winged sharpshooter (HOMALODISCA VITRIPENNIS) in California's commercial nurseries. Specifically, as in years past, we continue our efforts, in cooperation with the California Department of Food and Agriculture to refine the existing standardized quarantine treatment protocols for shipping nursery material throughout the state such that all stages of the glassy-wing sharpshooters are eliminated from nursery stock. As in years' past, our efforts this year consisted of additional revisions of best practices for eliminating glassy-winged sharpshooter from nursery shipments originating in Southern California. As part of these efforts we (and CDFA) continue to collect data regarding the efficacy of the quarantine program. Currently, almost all of Southern California commercial nurseries that export product to the north are participating in this program. As with 2014, Our analysis continues to demonstrate that since inception (2010), the quarantine treatment program has been 100% effective in preventing the commercial spread of this insect. In what is now a significant challenge, is our ability to complete modelling efforts aimed at predicting where this insect can survive and successfully reproduce in Western North America. Two factors frustratingly continue to limit our ability here: a determination of upper lethal temperature thresholds of the insect and acquisition of the necessary GIS layers (agricultural use, urban use, natural ecosystem, transportation corridors, etc.). Development of the statistical predictive models is essentially complete--that is, we have developed the tools and models to for predictive modelling, but we continue to lack all of the necessary GIS layers. Some advancement here has been made in that some of the GIS layers (agricultural use and environmental data) have been secured. We are endeavoring to obtain all other necessary layers. In related glassywinged sharpshooter research, we have completed year one of a three year project to detect the evolution of insecticide resistance(pyrethroid, carbamate, and neonicotinoid) in this insect. To date we have identified the genomic sequence for several sharpshooter genes that are the putative sites for resistance to carbamate, pyrethroid, and neonicotinoid insecticides. Genomic analyses are ongoing to further elucidate the genetic basis for insecticide resistance in several populations of GWSS throughout the state (Central Valley, Temecula Valley, urban areas of Southern California). Bioassay analysis to detect insecticide resistance in GWSS is also ongoing. Data from these early analyses suggest that there has been a shift in tolerance to neonicotinoids in the Kern County area. Insects appear to be less sensitive to this class of insecticide relative to other populations that have had limited exposure. Additionally, based on very limited sampling, there does not appear to be a major shift in resistance to organophosphate, carbamate or pyrethroid insecticides.

Publications

  • Type: Journal Articles Status: Published Year Published: 2016 Citation: Waterworth, R. A., L. J. Robinson, R. A. Redak, and J.M. Morse. 2016. Evaluating the performance and preference of Aphytis melinus (Hymenoptera: Aphelinidae) on an exotic species, Acutaspis albopicta (Hemiptera: Diaspididae) and Aonidiella aurantii (Hemiptera: Diaspididae). Enviorn. Entomol. 45:83-93.
  • Type: Journal Articles Status: Awaiting Publication Year Published: 2016 Citation: Briggs, C. M. and R. A. Redak. 2016. Seed selection by the harvester ant Pogonomyrmex rugosus (Hymenoptera: Formicidae) in coastal sage scrub: interactions with invasive plant species. Accepted in minor revision. Environ. Entomol.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2015 Citation: Redak, R. A. B. White, and F. Byrne, 2015. Management of insecticide resistance in glassy-winged sharpshooter populations using toxicological, biochemical, and genomic tools. In; Proceedings of the Pierces Disease Research Symposium. California Department of Food and Agriculture, Sacramento, CA 157-163.


Progress 10/01/13 to 09/30/14

Outputs
Target Audience: The target audience for these efforts include the nursery and ornamental plant industry of California with a focus on Southern California. This includes large commercial nursery operations as well as retail outlets for these products. It also include those industries and businesses responsible for pest control in the nursery and ornamental productions areas and in the urban enviornment in general. Finally, an important target audience of this work is the California Department of Food and Agriculture. Changes/Problems: The only significant challenge has been the acquisiton of the necessary GIS layers to complete the modeling portion of this project. What opportunities for training and professional development has the project provided? The project has provided significant training and professional develoopment for both the post-doctoral scientist and the graduate student. Both have learned advanced techniques in constructing developmental models for arthropods, and both have gained considerable experience in presenting results to both scientific and grower-based audiences. How have the results been disseminated to communities of interest? Results have been disseminated through internal reports to CDFA and through oral and poster presentations at a wide venue of meetings. What do you plan to do during the next reporting period to accomplish the goals? We will endeavor to secure the necessary GIS layers and modelling capabilities to complete the modelling portion of this project.

Impacts
What was accomplished under these goals? Under this reporting period, my lab continues to focus on the control and management of the Glassy-winged sharpshooter (HOMALODISCA VITRIPENNIS) in California's commercial nurseries. Specifically, as in years past, we continue our efforts, in cooperation with the California Department of Food and Agriculture to refine the existing standardized quarantine treatment protocols for shipping nursery material throughout the state such that all stages of the glassy-wing sharpshooters are eliminated from nursery stock. As in years' past, our efforts this year consisted of additional revisions of best practices for eliminating glassy-winged sharpshooter from nursery shipments originating in Southern California. Additionally, we continue to provide the ornamental industry with insecticide testing information related to limiting this insect's distribution as well as evaluating the treatment status of nursery shipments bound for the northern counties of the state. As part of these efforts we (and CDFA) continue to collect data regarding the efficacy of the quarantine program. Currently, almost all of Southern California commercial nurseries that export product to the north are participating in this program. As with 2014, Our analysis continues to demonstrate that since inception (2010), the quarantine treatment program has been 100% effective in preventing the commercial spread of this insect. In what is now a significant challenge, is our ability to complete modelling efforts aimed at predicting where this insect can survive and successfully reproduce in Western North America. Two factors are limiting our ability here: a determination of upper lethal temperature thresholds of the insect and acquisition of the necessary GIS layers (agricultural use, urban use, natural ecosystem, transportation corridors, etc.). Development of the statistical predictive models is continuing. In related glassywinged sharpshooter research, we have embarked on a study to detect the evolution of insecticide resistance (pyrethroid, carbamate, and neonicotinoid) in this insect. Within this area, we have recently obtained the sharpshooter genome from collaborators in Texas and have now identified the location of the KDR (knock down resistance)gene where resistance to pyrethroids, if it evolves, will be evident. We are now developing the methodologies to genetically screen for both KDR and well as carbamate resistance within the acetylcholinesterase gene.

