Integrating Wheat Cultivar And Fenitrothion For Control Of Sunn Pest (Eurygaster Integriceps Put)

The rate of sensitivity of nymphs and adults of Eurygaster integriceps put., fed on wheat cultivar falat, to fenitrothion insecticide was studied. The main objective of this study was to determine the possibility of integrating wheat cultivars with fenitrothion in an integrated sunn pest(E. integriceps) management programme. The experiments were conducted in laboratory and field in varamin during 1998-9 The sensitivity of 4th and 5th instar nymphs and new adults reared on falat to insecticide fenitrothion (a.i=50%) was enhanced, compared with those on sardari. LC50 of insecticide on all three life stages of insects fed on falat was less than sardari. The LC50 of insecticide on all three life stages of insects fed on falat was less than sardari. The LC50 of insecticide on sardari and falat for 4th instar nymphs was 42.16 and 33.48, for 5th instar nymphs was 147.03 and 114.01 and for new adults was 303.35 and 227.88 ppm, respectively. Therefore LC50 of insecticide for 4th and 5th nymphs and new adults fed on falat was reduced about 20,22 and 25 percent, respectively, compared with those on sardari. The results also showed that by increasing the life stages of insects reared on falat, the rate of sensitivity to insecticide was enhanced. The comparison of MRGR for 4th and 5th instars reared on falat and sardari with and without using sublethal doses of insecticide showed that there was synergism between falat and fenitrothion. sardari/falat ratio of MRGR with and without using insecticide for 4th nymphs was 1.53 and 1.23 and for 5th nymphs was 2.02 and 1.34, respectively.