Efficacy of Natural Insecticidal Mixtures against Major Soil Insect Pests of Potato (Solanum tuberosum L.) and their Impact on Soil Health in Jorhat, Assam, India
摘要
The use of synthetic insecticides on soil-dwelling insect pests in potato cultivation has resulted in long-term ecological threats, including pest resurgence and detrimental effects on soil health, microbial biomass, and broader environmental and human health issues. To address these challenges, the present study evaluated 14 naturally available eco-friendly insecticidal materials against three major soil pests of potato, viz. Agrotis ipsilon (cutworm), Lepidiota mansueta (white grub) and Dorylus orientalis (red ant) under laboratory conditions. The materials were categorized into four groups (Physical poisons, Bio-pesticides & bio-enhancer, Botanicals, and Minerals) based on their properties resulting in the selection of 11 effective insecticidal materials. Subsequently, 15 empirical combinations were formulated, from which five mixtures (Mixture-II, IV, VIII, XI, and XIII) consistently demonstrated the highest insecticidal activity across all target pests. Among these, Mixture-XI (mustard oil cake + cow urine + wood ash + pongamia seed powder + sawdust) applied at 250 kg ha⁻1, exhibited notable efficacy comparable to standard synthetic insecticides (malathion 5% dust and chlorpyriphos 20 EC) while significantly reducing pest damage under soil-amended conditions. In addition, soil treated with these mixtures showed improved microbial biomass and favourable changes in physicochemical properties, including enhanced organic carbon and nutrient availability, and reduced bulk density. Overall, the study highlights the potential of integrating organic and naturally derived materials into pest management strategies as sustainable alternatives to chemical insecticides, offering effective pest suppression while supporting long-term soil health and agricultural productivity.