Author(s)

Imen Blibech^1*, Mohieddine Ksantini¹, Taieb Jardak¹, Mohamed Bouaziz²

¹Laboratory of Genetic Resources Improvement and Protection of Olive Tree, Olive Tree Institute, Sfax, Tunisia.
²Electrochemistry and Environment Laboratory, National School of Engineers of Sfax, University of Sfax, Sfax, Tunisia.

This study investigated the direct effect of the insecticides deltamethrin and spinosad on three egg parasitoids species: Trichogramma oleae, T. cacoeciae and T. bourarachae. The parasitoid pupae were exposed to pesticide residues on fresh olive tree leaves at recommended concentrations (RC) at different time intervals: 3, 10, 17, 24 and 31 days after pesticide applications. Parasitism viability (% emergence from parasitized eggs) and adult emergence time (developmental time from pupa to adult emergence) were evaluated. Regarding to the International Organization of Biological Control (IOBC) guidelines, results of toxicity effects of insecticides show that: Deltamethrin was moderately harmful to all Trichogramma species at RC (Decis^® 100 milliliters·ha⁻¹), however, spinosad was harmless to moderately harmful at RC (Tracer^® 20 milliliters·ha⁻¹). Trichogramma species revealed differences with regard to adult emergence time and exhibited significant changes in parasitism viability with increasing time after pesticide treatment. While deltamethrin residues affected parasitism viability 31 days after the product application, spinosad displayed similar viability for almost species 24 days after the application. The usefulness of Trichogramma parasitoids used as biological control agents, in olive tree ecosystem, was discussed in integrated pest management programs for Prays oleae control when parasitoid species were exposed during pupal stage to the insecticide residue.

Insecticide Effect, Trichogramma Species, Olive Tree, Parasitism Viability, Emergence Time

Blibech, I. , Ksantini, M. , Jardak, T. and Bouaziz, M. (2015) Effect of Insecticides on Trichogramma Parasitoids Used in Biological Control against Prays oleae Insect Pest. Advances in Chemical Engineering and Science, 5, 362-372. doi: 10.4236/aces.2015.53038.