Publications


    Progress 01/01/13 to 09/30/13

    Outputs
    Target Audience: Commercial ornamental nursery production and commerical grape (wine, table, juice, raison) production. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Nothing Reported How have the results been disseminated to communities of interest? Results have been reported to two regional meetings of the Southern California nursery growers, and one national entomology meeting. What do you plan to do during the next reporting period to accomplish the goals? We expect to further our ability to model the potential distribution of the glassy-winged sharpshooter. To accomplish this we will need to have better success in develping our GIS modelling abilities and access to data layers necessary to complete the project.

    Impacts
    What was accomplished under these goals? Under this reporting period, my lab continues to focus on the control and management of the Glassy-winged sharpshooter (HOMALODISCA VITRIPENNIS) in California’s commercial nurseries. Specifically, as in years past, we continue our efforts, in cooperation with the California Department of Food and Agriculture to refine the existing standardized quarantine treatment protocols for shipping nursery material throughout the state such that all stages of the glassy-wing sharpshooters are eliminated from nursery stock. Work this year consisted of additional revisions of best practices for eliminating glassy-winged sharpshooter from nursery shipments originating in Southern California. Additionally, we continue to provide the ornamental industry with insecticide testing information related to limiting this insect’s distribution as well as evaluating the treatment status of nursery shipments bound for the northern counties of the state. As part of these efforts we (and CDFA) continue to collect data regarding the efficacy of the quarantine program. Currently, almost all of Southern California commercial nurseries that export product to the north are participating in this program. As with 2013, Our analysis continues to demonstrate that since inception (2010), the quarantine treatment program has been 100% effective in preventing the commercial spread of this insect. In what continues to be quite a challenge, the lab continues to determine both the lower and upper lower lethal temperature at which sharpshooters may survive and develop. Currently, we have determined that approximately -11 oC is the lower lethal temperature for both adult male and female insects. Our work continues in determining the lower lethal temperature for early and late instars. Data collected to date is now being used to refine our modelling for the potential distribution of the insect. Determining upper lethal temperature thresholds has become problematic as the insect can survive for short periods of time at temperatures greater than what we can accurately generate in a stable manner with existing equipment. Given this we must assume that higher temperatures in the desert areas of the state will not limit the distribution of the insect. Related toward our development of a climate-phenology based GIS predictive model for sharpshooter suitable habitat, we continue to developed the necessary modeling techniques necessary for our. We are currently developing the model using glassy-winged development data and various GIS data layers representing the urban and agricultural environment of California. Our advancement in this area has been slowed somewhat due to difficulty in obtaining the necessary data layers to complete the modelling analysis. Finally, in related research directed at integrated pest management within the California nursery industry, we have begun investigating the interactions between the giant whitefly (ALEURODICUS DUGESII), its host plant, its parasitoid wasps, and the environment in which they grow. Specifically we are now investigating the impact of climate on the growth of the whitefly and the efficacy of parasitization by a variety of wasp parasitoids. As a first step, a degree-day model was needed for whitefly development. This has been nearly completed during this reporting period; giant whiteflies require approximately 425 degree-days to complete their development with an optimum development temperature of approximately 28 degrees. Additionally we have begun behavioral studies of the wasp ovisposition preferences with respect to whitefly development stage and how the development stage of the whitefly is affected by temperature. The latter studies are ongoing at this time.

    Publications


      Progress 01/01/12 to 12/31/12

      Outputs
      OUTPUTS: Under this reporting period, my lab continues to focus on the control and management of the Glassy-winged sharpshooter (HOMALODISCA VITRIPENNIS) in California's commercial nurseries. Specifically, we continue our efforts, in cooperation with the California Department of Food and Agriculture to refine the existing standardized quarantine treatment protocols for shipping nursery material throughout the state such that all stages of the glassy-wing sharpshooters are eliminated from nursery stock. Work this year consisted of revising best practices for eliminating glassy-winged sharpshooter from nursery shipments originating in Southern California. Additionally, we continue to provide the ornamental industry with insecticide testing information related to limiting this insects distribution as well as evaluating the treatment status of nursery shipments bound for the northern counties of the state. As part of these efforts we (and CDFA) continue to collect data regarding the efficacy of the quarantine program. Currently, almost all of Southern California commercial nurseries that export product to the north are participating in this program. Our analysis continues to demonstrate that since inception (2010), the quarantine treatment program has been 100% effective in preventing the commercial spread of this insect. In what appears to be quite a challenge, the lab continues to determine both the lower and upper lower lethal temperature at which sharpshooters may survive and develop. Currently, we have determined that approximately -11 oC is the lower lethal temperature for both adult male and female insects. Our work continues in determining the lower lethal temperature for early and late instars. Lethal temperatures for late instars appear to be similar to adults. Determining lower lethal temperatures for early instars remains difficult due to the high mortality associated with handling and tremendous variance associated with the insects response. Our approach has now been refined somewhat as we continue to solve the issues with simply increasing sample size. Finally, related toward our development of a climate-phenology based GIS predictive model for sharpshooter suitable habitat, we have now developed the necessary modeling techniques necessary for our approach and tested the methods using an endangered insect species under various climate change scenarios. We are currently developing the model using glassy-winged development data and various GIS data layers representing the urban and agricultural environment of California. PARTICIPANTS: Nothing significant to report during this reporting period. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Not relevant to this project.

      Impacts
      Our work with controlling sharpshooters in commercial nurseries has demonstrated that these insects may be successfully managed such that transport of nursery materials from quarantined areas of the state can successfully performed. Our recommendations to the California Department of Food and Agriculture regarding modified quarantine treatments of ornamental nursery materials have been submitted and accepted. We continue to collect data such that shipment protocols are modified using best management practices derived from current data. These actions have resulted in the development of exceptionally effective state-wide program used to prevent the accidental shipment of this insect to the northern counties of California. To date, this program has completely prevented the spread of this insect on commercial nursery stock. This year we have developed the data and methods that now allow growers and agencies in areas un-infested with sharpshooters to adequately assess whether or not incoming plant shipments have been properly treated for insect eradication.

      Publications

      • Prentice, T. R. and R. A. Redak (2013). A new species of the spider genus Eridantes Crosby & Bishop from the southwestern United States and mainland Mexico with a revised diagnosis of the genus (Araneae, Linyphiidae, Erigoninae). Zootaxa. 3616: 357-366.
      • Cranshaw, W. S. and R. A. Redak (20130. Bugs Rule! An Introduction to the World of Arthropods. Princeton University Press. 474 pp.


