Progress 01/01/10 to 12/31/10
Outputs
OUTPUTS: On August, 2008, the Asian Citrus Psyllid, DIAPHORINA CITRI Kuwayama [Hemiptera: Psyllidae] (=ACP), was first detected on several dooryard lemon trees in San Diego, California. By December, 2010, i.e., two years later, ACP had spread from its initial site in San Diego to a number of sites in dooryard citrus and commercial citrus groves in the counties of San Diego, Orange, Los Angeles, Ventura, Riverside, San Bernardino, Imperial, and a portion of Santa Barbara and San Bernardino Counties in Southern California, all of these locations are under quarantine.The serious nature of this threat is several. First, when disease free Asian citrus psyllid (ACP) feeds on citrus, it damages the flush and stunts tip growth while extracting large quantities of sap (honey-dew) on which sooty mold grows. The copious amount of honeydew provides a substrate for sooty mold which stains the fruit and reduces its appeal in the market place. Of much more concern is the disease, Huanglongbing (HLB), which ACP can vector if it encounters it. This bacterial disease, CANDIDATUS LIBERIBACTER spp., aka citrus greening, results in inedible fruit and unproductive citrus trees. Thus under current circumstances the outcome of an infestation is the demise of citrus production. PARTICIPANTS: Dr. Anandasankar Ray conducts research on olfactory behaviours associated with Drosophila fruit flies and various diseases carrying mosquitos. In collaboration with Dr. Ray, we are adapting his system and methods to the conduct of similar research with the Asian Citrus Psyllid. MS Lisa Forster Staff Research Associate VI. Ms Forster is conducting the electrophysiological experiments in the University of California Riverside Quarantine facility to determine the response by the Asian Citrus psyllid to odors of interest. MS Jan Hare, Staff Research Associate I, manages the citrus seedlings in the glasshouse and she manages the Asian citrua psyllid colony in the USDA certified Quarantine. . We use these seedings to rear the asian citrus psyllid (ACP) within the UCR quarantine facility to determine the odors to which it responds. Dr. Robert Luck in collaboration with Dr Ray and Ms Forster are conducting experiments to identify odors of interest to which the Asian Citrus Psyllid responds. TARGET AUDIENCES: We deseminate our information and via presentations to the Citrus Research Board several times annually and also submit articles periodically to Citrograph, the citrus industry's journal, which is sent to the growers and other interested agriculturists. The semi-annual Citrus Research Board meetings also provide an excellent informal venue for exchanging information. We also participate in meetings arranged by University of California Coop Extension County Agents. These meetings also provide a venue for interacting with growers. We also meet informally with growers in the field and often end up discussing issues that educates the both of us especially on the changing management issues facing citrus. We also meet periodically with some of the members of the Association of Applied Insect Ecologists (AAIE) and exchange information and ideas. This is an organization in which a number of AAIE members specialize in citrus pest management or which entails a portion of their responsibility. Walking through a grove with a licensed pest control advisor (PCA) can be a terrific education. PROJECT MODIFICATIONS: The rapid spread of ACP in Southern California since its initial discovery in California, its ability to acquire and vector Huanglongbing, and its likely spread into San Joaquin Valley citrus has lead the citrus industry to redirect its resources and research efforts in citrus pest management. These changes have forced us to redirect our research involving the use of augmentative release of APHYTIS. SPP. [Hymenoptera: Aphelinidae] (= natural enemies) and the lemon fruit cultures on which we grew our two armored scale species: 1. Oleander scale [ASPIDIOTUS NERII Bouch] and 2. California red scale [AONIDIELLA AURANTII (Maskell) (Hemiptera: Diaspididae)] in the University of California, Riverside, (UCR) insectary. This redirection of resources also lead to the termination of several soft scale parasitoid cultures [METAPHYCUS SPP (Hymenoptera spp.)] which we reared on brown soft scale (COCCUS HEPERIDUM Linnaeus [Coccidae, Hemiptera])that fed on yucca leaves in the UCR insectary. This soft scale rearing system had sought to develop an augmentative biological control program for citricola scale in San Joaquin Valley citrus. And we were so close. However, the arrival of ACP and the redirection of the associated resources forced us to shift our research focus and dictated the establishment of an Asian citrus psyllid culture (ACP) (DIPHORINA CITRI] Kuwayama [Hemiptera: Psyllidae]) on citrus seedlings under quarantine conditions. We have established a disease free ACP culture in the USDA certified quarantine facilities within the UCR insectary to obtain ACP adults. These adults are used to screen for compounds that are active as ACP attractants or repellants, i.e., that alters ACP's behavior. We are testing these compounds for use in the management of ACP by identifying chemical compounds that alters ACP behavior. The product(s) of this research will be used to manage ACP and the disease, huanglongbing (HLB), that it vectors. Given the limited certified quarantine space, this project will attempt to provide UCR, USDA, CDFA, & CRB researchers with a reliable but limited supply of living psyllids with which to initiate and/or maintain a culture in the UCR quarantine space. A second goal is to supply disease free psyllids as controls for testing field collected ACP for the presence of HLB. Third, while ACP is under quarantine, we will provide both a limited number of citrus seedlings and/or psyllids to several projects to maintain their psyllid and natural enemy colonies while quarantine conditions exist. These include supplying ACP periodically: (1) to initiate ACP colonies, (2) to augment Asian Citrus Psyllids for use in testing host specificity of the imported ACP natural enemies, (3) to provide a limited number of citrus seedlings on which to rear citrus psyllids in the quarantined-insectary area, and (4) to provide seedlings for use in pesticide trials under quarantine conditions.
