2007 Annual Report 1a.Objectives (from AD-416) 1) Develop biological control and semiochemical approaches for managing the glassy-winged sharpshooter.. 2)Develop molecular genetic markers and DNA fingerprinting methods to genetically identify and track both pest and natural enemy populations that will support and enhance the success of current and future biological control programs.. 3)Conduct and evaluate biological control-based strategies for management of aquatic and terrestrial weeds. 1b.Approach (from AD-416) Molecular techniques will be developed and tested to: determine if key parasitoids of GWSS occur as a cryptic species complex; detect GWSS and related sharpshooters in the gut contents of native insect predators, to help IPM specialists determine which species are most important to conserve in the citrus-grape agroecosystem. Intensive surveys in native mustang grapes in Texas will be conducted to find potential biological control agents that attack the nymphal stage of GWSS and assess the occurrence of the Pierce's disease pathogen in wild sharpshooter populations. Complementary surveys in South America of related sharpshooters and parasitoids will also be conducted. Chemical ecology studies will be used to identify the role of plant semiochemicals in host plant location and aggregation for GWSS and its egg parasitoids. Research vineyards/orchards in Weslaco will be used to replicate the California agroecosystem where GWSS is invasive, and allow us to integrate our laboratory and field research to evaluate management strategies. New approaches to manage invasive and exotic weeds by: improving augmentative biological control of waterhyacinth; testing bioherbicides to control pigweeds in subtropical cropping systems; conducting field studies in South Texas to determine the impact of biological control agents released for saltcedar on closely related athel pine. 3.Progress Report Research was conducted to test the possibility that G. metanotalis, a prospective biocontrol agent for GWSS from Argentina, exists as a cryptic species complex. So far, the data suggest that at least three strains of G. metanotalis are present in Argentina. Further work on cross-mating studies and morphological analysis is ongoing or planned. Ongoing molecular and morphological studies will determine the phylogenetic relationship between two morphologically indistinguishable parasitoids, an undescribed species called Gonatocerus sp. 3, and G. tuberculifemur. If more than one strain or cryptic species is identified, then both biological and genetic characteristics must be performed on these strains to identify the proper prospective GWSS egg parasitoid candidate agent. The phylogenetic relationships of approximately 17 North and South American Gonatocerus species, egg parasitoids of the GWSS, are being determined by COI sequence data. Phylogenetic trees showed that each species, inferred by both COI and ITS2 gene fragments, formed their own unique taxonomic unit or clade with very strong bootstrap support values, confirming the species boundaries inferred by taxonomic work. The results showed that the ITS2 fragment appears to be phylogenetically more informative or valuable than that inferred by COI sequence data. Studies were made to determine if a pathogenic fungus could increase the efficacy of waterhyacinth weevils as biocontrol agents. The fungus was applied to the beetles prior to their release on waterhyacinth plants growing in experimental tanks. Direct applications of aqueous and oil-based solutions containing fungal spores and (in some cases) the herbicide to plants and weevils were evaluated to examine their efficacy and potential toxicity. Direct application of the fungus did not kill the plants. The fungal and herbicide solutions did not usually kill waterhyacinth weevils, suggesting that these solutions are compatible with the weevils for control of waterhyacinth. Research on biological control of saltcedar determined the ability of saltcedar beetles to establish populations and to damage saltcedar in South Texas. We also examined the effects of the beetles on exotic, but beneficial, athel trees. This species is closely related to saltcedar and grows commonly in this area. Beetle egg-laying and damage was 2- to 10-fold greater on saltcedar than on athel, although beetles failed to establish a permanent population on either plant at one South Texas site. The results suggested that saltcedar beetles that are successfully establishing on saltcedar will not cause disfiguring damage or kill athel trees. Surveys are being conducted in Texas to determine whether pipunculid parasitoids, that have been isolated from other native sharpshooter species exist in GWSS as well. Studies are examining whether immature GWSS can use odor + visual cue combinations to discriminate between nutritionally favorable and unfavorable host plants. 