Skip to main content
ARS Home » Research » Publications at this Location » Publication #174420
Title: COMPATIBILITY OF INSECTICIDES WITH NATURAL ENEMIES OF THE GLASSY-WINGED SHARPSHOOTER

Author
item TOSCANO, NICK - U CA, RIVERSIDE
item MORSE, JOSEPH - U CA, RIVERSIDE
item PRABHAKER, NILIMA - U CA, RIVERSIDE
item Castle, Steven
item Naranjo, Steven

Submitted to: CDFA Pierce's Disease Control Program Research Symposium
Publication Type: Proceedings
Publication Acceptance Date: 12/12/2004
Publication Date: 12/12/2004
Citation: Toscano, N.C., Morse, J.G., Prabhaker, N., Castle, S.J., Naranjo, S.E. 2004. Compatibility of insecticides with natural enemies of the glassy-winged sharpshooter. CDFA Pierce's Disease Control Program Research Symposium. pp. 378-381

Interpretive Summary: 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. Both imidacloprid and thiamethoxam when applied systemically through uptake in citrus leaves were found to be toxic to adult Gonatocerus ashmeadi and Aphytis melinus. 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. Fenpropathrin, a pyrethroid, was not toxic to G. ashmeadi for 3-4 days post-treatment while chlorpyrifos was quite toxic within 24 h to both G. ashmeadi and A. melinus. 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. 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.

Technical Abstract: 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. Both imidacloprid and thiamethoxam when applied systemically through uptake in citrus leaves were found to be toxic to adult Gonatocerus ashmeadi and Aphytis melinus. 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. Fenpropathrin, a pyrethroid, was not toxic to G. ashmeadi for 3-4 days post-treatment while chlorpyrifos was quite toxic within 24 h to both G. ashmeadi and A. melinus. 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. 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.