Laboratory-based toxicological assessments of new insecticides on mortality and fecundity of Neoseiulus fallacis (Acari: Phytoseiidae)

Abstract

Neoseiulus fallacis (Garman) is one of the most abundant predatory phytoseid in deciduous fruit orchards under an integrated pest management (IPM) regimen in eastern North America. Laboratory studies using N. fallacis, and the 'modified excised leaf disc method' identified four insecticides out of six, that would require second-tier field studies before inclusion in an IPM program for deciduous orchards. The overall egg mortality caused by flubendiamide, chlorantraniliprole, chlothianidin, novaluron, Spinetoram, and spirotetramat ranked from 0 to 37.6%. Larval mortality caused by spirotetramat, spinetoram, novaluron, and chlothianidin ranged from 100 to 78.3%, respectively. Chlorantraniliprole and flubendiamide were virtually nontoxic to larvae. Spinetoram, chlothianidin, and spirotetramat caused 100, 61.4, and 40.2% mortality of adult N. fallacis, respectively. Spirotetramat and chlothianidin significantly reduced fecundity, whereas novaluron, flubendiamide, and chlorantraniliprole had no such adverse effect for the duration of the study (168 h). Chlorantraniliprole and flubendiamide do not require further second tier field studies and may be included in deciduous orchard IPM programs. Spirotetramat is toxic to several growth stages but it has a very short residual activity, and along with novaluron, which is toxic only to larvae, should be evaluated in second-tier field studies. Clothianidin and spinetoram should be evaluated in second-tier field studies only if alternatives are unavailable.