      Progress 01/01/11 to 12/31/11

      Outputs
      OUTPUTS: Under this reporting period, my lab continued to focus on a single major research area related to the control and management of the Glassy-winged sharpshooter (HOMALODISCA VITRIPENNIS) in California's commercial nurseries. Specifically I continued my efforts to refine the existing standardized shipment treatment protocol to eliminate this insect in commercial nursery shipments and release the industry from costly inspections. Work this year consisted of completing a determination of the insecticide residue levels (fenpropathrin and carbaryl) on a variety of ornamental plants. These values are to be used to assess the adequacy of treatment for preventing movement of sharpshooters on nursery stock. Indeed, through outreach activities, this data is already being used in the state's quarantine and approved treatment programs. Additionally, throughout this reporting period, I have continued to work with the California Department of Food and Agriculture, refining and monitoring a quarantine control program aimed at preventing the spread of glassy-winged sharpshooter to Northern California counties. The initial program was developed by my lab in 2006-07, tested in 2007-2008, and is now fully implemented and expanding in use. Currently, almost all Southern California commercial nurseries that export product to the north are participating in this program. Both CDFA and my laboratory continue to monitor and analyze shipping data derived from this program; all data collected, to date (July, 2011), indicate that the program has been 100% effective in preventing the spread of this insect. As of July 2011, over 25,000 shipments and 9 million plants have been successfully moved out of the quarantine area without accidentally transporting a single insect of any developmental stage. The lab continues to determine the lower lethal temperature at which sharpshooters may survive. Currently, we have determined that approximately -11 oC is the lower lethal temperature for both adult male and female insects. Our work continues in determining the lower lethal temperature for early and late instars. Lethal temperatures for late instars appear to be similar to adults. Lower lethal temperatures for early instars is proving difficult to obtain due to the high mortality associated with handling. We are investigating new methods to obtain this information for the early instars. Finally, related toward our development of a climate-phenology based GIS predictive model for sharpshooter suitable habitat, we have now developed the necessary modeling techniques necessary for our approach and tested the methods using an endangered insect species under various climate change scenarios. PARTICIPANTS: Nothing significant to report during this reporting period. TARGET AUDIENCES: Research results were presented to several University of California Cooperative Extension sponsored meetings that included commodity growers (California Association of Nurseries and Garden Centers, Southern California grape, date, and citrus, growers), state, and county agricultural officials. Additionally, research results were presented at the annual meeting of the Entomological Society of America PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

      Impacts
      Our work with controlling sharpshooters in commercial nurseries has demonstrated that these insects may be successfully managed such that transport of nursery materials from quarantined areas of the state can successfully performed. Our recommendations to the California Department of Food and Agriculture regarding modified quarantine treatments of ornamental nursery materials were submitted and accepted. We continue to collect data such that shipment protocols are modified using best management practices derived from current data. These actions have resulted in the development of exceptionally effective state-wide program used to prevent the accidental shipment of this insect to the northern counties of California. To date, this program has completely prevented the spread of this insect on commercial nursery stock. This year we have developed the data and methods that now allow growers and agencies in areas un-infested with sharpshooters to adequately assess whether or not incoming plant shipments have been properly treated for insect eradication.

      Publications

      • Redak, R. A. and R. Krieger. 2010. Evaluation of additional insecticides for quarantine against the glassy-winged sharpshooter in California's commercial ornamental nurseries. Tehcnical Report to California Department of Food and Agriculture. 13 pp.
      • Redak, R. A. and R. Krieger. 2011. Residual efficacy of materials used for quarantine against the glassy-winged sharpshooter in California's commercial ornamental nurseries. Technical Report to California Department of Food and Agriculture. 21 pp.
      • Waterworth, R.A., R. A. Redak, and J. G. Millar. 2012. Probably site of sec pheromone emission in femaile vine and obsucrue mealy bugs (Hemiptera: Pseudococcidae). J. Insect. Behav. 25:287-296.
      • Preston, K. L., R. A. Redak, M. F. Allen, J. T. Rotenberry. 2012. (In Press). Changing Distribution Patterns of the Endangered Quino Checkerspot: Linking Local Extinction Patterns and Variable Habitat Relationships. Biol. Conserv. 100 ms pp.
      • Prentice, T. R. and R. A. Redak. 2012. (In Press). Esophyllas, a new genus of erigonine spiders from southern California (Araneae: Linyphiidae: Erigoninae). Zootaxa. 31 ms pp.


      Progress 01/01/10 to 12/31/10

      Outputs
      OUTPUTS: Under this reporting period, my lab continued to focus on a single major research area related to the control and management of the Glassy-winged sharpshooter (HOMALODISCA VITRIPENNIS) in California's commercial nurseries. Specifically I continued my efforts to refine the existing standardized shipment treatment protocol to eliminate this insect in commercial nursery shipments and release the industry from costly inspections. Work this year largely consisted of completing an evaluation of additional materials potentially used to limit the spread of this insect via the transport of commercial nursery products. Secondarily, I initiated a related study that establishes the relationship between residue levels of known effective control compounds (fenpropathrin and carbaryl) duration of effective control. These data, when available, will allow regulatory agencies to quickly determine if, and when, nursery products were effectively treated. In this area, I continue to work with the California Department of Food and Agriculture, refining and monitoring a quarantine control program aimed at preventing the spread of glassy-winged sharpshooter to Northern California counties. The initial program was developed by my lab in 2006 and taken to full implementation in 2007-2008. Currently, all Southern California commercial nurseries that export product to the north are participating in this program. Both CDFA and my laboratory are continuously analyzing shipping data derived from this program; all data collected, to date (Dec, 2010), indicate that the program has been 100% effective in preventing the spread of this insect. My lab continues to work with CDFA to monitor this program My lab has finally completed a series of experiments to evaluate additional compounds for quarantine control of glassy-winged sharpshooter. Historically, only two compounds (carbaryl and fenpropathrin) have shown the necessary efficacy to prevent shipment of egg masses. These experiments evaluated acetamiprid, spirotetramat, spinoteram, and cyfluthrin. Our completed analysis now indicates that none of these compounds were effective in eliminating egg masses in during either reproductive period of the insect. Additionally, this year we began a serious of experiments attempting to relate insecticide residue data with time of initial treatment. The thrust of this research was to provide regulatory agencies with data to allow a determination as to whether or not nursery products (1) had been treated efficaciously, (2) when they were treated, and (3) if detected residues were at a sufficient level to prevent successful egg emergence by the sharpshooter. We are currently analyzing the first set of lab- and field-based experiments dealing with this issue and are hopeful results will be forthcoming within a few months of this date. PARTICIPANTS: Not relevant to this project. TARGET AUDIENCES: California Department of Food and Agriculture. Commercial Nursery Industries located in California, Arizona, Oregon. PROJECT MODIFICATIONS: Not relevant to this project.

