Source: PENNSYLVANIA STATE UNIVERSITY submitted to NRP
SOLUTIONS FOR MANAGING ALLIUM LEAFMINER: A NEW INVASIVE THREAT TO ALLIUM CROPS IN NORTH AMERICA
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
COMPLETE
Funding Source
OTHER GRANTS
Reporting Frequency
Annual
Accession No.
1017443
Grant No.
2018-70006-28920
Cumulative Award Amt.
$325,000.00
Proposal No.
2018-04503
Multistate No.
(N/A)
Project Start Date
Sep 1, 2018
Project End Date
Aug 31, 2022
Grant Year
2018
Program Code
[ARDP]- Applied Research and Development Program
Recipient Organization
PENNSYLVANIA STATE UNIVERSITY
408 Old Main
UNIVERSITY PARK,PA 16802-1505
Performing Department
Entomology
Non Technical Summary
Allium leafminer is an invasive species that has crossed the Atlantic, reaching the U.S. in 2016, and established itself as a pest of multiple Allium species, which include onion, garlic, leek, scallions, shallots, and chives. Onion is the crop with the largest acreage, grown commercially in over 20 states, literally border-to-border and coast-to-coast. The annual farm-gate value of onion and garlic in the US exceeds $1.2 billion and generates $5-7 billion at consumer purchase level. Over 20% of the world's onion seed is produced in the US and is valued at over $100 million annually. Allium leafminer is currently causing economic damage in diversified farm settings in the northeastern US, where allium production is often associated with a highly diverse, fresh-market production system distributed among heterogeneous landscapes and farmer demographics. These farms include local CSAs, certified organic farmers, and Amish-Mennonite farming communities, that rely on producing onion, garlic, leeks, scallions and chives at volumes that ensure continuous supply to local customers. This pest also infests ramps ('wild leek'), a native of forestlands with strong cultural ties and economic development opportunity tied to tourism throughout Appalachia. Ramps have rapidly grown in popularity as a wild food delicacy, but the utilization of ramps by this invasive species only exacerbates growing concerns about the sustainability of this agro-forestry crop. Allium leafminer also could pose a threat to an endangered Allium species in California, and the potential exists for this new invasive pest to affect import, export, and interstate transport of Alliums. Science-based trials to provide management solutions are sparse, and initial responses include increased insecticide inputs, which in addition to creating environmental and farm-worker concerns, also exacerbate existing problems with management of other insect pests of alliums, such as onion thrips. Until recently, thrips control had been unpredictable because of resistance, but extensive research has reduced the average number of foliar insecticide applications in half in large onion production areas. However, additional insecticides aimed at Allium leafminer could upset this balance.The goal of our proposal, which is focused around four objectives, is to provide solutions for managing ALM in the currently infested area and in areas yet to be invaded. The first objective develops a science-based approach to understanding and predicting when crops are at risk, and rapidly delivering that information to growers, enabling them to minimize the time frame of deploying insecticides or other management tactics. The second develops a science-based approach to understanding how behavior by this pest is mediated through host-plant volatiles cues, variation in response to host species and age, and locations within fields. This enables growers to develop trap-cropping methods, and tools for monitoring the pest. Our third objective is focused on advancing biological control, building from our finding of parasitism within US populations. Our fourth objective strives to provide effective insecticide management solution that are relevant to both conventional and organic growers, avoid exacerbation of other pest species, and minimize the time span over which insecticides are needed.Our work is designed to be useful for both large and small producers, in both large-acreage and highly diversified production systems, and for both conventional and organic growers. Anticipated impacts from the integration of all objectives include a more rapid and effective management of an invasive species, thus slowing its geographic expansion. Our work will shed light on the 'why' and 'how' pest status is minimized and provide solutions for when pest status is reached in both currently invaded areas, and areas that may become invaded. Results will be communicated to stakeholders via an experienced network of extension educators.
Animal Health Component
60%
Research Effort Categories
Basic
40%
Applied
60%
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
2163110113025%
2163110107025%
2161451113050%
Knowledge Area
216 - Integrated Pest Management Systems;

Subject Of Investigation
1451 - Onion, garlic, leek, shallot; 3110 - Insects;