Impacts
The rapid spread of ACP in California and its potential to vector Huanglongbing (HLB) has dictated a shift in our research focus and resources in citrus pest management. The limited quarantine space in the UCR insectary forced us to terminate our APHYTIS. SPP. [Hymenoptera: Aphelinidae] (= natural enemies) and lemon fruit cultures on which we grew our two armored scale species: 1. Oleander scale [ASPIDIOTUS NERII Bouche] and 2. California red scale [AONIDIELLA AURANTII (Maskell) (Hemiptera: Diaspididae)] in the University of California, Riverside, (UCR) insectary. This also required the termination of several soft scale parasitoids [METAPHYCUS SPP (Hymenoptera spp.)] cultures on which were reared on brown soft scale (COCCUS HEPERIDUM Linnaeus [Coccidae, Hemiptera]) on yucca leaves in the UCR insectary. This soft scale rearing sought to develop an augmentative biological control program for citricola scale in San Joaquin Valley citrus. However, the arrival of ACP forced us to shift our research focus and dictated the establishment of an Asian citrus psyllid culture (ACP) (DIPHORINA CITRI] Kuwayama [Hemiptera: Psyllidae]) on citrus seedlings under quarantine onditions. We have established a disease free ACP culture in the USDA certified quarantine facilities within the UCR insectary to obtain ACP adults. These adults are used to screen for compounds that are active as ACP attractants or repellants, i.e., that alters ACP's behavior. We are testing these compounds for use in the management of ACP by identifying chemical compounds that alters ACP behavior, either by acting as an attractant or a repellant. The product(s) of this research will be used to manage ACP and the disease, huanglongbing (HLB), that it vectors. Also, given the limited certified quarantine space, this project will attempt to provide UCR, USDA, CDFA, & CRB researchers with a reliable but limited supply of living psyllids with which to initiate and/or maintain a culture in the UCR certified quarantine space. A second goal is to supply disease free psyllids as controls for testing field collected ACP for the presence of HLB. Third, while ACP is under quarantine, we will provide both a limited number of citrus seedlings and/ or psyllids to several projects to maintain their psyllid and natural enemy colonies while quarantine conditions exist. These include supplying ACP periodically: (1) to initiate ACP colonies, (2) to augment Asian Citrus Psyllids for use in testing host specificity of the imported ACP natural enemies, (3) to provide a limited number of citrus seedlings on which to rear citrus psyllids in the certified quarantined-insectary area, and (4) to provide seedlings for use in pesticide trials under quarantine conditions. Our project will also use seedlings to establish citrus psyllids colonies for use in identifying the volatile citrus compounds that elicit sensory responses by the Asian Citrus Psyllid. We have modified a space in quarantine for the equipment that is being used to evaluate and identify panels of volatile compounds of interest.
Publications
- Kapranas, A, I. C. Hardy, J. G. Morse, and R. F. Luck 2010. Parasitoid developmental mortality in the field: patterns, causes and consequences for sex ratio and virginity. Journal of Animal Ecology. In Press 32 MS pgs. Accepted 09/20/2010.
- Tena, A. A., A. Kapranas, G. P. Walker, F. Garcia-Mari, and R. F. Luck. 2010 Larval competition in a gregarious endoparasitoid: cannibalism and physiological suppression. Bulletin of Entomological Research. In Press 6 MS pgs. Accepted 09/28/2010.
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Progress 01/01/09 to 12/31/09
Outputs
OUTPUTS: (1) Citrus Leafminer: PHYLLOCNISTIS CITRELLA Stainton (CLM): A) We finished a phenology study in three southern California lemon groves by counting flush tips in each of 3 leaf-size classes. We sub-sampled leaves to estimate CLM eggs, instars, and pupal densities and estimated CLM density per tip (=flush) and predation of immature CLM. We isolated CLM larvae and reared the parasitoids from them. These data estimated CLM density, age structure, parasitism and predation in each lemon grove. B) Additional leaf flush was collected to identify indigenous parasitoids adopting CLM in southern California and in Ventura County citrus. C) We collaborated with a Ventura County Farm Advisor to assess CLM's impact on lemon yields using packout records from lemon groves 4 years prior to and 4 years after CLM's arrival in Ventura Co. We vet and reanalyze annually as subsequent annual packout records are reported (2010 = 4 years post CLM). D.) We established a program to determine the efficacy of CIRROSPILUS COACHELLAE Gates (Hymenoptera: Eulophidae) releases in the San Joaquin Valley (SJV) for the suppression and establishment on peelminer, MARMARA GULOSA (Lepidoptera: Gracillariidae) (PM). C. COACHELLAE parasitizes both CLM and PM. All C. COACHELLAE released in 2009 were concentrated in selected SJV citrus groves with both CLM and PM populations. These sites also had oleander, NERIUM OLEANDER L, near by, which is an alternate host for PM, when fruit is not available on citrus. Spring and early summer releases were made only in the oleander. We are testing whether CLM will serve as an alternative host for C. COACHELLAE in SJV citrus as it does in Coachella Valley citrus. Moreover, CLM will serve as a year round host for this parasitoid and allow it to parasitize PM larvae in the fall when PM begins to colonize and mine the citrus fruit (rind) in late summer. All C. COACHELLAE were reared at UCR on citrus seedlings infested with CLM and then shipped to the SJV for release. (2) We finished laboratory evaluations of citricola scale, COCCUS PSEUDOMAGNOLIARUM, (Hemipteran: Coccidae) A) We have determined which parasitoids in southern California attack citricola scale. B) We developed molecular markers to identify the five parasitoid species that parasitize soft scales in citrus which we will use to identify immature parasitoid species and offspring composition in parasitized immature soft scales in California. C) We completed behavioral studies of four METAPHYCUS species parasitizing citricola scale to determine host stage and size preferences. These data provide the underpinning to begin our field testing and implementation of a sustainable, biologically-based, IPM program for citricola scale management in SJV citrus. (3) We produce and supply California red scale, AONIDIELLA AURANTII, and oleander scale, ASPIDIOTUS NERII Bouche, to evaluate APHYTIS species and strains, and to evaluate scale dispersal. All results are presented as Citrus Research Board reports published in Citrograph. Findings were presented as poster, oral and written presentations reported through UCIPM: Invasive and Exotic Pest Program and Hansen Trust of Ventura County. PARTICIPANTS: Ms. Lisa Forster SRA V is responsible for day to day operations of the laboratory and rearing facilities. She manages the laboratory, the budget, develops