      Impacts
      Our work with controlling sharpshooters in commercial nurseries has demonstrated that these insects may be successfully managed such that transport of nursery materials from quarantined areas of the state can successfully performed. Our recommendations to the California Department of Food and Agriculture regarding modified quarantine treatments of ornamental nursery materials was submitted and accepted. These actions have resulted in the development of a state-wide program used to prevent the accidental shipment of this insect to the northern counties of California. To date, this program has completely prevented the spread of this insect on commercial nursery stock. This year we confirmed that additional recommended compounds were not efficacious in preventing movement of sharpshooter eggs; current recommendations for quarantine will necessarily remain unchanged. We are now continuing this research to determine the relationship between insecticide residue and time of treatment.

      Publications

      • Prentice, T.R., Redak, R.A. and C. Barrows. 2011. (In press) Survey methodology and distribution of a cryptic Jerusalem cricket species, Stenopelmatus cahuilaenis Tinkham (Orthoptera, Stenopelmatidae). Pan-Pacific Entomologist. (22 manuscript pages).
      • Waterworth, R.A., R. A. Redak, and J. G. Millar. 2011. (In press) Pheromone-baited Traps for Assessment of Seasonal Activity and Population Densities of Mealybug Species (Hemiptera: Pseudococcidae) in Nurseries Producing Ornamental Plants. Journal of Economic Entomology. (43 manuscript pages.)


      Progress 01/01/09 to 12/31/09

      Outputs
      OUTPUTS: Under this reporting period, my lab focused on a single major research areas related to the control and management of the Glassy-winged sharpshooter (HOMALODISCA VITRIPENNIS) in California's commercial nurseries. Specifically I continued my efforts to refine the existing standardized shipment treatment protocol to eliminate this insect in commercial nursery shipments and release the industry from costly inspections. Work this year largely consisted of evaluating additional materials in an effort to broaden the type of control methods available to ornamental plant producers. In this area, I continue to work with the California Department of Food and Agriculture, refining and monitoring a quarantine control program aimed at preventing the spread of glassy-winged sharpshooter to Northern California counties. The initial program was developed by my lab in 2006 and taken to full implementation in 2007-2008. Currently, all Southern California commercial nurseries that export product to the north are participating in this program. Both CDFA and my laboratory are continuously analyzing shipping data derived from this program; all data collected, to date, indicated that the program has been 100% effective to date in preventing the spread of this insect. I am just now completing a new series of experiments to evaluate additional compounds for quarantine control of glassy-winged sharpshooter. Historically, only two compounds (carbaryl and fenpropathrin) have shown the necessary efficacy to prevent shipment of egg masses. This year's efforts evaluated acetamiprid, spirotetramat, spinoteram, and cyfluthrin. Unfortunately, none of these compounds were effective in eliminating egg masses in during the period in which the first generation is reproductive. I am currently analyzing the data collected in late summer and fall to determine if these compounds were any more effective under different environmental conditions. PARTICIPANTS: Not relevant to this project. TARGET AUDIENCES: Not relevant to this project. PROJECT MODIFICATIONS: Not relevant to this project.

      Impacts
      Our work with controlling sharpshooters in commercial nurseries has demonstrated that these insects may be successfully managed such that transport of nursery materials from quarantined areas of the state can successfully performed. Our recommendations to the California Department of Food and Agriculture regarding modified quarantine treatments of ornamental nursery materials was submitted and accepted. These actions have resulted in the development of a state-wide program used to prevent the accidental shipment of this insect to the northern counties of California. To date, this program has completely prevented the spread of this insect on commercial nursery stock. Although for this year, we determined that the recommended additional compounds were not efficacious in preventing movement of sharpshooter eggs, we are continuing this research to make it more applicable and flexible for the grower.

      Publications

      • Prentice, T. R. and R. A. Redak. 2009. A new species of Ceraticelus Simon from southern California and a redescription of Ceraticelus phylax Ivie & Barrows, its probable sister species (Araneae: Linyphiidae). Zootaxa 2233:39056
      • Sorensen, M. A., J. A. Bethke, and R. A. Redak. 2010. Potential host plants of Trirhabda geminate (Coleoptera: Chyrsomelidae): Impacts on survival, development, and feeding. Environ. Entomol. 39:159-163.


      Progress 01/01/08 to 12/31/08

      Outputs
      OUTPUTS: Under this reporting period, my lab focused on two major research areas related to the control and management of the Glassy-winged sharpshooter (HOMALODISCA VITRIPENNIS) in California's commercial nurseries: (1) continuing our efforts to refine our existing a standardized shipment treatment protocol to eliminate this insect in commercial nursery shipments and release the industry from costly inspections, (2) continue our determination of the temperature limits for successful growth and survival of this insect. I continue to working with the California Department of Food and Agriculture, refining and monitoring a quarantine control program aimed at preventing the spread of glassy-winged sharpshooter to Northern California counties. The initial program was developed by my lab in 2006 and taken to full implementation in 2007-2008. Currently, all Southern California commercial nurseries that export product to the north are participating in this program and CDFA and my laboratory are currently analyzing the data that evaluates this program. These preliminary data suggest the program has been 100% effective to date in preventing the spread of this insect. In related work, I am just now initiating a new series of experiments to evaluate additional compounds for quarantine control of glassy-winged sharpshooter. Currently, only two compounds have shown the necessary efficacy to prevent shipment of egg masses; this additional research will hopefully provide the data necessary to include additional materials in the available arsenal that growers may use to restrict the movement of this pest. Finally, my lab continues to determine the lower lethal temperature at which sharpshooters may survive. Currently, we have determined that -11 oC is the lower lethal temperature for both adult male and female insects. This also appears to be the lower lethal temperature for late instars. We are now in the process of determining the lower lethal temperatures of the early instars. Results of all of these efforts were distributed through oral and poster presentations given throughout the state under various venues. PARTICIPANTS: Not relevant to this project. TARGET AUDIENCES: Not relevant to this project. PROJECT MODIFICATIONS: Not relevant to this project.

      Impacts
      Our work with controlling sharpshooters in commercial nurseries has demonstrated that these insects may be successfully managed such that transport of nursery materials from quarantined areas of the state can successfully performed. Our recommendations to the California Department of Food and Agriculture regarding modified quarantine treatments of ornamental nursery materials was submitted and accepted. These actions have now resulted in the development of a state-wide program used to prevent the accidental shipment of this insect to the northern counties of California. To date, this program has completely prevented the spread of this insect on commercial nursery stock. We are actively evaluating additional compounds and approaches to lend the existing program flexibility in treatment and control options.

