Naturally Available Insecticidal Materials and their Mixtures: An Eco-friendly Approach for the Management of Soil Dwelling Insect Pests of Potato

The persistent use of synthetic insecticides against the soil-dwelling insect pests in potato may initially give some control against these pests, but in the long term, it will pose a threat to the ecosystem causing the resurgence of other pest species. Moreover, indiscriminate use of insecticides and their residues in the soil and plant system are causing hazardous effects on the Soil Microbial Biomass Carbon (SMBC), soil physico-chemical properties, soil enzymatic activities, beneficial insect fauna, human and animal health as well as environment. Furthermore, considering the present pest management scenario, there is an urgent need to embrace organic pest management strategies instead of chemocentric approaches. The aim of the study was to evaluate the effectiveness of some naturally available insecticidal materials against major soil insect pests of potato under laboratory conditions. During the study, locally and naturally available eco-friendly insecticidal materials (14 nos.) were collected and categorized into four groups (Physical poisons, Biopesticides & bio-enhancer, Botanicals and Minerals) based on their different properties. Individual screening of these 14 individual insecticidal materials was carried out under laboratory conditions against the test insects i.e. cutworm (Agrotis ipsilon), white grub (Lepidiota mansueta) and red ant (Dorylus orientalis). Based on the performance of 14 individual insecticidal materials, 11 insecticidal materials were selected and 3 materials (cow dung powder, lime powder and rock phosphate) were discarded. From 11 insecticidal materials, 15 mixtures (Mixture I-XV) were prepared by following the "Trial and Error" method. Considering the efficacy performance of these 15 insecticidal mixtures against the above-mentioned test insects, 5 superior insecticidal mixtures (Mixture-II, IV, VIII, XI and XIII) were selected. Highest mortality (100%) of A. ipsilon larvae was recorded in Mixture-II, Mixture-IV, Mixture-VIII, Mixture-XI and Mixture-XIII and found to be significantly superior over rest of the mixtures after 144 hrs of exposure (P=.05, CD=4.44). A similar trend of results was also registered against L. mansueta grubs. Likewise, significant mortality of D. orientalis was recorded in Mixture-II, Mixture-IV, Mixture-VIII, Mixture-XI and Mixture-XIII over the other mixtures (I, V, VI, VII, X, XIV & XV) after 48 hrs of exposure (P=.05, CD=17.42). This research relates to the development of organic insecticidal mixtures by using naturally available eco-friendly insecticidal materials with an aim to address the soil dwelling insect pests problems in potato grown organically. However, these organic insecticidal mixtures will act as ‘bioenhancers’ favouring the multiplication of beneficial soil microbes and other microarthropods besides improving the physico-chemical properties of soil and might be used to replace the commonly used synthetic insecticides. Exploration of these findings has enough scope for researchers to study the efficacy of these mixtures at field conditions against soil-dwelling insect pests with an aim to replace the commonly used synthetic insecticides. Farmers can reduce their reliance on synthetic pesticides and implement a more resilient and sustainable IPM strategy by combining these mixtures with biological, cultural and mechanical control techniques.