Field Of Science
1130 - Entomology and acarology; 1070 - Ecology;
Goals / Objectives
This is an ARDP Research-Led project, under focus area Plant Protection Tools and Tactics, to develop management solutions targeting the Allium leafminer (ALM), Phytomyza gymnostoma (Diptera: Agromyzidae), an invasive species first recorded in the Western Hemisphere in December, 2015. ALM attacks high-value crops in the Allium genus such as onion, garlic, leek, scallions, shallots, and chives; it also threatens an emerging agroforestry crop, and could pose a threat to an endangered Allium. High ALM infestations have occurred in onion and leek fields with as many as 20 pupae per plant, and 100% of plants infested. In PA and NY, some growers have had total losses to their leek crop from ALM. Our work will (1) Identify ALM fly-free periods during the season through studies of phenology and delivery of monitoring programs, (2) Determine the behavioral response of ALM to variation in host species, host growth stages, and plant volatiles, and quantify the within-field distribution of ALM infestations, (3) Enable future opportunities for biological control through baseline natural enemy surveys, building on our finding of parasitism in U.S. populations, and (4) Improve the use of conventional and organic insecticides to manage ALM through efficacy trials, while minimizing flare ups of insecticide-resistant onion thrips. Results will be communicated to stakeholders via an experienced network of extension educators.
Project Methods
We will measure the timing of initial adult flight by scouting hosts on farms, and on sentinel plots weekly during the spring and fall generations. Initial activity will be defined as the occurrence of oviposition marks or mines in leaf tissue. Hobo data loggers will be placed at each site to collect air and soil temperature data. A second measure will use emergence cages placed over infested allium. Degree-day accumulation will occur using Hobo data loggers, and web-service tools. To model initial spring activity, we will measure degree days from January 1 to initial adult activity using iterative methods that minimize differences between predicted and observed activity across a range of base thresholds, using data from a series of site-years. Grower alerts of when adult activity starts will be initiated at the first sign. Grower alerts of when adult activity ends will be our synthesis of (i) data from the emergence cages, (ii) degree-day estimates of egg-to-adult, and (iii) the dynamics of oviposition marks over time, which we expect to follow a sigmoid pattern. Extension alerts will be led by the Extension personnel at both Penn State and Cornell.Response of ALM to variation in allium growth stages will be evaluated in randomized complete block trials. The effect of plant age at harvest on infestation rate will be analyzed with regression. Response of ALM to host species (leeks, onions, chives, garlic, and ramps) will be determined in greenhouse settings, with caged field-collected adults. Adults will be removed 5 days after introduction, and plants evaluated for oviposition marks. Plants will be held for an additional 40 days, and then dissected to record numbers of larvae or pupae. The effect of plant species will be analyzed with ANOVA. We will assess the behavioral responses of ALM to uninfested plants using a glass y-tube olfactometer, and host plant volatiles will be collected for these behavioral assays. Within-field distribution of ALM will occur in larger fields in NY, by quantifying distribution of oviposition marks as a function of distance from field edge. Infestation rate will be modeled as a function of distance from field edge with regression, with field size as a covariate.Parasitism rates will be determined from pupae dissected from infested leaf/bulb tissue collected on farms. Collected pupae will be held individually in microcentrifuge tubes and examined twice weekly for emerging parasitoids. If no emergence of either ALM adults or parasitoids have occurred, pupae will be dissected to determine if parasitoids had developed. Identifications will occur through the collaboration of experts.Efficacy of both conventional and organic insecticides will be accomplished with replicated complete block experiments. Choice of materials and application methods will reflect the most relevant horticultural methods and markets for alliums in each state. Separate trials will focus on efficacy of materials, and optimal time of application.