      Publications

      • Thompson, S. N., Redak, R.A. 2008. Parasitism of an insect Manduca sexta alters diet consumption and nutrient utilization to influence developmental success of the parasitoid Cotesia congregata. J. Comp. Physiol. B. 178:515-527.
      • Preston, K. L. J. T. Rotenberry, R. A. Redak, and M. F. Allen. 2008. Habitat Shifts of Endangered Species under Altered Climate Conditions: Importance of Biotic Interactions. Global Change Biology 14:2501-2515.


      Progress 01/01/07 to 12/31/07

      Outputs
      Under this reporting period, my lab focused on three major research areas related to the control and management of the Glassy-winged sharpshooter (HOMALODISCA VITRIPENNIS) in California's commercial nurseries: (1) continuing our efforts to develop a standardized shipment treatment protocol to eliminate this insect in commercial nursery shipments and release the industry from costly inspections, develop techniques to directly manage adult and nymphal stages of this insect in commercial nursery plantings, (2) continuing our efforts to seek a method to disrupt oviposition by female insects such that the probability of shipping viable egg masses is reduced, and (3) continue our determination of the temperature limits for successful growth and survival of this insect. In a new series of experiments, dinotefuran, imidacloprid, acetamiprid, beta-cyfluthirn, deltamethrin, and carbaryl were field evaluated for their ability to deter oviposition by glassy-winged sharpshovoter adult females. Similar to last year, while providing reasonably good control in terms of adult mortality, none of these compounds significantly deterred oviposition by the females. I continue to working with the California Department of Food and Agriculture, implementing and monitoring a pilot program to evaluate under real-world situations the proposed standardized disinfestations procedures for the control of movement of sharpshooter egg masses. The initial protocol was developed by my lab in 2006. Three commercial nurseries currently are cooperating in this study that evaluates prophylactic applications of either fenpropathrin or carbaryl to prevent successful emergence of glassy-winged sharpshooter eggs. We now have three years of data; the program has been a complete success. There has been 100% control of all life stages of the insect on all nursery products evaluated. At the time of this writing, CDFA is in the process of implementing this program formally on a statewide basis. Further testing of additional compounds to prevent egg emergence will continue to provide alternate disinfestations tools. Finally, I have completed the work developing a post-embryonic degree-day model for glassy-winged sharpshooter development. The lower temperature threshold was determined to be 11oC. The developmental rate vs. temperature relationship was determined to be rate=e0.20*Temp - e6.508-(32.54-Temp)/0.499]. At the optimum developmental temperature of 27.5oC a total of 805 degree-days will be required for the insect to emerge from the egg and develop to the adult stage. Additionally, my lab has determined the lower lethal temperature that adult sharpshooters may survive (-11 oC). We are now in the process of determining the lower lethal temperatures of the individual stages of juvenile development.

      Impacts
      Our work with controlling sharpshooters in commercial nurseries has demonstrated that these insects may be successfully managed such that transport of nursery materials from quarantined areas of the state can successfully performed. Our recommendations to the California Department of Food and Agriculture regarding modified quarantine treatments of ornamental nursery materials was submitted and accepted. These actions have now resulted in the development of a state-wide pilot program evaluating these techniques. To date, the pilot program has completely prevented the spread of this insect on commercial nursery stock. As of this date, CDFA is now implementing a formal statewide procedure for transporting nursery commodities based on these results. Once fully implemented millions of dollars in inspection and tracking costs will be saved. Additionally, we have now created a degree-day model for the post-embryonic development of the insect and determined the lower temperature at which this insect can survive. Using these two pieces of information we will can now move forward with the development of a comprehensive predictive mapping system that identifies those areas of the state in which successful sharpshooter establishment can occur. This approach will allow a concentration of management resources in those areas mostly likely to be invaded by and support populations of this insect.

      Publications

      • Coviella, C.E., Garcia, J.F., Jeske, D.R., Redak, R.A., Luck, R.F. 2006. Feasibility of tracking within-field movements of Homalodisca coagulata (Hemiptera : Cicadellidae) and estimating its densities using fluorescent dusts in mark-release-recapture experiments. Journal of Economic Entomology. Vol. 99: 4 p.1051-1057.
      • Thompson, S.N., Redak, R.A. 2007. Nicotine moderates the effects of macronutrient balance on nutrient intake by parasitized Manduca sexta L. Journal of Comparative Physiology B Biochemical Systemic and Environmental Physiology. Vol. 177: 3 p.375-391.
      • Thompson, S.N., Redak, R.A. 2007. Parasitism of an insect Manduca sexta alters diet consumption and nutrient utilization to influence developmental success of the parasitoid Cotesia congregata . In Press Journal of Comparative Physiology B. Biochemical Systemic and Environmental Physiology. (Submitted 08/24/2007.)


      Progress 01/01/06 to 12/31/06

      Outputs
      Under this reporting period, my lab focused on three major research areas related to the control and management of the Glassy-winged sharpshooter (HOMALODISCA COAGULATA) in California's commercial nurseries: (1) continuing our efforts to develop a standardized shipment treatment protocol to eliminate this insect in commercial nursery shipments and release the industry from costly inspections, develop techniques to directly manage adult and nymphal stages of this insect in commercial nursery plantings, (2) disrupt oviposition by female insects such that the probability of shipping viable egg masses is reduced, and (3) complete development of a post-embryonic developmental degree-day model for this insect.. Dinotefuran, imidacloprid, acetamiprid, beta-cyfluthirn, deltamethrin, and carbaryl were field evaluated for their ability to deter oviposition by glassy-winged sharpshooter adult females. While providing reasonably good control in terms of adult mortality, none of these compounds significantly deterred oviposition by the females. Further studies are underway examining additional compounds and approaches to limit oviposition in the commercial nursery environment. Working with the California Department of Food and Agriculture, we implemented a pilot program to evaluate under real-world situations the proposed standardized disinfestations procedures for the control of movement of sharpshooter egg masses. These procedures were developed by my lab the previous year. Three commercial nurseries are cooperating in this study that evaluates prophylactic applications of either fenpropathrin or carbaryl to prevent successful emergence of glassy-winged sharpshooter eggs. To date, the program has been a complete success; there has been 100% control of all life stages of the insect on all nursery products evaluated. Further testing continues with a broadening out of nursery materials shipped under these procedures. Finally, we have completed our work developing a post-embryonic degree-day model for glassy-winged sharpshooter development. The lower temperature threshold was determined to be 11oC. The developmental rate vs. temperature relationship was determined to be rate=e0.20*Temp - e[6.508-(32.54-Temp)/0.499]. At the optimum developmental temperature of 27.5oC a total of 805 degree-days will be required for the insect to emerge from the egg and develop to the adult stage.

