EVALUATION OF INSECTICIDE RESISTANCE IN TWO STRAINS OF FRUIT FLY, BACTROCERA ZONATA (SAUNDERS) (TEPHRITIDAE: DIPTERA), WITH FRUIT DIP METHOD

Present study was conducted to determine the level of insecticide resistance in five insecticides, viz., malathion, trichlorfon, lambda-cyhalothrin, spinosad and bifenthrin, commonly being used for the control of fruit flies, in two field strains of fruit fly, bactrocera zonata (saunders) (tephritidae: diptera) by using fruit dip bioassay method under laboratory conditions. response data were collected at 24 and 48 hours after releasing graved females in the cages having fruits dipped in appropriate concentrates of each insecticide. results showed that b. zonata from multan and faisalabad zones were resistant to trichlorfon, malathion, lambda-cyhalothrin and bifenthrin ranging 3-19 fold, however, population from these places were susceptibility to spinosad. malathion registered resistances ratio (3-6 fold) less than bifenthrin (8-11 fold), trichlorofon (10-19 fold) and cyhalothrin (4-9 fold). the data suggest that b. zonata has developed resistance to trichlorfon and indicate a danger for its use as cover spray and in baits.