4.Accomplishments Genetic characterization of the South American egg parasitoid, Gonatocerus tuberculifemur, a prospective egg parasitoid for GWSS: As a means of increasing parasitism of glassy-winged sharpshooter (GWSS) in California, egg parasitoids of sharpshooters are being sought from regions in South America that are climatically similar to California. Scientists from ARS-Weslaco, South American Biological Control Laboratory, European Biological Control Laboratory, and the University of California (Riverside) are involved in this project. Molecular, reproductive, and morphological studies indentified a novel species complex that previously was considered a single species, G. tuberculifemur. The identification of these species is necessary to determine which parasitoids would likely spread to other geographical areas in the event of release in California. (NP 304, Crop Protection and Quarantine, Component I: Identification and classification of insects and mites, Problem Area IC: Systematic studies of high priority pests and beneficial insects) Discovery of a nymphal parasitoid of sharpshooters: Immature glassy-winged sharpshooters (GWSS) are vulnerable to parasitism, but little information is available about nymphal parasitoids. Surveys in the native range of GWSS in Texas led to the discovery of a fly parasitioid of nymphal sharpshooters by scientists at ARS-Weslaco and Ag Canada. The fly, Eurydorylas viereckii (Pipunculidae), was collected from Oncometopia orbono, a sharpshooter closely related to GWSS. Intensive surveys are in progress to collect the Eurydorylas from GWSS. Nymphal parasitoids could complement the egg parasitoids already established in California. (NP 304, Crop Protection and Quarantine, Component II, Biology of Pests and Natural Enemies) Biological control of saltcedar: Non-target species may be vulnerable to exotic biocontrol agents used against bona fide pest species. A scientist at ARS-Weslaco demonstrated that biological control of saltcedar using the saltcedar leaf beetle Diorhabda elongata will not harm closely related athel trees. The impact of the beetles on athel trees, which are used as windbreaks and for shade, was one of several concerns of Mexican agencies from which the USDA-ARS sought concurrence prior to releasing beetles along saltcedar-infested sections of the Rio Grande. Field releases at sites safely removed from the U.S.-Mexico border showed that saltcedar beetles do not establish on athel. Mexican authorities have granted permission for further studies near the U.S.-Mexican border. (NP 304, Component 9, Biological Control of Weeds, Problem C, Field Evaluation) Host-plant searching behavior in GWSS: Scientists at ARS-Weslaco and Texas A&M University-Kingsville used olfactometery and behavioral assays to determine that foliar odors are used during host-plant location by adult and immature glassy-winged sharpshooter (GWSS). The results of studies that measured GWSS response to color + odor treatment combinations indicated that GWSS response to visual cues is enhanced by exposure to olfactory cues. A subsequent study indicated that immature GWSS could learn to associate novel odors with the presence of host plants. Prior to these studies, virtually nothing was known about the possible role of olfactory cues in the host-plant searching behavior of GWSS. An enhanced understanding of host-plant-finding behavior in GWSS will help in the development of management strategies, such as trap-cropping. (NP 304 Component IV, Postharvest, Pest Exclusion, and Quarantine Treatment, Problem Area: IVD, Fundamental Biology and Ecology of Exotic Pest Insects) 6.Technology Transfer Number of non-peer reviewed presentations and proceedings 21 Number of newspaper articles and other presentations for non-science audiences 3 Review Publications Goolsby, J., Bextine, B., Munyaneza, J.E., Setamou, M., Adamczyk Jr, J.J., Bester, G. 2007. Seasonal abundance of sharpshooters, leafhoppers, and psyllids associated with potatoes affected by zebra chip disorder. Subtropical Plant Science. 59:15-23. Moran, P.J. 2006. Water nutrients, plant nutrients, and indicators of biological control on waterhyacinth at Texas field sites. Journal of Aquatic Plant Management. 44:109-115.