      Impacts
      Our work with controlling sharpshooters in commercial nurseries has demonstrated that these insects may be successfully managed such that transport of nursery materials from quarantined areas of the state can successfully performed. Our recommendations to the California Department of Food and Agriculture regarding modified quarantine treatments of ornamental nursery materials was submitted and accepted. These actions have now resulted in the development of a state-wide pilot program evaluating these techniques. To date, the pilot program has completely prevented the spread of this insect on commercial nursery stock. These results are extremely encouraging suggesting that if fully implemented potentially millions of dollars in inspection and tracking costs can be saved. Additionally, we have now created a degree-day model for the post-embryonic development of the insect. Using this model we will now move forward with the development of a predictive mapping system that identifies those areas of the state in which successful sharpshooter establishment can occur. This approach will allow a concentration of management resources in those areas mostly likely to be invaded by and support populations of this insect.

      Publications

      • Blua, M. J., R. A. Redak. 2006. Curtailing oviposition by the Glassy-Winged Sharpshooter on Nursery Plants. In: Proceeding of the Pierce's Disease Research Symposium. California Department of Food and Agriculture, San Diego, CA. 321 pp.
      • Thompson, S. N., R. A. Redak, and L.-W. Wang. 2005. Nutrition Interacts with Parasitism to Influence Growth and Physiology of the Insect Manduca sexta L. J. Exper Biol.. 208: 611-623
      • Thompson, S. N., R. A. Redak, and L.-W. Wang. 2005. Host Nutrition Determines Blood Nutrient Composition and Mediates Parasite Developmental Success: Manduca sexta L. Parasitzed by Cotesia congregata (Say). J.Exper. Biol. 208: 625-635
      • Thompson, S. N.; Redak, R. A. 2005. Feeding behaviour and nutrient selection in an insect Manduca sexta L. and alterations induced by parasitism. J. Comp. Physiol. A. 191:909-923.


      Progress 01/01/05 to 12/31/05

      Outputs
      Under this reporting period, my lab focused on three major research areas related to the control and management of the Glassy-winged sharpshooter (HOMALODISCA COAGULATA) and Pierce's disease (XYLELLA FASTIDIOSA) in vineyards: (1) completing our efforts to develop a standardized treatment protocol to eliminate this insect in commercial nursery stock, (2) develop techniques to manage this insect in commercial nursery plantings, and (3) develop marking techniques for studying adult sharpshooters in the field. Carbaryl, fenpropathrin, deltamethrin and acetamiprid were field evaluated for their ability to kill glassy-wing sharpshooter nymphs emerging from the egg mass under standard commercial nursery operations. Carbaryl provided near absolute control (>98%) of emerging nymphs on all plant types (trees, shrubs, bedding plants). Fenpropathrin also achieved very good control. Control was poorest on bedding plants due to difficulty in achieving adequate coverage of the insecticides. The results of this research have now been incorporated into a state-wide pilot program for transporting nursery products. To date, the program is 100% effective in preventing movement of the insect. We examined H. coagulata orientation and flight direction when placed near or on large screen barriers used to reduce the number of adult sharpshooters entering a nursery. When sharpshooters were released midway between a barrier and adjacent vegetation 71.5% of H. coagulata flew away from the barrier and in the direction of the vegetation; whereas 29.5% flew in the direction of the barrier. Of the total number of H. coagulata released, 7.5% flew over the barrier. When placed on the barrier, H. coagulata generally climbed up an average of 1.16 m before flying away from the structure. Of the total number of H. coagulata placed on the barrier, 6% flew over it. Thus, the benefit of the barrier extends beyond simply physically excluding the insects in includes acting as a visual deterrent. Finally, we tested a mark-release-recapture technique to track the field movements of adult glassy winged sharpshooters and to estimate population densities. The use of colored dust to mark sharpshooters proved to be both reliable, and a cost- and time-effective technique for mark-release-recapture studies with this insect. No differences in mortality rates were observed between marked and unmarked insects over a 30-day period when they were released into cages. In the field, we recovered insects with easily recognizable markings up to 78 days post release. Marked adults were able to fly beyond 100m in a field devoid of vegetation within minutes of their release, and the marking did not affect overall flight behavior significantly when compared to unmarked individuals. Using mark-release-recapture data obtained, we estimated that over 2 million adult sharpshooters may occur in small groves (few hundred trees) of citrus.

      Impacts
      Our work with controlling sharpshooters has demonstrated that the layered application of neonicotinoid pesticides coupled with a foliar barrier, such as kaolin, initially reduces the spread and incidence of Pierce's disease in grapes but under relatively high insect densities no approach ultimately is successful in preventing disease incidence and spread. Our recommendations to the California Department of Food and Agriculture regarding modified quarantine treatments of ornamental nursery materials was submitted and accepted, and in conjunction with state authorities, we have developed the necessary data to now allow state agricultural authorities to initiate a pilot program for transporting nursery stock throughout the state with limited inspections, resulting in a savings of potentially millions of dollars in inspection and tracking costs. Additionally, we have shown the impacts of a large screen barriers extend beyond physically preventing the spread of the insects; barriers act as a visual deterrent causing insects to fly away from enclosed areas. Finally, we have developed a inexpensive, reliable and relatively long-lasting method for marking adult sharpshooters in the field.