and oversees the rearing of California red and oleander scale, including the APHYTIS parasitoids, the seedlings used to rear citrus leafminer, PHYLLOCNISTIS CITRELLA, which we use to rear its parasitoid, CIRROSPILUS COACHELLA. She designed and built the brown soft scale, COCCUS HESPERIDUM, and parasitoid rearing systems for four METAPHYCUS spp, (soft scale parasitoids). She developed the rearing and augmentative release programs focusing on citricola scale in citrus and several soft scales species which are problems in mall plantings, interiorscapes, and atria. Ms Jan Hare is responsible for the day to day maintenance of the soft scales, armored scales, and citrus leafminer colonies. She also processes the citrus leafminer and peelminer samples from our field sampling and enters the data into our computer system. Ms Jan Hare, Ms Kimberly Oporto, and Mr. Robert Trautman assist in maintaining the soft scale and leafminer colonies and associated parasitoids. Mr. Trautman also assists in the leafminer sampling: Dr. Grafton-Caldwell collaborates and advises us on pest management and grower attitudes in the San Joaquin Valley (SJV) and assists us in the release of C. COACHELLAE in our peelminer- leafminer augmentative release studies. Farm Advisors: Dr Ben Faber, Ventura and Santa Barbara County Farm Advisor, arranged with Limoniera Company for us to have access to their lemon groves for sampling citrus leafminer. He has also assisted us in choosing the lemon blocks for our yield studies and obtained the necessary packout data required for our research. Neil O'Connell, Tulare County Farm Advisor, has helped us locate and identify groves for our citricola and red scale studies in the SJV. He has also helped us understand San Joaquin Valley citrus production and grower attitudes. Craig Kallsen, Kern County, Farm Advisor has also helped us identify groves for red scale and citricola scale research. He too has helped us understand citrus production in the SJV. Mr. Earl Rutz, a citrus grower, has allowed us to sample his lemon block for citrus leafminer and to survey for the soft scale parasitoids in his orange groves. Soboba Reservation has allowed us to sample for the citrus leafminer in one of their Oroblanco blocks. Mr. Joe Barcinas, a pest control advisor has helped us to locate citrus acreage in southern California for our CLM projects. Mr. Gus Gunderson, Limoniera Company, has allowed us to sample several lemons blocks for leafminer damage in the Santa Paula area of Ventura County. Mr. Rick Dunn, Pest Management, Badger Farms has identified San Joaquin Valley groves in which to sample citricola scale in developing a non-linear sequential sampling plan for this scale. He also helped us understand citrus production and pest management in the San Joaquin Valley. Mr. James Stewart, Ag IPM Consultants, assisted us in locating citrus blocks in which to conduct experiments and to sample for citricola and armored scales. He has helped us understand citrus pest management in the San Joaquin Valley. TARGET AUDIENCES: Our audience involves conventional and organic citrus growers, pest control advisors (PCA), farm advisors, commercial insectary producers and extension specialists involved in the citrus industry. We present our research results several times annually to the Citrus Research Board. We are also involved in grower meetings, informal meetings with several individuals, with pest management consultants, and with growers on a one to one basis. We also discuss potential problems or ideas with growers and County Farm Advisors who are intimately involved with the citrus industry. We also interact with pest managers in Australia and Spain via e-mail. This includes several insectary/pest management specialists and researchers in Australia and Spain. These interactions are often an exchange of information in which both parties benefit. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
(1) Citrus Leafminer (CLM): PHYLLOCNISTIS CITRELLA Stainton: A) CLM densities peak in fall, but the tree's flush peaks in spring, thus a small fraction of a tree's total flush is at risk to CLM damage annually. The largest flush occurs when CLM is rare. B) We have identified 11 parasitoid species (Eulophidae: Hymenoptera) that have adopted CLM in three southern California counties and their diversity increased annually since CLM's invasion. San Diego County has 8 species; Ventura has 7 species; and Riverside has 5 species. C) We have packout records for 4 years prior to CLM's arrival and 3 years after in Ventura County. We have not detected significant yield reductions in lemons before versus after CLM's arrival. We chose Ventura Co. for this study because of its climate, and because it's principal cultivar is lemon. If CLM affects lemon yields economically, we expect to see it in Ventura Co because of the additional flushing cycles and fruit sets in this climate. Three years of post data suggest that Ventura lemons do not experience reduced yields. D.) Most groves with heavy peelminer (PM) damage in 2005 now have much less fruit scarring from PM. We attribute this reduction to the weekly C. COACHELLAE releases (2007 to 2009) and to the establishment of CLM in the SJV. Even severe PM scarred fruit blocks that are adjacent to oleander wind breaks experienced less damage. Early spring releases that were made in the oleander, prior to PM's movement into citrus, significantly reduced fruit scarring in these blocks. Larval predation by CHRYSOPERLA contributed to PM mortality as evinced by the physical damage left in the mines on fruit. PM is difficult to suppress chemically, especially in the lower inside tree canopy where substantial fruit is produced. Non-specific treatments also disrupt management of other associated pests. (2) Citricola scale was a key pest in southern and central California citrus during the first half of the 20th century. With the presence of ants and brown soft scale in southern California citrus, citricola scale has disappeared. This univoltine scale is a key pest in San Joaquin Valley when multivoltine brown soft scale populations are absent. A & C) METAPHYCUS spp are the principle parasitoids attacking citricola scale. COCCOPHAGUS LYCIMNIA (Walker), a heteronomous hyperparasitoid, is not a factor, and our laboratory trials showed that M. ANGUSTIFRONS is quite unsuccessful attacking or reproducing on this scale, and will not be used in augmentative releases. The three other METAPHYCUS species readily parasitize citricola scale (M. LUTEOLUS, M. nr. FLAVUS, & M. STANLEYI). B) We can identify all of the parasitoids using multiplex PCR techniques, and we are confirming them taxonomically. (3) Oleander scale, ASPIDIOTUS NERII Bouche disperses phoretically on flies with special adaptations (projections). Avocado shipments from Mexico have had fruit infested with exotic armored scale species. Flies oviposit in such fruit and the crawlers are able to hitch a ride on these ovipositing flies as a means of dispersal.