Progress 09/01/18 to 08/16/22

Outputs
Target Audience:Our target audience includes commercial and non-commercial growers of Allium crops, and entomologists working with Allium species in both managed and non-managed settings. Changes/Problems:Work restrictions due to Covid caused us to take a year longer than originally anticipated to compete the proposed work. What opportunities for training and professional development has the project provided?Graduate students who were working on other projects related to IPM in vegetable crops also participated in field and lab work with Allium leafminer. In doing so, graduate students gained experience in rearing out parasitoids, collecting host plant volatiles, and conducting insecticide efficacy trials. Graduate students and research technicians gained experience in communicating with growers in Extension programs. How have the results been disseminated to communities of interest?We have reached growers through articles in grower outlets (Onion World, Proceedings at grower meetings, the Garlic Press Newsletter), talks at grower meetings, field days, inclusion of spring emergence alerts in Extension outlests, and reporting real-time scouting data in a 1-800 telephone outlet. We have also disseminated results at meetings of Amish/Mennonite growers who typically are not aware of research outputs. We have reached scientists through publishing in a professional journal, talks at professional meetings, and talks at the major trade and production meetings for allium crops for both the US and internationally. We reached those who hold regulatory responsibilities through direct communications and providing information to those writing risk assessments. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? (1) Identify ALM fly-free periods during the season through studies of phenology and delivery of monitoring programs. We determined the timing of adult flight and oviposition activity in spring and fall, along with methods for measuring this. We also developed degree-day models to project spring activity, and for immature development. This enabled us to advise growers when to initiate and when to end both insecticidal control, and cultural controls including timing of planting or application of row covers. This project has produced an awareness by producers of the time that their crop is susceptible to infestation of a new invasive species. (2) Determine the behavioral response of ALM to variation in host species, host growth stages, and plant volatiles, and quantify the within-field distribution of ALM infestations, We collated information about variation in damage due to host plant species. This helped growers understand their risk of yield or quality loss depending on what crop they were growing, and when in the season they were growing that crop. This work enabled onion growers to limit risk, whereas leek growers need to be cognizant of increased risk. (3) Enable future opportunities for biological control through baseline natural enemy surveys, building on our finding of parasitism in U.S. populations We developed new knowledge of parasitoids of a new invasive pest species in the United States. We determined that there were 2 parasitoids utilizing this pest as a host in the US, and collaborated with USDA at the European Biological Control Lab (EBCL) in Montpellier, France. Although the parasitism rate in both the US and France is low, collaborators documented a rich assemblage of 7 parasitoids in France, opening the potential of classical biological control. Rearing has been established at the EBCL. (4) Improve the use of conventional and organic insecticides to manage ALM through efficacy trials, while minimizing flare ups of insecticide-resistant onion thrips We determined the efficacy of multiple insecticides for control of allium leafminer, and showed which ones are best to control this pest for both convention and organic production systems. We further determined how to minimize the frequency of insecticide applications while maintaining high, commercially relevant, levels of control. This is resulting in growers minimizing insecticides targeting allium leafminer. This includes limiting the number of applications, and the area of a field sprayed, based on an understanding of allium leafminer behavior. This is also enabling growers to maintain control of onion thrips, without additional insecticide resistance, and organic growers being able to control allium leafminer, with both cultural methods and allowable insecticides. The geographic expansion of this invasive pest to other regions of the U.S. will be slowed due to our research and outreach activities in the infested range, and the ability to respond quickly if isolated interceptions occur. The US onion industry will have improved capacity to address trade and transport issues that arise due the presence of a new invasive species.