      Publications

      • Bextine, B., M. J. Blua and R. A. Redak. 2004. Developing a method to detect Xylella fastidiosa in the Glassy-winged sharpshooter. pp. 249-252. In: Proceedings of the Pierce's Disease Research Symposium. California Department of Food and Agriculture, Coronado Island, CA, 391 pp.
      • Blua, M. J., K. Campbell, D. J. W. Morgan, and R. A. Redak 2005. Impact of a screen barrier on dispersion behavior of Homalodisca coagulata (Hemiptera: Cicadellidae). J. Econ. Entomol. 98: 1664-1668.
      • Coviella, C. E. , J. F. Garcia, D. R. Jeske, R. A. Redak, and R. F. Luck. 2005. The feasibility of tracking within field movements of Homalodisca coagulata (Say) (Hemiptera: Cicadellidae) and estimating its densities using fluorescent dusts in mark-release-recapture experiments. J. Econ. Entomol. (in press)
      • Bethke, J. A., O. F. Z. Siapno, and R. A. Redak. 2005. Effect of the residual of selected insecticides against adult sharpshooters. Summer 2004. Available online only at http://www.entsoc.org/Protected/AMT/AMT30/


      Progress 01/01/04 to 12/31/04

      Outputs
      Under this reporting period, my lab focused on three major research areas: (1) continue to developing and evaluate layering of various techniques to minimize Glassy-winged sharpshooter (HOMALODISCA COAGULATA) and Pierce's disease (XYLELLA FASTIDIOSA) incidence in vineyards, (2) continuing our efforts to develop a standardized treatment protocol to eliminate this insect in commercial nursery stock, and (3) develop techniques to manage this insect in commercial nursery plantings. A variety of plant and insect treatment combinations were evaluated as to their ability to prevent/limit Pierce's disease of grapes. A combination of neonicotinoids (imidacloprid plus acetamiprid) and kaolin film provided the best protection against glassy-winged sharpshooter, reducing densities by approximately 90%. The same treatment combination reduced sharpshooter oviposition by 75%. Egg parasitism was unaffected by any of the treatments. The layering of neonicotinoids and kaolin limited the incidence of PD to 30% after 18 months, but PD incidence climbed to above 70% in all treatments after 30 months. We concluded that under high vector densities, no combination of existing treatments will control Pierce's disease. Carbaryl, fenpropathrin, deltamethrin and acetamiprid were field evaluated for their ability to kill glassy-wing sharpshooter nymphs emerging from the egg mass under standard commercial nursery operations. Carbaryl provided near absolute control (>98%) of emerging nymphs on all plant types (trees, shrubs, bedding plants). Fenpropathrin also achieved very good control. Control of emerging sharpshooters was poorest on bedding plants; this is largely due to difficulty in achieving adequate coverage of the insecticides on these types of plants. Few of the biorational/organic/reduced products tested are applicable for glassy-winged sharpshooter control or eradication (poor mortality, slow knock down activity, poor residual activity). To date, none of the products we tested achieved high mortality against both adult and juvenile sharpshooters. With the possible exception of rotenone and pyrethrins (PyGanic), conventional pyrethroids, organophosphates, and chloronicotinyls were more effective than all other compounds tested. Large screen barriers used to prevent immigration of sharpshooters into commercial nurseries were partially effective. Barriers significantly reduced the number of immigrating insects into the nursery. To be effective, barriers must completely surround the nursery or completely isolate the nursery from the source of infestation. We demonstrated that barriers not only physically prevent immigration, but also function as a visual deterrent to this insect; they fly away from the barrier if given a choice. Upon landing on the barriers, we demonstrated sharpshooters were more likely to fly away from the nursery as than climb over the barrier.

      Impacts
      Our work with controlling sharpshooters has demonstrated that the layered application of neonicotinoid pesticides coupled with a foliar barrier, such as kaolin, reduced the spread and incidence of Pierce's disease in grapes. This approach failed however after two years under heavy sharpshooter infestation. We continue to provide and update to state agricultural authorities a working list of biorational pesticides that should not be considered for use in urban eradication efforts for the glassy-winged sharpshooter. Our recommendations to the California Department of Food and Agriculture regarding modified quarantine treatments of ornamental nursery materials was submitted and accepted. As a result of this work the state of California is changing the quarantine requirement for shipment of nursery materials resulting in a savings of potentially millions of dollars in inspection and tracking costs.

      Publications

      • Bextine, B., M. J. Blua, and R. A. Redak. 2003. Developing a Method to Detect Xylella fastidiosa in the Glassy-Winged Sharpshooter. pp. 182-185. In: Proceedings of the Pierce's Disease Research Symposium. California Department of Food and Agriculture, Coronado, CA. 323. pp.
      • Blua, M. J.,and R. A. Redak. 2003. Relationships Between Total Population Counts of Glassy-Winged Sharpshooters and Numbers Obtained from Various Sampling Methods. pp. 185-188. In: Proceedings of the Pierce's Disease Research Symposium. California Department of Food and Agriculture, Coronado, CA. 323. pp.
      • Blua, M. J., and R. A. Redak. 2003. Impact of a Screen Barrier on the Introgression of the Glassy-Winged Sharpshooter into a Nursery Yard. pp. 282-286. In: Proceedings of the Pierce's Disease Research Symposium. California Department of Food and Agriculture, Coronado, CA. 323. pp.
      • Redak, R. A. and J. A. Bethke. 2003. Pesticide Screening Against the Glassy-Winged Sharpshooter, Homalodisca coagulata (Say), Using Commercially Available Biorational, Organic and Reduced Risk Pesticides. pp. 302-306. In: Proceedings of the Pierce's Disease Research Symposium. California Department of Food and Agriculture, Coronado, CA. 323. pp.
      • Redak, R. A. and J. A. Betke. 2003. Toward a Standardized Treatment Protocol to Eliminate Glassy-Winged Sharpshooter Egg Masses in Commercial Nursery Stock. pp. 308-311. In: Proceedings of the Pierce's Disease Research Symposium. California Department of Food and Agriculture, Coronado, CA. 323. pp. Department of Food and Agriculture, Coronado, CA. 323. pp.
      • Bethke, J. A., O. F. Z. Siapno, and R. A. Redak. 2003. Control of glassy-winged sharpshooter egg masses on chrysanthemum under greenhouse conditions using selected pesticides, Spring 2003. Available online only at htttp://www.entsoc.org/Protected/AMT/AMT29/
      • Bethke, J. A., O. F. Z. Siapno, and R. A. Redak. 2003. Control of glassy-winged sharpshooter egg masses on chrysanthemum under greenhouse conditions using selected pesticides, Summer 2003. Available online only at htttp://www.entsoc.org/Protected/AMT/AMT29/
      • Bethke, J. A., O. F. Z. Siapno, and R. A. Redak. 2003. Control of long-tailed mealybugs on chrysanthemums using selected pesticides, Summer 2003. AMT 29
      • Bethke, J. A., O. F. Z. Siapno, and R. A. Redak. 2003. Control of melon aphid on chrysanthemums under greenhouse conditions, Fall 2002. Available online only at htttp://www.entsoc.org/Protected/AMT/AMT29/
      • Bethke, J. A., O. F. Z. Siapno, and R. A. Redak. 2003. Effect of the residual of selected insecticides against adult sharpshooters, Fall 2002. Available online only at htttp://www.entsoc.org/Protected/AMT/AMT29/
      • Bethke, J. A., O. F. Z. Siapno, and R. A. Redak. 2003. Control of adult sharpshooters using selected insecticides, Fall 2002. Available online only at htttp://www.entsoc.org/Protected/AMT/AMT29/


