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

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 LC50 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 + nematode 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.