Development of techniques for detecting resistance in crop pests to insecticides Dhingra Swaran, Sarup Prakash, Head Division of Entomology, Indian Agricultural Research Institute, New Delhi-110 012 (India). Abstract Various techniques have been in vogue for detecting resistance in crop pests to various insecticides. Out of various techniques, the leaf-residue method provides conditions almost siinilar to those prevailing in the field. The method is easy to handle, less labour intensive, and has an added advantage due to its direct insecticidal treatment in the field, thus circumventing the laboratory testing and at the same time simulating field conditions. Obviously, the applicability of this method of assessment for resistance management is now emerging. The results of this method were comparable with those obtained from direct spray and dip techniques. The base-line data for detecting resistance to insecticides in various crop pests was generated for nearly four decades in India. The utility of base-line data can be gauged in detecting resistance in seven important pests, viz, Galerucella birmanica Jacoby, Spodoplem litura (Fabricius), Plutella xyllostela Linn., Lipaphis erysimi Kalt, Myzus persicae Sulz., Heliothis armigera Hubner and Drosicha mangiferae Green. The importance of diagnostic dose lessens in cases where it is very high, being unrealistic practically as also in those pests, viz, Mylabris pustulata Thunb., Cylasformicarius Fabricius and Schistocera gregaria Forsk., where natural tolerance to insecticides exists. Top |