Publications
- Kapranas, A., B. A. Federici, R. F. Luck and J. Johnson. 2009. Cellular immune response of brown soft scale COCCUS HESPERIDUM L. (Hemiptera: Coccidae) to eggs of METAPHYCUS LUTEOLUS Timberlake (Hymenoptera: Encyrtidae). Biological Control 48: 1-5.
- Tena, A., A Kapranas, F. Garcia-Mari and R. F. Luck. 2009. Larval canabalism during the late developmental stages of a faculatively gregarious encyrtid endoparasitoid. Ecological Entomology. 34: 669-676.
- Kapranas A., E. Wajnberg, and R.F. Luck. 2009. Sequences of sex allocation and mortality in clutches of METAPHYCUS parasitoids of soft scale insects and the prevalence of all-female broods. Ecological Entomology, 34, 652-662.
- Payal, K., Shah, P. K., D. R. Jeske, and R. F. Luck. 2009. Sequential Hypothesis Testing Techniques for Pest Count Models with Nuisance Parameters. Journal of Economic Entomology 102, 1970-1976.
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Progress 01/01/08 to 12/31/08
Outputs
OUTPUTS: (1.) Citrus Leafminer: PHYLLOCNISTIS CITRELLA Stainton (CLM): We continued to sample the flush present on each of 20 randomly selected trees at each of three southern California citrus groves once a month from June to December and every other month from January to May. We returned the sample tips to the laboratory and counted the number of immature CLM stages (eggs, instars 1-4+, and pupae) present in each of three leaf-size classes. These counts estimated the CLM densities per tip (=flush) and the predation rates of immature CLM. We isolated parasitized CLM larvae and reared the parasitoids for identification. We used these data to estimate CLM density, age structure, and parasitism and predation rates. (2.) To assess CLM's economic impact on lemons, we have initiated a yield study in lemons grown in Ventura Co., in collaboration with a Ventura County Farm Advisor, to compare the pack out records prior to CLM's arrival with those after its arrival. (3.) We imported and tested whether CITROSTICHUS PHYLLOCNISTOIDES (Narayanan) parasitizes citrus peelminer (CPM) (MARMARA SP.) in UCR's quarantine facility. (4) We reared and, in collaboration with the Director of the Lindcove Research & Extension Center, released over 20 thousand CIRROSPILLUS COACHELLAE Gates (Hymenoptera: Eulophidae) in selected San Joaquin Valley (SJV) pomelo, oroblanco, and navel orange groves to test whether this parasitoid suppresses citrus peelminer on the fruit of these cultivars in California's San Joaquin Valley. We are testing whether C. COACHELLAE released from late spring through summer in San Joaquin Valley citrus groves results in a decrease of CPM larvae when they begin to mine the fruit rind in autumn. (5) We continued to refine and optimize our mass rearing of METAPHYCUS SPP. parasitoids for use as augmentative release agents against soft scale pests in agricultural and ornamental settings, including indoor interiorscapes. We supplied several thousand METAPHYCUS SPP. for release in glasshouses and interiorscapes to determine whether such releases seemed efficacious. (6) A visiting graduate student from the University of Palermo, Italy, conducted behavioral experiments to determine whether unmated female METAPHYCUS FLAVUS emits a sex pheromone that attracts the males. (7) We are developing a set of molecular markers to differentiate among the larvae comprising the complex of five parasitoid species exploiting the immature stages of soft scales insects in citrus. We will also use these molecular techniques to evaluate the mating structure and offspring composition in parasitoid clutches allocated to the different soft scale stages and species in California. (8) We produce and supply armored scale insects, California red scale, AONIDIELLA AURANTTI, and oleander scale, ASPIDIOTUS NERII Bouche for use by faculty and graduate students in their research projects and for use in Entomology laboratory classes. (9) We continue to supply the adults of the armored scale parasitoid, APHYTIS MELINUS, for use in a thesis research project of a graduate student that seeks to evaluate the quality of this parasitoid produced by commercial insectaries. PARTICIPANTS: Ms. Lisa Forster SRA IV is responsible for the day to day operations of the laboratory and rearing facilities. She manages the laboratory budget, develops and oversees the rearing of California red and oleander scale, including the APHYTIS parasitoids, the seedlings used to rear citrus leafminer, PHYLLOCNISTIS CITRELLA, which we use to rear its parasitoid, CIRROSPILLUS COACHELLA. She designed and built the brown soft scale, COCCUS HESPERIDEM, and parasitoid rearing systems for four METAPHYCUS spp, (soft scale parasitoids). She developed the rearing and augmentative release programs focusing on citricola scale in citrus and several soft scales species which are often problems in mall plantings, interiorscapes, and atria. We also supply parasitoids to suppress soft scales in greenhouses, indoor plantings, and atria. Ms Jan Hare is responsible for the day to day maintenance of the soft scales, armored scales, and citrus leafminer colonies. She also processes the citrus leafminer and peelminer samples from our field sampling and enters the data into our computer system. Ms Jan Hare, Ms Kimberly Oporto, and Mr. Robert Trautman assist in maintaining the soft scale and leafminer colonies and associated parasitoids. Mr. Trautman also assists in the leafminer sampling. Dr. Beth Grafton Caldwell's collaborates and advises us on pest management and grower attitudes in the San Joaquin Valley and assists us in the release of CIRROSPILLUS COACHELLAE in our peelminer- leafminer augmentative release studies. Farm Advisors: Dr Ben Faber, Ventura and Santa Barbara County Farm Advisor, arranged with Limoniera Company for us to have access to their lemon groves for sampling citrus leafminer. He has also advised and assisted