Publications

  • Type: Journal Articles Status: Published Year Published: 2022 Citation: Nault, B. A., R. K. Sandhi, R. S. Harding, E. A. Grundberg, and T. Rusinek. Optimizing Spinosyn Insecticide Applications for Allium Leafminer (Diptera: Agromyzidae) Management in Allium Crops. J. Economic Entomology 115: 618-623.
  • Type: Websites Status: Published Year Published: 2022 Citation: Fleischer, S. J. and T. Elkner. 2022. Allium leafminer emerging soon. https://extension.psu.edu/2022-pest-alert-allium-leafminer-emerging-soon#:~:text=Allium%20leafminer%20is%20an%20invasive,County%2C%20Pennsylvania%20in%20December%202015.&text=Allium%20leafminer%20(ALM)%20(Figure,scallions%2C%20shallots%2C%20and%20chives.
  • Type: Conference Papers and Presentations Status: Accepted Year Published: 2018 Citation: Fleischer, S. J. 2018. Allium leafminer: life cycle, location, and management. Proc., Mid-Atlantic Fruit and Vegetable Convention. Hershey, PA. January 30  February 1.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Nault, B., S. J. Fleischer, E. Grundberg, T. Rusinek, D. Roberts & T. Elkner. 2018. Biology and management of Phytomyza gymnostoma: a new invasive pest of Allium crops in the eastern US. Eastern Branch of the Entomological Society of America. Annapolis, MD. Mar. 17-19
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Fleischer, S. J., T. Elkner, C. M. McGrady, D. Roberts, B. A. Nault, T. Rusinek, E. Grundberg, J. Ali, S. Ray & B. Lingbeek. 2018. Allium leafminer: A new invasive threat to Allium crops in North America. Entomological Society of America. Vancouver, Canada. Nov. 10-13
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Nault, B., S. J. Fleischer, T. Elkner, E. Grundberg, T. Rusinek, R. Harding & B. Lingbeek. 2019. Initial steps in managing the new invasive Allium leafminer in Allium crops. Eastern Branch of the Entomological Society of America. Blacksburg, VA. March 9-12
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Nault, B., R. Harding, L. Iglesias, E. Grundberg, T. Rusinek, T. Elkner, B. Lingbeek and S. Fleischer. 2019. Management of Allium leafminer (Phytomyza gymnostoma): A new invasive pest of Allium crops in North America. Entomological Society of America. St. Louis, MO. Nov. 16-20
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Lingbeek, B., S. J. Fleischer, A. Corcoran and T. Elkner. 2019. Predicting allium leafminer (Phytomyza gymnostoma) emergence with degree-day accumulations and phenological observations. Entomological Society of America. St. Louis, MO. Nov. 16-20
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Nault, B. A., S. Fleischer, E. Grundberg, T. Rusinek, T. Elkner, R. Harding and B. Lingbeek. 2019. What we know and dont know about the Allium leafminers threat to the U.S. Allium Industry. International Allium Conference, Madison, WI. July 25, 2019.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Nault, B. A. 2019. Managing major insect pests of onion including the new invasive Allium leafminer. The New England Vegetable and Fruit Conference, Manchester, NH. December 11, 2019.
  • Type: Other Status: Other Year Published: 2019 Citation: Nault, B.A. 2019. What New York onion growers need to know about Allium leafminer as it may affect trade. 2019 Elba Muck Onion Twilight Meeting. Cornell Cooperative Extension Vegetable Program. Elba, NY. August 20, 2019.
  • Type: Other Status: Other Year Published: 2019 Citation: Nault, B. A., and E. Grundberg. 2019. Insecticide evaluations for Allium leafminer management. Orange County Onion School. Cornell Cooperative Extension Eastern New York Commercial Horticulture. Pine Island, NY. March 5, 2019.
  • Type: Other Status: Other Year Published: 2019 Citation: Nault, B. A. 2019. Allium leafminer: A new invasive pest of Allium crops in the US. Meeting with Deputy Administrator of APHIS PPQ, Osama El-Lissy. April 11, 2019. Washington D.C.
  • Type: Other Status: Other Year Published: 2020 Citation: Nault, B.A. 2020. Managing onion maggot and allium leafminer in allium crops  a northeastern US perspective. Hermiston Farm Fair, Oregon State University. Virtual. December 4, 2020.
  • Type: Other Status: Other Year Published: 2020 Citation: Nault, B.A. 2020. Flies in the ointment: Update on onion maggot and allium leafminer management. Empire State Producers EXPO. Cornell Cooperative Extension. Syracuse, NY. January 15, 2020.


