Sub-lethal Dose Reponses of Native Polyhydroviruses and Spinosad for Economical and Sustainable Management of Spodoptera litura in Pakistan

Abstract

In the present investigation, laboratory trials were conducted to investigate the synergistic, additive or antagonistic effect of three sub-lethal dose rates (2 x 10 3 , 4.5 x 10 3 , and 6 x 10 3 PIB/Larva) of native isolated Nucleopolyhydrovirus (NPV) from Spodoptera litura and Spinosad (0.01 ppm) against 3 rd and 4 th instar larvae collected from three different geographical areas of Punjab (Pakistan). A difference in larval mortality, pupation, adult emergence and egg ecluson was observed. The higher but sub-lethal dose rate of NPV with Spinosad exhibited synergistic interaction, while the rest of the combinations were found additive in all the tested populations. The results confirmed the population of S. litura from Rahim Yar Khan Region least susceptible, and that of Faisalabad highly susceptible. It may be inferred that the mixtures of the correct sub-lethal doses of Spinoad and NPV in combination may be used against destructive pests such as S. litura. This strategy also has a great potential in insecticide resistance management (IRPM) against such pests in vegetable and major crop growing areas of Pakistan.