us in choosing the lemon blocks for our proposed yield studies. Neil O'Connell, Tulare County Farm Advisor, has helped us locate and identify groves for our citricola and red scale studies in the San Joaquin Valley. He has also helped us understand San Joaquin Valley citrus production and grower attitudes. Craig Kallsen, Kern County, Farm Advisor has also helped us identify groves for red scale and citricola scale research. He too has helped us understand citrus production in the San Joaquin Valley. Mr. Earl Rutz, a citrus grower, has allowed us to sample his lemon block for citrus leafminer and to survey for the soft scale parasitoids in his orange groves. Soboba Reservation has allowed us to sample for the citrus leafminer in one of their oroblanco blocks. Mr. Gus Gunderson, Limoniera Company, has allowed us to sample several lemons blocks for leafminer damage in the Santa Paula area of Ventura County. Mr. Rick Dunn, Pest Management, Badger Farms has identified San Joaquin Valley groves in which to sample citricola scale in developing a non-linear sequential sampling plan for this scale. He also helped us understand citrus production and pest management in the San Joaquin Valley. Mr. James Stewart, Ag IPM Consultants, assisted us in locating citrus blocks in which to conduct experiments and to sample for citricola and armored scales. Mr. Devin Carroll helps us to understand the management of organic citrus in the San Joaquin Valley. TARGET AUDIENCES: Our target audience involves the growers and pest control advisors involved in the California citrus industry. We present our research results several times annually to the Citrus Research Board in California. We are also involved in grower meetings, informal meetings with several individuals, with pest management consultants, and with growers on a one to one, or on a one to several bases. We also discuss potential problems or ideas with growers and County Farm Advisors who are intimately involved with the citrus industry. I also interact with pest managers in Australia and Spain via e-mail. This includes several insectary/pest management specialists and researchers in Australia and Spain. It is a two way exchange and I am as much interested in learning from them as I am interested in dispensing information. These interactions are often and exchange of information in which I learn far more from the growers and colleagues than I probably provide them. PROJECT MODIFICATIONS: No major changes
Impacts
(1) Citrus Leafminer (CLM): PHYLLOCNISTIS CITRELLA Stainton: We have sampled CLM densities for two and half years in two southern California lemon groves and in one oroblanco grove monthly from May to October, and bimonthly from November to March, to determine if CLM affects yield in bearing citrus. Although the lemon leaves are obviously mined by late summer-early fall, this mining does not appear until summer and thus does not seem to affect yield. (2) We found six resident parasitoid species using citrus leafminer as a host in southern California. These include CHRYSOCHARIS WALLEYI Yoshimoto, CLOSTEROCERUS CINCINNATUS Girault, CLOSTEROCERUS UTAHENSIS Crawford, NEOCHRYSOCHARIS FORMOSA Westwood, PNAGALIO COLONI Girault, and ZAGRAMMOSOMA AMERICANUM Girault [all are Eulophidae: Hymenoptera]) of which C. WALLEYI and P. COLONI are the most common. We have several unknown species submitted for identification. (3) We imported and tested whether CITROSTICHUS PHYLLOCNISTOIDES (Narayanan) parasitizes MARMARA GULOSA Guillen and Davis (citrus peelminer) (Gracillariidae: Lepidoptera) in UCR's certified quarantine facility. It did not parasitize the citrus peelminer although it readily parasitized citrus leafminer. (4) We reared and released over 20 thousand CIRROSPILLUS COACHELLAE Gates (Hymenoptera: Eulophidae), the facultatively gregarious parasitoid of citrus leafminer and citrus peelminer. The year-round, multivoltine CLM appears to serve as an alternate host for this parasitoid species which also attacks CPM. Oroblanco/Pomelo (citrus) fruit samples in our preliminary experiments show 65 percent parasitism of CPM in groves in which we have released C. COACHELLAE inoculatively. We also noted substantial predation by Chrysopidae. Thus, our preliminary test suggests that we may be able to use the uneconomic, multivoltine CLM larval population mining the leaves in a citrus grove as an alternate host for C. COACHELLAE. This allows the C. COACHELLAE parasitoid population to bridge the period when the citrus peelminer and the fruit it mines are harvested and absent from a grove until the nest crop is set. If these results continue, it will ensure a resident parasitoid population that can adopt CPM. The lower inside fruit in these trees are not covered adequately when sprayed. If we can establish a resident parasitoid population in these groves we may reduce peelminer damge while minimizing the disruption of the associated arthropod complex. 5) Behavioural experiments conducted by a graduate student has shown that unmated female METAPHYCUS spp. leave a pheromone trail on the substrate, e.g., leaf, which the male METAPHYCUS uses to locate an unmated female. 6) Colleagues using our red scale colony, AONIDIELLA AURANTI Maskell (Homoptera: Coccidae), have shown that first instar armored scale (=crawlers) (Homoptera: Coccidae) disperse phoretically by hitching a ride on flies with special adaptations (projections). Avocado shipments from Mexico occasionally have fruit that are scale infested with an exotic species. Flies oviposite in such fruit and the first instar crawlers occassionally hitch a ride on these ovipositing flies.
Publications
- Luck, R. F., L. D Forster, J. G. Morse and A. Kapranas 2007. Augmentative bological control of ctricola scale, Coccus pseudomagnoliarum, in San Joaquin Valley citrus. Poster. Entomological Society of America. San Diego Meeting. Dec 2007.