Progress 09/01/18 to 08/11/22

Outputs
Target Audience:Our target audience includes commercial and non-commercial growers of Allium crops, and entomologists working with Allium species in both managed and non-managed settings. Changes/Problems:Work restrictions due to Covid caused us to take a year longer than originally anticipated to compete the proposed work. What opportunities for training and professional development has the project provided? Nothing Reported How have the results been disseminated to communities of interest?We have reached growers through articles in grower outlets (Onion World, Proceedings at grower meetings), talks at grower meetings, field days, inclusion of spring emergence alerts in Extension outlests, and reporting real-time scouting data in a 1-800 telephone outlet. We have also disseminated results at meetings of Amish/Mennonite growers who typically are not aware of research outputs. We have reached scientists through publishing in a professional journal, talks at professional meetings, and talks at the major trade and production meetings for allium crops for both the US and internationally. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? (1) Identify ALM fly-free periods during the season through studies of phenology and delivery of monitoring programs. We determined the timing of adult flight and oviposition activity in spring and fall, along with methods for measuring this. We also developed degree-day models to project spring activity, and for immature development. This enabled us to advise growers when to initiate and when to end both insecticidal control, and cultural controls including timing of planting or application of row covers. This project has produced an awareness by producers of the time that their crop is susceptible to infestation of a new invasive species. (2) Determine the behavioral response of ALM to variation in host species, host growth stages, and plant volatiles, and quantify the within-field distribution of ALM infestations, We collated information about variation in damage due to host plant species. This helped growers understand their risk of yield or quality loss depending on what crop they were growing, and when in the season they were growing that crop. This work enabled onion growers to limit risk, whereas leek growers need to be cognizant of increased risk. (3) Enable future opportunities for biological control through baseline natural enemy surveys, building on our finding of parasitism in U.S. populations We developed new knowledge of parasitoids of a new invasive pest species in the United States. We determined that there were 2 parasitoids utilizing this pest as a host in the US, and collaborated with USDA at the European Biological Control Lab (EBCL) in Montpellier, France. Although the parasitism rate in both the US and France is low, collaborators documented a rich assemblage of 7 parasitoids in France, opening the potential of classical biological control. Rearing has been established at the EBCL. (4) Improve the use of conventional and organic insecticides to manage ALM through efficacy trials, while minimizing flare ups of insecticide-resistant onion thrips We determined the efficacy of multiple insecticides for control of allium leafminer, and showed which ones are best to control this pest for both convention and organic production systems. We further determined how to minimize the frequency of insecticide applications while maintaining high, commercially relevant, levels of control. This is resulting in growers minimizing insecticides targeting allium leafminer. This includes limiting the number of applications, and the area of a field sprayed, based on an understanding of allium leafminer behavior. This is also enabling growers to maintain control of onion thrips, without additional insecticide resistance, and organic growers being able to control allium leafminer, with both cultural methods and allowable insecticides. The geographic expansion of this invasive pest to other regions of the U.S. will be slowed due to our research and outreach activities in the infested range, and the ability to respond quickly if isolated interceptions occur. The US onion industry will have improved capacity to address trade and transport issues that arise due the presence of a new invasive species.

Publications

  • Type: Journal Articles Status: Published Year Published: 2022 Citation: Nault, B. A., R. K. Sandhi, R. S. Harding, E. A. Grundberg, and T. Rusinek. Optimizing Spinosyn Insecticide Applications for Allium Leafminer (Diptera: Agromyzidae) Management in Allium Crops. J. Economic Entomology 115: 618-623.
  • Type: Websites Status: Published Year Published: 2022 Citation: Fleischer, S. J. and T. Elkner. 2022. Allium leafminer emerging soon. https://extension.psu.edu/2022-pest-alert-allium-leafminer-emerging-soon#:~:text=Allium%20leafminer%20is%20an%20invasive,County%2C%20Pennsylvania%20in%20December%202015.&text=Allium%20leafminer%20(ALM)%20(Figure,scallions%2C%20shallots%2C%20and%20chives.


Progress 09/01/20 to 08/31/21

Outputs
Target Audience:We have reached growers through articles in grower outlets (Onion World, Proceedings at grower meetings), talks at grower meetings, field days, inclusion of ALM spring emergence alerts in Extension outlets, and reporting real-time scouting data in a 1-800 telephone outlet. We have reached scientists through publishing in a professional journal and talks at professional meetings. Changes/Problems:The covid pandemic limited our ability to conduct field and lab work throughout 2020. We adapted by getting some data from collaborators at field sites that either did not require travel, or during times and places where travel was allowable. We emphasized analyses of phenological and developmental data and pooling the parasitoid data with developmental data as we published this information. We utilized web resources to deliver phenological advance warnings to growers, alerting them to the time of spring emergence of adult allium leafminers. We pivoted to virtual presentations to deliver information to growers. We acquired a no-cost extension, allowing us to repeat the insecticide optimization trial. What opportunities for training and professional development has the project provided?A research technologist developed and presented results of the phenological lab and field studies at a professional meeting. How have the results been disseminated to communities of interest?We have reached growers through articles in grower outlets (Onion World, Proceedings at grower meetings), talks at grower meetings, field days, webpages as part of Vegetable Production Teams, and reporting real-time scouting data in a 1-800 telephone outlet. We have reached scientists through publishing in a professional journal and talks at professional meetings. What do you plan to do during the next reporting period to accomplish the goals?We will utilize the spring emergence phenology model to deliver alerts to growers through Extension outlets, and incorporate ALM management information in Extension talks. In New York, we intend to repeat the insecticide optimization trial in the fall to determine if 2020 results can be replicated.

