![]() Based on these findings, our research will focus on understanding which chemicals are the most beneficial for maintaining a minimal impact on important parasitoids on citrus and grapes. Future tests will measure the amounts of imidacloprid and thiamethoxam that are on the surface of citrus leaves affecting the survival of the parasitoids using ELISA. ashmeadi for 3-4 days post-treatment while chlorpyrifos was quite toxic within 24 h to both G. Fenpropathrin, a pyrethroid, was not toxic to G. However, systemic treatments of citrus and willow leaves infested with parasitized GWSS eggs did not impact the emergence of parasitoids significantly, suggesting they are relatively safe to the parasitoids while they are within the GWSS eggs. Both imidacloprid and thiamethoxam when applied systemically through uptake in citrus leaves were found to be toxic to adult Gonatocerus ashmeadi and Aphytis melinus. ![]() To enhance control of the glassy-winged sharpshooter (GWSS), relative toxicity of neonicotinoids, imidacloprid and thiamethoxam, and other conventional insecticides, chlorpyrifos, cyfluthrin and fenpropathrin, was examined to assess compatibility with parasitoids while being toxic to GWSS. Few predators were observed on the yellow sticky cards. Seasonal patterns were obvious with higher parasitoid numbers in summer compared to fall collections with a parasitism rate at >90% based on the egg collection method. Relative numbers of the pest (GWSS) and beneficials (Gonatocerus ashmeadii, Gonatocerus triguttatus and Ufens spp.) varied based on the sampling method. Relative numbers of GWSS and its natural enemies from Riverside were determined using two sampling methods, collection of fresh GWSS egg masses on two host plants (citrus and willow) and using yellow sticky cards. Further research is underway to determine how the parasitoids are exposed to the two systemics. Results indicated the presence of varying levels of these two compounds in the parasitoids as well as in citrus leaves suggesting that although parasitoids are non-plant feeders, they were exposed to the systemic chemicals. To understand these bioassay results with the two systemics, further studies included the quantification of imidacloprid and thiamethoxam in both the parasitoids and the test citrus leaves by ELISA kits. Results from laboratory studies suggest that both systemics, imidacloprid and thiamethoxam, may not preserve these parasitoids as much as expected. ![]() In additional studies, higher concentrations of imidacloprid and thiamethoxam were found to be toxic over time to two predators, Geocoris punctipes and Orius insidiosus. All insecticides tested were highly toxic to A. Results from this study allow ranking of the eight insecticides based on their increasing toxicity as follows for Gonatocerus spp.: fenpropathrin > pyriproxyfen > buprofezin > imidacloprid > thiamethoxam > acetamiprid > bifenthrin > chlorpyrifos. Our results indicated that a number of insecticides tested are toxic to the egg parasitoids, Gonatocerus spp., as well as to A. Survivorship of adult parasitoids on citrus leaves with residues of these insecticides (within Petri dishes) was determined after 24, 48 and 72h. Most of the selected insecticides tested are used against GWSS and other pests on citrus and grapes. melinus), an endoparasitoid of armored scale insects found on citrus in California. The toxicity of two insect growth regulators (IGRs), buprofezin and pyriproxyfen three neonicotinoids, acetamiprid, imidacloprid and thiamethoxam and three conventional insecticides, bifenthrin, fenpropathrin, and chlorpyrifos were tested in the laboratory for compatibility with egg parasitoids (Gonatocerus ashmeadi, Gonatocerus triguttatus) of glassy-winged sharpshooter (GWSS), Homalodisca coagulata and against Aphytis melinus (A.
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