- Tena A, A. Kapranas, F. Garcia-Mari and R. F. Luck. 2008 Host discrimination, superparasitism, and infanticide by a gregarious endoparasitoid. Animal Behaviour.76: 789-799.
- Kapranas, A. and R. F. Luck. 2008 Egg maturation, host feeding , and logevity in two Metaphycus parasitoids of soft scale insects. Biological Control 47: 147-153.
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Progress 01/01/07 to 12/31/07
Outputs
OUTPUTS: 1. Citrus leafminer, PHYLLOCNISTIS CITRELLA Stainton (CLM): a) Identify the indigenous parasitoid complex that adopts CLM in the Coachella, the interior and inland coastal valleys of southern California and the San Joaquin Valley as CLM invades California's citrus regions. b) Evaluate the impact of the natural enemy complex on citrus leafminer populations in these regions. c) Establish a CLM culture on citrus seedlings in UCR's insectary when leafminer has become established in southern California's inland valleys. d) Import and establish a culture of AGENIASPIA CITRICOLA Logvinoskaya, in UCR's quarantine facility and conduct the required evaluations to obtain permits for its release into California. e) Rear and release A. CITRICOLA into areas infested with CLM and evaluate its impact on their populations. f) Conduct field experiments at Agriculture Operations to evaluate CLM's economic impact on citrus cultivars used commercially in California. 2. Citricola, COCCUS
PSEUDOMAGNOLIARUM (Kwana) and black scale, SAISSETIA OLEAE (Olivier): a) Continue developing and refining the rearing system to produce parasitoids of citricola scale and determine production cost per unit (1,000 female wasps). Develop rearing methods to replace that currently being used to commercially rear black scale parasitoids using NERIUM OLEANDER as the host plant, which is being killed by oleander scorch, a XYLELLA FASTIDIOSA strain. b) Continue to conduct and evaluate an augmentative release strategy for citricola scale in San Joaquin Valley's commercial citrus. c) Continue developing a presence-absence sampling system to detect economic spring populations of citricola scale. d) Conduct behavioral studies of the host-parasitoid interactions to optimize rearing and release methodologies. 3. Selective Pesticides: Continue developing a sustainable pest management program for citrus by determining selectivity, timing, and compatibility of various pesticides registered for use in
California citrus. Determine the effect of these selective materials, including pesticides currently registered for use against the glassy-winged sharpshooter, on established and/or released natural enemies that suppress various citrus pests.
PARTICIPANTS: Personnel: Investigators Joseph Morse John Heraty Richard Stouthamer Beth Grafton-Cardwell Jocelyn Millar Technical Staff Lisa Forster Janet Hare Robert Trautman Porfirio Pacheco Kimberly Oporto Alan Urena Graduate students Daniella LoGiudice Ph. D. Candidate (Italy) 2007-08 Institutional Units Involved: Peggy Mauk, CCSR, DANR Georgios Vidalakis, UCCE, Plant Pathology Ben Faber, UCCE-Ventura County Craig Kallsen, UCCE-Kern County Neil O'Connell, UCEE-Tulare County Thomas Shea, UCCE-Riverside County Cooperation: Cooperation will occur as needed with other researchers and other Universities; and with representatives of the California citrus industries, U.S. Dept. of Agriculture, California Department of Food & Agriculture and various other international agencies. Our current list of expected/continued collaborators is as follows: Kris Godfrey, CDFA Citrus Research Board David Headrick, Cal Poly State University, San Luis Obispo David Kellum, San Diego County Agricultural
Commissioner' Office Haruhiko Yatsuzuka, Certified Organic Citrus Grower Farm Advisors: Craig Kallsen (Kern County) Neil O'Connell (Tulare County) Ben Faber (Ventura & Santa Barbara County) Pest Control Advisors: Joe Barcinas (Riverside Co.) Sylvie Robillard (Kern Co.), Tom Roberts (Ventura Co.)
TARGET AUDIENCES: California citrus growers
Impacts
PROGRESS: 2007/01 to 2007/12 We continue to evaluate several METAPHYCUS SPP. as potential augmentative release agents for the suppression of citricola scale, COCCUS PSUDOMAGNOLIARUM, in San Joaquin Valley citrus groves. Our concept is similar to the Fillmore Protective District's use of an augmentative release agent to suppress black scale, SAISETTIA OLEAE, in its southern California citrus groves. To select an appropriate parasitoid species to mass-rear and release against citricola scale, we compared the species specific egg maturation and resorption rates of M. FLAVUS and M. LUTEOLUS when mass-reared. We chose these two species because they exploit the smaller/younger stages of this univoltine scale, which are the stages that are present during early spring. We compared female longevity and life time reproductive potential given water only, a carbohydrate diet (honeydew), or a carbohydrate diet with access to soft scales on which to host feed. Females of both
species lack eggs when they emerge and with access to water die in three days. In the presence of a carbohydrate source, honeydew, they begin maturing eggs one day after emergence with their maximum egg load occurring three days post emergence. They then begin resorbing eggs sequentially using them to extend their life. Egg maturation rates are temperature dependent and the host meal size influences the number of eggs they mature. Female body size explains little variation in female longevity because it depends on diet. Females live longer when they feed on carbohydrates and a host versus when they feed on carbohydrates only. Our results indicate that M. LUTEOLUS uses more resources from its host meals for reproduction (egg maturation), whereas M. FLAVUS uses more of these resources for metabolic maintenance (longevity). This information emphasizes the need to ship the parasitoids with carbohydrate and egg supplement.
