Spinosad combined with entomopathogenic nematode for biocontrol of the Mediterranean fruit fly (Ceratitis capitata [Wiedemann]) on citrus

Abstract

Background Cultivation of citrus (Sapindales: Rutaceae) crops is continuously expanding in Egypt given the favorable ingredients of citriculture. Notwithstanding the Egyptian rank as the world s largest orange exporter, the Mediterranean fruit fly (Medfly), Ceratitis capitata (Wiedemann) (Diptera: Tephritidae), is one of the major pests that considerably reduces the quality of citrus crops. Contrary to hazardous organophosphate insecticides that are commonly used to control the Medfly, biologically-based C . capitata control tactics were tried herein. The effect of spinosad as a bacterial fermentation product and the nematode Steinernema riobrave as biological insecticides applied singly or in combination on laboratory and field strains of Medfly were investigated. Results A significant difference in LC 50 values was observed between laboratory strain (4.78 PPM) and field strain (8.12 PPM) of C . capitata larvae exposed to spinosad . A 1.7 fold decrease in susceptibility of field strain was recorded after treatment with spinosad. In a field experiment, a reduction in Medfly population by 80, 37, and 92% for spinosad, S . riobrave , and spinosad\u2009+\u2009nematode treatments was recorded, respectively. Conclusions Utilization of spinosad- S . riobrave combination in citrus fields, as a novel alternative for unhealthy chemical insecticides to control C . capitata in Egypt can be suggested. Use of this combination should be incorporated into a holistic management package that can be economically feasible and environmentally sustainable for Egyptian agriculture.