Study On Optimal Parameters For Propagation Of Cydia Pomonella Granulovirus

Studies were designed to find the optimal parameters for propagation of Cydia pomonella granulovirus Zhangye strain(CypoGV-ZY), this paper studied the influence of different artificial diets, instar of the host larvae and the dose of CypoGV on proliferation of CypoGV-ZY. The main results were summarized as follows:1. Four main nutrients: apple powder and yeast, wheat flour and corn flour were used to determine the effect of different artificial diet on the development of C. pomonella and the yield of CypoGV-ZY by stomach toxicity. The CypoGV-ZY infected larvae weight and yield of virus were significantly improved with the yeast adding in diet. The formula C diet fed virus infected larvae would gain highest CypoGV-ZY yeild, and the dead larvae weight, the virus yield of average per larva and the virus yield of average per gram dead larva was, 30.56 mg, 8.63×109 OBs/Larva, 28.25×1010 OBs/g, respectively. Compare to C formula diet, the replacement of wheat flour,of corn flour would lead to lower CypoGV production, as well as the larval weight. The results indicate that among the five kinds of artificial diets, formula C, contained yeast and wheat flour, significantly improved the yield of CypoGV-ZY, and this formula of diet could be a suitable diet for virus propagation.2. On the basis of research on artificial diet, the influence of instar of the host larvae and the dose of CypoGV on larvae mortality,dead larvae weight and the yield of CypoGV were studied. The main results as follows:The results indicated that the larval instar, the virus dose and their different combinations significantly affected, larval mortality, dead larvae weight, the yield of virus occlusion bodies( OBs) per larva and total virus yield.(1) The infection dose of CypoGV is the main factor affecting the codling moth larvae mortality, the mortality rate of larvae decreased with the increase of infection instar, and increased with the dose of infection.(2) The infection instar of CypoGV is the main factor affecting the dead larvae weight, the dead larvae weight increased with the increase of infection instar, and decreased with the dose of infection.(3) The infection instar of CypoGV is the main factor affecting the yield of virus. The maximum virus yield were obtained when the 5th instar larvae were fed with the virus at the dose of 100 OBs /larva.The average total yield of virus were 12.19×1011 OBs for 100 infected 5th instar larvae.