Thesis (M.Sc.) - Cairo University - Faculty of Agriculture - Department of Economic Entomology and Pesticides

The tomato leaf miner, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), is a destructive pest affecting the tomato crop causing a loss of 60{u2013}100% of the tomato crop production. In the present study, the lethal and sub-lethal effects of Bacillus thuringiensis (Bt), spinosad, and emamectin benzoate as bio-insecticides comparing with 2 synthetic insecticides: chlorpyrifos and indoxacarb against T. absoluta under laboratory and field conditions were evaluated. Take in consideration, life tables and reproductive parameters of treated larvae with LC30 for each pesticide (bio and chemical -insecticides) by using leaf dipping technique were calculated. The results showed that Bt formulation of Lepinox plus was the most effective one against the early 2nd instar larvae with LC50 of 0.01 {u00D7} 10⁻² ppm, followed by spinosad with 0.07 {u00D7} 10⁻² ppm comparing to indoxacarb and chlorpyrifos (0.01 and 11.44 ppm, respectively). Sub-lethal effect of the Bt formulations significantly increased the pupal mortality by 29.77, 33.30, and 26.94% for Lepinox plus, Dipel 2{u00D7}, and Protecto, respectively. In addition to their efficiency, Bt formulations and emamectin benzoate increased the larval developmental period and reduced adult emergency percentage to 70.28, 66.70, 73.06, and 75.55% for Lepinox plus, Dipel 2{u00D7}, Protecto, and emamectin benzoate, respectively. Under field conditions all treatments had gained a significant reduction against T. absoluta populations in two different Governorates (Giza, and Qualybia) and crop yield quality. Emamectin benzoate was the efficious treatment followed by Bt formulations and spinosad. As well as, Bt formulations have proved no hazard effect towards the natural enemies. All bio-insecticides including Bt formulations, spinosad, and emamectin benzoate caused abnormalities in different life stages. Furthermore, the residue of emamectin benzoate in tomato fruits declined rapidly and has shorter half-life value compared with chemical insecticides.The results suggest that bio-insecticides are promising alternatives to synthetic insecticides for T. absoluta management

Issued also as CD