Viral insecticides were formulated with Spodoptera litura nuclear polyhedrosis virus and different U.V. protectants based on white carbon, molasses, and white carbon and molasses mixture to use as microbial control agents. Effect of rainfall on the attachment of formulated viruses to leaves was no different between the treated and the non-treated experiment. Persistence of the formulations was lated 5 days on the surface-sprayed leaves and 12 days on the under-sprayed leaves which was showing 60% mortality. Total mortality of the viral insecticides was more than 97% with no differences among them. Field evaluation of three viral insecticides in soybean field was very successful then carried out in Chinju, a southern part of Korea. Mortality by the formulation in the field during 14 days was more than 93%, but the formulations contained molasses showed phytotoxicity on soybean leaves. Spray effect of the viral insecticides was begun to appear from 7 days later than that of chemical insecticide.