Impacts
What was accomplished under these goals? During this reporting period, we compiled and analyzed information to define ALM phenology, larval and pupal development, and status of parasitism. Our work has resulted in a model predicting spring emergence, developed from intensive field scouting coupled to a statistical approach of estimating a lower developmental threshold and degree-day accumulations above this threshold. Results to date estimated initial spring activity within six days of observed values in 90% of 20 sites distributed over 3 states and 2 years, and we started to use this model, along with flight duration data compiled from 2 years, to alert growers to 'ALM fly-free' periods. We worked through the Northeast Weather Association to make the phenology model accessible through the web. We used partial rearing and x-ray visualizations to estimate temperature thresholds for pupae. We documented the presence of two species of parasitoids. We published a manuscript covering this phenology, development, and parasitoid information. We also completed host-plant interaction studies, however connecting behavioral responses to host plant volatiles was not successful. We documented that allium leafminer will utilize ramps (Allium tricoccum) as a host. Results from the work reported here, along with the results of the conventional and organic insecticide efficacy studies reported in previous progress reports, are being delivered to growers and companies in a manner that improves management and influencing insecticide labels. Additionally, building from the efficacy trials described in previous reports, studies in New York were initiated to identify how best to optimize the application of foliar insecticides to manage ALM in scallion and leek. While 4-6 weekly applications of either spinetoram or spinosad provided complete protection of the crop from ALM, we discovered that 2 applications timed 7 to 14 days apart beginning two to three weeks after ALM adults were initially observed colonizing the field provided between 85% and 98% control. This was a huge advancement in our understanding of how best to manage this pest with insecticides in allium crops grown for conventional and organic production.

Publications

  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Nault, B. A., L. E. Iglesias, R. S. Harding, E. A. Grundberg, T. Rusinek, T. Elkner, B. Lingbeek and S. J. Fleischer. 2020. Managing Allium leafminer (Diptera: Agromyzidae): an emerging pest of allium crops in North America. J. Econ. Entomol. 113(5): 23002309
  • Type: Websites Status: Published Year Published: 2020 Citation: Elkner, T. and S. J. Fleischer. 2020 fall generation of Allium leafminer emergence (PA Extension Webpage) https://extension.psu.edu/2020-fall-generation-of-allium-leafminer-emergence
  • Type: Websites Status: Published Year Published: 2020 Citation: Lingbeek, B. and S. J. Fleischer. Allium leafminer 2020 : first emergence alert. (PA Extension Webpage)https://extension.psu.edu/allium-leafminer-2020-first-emergence-alert
  • Type: Journal Articles Status: Published Year Published: 2021 Citation: Lingbeek, B., D. Roberts, T. Elkner, M. Gates, and S. J. Fleischer. 2021. Phenology, development, and parasitism of Allium Leafminer (Diptera: Agromyzidae), a recent invasive species in the US. Environmental Entomology doi: 10.1093/ee/nvab043
  • Type: Websites Status: Published Year Published: 2021 Citation: Fleischer, S. J. and T. Elkner. Time to prepare for protecting Allium crops from Allium leafminer. (PA Extension webpage) https://extension.psu.edu/time-to-prepare-for-protecting-allium-crops-from-allium-leafminer


