Evaluation of the Efficacy of Bio Rational Pesticides for Eco Friendly Management of Leaf Curl Complex in Chili (Capsicum annum)
Anuruddhika Rajapaksha, Bandula Ranaweera, Indika Karunarathna and Susantha Somasiri
Abstract
Background: Leaf curl complex can be identified as a major disease found in most of the Solanaceous vegetable crops, including green chili. Thrips (Scirtothrips dorsalis H.) and white flies (Bemisia tabaci) are the major vectors responsible for the spread of Leaf curl complex. Farmers tend to use synthetic chemicals as the main control method of this disease. Continuous use of synthetic insecticides results in serious health and environmental hazards. Therefore, application of bio rational pesticides is one of the best alternatives for it. This experiment was conducted to evaluate the efficiency of six bio rational pesticides for the control of leaf curl complex in chili.
Methods: A combination of natural plant extract (T2), Neem (Azadiractin) based product (T3), Beauveria bassiana based product (T4), Metarhizium anisopliae based product (T5), Saccharopolyspora spinosa based product (Spinosad) (T6) and a combination of Beauveria bassiana and Metarhizium anisopliae based product (T7) were applied to chili plants, starting from three weeks after transplanting, while control (T1) remained without any pesticide application. The Disease Incidence (DI) and Disease Severity Index (DSI) were calculated for each treatment.
Results: Mean DSI and DI values reported significant differences among the treatments (P<0.05). The control treatment recorded the highest DSI value (44.3±2%), while the treatment 6 (Spinosad) recorded the lowest DSI value (31.1±4%). Similarly, the control plot recorded the highest DI (73.6±1%) value, while T6 (Spinosad) plot recorded the lowest DI value (58.8±3%). Spinosad bio rational pesticide (T6) showed a significantly lower disease severity and disease incidence.
Conclusions: Based on the overall findings, Spinosad bio rational pesticide (T6) was identified as the bio rational with a high potential to control leaf curl complex in chili. Further studies are suggested to optimize the effect and minimize the hazard to pollinators.
Keywords: Bio Rational, Green Chili, Leaf Curl Complex, Saccharopolyspora spinosa