Publications
- Robert F Luck, Lisa D Forster, Joseph G Morse and Apostolos Kapranas 2007. Augmentative biological control of citricola scale, COCCUS PSEUDOMAGNOLIARUM, in San Joaquin Valley citrus Poster. Entomological Society of America. San Diego Meeting IN PRESS: ACCEPTED
- Kapranas, A., J. G. Morse, L. D. Forster, P. Pacheco, and R. F. Luck. 2008. Precise sex allocation by several encyrtid (Hymenoptera: Encyrtidae) parasitoid species exploiting brown soft scale, COCCUS HESPERIDUM L. (Hemiptera: Coccidae). Behavioral Ecology and Sociobiology In Press. (Ref.)
- Bernal J. S. and R F. Luck. 2007. Mate finding via a trail sex pheromone by APHYTIS MELINUS DeBach (Hymenoptera: Aphelinidae) males. Journal of Insect Behavior. Submitted 25 pp.
- Kapranas, A., J. G. Morse, L. D. Forster, P. Pacheco, and R. F. Luck. 2007. Survey of brown soft scale (COCCUS HISPERIDUM L.) (Hemiptera: Coccidae) parasitoids in southern California citrus. Biological Control. 42 (3): 288-299 (Ref.).
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Progress 01/01/06 to 12/31/06
Outputs
PROGRESS: 2006/01 TO 2006/12 We have completed an evaluation of the parasitoid complex that parasitize the soft scale insects on citrus (COCCIDAE) in California citrus groves, determined the host stages/sizes they use, and characterized the relationship between host size and host choice. METAPHYCUS ANGUSTIFRONS accounted for 38% of parasitized scales followed by M. LUTEOLUS (18%), M. STANLEYI (13%), M. HELVOLUS (6%), and MICROTERYS NIETNERI (7%) (all ENCYRTIDAE). Four COCCOPHAGUS SPECIES accounted for 11% of the parasitized scales, whereas collectively the, DIVERSINERVUS ELEGANS, ENCYRTUS LECANIORUM (both ENCYRTIADAE), MARIETTA MEXICANA (APHELINIDAE), CHARTOCERUS sp, (SIGNIPHORIDAE) and APROSTOCETUS SP. (EULOPHIDAE) were uncommon and accounted for the remaining 7% of the parasitized scales. The four species of METAPHYCUS and the one MICROTERYS SP., M. NIETNERI, laid more than one egg per host scale (they are gregarious) and the number of eggs they laid increased with
the size of the host scale. M. ANGUSTIFRONS, M. LUTEOLUS, M. STANLEYI, and M. NIETNERI all laid female biased sex ratios that, under field conditions, were very precise, i.e., the parasitoid allocated their offspring's sex non-binomially (=non-random). If the female fertilizes an egg when she laid it, it was diploid and became a daughter; if she did not fertilize it, it was haploid and became a son. Thus, a clutch normally consisted of one male and from two to five females per host scale and they were laid gregariously. Moreover, the sex ratio remained female biased even when other parasitized in the presence of other searching females and parasitized hosts, factors know to induce a less female biased sex ratio in parasitoids exploiting host patches such as those produced by soft scales on citrus. This latter condition has been shown in other parasitoid systems to increase the number of male offspring a female will allocate, i.e., it arises from local mate competition.
Impacts
IMPACT: 2006/01 TO 2006/12 We previously developed a mass rearing system for brown soft scales and their METAPHYCUS parasitoids. Understanding sex allocation by Metaphycus allows us to design a system that produces a female biased sex ratio when we mass-reared them in an insectary for augmentative release in the field against citricola scale (COCCUS PSEUDOMAGNOLIARUM). This understanding translates to the development of a more economic production of females since females are the gender that suppresses the scale, i.e., they kill the scale when they lay their eggs in the scale. Moreover, because more than one parasitoid offspring is produced per parasitized scale and more female than male offspring are produced (female biased) the effect of a release is to amplify the mortality because every scale that is parasitized in the field issues one male and the rest females. This contrasts with most other scale parasitoids that produce equal numbers of male and female
offspring. Each of these females offspring then parasitize additional scales during the next generation and also produce a female biased sex ratio. The consequence is a rapid increase in parasitized scales in the field when releases are timed properly. Knowing the preferred scale stages used by each METAPHYCUS species allows us to maximize the effect of these parasitoid releases by maximizing the production of female parasitoids in the field.
Publications
- Guillen, M., R. F. Luck, and J. M. Heraty. 2006 Preferred Host Stages, Clutch Size, and Sex Allocation by Cirrospilus coachellae (Hymenoptera: Eulophidae), a Parasitoid of Marmara gulosa (Lepidoptera: Gracillariidae). Biological Control. In Press (Ref.)
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Progress 01/01/05 to 12/31/05
Outputs
Citricola scale, COCCUS PSEUDOMAGNOLOIARUM (Kuwana) (COCCIDAE), remains a key pest in San Joaquin Valley citrus but is virtually absent in southern California, although it was once a key pest in this region also. We seek to determine why citricola scale has been controlled successfully in southern California in the absence of pesticides and the likely parasitoids responsible for this control. A two year, bi-weekly, year round survey at 10 sites in the interior citrus groves of southern California has identified 10 species of primary parasitoids associated with soft scales (COCCIDAE). The exposed scales on the plant material are returned to the laboratory and a representative sample of the parasitized scales are individually isolated and reared. The parasitoid species are identified, and their clutch sizes and sex ratios are characterized with respect to host size and age. Of the 10 parasitoid species we have recovered from these samples, METAPHYCUS ANGUSTIFRONS
Compere (METAPHYCUS) is a new record in southern California. It was released in 1952-54 as a biological control agent against soft scales but has not been recorded as established in California. We are also evaluating the efficacy of several METAPHYCUS species as augmentative biological control agents for release against citricola scale, a key pest in San Joaquin Valley citrus. All four METAPHYCUS species from our southern California field survey parasitize citricola scale. We are also continuing to evaluate the parasitoid complex attacking black scale, SAISSETIA OLEAE (Olivier), in California citrus.
