Side-effects of some insecticides used in citrus cultivation on the egg parasitoid Trichogramma cacoeciae Marchal immature stages
Hached Wiem, Chamkhi Amal and Lebdi-Grissa Kaouthar
In order to monitor Ectomyelois ceratoniae Zeller (Lepidoptera: pyralidae) in citrus orchards, an integrated pest management (IPM) approach is needed. However, this control method implies the releases of natural enemies such as Trichogramma species besides to pesticides spraying which represents a potential risk for the useful fauna. Thus, the aim of this study is to investigate the side effects of six insecticides commonly used in citrus fields on the Trichogramma cacoeciae Marchal immature development stages. In the National Agronomic Institute of Tunisia, laboratory studies were carried out in May 2016. Two biological (Spinosad and Bacillus thuringiensis) and four chemical (Abamectin, Dimethoate, Malathion and Chlorpyriphos-ethyl) treatments were tested under laboratory conditions (25±1°C; 60±10% RH; L/D: 16/8) on T. cacoeciae immature development stages (larvae, prepupae and pupae). According to the International Organization of Biological Control (IOBC), the results obtained confirmed that Spinosad treatment was more toxic when applied on the larvae stage compared to prepuape and pupae stages. Whereas, Abamectin, Dimethoate and Bacillus thuringiensis treatments have a slightly harmful effect on T. cacoeciae independently of the development stage. However the Malathion effect, varied according to the immature stage on which it was applied on. Concerning Chlorpyrifos-ethyl, this chemical treatment was harmful towards all the development stages of the tested Trichogramma species. These findings will allow determining the proper time of treatments spraying to preserve the useful fauna.
Hached Wiem, Chamkhi Amal, Lebdi-Grissa Kaouthar. Side-effects of some insecticides used in citrus cultivation on the egg parasitoid Trichogramma cacoeciae Marchal immature stages. J Entomol Zool Stud 2017;5(6):2176-2178.