Entomopathogenic fungi as biological control agents of Phyllocoptruta oleivora (Prostigmata: Eriophyidae) under greenhouse conditions

摘要

The citrus rust mite, Phyllocoptruta oleivora Ashmead (Acari: Eriophyidae), is a major pest of citrus, affecting both quality and yield. Although entomopathogenic fungi such as Beauveria bassiana (Bals.-Criv.) Vuill. (Cordycipitaceae), Metarhizium anisopliae (Metschn.) Sorokīn (Clavicipitaceae), and Isaria fumosorosea Wize (Cordycipitaceae) have been used for insect and mite control, the last 2 have never been applied to control citrus rust mite. The aim of this study was to evaluate the effect of 3 concentrations of B. bassiana, M. anisopliae, and I. fumosorosea on mortality and growth rate (r) of P. oleivora populations under greenhouse conditions. The fungi were isolated from agricultural soil samples. Mobile stages of P. oleivora were collected from leaves of commercial Valencia orange groves. At a concentration of 1 × 108 conidia mL-1, B. bassiana and M. anisopliae caused > 60% mortality in P. oleivora populations, whereas mortality due to I. fumosorosea never exceeded 50%. There was a significant inverse relationship between the percent mortality and the LT50. Application of B. bassiana resulted in the slowest growth rate of P. oleivora populations, which was 10.5 × slower than the control population receiving no fungus application. Our results demonstrate that B. bassiana and M. anisopliae are efficient in control of P. oleivora populations under greenhouse conditions, whereas I. fumosorosea produces moderate control.