Progress 09/01/19 to 08/31/20

Outputs
Target Audience:We reached growers using multiple Extension outlets, including a 1-800 hotline, newsletters, Extension webposts, postings by commercial production organizations, and speaking at grower conferences. We reached scientists through presentations at national conferences, and through publishing results in professional journals. Changes/Problems:The covid pandemic limited our ability to conduct field and lab work in the spring of 2020. We adapted to this by getting some data from collaborators, and focusing on analyses of phenological data. We anticipate being able to complete the project through a 1-year no-cost extension. What opportunities for training and professional development has the project provided?A research technologist developed and presented results of the phenological lab and field studies at a professional meeting. How have the results been disseminated to communities of interest?We have reached growers through articles in grower outlets (Onion World, Proceedings at grower meetings), talks at grower meetings, field days, and reporting real-time scouting data in a 1-800 telephone outlet. We have reached scientists through publishing in a professional journal and talks at professional meetings. What do you plan to do during the next reporting period to accomplish the goals?Our next focus will be to complete the phenological data collection and publish these results (focusing on objective 1). We developed a prediction of spring emergence from 2019 field observations of first occurance from multiple sites, using a statistical approach that minimizes error from a matrix of potential base thresholds and accumulated degree days at that site. We repeated this, across a wider array of sites, in 2020. We are currently synthesizing results across years. We will compile these results with lab rearing, X-ray data of pupal morphogensis, and 2 years of field observations of the duration of adult flight activity, into a manuscript that advances our understanding of allium leafminer phenology. We will use this in Extension programming to provide advance alert to the timing of initiation of adult srping activity, and advice (along with scouting) about the duration of this activity. This will enable growers to optimize timing of management tactics. We also plan to publish a short note about which hymenopterous parasitoids have been recovered from allium leafminer since it's discovery in North America.

Impacts
What was accomplished under these goals? We completed efficacy trials of conventional and organic insecticides from multiple allium crops and application methods, compiled results, related results to the biology and ecology of both the pest and crop, and published this. We also delivered this information to grower audiences through multiple Extension venues. Thus, we met the goals outlined in objective 4. We focused on determining 'fly-free periods' (objective 1) through field and laboratory studies of allium leafminer phenology, developed a degree-day model to predict spring emergence, and synthesized lab studies into developmental models of immature life stages. We ran behavioral choice assays in lab settings, and collected volatiles from host plants. We found very low rates of larval/pupal parasitism, and compiled results of parasitism to date.

Publications

  • Type: Journal Articles Status: Accepted Year Published: 2020 Citation: B. A. Nault, L. E. Iglesias, R. S. Harding, E. A. Grundberg, T. Rusinek, T. Elkner, B. Lingbeek and S. J. Fleischer. 2020. Managing Allium leafminer (Diptera: Agromyzidae): an emerging pest of allium crops in North America. J. Econ. Entomol. (in press)
  • Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: S. J. Fleischer, T. Elkner, B. Lingbeek, L. Briggs. 2020. Allium leafminer: when and how to control. Proceedings, MidAtlantic Fruit and Vegetable Convention. Hershey, PA.
  • Type: Other Status: Published Year Published: 2020 Citation: L. Iglesias and B. Nault. 2020. Allium leafminer is no minor inconvenience. Onion World. April issue. https://onionworld.net/2020/04/21/allium-leafminer-is-no-minor-inconvenience/


Progress 09/01/18 to 08/31/19

Outputs
Target Audience:We reached growers, Extension Educators, scientists working with Allium crops in multiple states, and scientists working with this insect pest in Europe. Changes/Problems:We have not been able to develop lab-based behavioral assays that correspond to the host-plant choices we have documented in the field. We plan on trialing novel volatile collection methods to see if we can address this. What opportunities for training and professional development has the project provided?We have involved one technician and one summer wage employee. Both have obtained training in field ecology and also with collection of volatiles relevant to studying host-plant interactions. How have the results been disseminated to communities of interest?Results have been disseminated to growers through county-based Extension meetings, state-level meetings, posters at kiosks that are placed at sites where Amish/Mennonite farmers market their produce, and in Extension websites. Results have been disseminated to peer scientists at the national meeting of the Entomological Society of America. What do you plan to do during the next reporting period to accomplish the goals?Plans for 2020 include validation of the phenological predictions, and writing up results into manuscripts for peer-review. One manuscript will summarize phenology, and one will summarize organic and conventional control. We also plan to submit a short note to the peer review journals documenting the parasitoid species that have been recovered.

Impacts
What was accomplished under these goals? We have developed a degree-day model to predict the time of first emmergence of the adult fly in the spring, and we will be running validation tests in 2020. We also now have multiple years of data for the time span of adult activity based on monitoring for both the spring and fall flight. Together, this allows us now to alert growers to the 'fly-free' period, which growers can use to optimize timing of management practices. We have also shown strong preferences under field conditions for scallions and leeks, relative to bulb onions. We have collected and identified larval/pupal parasitoids - these parasitism rate has been very low, but the collections have occured from multiple locations. We have completed efficacy trials of both organic and conventional insecticides and collated that information and delivered this to growers.

Publications