Submitted to: Florida Entomologist
Publication Type: Peer reviewed journal
Publication Acceptance Date: 8/23/2005
Publication Date: 3/1/2006
Citation: Ulmer, B.J., Lapointe, S.L., Pena, J.E., Duncan, R.E. 2006. Toxicity of pesticides used in citrus to Aprostocetus vaquitarum (Hymenoptera: Eulophidae), an egg parasitoid of Diaprepes abbreviatus (Coleoptera: Curculionidae). Florida Entomologist. 89(1):10-19. Interpretive Summary: Integrated Pest Management (IPM) requires analysis of the impact of crop management actions such as pesticide applications on biological control agents. We are currently engaged in release and establishment in Florida of egg parasitoids from the Caribbean for the control of the Diaprepes root weevil, a major pest of citrus and ornamental plants. This study reports the toxicity of a number of commonly used chemical pesticides towards an egg parasitoid, Aprostocetus vaquitarum, that was released in 7 Florida countries between 2000 and 2003. In that time, this species has become established in southern Florida. The effect of the pesticides tested ranged from highly toxic (Sevin 80WSP, Malathion 5EC, and Imidan 70WSB) to less toxic or harmless (Kocide 101WP, Citrus Soluble Oil, Micromite 80WGS, Acramite 50WS, Micromite 80WGS + Citrus Soluble Oil, Aliette WDG and Agrimek 0.15EC + Citrus Soluble Oil). This provides citrus growers with information upon which to base product choice decisions that will minimize disruption of biological control for the Diaprepes root weevil.
Technical Abstract: Twelve pesticides used in citrus were tested for their contact toxicity to Aprostocetus vaquitarum Wolcott (Hymenoptera: Eulophidae) a parasitoid of Diaprepes abbreviatus L. (Coleoptera: Curculionidae). Sevin 80WSP, Malathion 5EC, and Imidan 70WSB resulted in the most rapid death of A. vaquitarum adults. Admire 2F, Danitol 2.4EC, and Surround WP were also very harmful. Kocide 101WP, Citrus Soluble Oil, Micromite 80WGS, Acramite 50WS, Micromite 80WGS + Citrus Soluble Oil, Aliette WDG and Agrimek 0.15EC + Citrus Soluble Oil were less toxic to harmless. The relative toxicity of the pesticides was consistent up to four weeks after application. Significanlty fewer adult A. vaquitarum emerged from D. abbreviatus eggs laid on foliage treated in the field with Sevin XLR and Imidan 70WSB than emerged from the water treated control, Sevin XLR remained toxic for seven days in the field while the effects of Imidan 70WSB were no longer significant after one week. The number of A. vaquitarum emerging from host eggs laid on treated foliage was not significantly different among Micromite 80WGS, Acramite 50WS and the control but significantly fewer adults emerged from foliage treated with either Micromite 80WGS + Citrus Soluble Oil or Citrus Soluble Oil alone. There were no significant differences between oviposition or new generation adults for females exposed to Micromite 80WGS and those exposed to a water control.