A Comparative Study of Manual and Drone-based Granular Insecticide Application Impact on Beneficial Population Dynamics in Rice

Abstract

Aim: Evaluation of the effects of application of granular insecticides manually vis a vis drone on coccinellids and spiders in rice fields. Place and Duration of Study: Main Farm, Agricultural Research Institute, Professor Jayashankar Telangana Agricultural University (PJTAU), Rajendranagar, Hyderabad during kharif 2024 (wet season. July-November). Methodology: Rice variety Telangana Sona (RNR 15048) was used for the study and granular insecticides recommended for management of lepidopteran pests (Table 2&3) were applied either manually or using drone at 30 days after transplanting (DAT), after pest populations reached the economic threshold level (ETL). Application of granular insecticides was made twice at an interval of 14 days. Observations were recorded before application and at 7 and 14 days after each granular insecticide application. Results: The study showed that both the drone and manual application of granular insecticides led to a temporary decline in beneficial arthropods, such as coccinellids and spiders, at 7 days post-application. However, populations recovered within 14 days (two weeks), non-significant differences were noticed between treated and untreated plots Among the insecticides tested, chlorantraniliprole 0.5% + thiamethoxam 1.0% GR and chlorantraniliprole 0.4G exhibited the least adverse effects, promoting better retention of natural enemies. Conclusion: These findings indicate that drone-based granular insecticide application is an efficient and environmentally sustainable alternative over manual application of granular insecticide.