      Progress 01/01/03 to 12/31/03

      Outputs
      Under this reporting period, my lab focused on three major research areas: (1) developing and evaluating 'layering' of various techniques to minimize Glassy-winged sharpshooter (HOMALODISCA COAGULATA) and Pierce's disease (XYLELLA FASTIDIOSA) incidence in vineyards, (2) continuing our efforts to develop a standardized treatment protocol to eliminate this insect in commercial nursery stock and and (3) evaluate a variety of so-called biorational pesticides for controlling. A variety of plant and insect treatment combinations were evaluated as to their ability to prevent/limit Pierce's disease of grapes. A combination of neonicotinoids (imidacloprid plus acetamiprid) and kaolin film provided the best protection against glassy-winged sharpshooter, reducing densities by approximately 90%. The same treatment combination reduced sharpshooter oviposition by 75%. Egg parasitism was unaffected by any of the treatments. The layering of neonicotinoids and kaolin limited the incidence of PD to 30% after 18 months, but PD incidence climbed to above 70% in all treatments after 30 months. Antibiotic therapy (metalosate), alone or in combination, did not affect PD incidence. Carbaryl, fenpropathrin, deltamethrin and acetamiprid were evaluated for their ability to kill glassy-wing sharpshooter nymphs emerging from the egg mass under standard commercial nursery operations (including transportation). Carbaryl provided the best overall results resulting in near absolute control (>98%) of emerging nymphs on all plant types (trees, shrubs, bedding plants). Fenpropathrin also achieved very good control. Control of emerging sharpshooters was poorest on bedding plants; this is largely due to the tremendous number of densely packed leaves within a small plant canopy and the resultant difficulty in achieving adequate coverage of the insecticides. Few of the biorational/organic/reduced products tested are applicable for glassy-winged sharpshooter control or eradication (poor mortality, slow knock down activity, poor residual activity). None of the products tested achieved high mortality against both adult and juvenile sharpshooters. Rotenone and 10% rosemary oil (Ecotrol) may be the only exceptions when used strictly against adults; however, their level of control is below that of the pryrethroids, chloronicotinyls, organophosphates, and carbamates. With the possible exception of rotenone and pyrethrins (PyGanic), conventional pyrethroids, organophosphates, and chloronicotinyls were more effective than all other compounds tested.

      Impacts
      Our work with controlling sharpshooters has demonstrated that the layered application of neonicotinoid pesticides coupled with a foliar barrier, such as kaolin, reduced the spread and incidence of Pierce's disease in grapes. This approach failed however after two years under heavy sharpshooter infestation. We have provided a working list to state agricultural authorities of biorational pesticides that should not be considered for use in urban eradication efforts for the glassy-winged sharpshooter. Finally, we are in the process of developing strategies of controlling the movement of glassy-wing sharpshooters in intra-state shipment of nursery products. This work should be complete by Summer of 2004.

      Publications

      • Redak, R.A., Purcell, A.H., Lopes, J.R.S., Blua, M.J., Mizell, R.F. and Andersen, P.C. 2004. The biology of xylem fluid-feeding insect vectors of Xylella fastidiosa and their relation to disease epidemiology. Annual Review of Entomology 49: 243-270.
      • Burks, R.A. and Redak, R.A. 2003. The identity and reinstatement of Homalodisca liturata Ball and Phera lacerta Fowler (Hemiptera : Cicadellidae). Proceedings of the Entomological Society of Washington 105(3): 674-678.
      • Bethke, J. A., M. J. Blua, and R. A. Redak. 2002. Effect of Selected Insecticides on Homalodisca coagulata (Homoptera: Cicadellidae) and Transmission of Oleander Leaf Scorch in a Greenhouse Study. J. Econ Entomol. 94:1031-1036.
      • Blua, M. J., R. A. Redak, D.J.W. Morgan, and H. S. Costa. 2002. Seasonal Flight Activity of Two Homalodisca Species (Cicadellidae: Homoptera) that Spread Xylella fastidiosa in Southern California. J. Econ. Entomol. 94:1506-1510.
      • Bethke, J. A., K. L. Robb, H. S. Costa, and R. A. Redak. 2002. Making the best use of pesticides. pp. 49-55. In: Proceedings of the Society of American Florist's 18th Annual Conference on Insect and Disease Management on Ornamentals (J. Hall and K.Robb, eds.). Society of American Florists, Alexandria VA.
      • Petro, L., R. Redak, J. Bethke, and T.M. Perring. 2002. Preference and performance of silverleaf whitefly on selected poinsettia cultivars. pp. 191. In: Silverleaf whitefly: National research, action, and technology transfer plan, fourth annual review of the second 5-year plan and final report for 1992-2002 (Henneberry, T.J., R.M. Faust, W.A. Jones, and T.M. Perring, eds.). USDA June 2002. 446 pp.
      • Luck, R. F., and R. A. Redak. 2002. Seasonal changes in the glassy-winged sharpshoter's age structure, abundance, host plant use, and dispersal. pp. 107-108. In: Proceedings of the Pierce's Disease Research Symposium . California Department of Food and Agriculture, Coronado Island, CA, 177 pp.
      • Blua, M., R. A. Redak, C. Coveilla, and D. Akey. 2002. Relationship between total populaiton counts of glassy-winged sharpshooter and numbers obtained from various sampling methods. pp. 118-119. In: Proceedings of the Pierce's Disease Research Symposium . California Department of Food and Agriculture, Coronado Island, CA, 177 pp.
      • Blua, M., B. Bextine, and R. A. Redak. 2002. Developing a method to detect Xylella fastidiosa in glassy-winged sharpshooter. pp. 120-121. In: Proceedings of the Pierce's Disease Research Symposium . California Department of Food and Agriculture, Coronado Island, CA, 177 pp.
      • Hix, R., N. Toscano, R. A. Redak, and M. Blua. 2002. Area-wide management of the glassy-winged sharpshooter in the Temecula Valley. pp. 157-158. In: Proceedings of the Pierce's Disease Research Symposium . California Department of Food and Agriculture, Coronado Island, CA, 177 pp.
      • Redak, R. A. and M. Blua. 2002. Impact of layering control tactics on the spread of Pierce's disease by the glassy-winged sharpshooter. pp. 159-160. In: Proceedings of the Pierce's Disease Research Symposium . California Department of Food and Agriculture, Coronado Island, CA, 177 pp.