Determination of Level of Insecticide Resistance in Fruit Fly, Bactrocera zonata (Saunders) (Diptera: Tephritidae) by Bait Bioassay

In order to determine the level of resistance in fruit fly (Bactrocera zonata) to different insecticides mostly used in the field for fruit fly control, bait bioassays were conducted by using insecticides in protein hydrolysate. Adult fruit flies were collected from Multan area exposed to bait and compared with a laboratory reared population of B. zonata. Insecticides included in the bioassays were, Talstar 10 EC, Confidor 70WS, Curacron 50 EC, Deltamethrin 2.5 EC, Diptrex 80 WP, Proclaim 1.9 EC, Karate 2.5 EC, Malathion 57 EC, Tracer 240 SC, Steward 360 SC. Each treatment was repeated three times. The mortality in adult flies was noted at 24 and 48 h after the treatment application and LC50 values were estimated using Probit analysis (Polo Plus). These values of field and susceptible populations were compared to determine the level of resistance. The results revealed that the field strain exhibited varying ratios of insecticide resistance; being highest against Diptrex (65.32) followed by Curacron (13.20), Confidor (7.12), Talstar (5.97), Karate (5.73), Malathion (5.54) and Deltamethrin (2.35) at 24 h. The difference in LC50 of Proclaim and Tracer between two strains was non-significant at 24 and 48 h after treatment. (C) 2011 Friends Science Publishers