Selectivity of acaricides to Neoseiulus barkeri (Hughes) (Acari: Phytoseiidae)

Abstract

AbstractNeoseiulus barkeri Hughes has been used to control several pests, including the red palm mite, Raoiella indica Hirst. However, in some situations, the exclusive use of biocontrol agents is not sufficient to prevent the damage caused by pests. In these scenarios, the integration of chemical and biological controls is desired. For that purpose, the determination of selective acaricides, avoiding or reducing deleterious effects on the biological control agent is desirable. This study evaluated the lethal and sublethal effects of acaricides (abamectin, azadirachtin, fenpyroximate and pyridaben) on the predatory mite N. barkeri. We investigated the toxicity and selectivity of the acaricides and the survival, fertility, egg viability and instantaneous growth rate (ri) of N. barkeri exposed to acaricides. Additionally, we classified the acaricides according to the scale proposed by the International Organization for Biological Control (IOBC). Among the acaricides evaluated, abamectin was selective for N. barkeri because the estimated lethal concentration (LC50) for N. barkeri was higher than that for R. indica. None of the acaricides affected predator survival curves. However, azadirachtin and fenpyroximate reduced the average predator survival time. Pyridaben was the only acaricide that reduced the fertility of N. barkeri females and, consequently, their instantaneous growth rate (ri). All the acaricides affected the viability of N. barkeri eggs. Pyridaben was classified as moderately harmful, whereas other acaricides were classified as harmless.