Evaluation of Bio-Pesticides against the South American Tomato Leaf Miner, Tuta absoluta Meyrick (Lepidoptera: Gelechiidae) in India

Abstract

Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) is one of the most economically important pests of tomato worldwide. Despite its global importance, the management of this oligophagous pest has still been a challenging task, due to its high capability to develop resistance against synthetic insecticides. Given the limited studies on the effectiveness of different bio-pesticides in India, the objective of this research was to determine the pathogenicity of different commercial formulations of Beauveria bassiana, Bacillus thuringiensis, and neem (Azadirachtin), against T. absoluta, under laboratory and field conditions. For the Bacillus thuringiensis formulations, Green Larvicide® and Delfin® recorded an LC50 of 4.10 × 10⁹ CFU/mL and 8.06 × 106 spores/mg, respectively, while for the B. bassiana formulations, Green Beauveria® and BB Power® were 4.473 × 107 spores/mL and 1.367 × 107 CFU/g, respectively. Furthermore, the results showed high susceptibility to both the commercial neem formulations with Ecotin®, recording an LC50 of 91.866 ppm, and Econeem Plus® recording 212.676 ppm. The results from the field conditions at different locations of Andhra Pradesh, India, showed significant differences (p < 0.001) for leaf and fruit infestation among the interaction effect of treatments and locations. Bio-pesticides, especially neem and B. thuringiensis formulations, reduced T. absoluta infestation similarly to the chemical treatment, without affecting the yield. Therefore, bio-pesticides can be considered as safe alternatives to synthetic pesticides, for the management of T. absoluta.