Effect of some important insecticides on the pupal stages of five ecotypes of Trichogramma chilonis Ishii

Six insectiddes, viz, carbaryl, phosphamidon, monochrotophos, methyl parathion, quinalphos and endosulfan were evaluated as, contact poisons against the pupal stages of five ecotypes of Trichogramma chilonis Ishii. These were collected from groundnut, potato, maize, green gram (mung) and Lantana sp. The LC₅₀ and ‘t’ values showed that methyl parathion was the most toxic to all the ecotypes foliowed by quinalphos, while phosphamidon was the least toxic. Carbaryl, monocrotophos and endosulfan showed intermediate range of toxicity to the ecotypes. In general, ecotypes I, III, and V collected from groundnut, maize and Lantana sp., respectively, exhibited considerable tolerance to insecticidal treatments. Ecotypes I(groundnut) and I11 (maize) showed exceptional tolerance to methyl parathion, whereas ecotypes III (maize), IV (mung) and V (hnbna sp.) revealed tolerance to quinalphos. The findings suggest the possibility of utilizing dimerent ecotypes of T. chilonis under variable insecticide stress situations.