Comparative Susceptibility of Adult African Invader Fly Bactrocera invadens (Diptera: Tephritidae) to Some Selected Insecticides in Ghana

With the recent introduction of B. invadens in Africa and its devastating role in crop production, especially mango, with currently no registered insecticides for use against this fly in Ghana, the susceptibility of the fly to four commercially available insecticidal products namely, Cydim Super, Pyrinex 48 EC, Diazol 50 EW and Deltapaz was evaluated in the laboratory. The bioassay was conducted using three (3) different doses of each insecticidal product, by dipping 4x4 cm hardboard panels into the respective doses. Susceptibility of the flies to insecticides were assessed on freshly treated panels, 3-day-old and 6-day-old treated panels in some ventilated transparent bottles of 1 litre capacity. Adult flies aged between 4-12 days were used for the bioassays. The bioassay results indicated that the adult flies were more susceptible to Diazol (Diazinon) (LC50 = 0.6 ml/L; LC90 = 1.3 ml/L) and Pyrinex (Chlorpyrifos) (LC50 = 0.8 ml/L; LC90 =1.0 ml/L), and hence gave the least LT50 and LT90 times. Least susceptibility was recorded with Deltapaz (Deltamethrin) (LC50 = 3.1 ml/L; LC90 = 5.2 ml/L). It could be concluded that the control of B. invadens can be achieved more effectively by the use Pyrinex (Chlorpyrifos) and Diazol (Diazinon). The use of Pyrinex appears to be more economical to the resource poor farmers as it had least LC90 of 1.0 ml/L compared to 1.3 ml/L for Diazol in 30 min.