Effects of five insecticides used in apple orchards on Hyaliodes vitripennis (Say) (Hemiptera : Miridae)

Azinphos-methyl, carbaryl, dimethoate, phosmet and phosalone were used in a pple orchards to manage apple aphid, apple maggot, woolly apple aphid and l eaf eating caterpillars. Among the five insecticides evaluated, dimethoate, carbaryl and azinphosmethyl were the most toxic to the nymphs and adults o f Hyaliodes vitripennis (Say) from two regions. Phosalone was the least tox ic, Nymphs were more resistant than the adults. While the LC50 for dimethoa te was 130 ppm for nymphs, it was 3 ppm for adults from St. Jean-Baptiste-d e-Rouville. There were also significant differences in the level of resista nce between the two regions where the H. vitripennis were collected. At St. Alexandre the LC50 for phosalone on nymphs was 19, 250 ppm whereas, at St. Jean-Baptiste-de-Rouville it was 160, 000 ppm.