Invasive Species Compendium

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Abstract

The effects of some biorational insecticides on immature stages of Tuta absoluta and tomato yields under field conditions.

Abstract

In this study, the effects of the biorational insecticides, azadirachtin (neem) from Azadirachta indica A. Juss, Bacillus thrungiensis var. kurstakii Berliner and the entomopathogenic nematode, Heterorhabtidis bactheriophora Poinar, were compared with product containing the synthetic insecticide, chlorantraniliprole (CTPR)+abamectin, against the immature stages of the tomato leaf borer, Tuta absoluta Meyrick under field conditions during the 2014 and 2015 tomato-grown seasons. In 2014, the T. absoluta infestation rates were 11.27, 12.86, 15.16 and 7.94%, as per the order of insecticides given above. In 2015, these values (in the same order) were 3.11, 3.72, 5.22 and 2.61%. For the 2014 and 2015 tomato growing-seasons, the infestation rates were 15.08% and 4.72%, respectively, in the control plots which had received no pesticideapplications against T. absoluta. In 2014, the tomato yields for azadirachtin, B. thuringiensis var. kurstakii, H. bacteriophora, CTPR+abamectin treatments and the control treatment were 4.19, 3.91, 4.64, 5.02 and 3.62 kg/plant, respectively. In 2015, in the same order, these yields were 1.76, 1.62, 1.41, 1.97 and 1.52 kg/plant. Across both years, the synthetic insecticides (CTPR+abamectin) had the highest effect against T. absoluta, followed by azadirachtin, B. thuringiensis var. kurstakii and H. bacteriophora.