The effects of treatments against Bactrocera oleae (Gmelin) on the entomo-fauna of the olive ecosystem

Summary

Only a limited number of studies have examined the efficacy and environmental effects of treatments against Bactrocera oleae in organic production of olives, especially in terms of the insect community present in these ecosystems. Herein, we compared the effects of a conventional insecticide (dimethoate),used with a plant protection system allowed by organic legislation (mass trapping plus rotenone)against B. oleae , with an untreated control field . The experiments were performed in the Calabria region at Mirto Crosia (on the Ionic side of Cosenza province)in a grove with extensive active insect infestation. In two conventionally treated fields with a surface area of 2 hectares each, two treatments were performed (in August and September) utilizing dimethoate (150 g in 100 liters water). In another 2 hectare area, mass-trapping devices (attract and kill) were installed and treatment with rotenone (Rotena 300 g in 100 l water) was performed in September. The entomo-fauna present in the different areas was evaluated by insect capture utilizing cromotropic traps. The integrated protection system (mass-trapping plus rotenone treatment) led to a reduction in the total number of insects in comparison to the traditional method (dimethoate treatment). It proves the negative effect of the tested organic system on the olive ecosystem entomo-fauna.