Impacts
We continue to develop an ecological understanding of the relationships between the soft scale hosts and their parasitoid complex in California citrus. With this understanding, we will be able to develop an augmentative biological control program as a basis for an ecologically-based, sustainable, IPM program for California citrus. We have already adapted an augmentative release program for California red scale, AONIDIELLA AURANTII (MASKELL) (DIASPIDIDAE), in San Joaquin Valley citrus.
Publications
- No publications reported this period
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Progress 01/01/04 to 12/31/04
Outputs
We continue to evaluate the efficacy of several METAPHYTCUS species as augmentative biological control agents for release against citricola scale, COCCUS PSEUDOMAGNOLOIARUM (Kuwana), in San Joaquin Valley citrus. Citricola scale remains a key pest of citrus in this region where over 50% of the citrus is now grown in California. We are also continuing to evaluate the parasitoid complex attacking black scale, SAISSETIA OLEAE (Olivier), in southern California citrus. When pesticide applications cease in San Joaquin Valley citrus groves, citricola scale re-emerges as a key pest requiring chemical control. We are now able to mass rear several METAPHYCUS species and are continuing to evaluate their efficacy as augmentative biological control agents. To evaluate the parasitoid complex on soft scale in southern California citrus groves, including METAPHYCUS species, and its phenology, we are conducting a year round survey of soft scale parasitoids. We place scale infested
plant material in untreated interior southern California citrus groves and replace them bi-weekly. The exposed plant material is returned to the laboratory for parasitoid rearing and identification. This information provides a base line with which to evaluate the species complex of parasitoids and its phenology on soft scales in San Joaquin Valley citrus groves. We plan to expand the survey into the San Joaquin Valley using the same protocol and by placing scale infested plant material in organic citrus groves this next season.
Impacts
We continue to develop an understanding of the relationships between the soft scale hosts and their parasitoid complex. With this understanding we will be able to develop an ecologically based IPM program for California citrus. During the last two decades our research with citrus pests has led to the development of an ecologically based pest management program that has reduced pest control costs and pesticide use in California citrus groves.
Publications
- Lo Bue, P., D. Forster, J. G. Millar, S. Colazza, and R. F. Luck. 2004. Responses of Metaphycus sp. nr. flavus to semiochemicals released from a scale host, Coccus hesperidum. Chemoecology 14: 152-6.
- Kapranas, A., J. G. Millar, and R. F. Luck. 2004. Chemical cues mediating host recognition by two Metaphycus sp., parasitoids of brown soft scale: Initial extraction, bioassay, and role in host selection. In: Proceeding of the California Conference on Biological Control. July 13-15, 2004, Berkeley, CA. pp. 113-117.
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Progress 01/01/03 to 12/31/03
Outputs
This is a new project established autumn 2003. We have had little time with which to conduct research under the aegis of this project. This project seeks to continue the development of a pest management program for citrus that relies on natural enemies, both those that reside in a grove and those that are released augmentatively to supplement the resident natural enemies. They will be supplemented with the judicious use of selective pesticides, when the latter are necessary. Objective 1: We have not initiated research on the citrus leafminer PHYLLOCNISTIS CITRELLA as it is not yet established in the inland coastal valleys, although it was reported to be present in the Escondido California area late autumn 2003. It is currently under eradication. Objective 2: We are conducting behavioral studies of a COCCIDAE parasitoid, METAPHYCUS sp. nr FLAVUS, that we imported from Turkey for release against citricola scale, COCCUS PSEUDOMAGNOLARIUM, a pest of citrus in the San
Joaquin Valley. We are testing its response to chemical cues associated with several soft scale spieces, COCCUS HESPERIDUM, COCCUS PSEUDOMAGNOLIARUM and SAISETTIA OLEAE, all of which are used by METAPHYCUS sp. nr FLAVUS. We seek to determine whether METAPHYCUS sp nr FLAVUS uses the same or similar chemical cues to orient (i.e. volatile cues) and to recognize (contact cues) these soft scales as hosts. METAPHYCUS sp nr FLAVUS uses all three soft scale species as a host yet the scales' likely geographical origins are different, as is that of the parasitoid. We use brown soft scale as an insectary host on which to rear large numbers of the parasitoid for field release against citricola scale. If the chemical cues used by the parasitoid differ among the host scales, we may be reducing the parasitoids efficacy by exposing it to an inappropriate chemical environment when use a rearing host that differs from the host we are targeting for augmentative releases. Secondly, we continue to modify
the system that we use to rear large numbers of METAPHYCUS sp. nr FLAVUS. We use brown soft scale grown on YUCCA sp. leaves, excised from the yucca plant and grown hydroponically. We continue to reduce the costs of parasitoid production, as they will determine whether augmentative control with METAPHYCUS species is economically competitive with traditional chemical control.
Impacts
We expect this research to reduce the frequency of pesticide use for COCCUS PSEUDOMAGNOLIARUM. This will reduce disruptions of biological control agents for other pests and potential pests in a central valley citrus grove, such as that associated with increased katydids. It will also allow augmentative releases of insectary produced APHYTIS MELINUS for the suppression of California red scale, AONIDIELLA AURANTII. These practices will reduce the use of synthetic organic pesticides. It will also allow the resident leafminer parasitoids to adapt to the citrus leafminer as they have elsewhere in the world. Citrus leafminer is a multivoltine species with 9 or more annual generations. It is to costly to control on bearing citrus with pesticides; thus, it must be controlled biologically. Fortunately, most of the parasitoids that use citrus leafminer will be indigenous parasitoids of indigenous leafminer parasitoids. To exploit this indigenous resource, we must prevent
pesticide residues from disrupting the leafminer parasitoids. The most judicious way of doing so is to establish biological control agents or to use such agents augmentatively. This is the rational for this project.
Publications
- No publications reported this period
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