Bioassay, cross-infectivity and shelf life studies of Spodoptera litura nuclear Polyhedrosis Virus
Pritha Ghosh, NS Satpute, Vrunda Thakare and SM Dadmal
An investigation was carried out to determine the lethal dose and lethal time of SLNPV against S. litura, besides cross infectivity and shelf life under laboratory condition in Department of Entomology, Dr. PDKV Akola, Maharashtra. Bioassays conducted against late second instar larvae showed LC50 value of 6.02 x 105 POBs/ml and LC90 of 5.08 x 109 POBs/ml. The data on the lethal time required revealed that the LT50 value was 98 hrs (4.08 days) and LT90 was 167 hrs (6.95 days). The cross infectivity studies confirmed the species specificity of SlNPV as no cross-infectivity was recorded against other tested insects, viz, gram pod borer, diamond back moth, castor semilooper and soybean semilooper. The laboratory analysis for shelf-life of SlNPV showed reduction in POB count/ml over a period of 6 months. The POB count indicated reduction of 20.71%, 14.28% and 9.48% in case of sole NPV, NPV with UV protection agent and NPV with antimicrobial agent, respectively. Addition of UV protectant and antimicrobial agents in the crude SlNPV proved to confer prolonged viability of POBs/ml in NPV suspension. Thus, the present investigation confirmed the efficacy of SlNPV as biocontrol agents against S. litura that can be exploited under field conditions while planning for pest control strategies in an ecofriendly manner.