Abstract: Employing single factor experiment and orthogonal combination design, the effects of three main ingredients of the diet on the yields of Spodoptera exigua nuclear polyhedrosis virus (SeNPV) had been studied. When late third instar larvae were reared on artificial diet only composed either of soybean or of brewers yeast or wheat bran, or composed of two of these three ingredients, the virus yields were not depended on the level of polyhedra per g dead larva. The yields were determined by the mortalities of infected larvae and the level of polyhedra per larva together. When the three ingredients were combined together, the yields significantly increased. However, the mortalities of infected larvae among these treatments were not obviously different. The virus yields were increased as the increase of brewers yeast and the other two ingredients, soybean powder and wheat bran in the diet. Whereas the virus yields were decreased when the levels of soybean powder and wheat bran in the diet were too high. The order in effectiveness of the three ingredients on the virus yield is brewers yeast, soybean powder and wheat bran. The optimum combination of the three main ingredients in diet giving a highest yield of SeNPV was that in every 120?g of artificial diet preparation the contents of brewers yeast, soybean powder and wheat bran were 7?g, 14?g and 6?g respectively. Additionally, the effect of four mineral salts and a nonprotein nitrogen component on the virus yields were also studied.

Key words: ingredient, Spodoptera exigua, nucleopolyhedrovirus, yield