Abstract: The regresive linear equation of the mortality of Erannis ankeraria Stardinger infected with Ea NPV is y=1.9621+0.5056×LD50=106.01;laval mortality increased with the increase of days of infection within a certain period of time;LT50 decreased with the increase of infective concentration;the toxicity of EaNPV reduced gradually with the prolongation of its storage: the toxicity of 24 month.storage EaNPV decreased by 36.5-58.5% compared with that of 11 month-storage EaNPV.The degree of destruction of sunshine to EaNPV increased with timeof exposure to it;EaNPV remaining on the trees for one year showed certain activity,with a decrease of toxicity of 63.2% compared with EaNPV kept in the refrigerator.The average lethal polyhedron numbers for the 2nd,3rd,4th and 5th in-star larvae and pupae were 96.6,267.5,533.5,600-1500 and 176.6 million per larva.NO symptom of disease appeared by using EaNPV of 1×l07/ml and PIB of 1×108/ml to infect cabbage worm,army worm,corn borer,cotton leaf roller,Gastropacha Populifolia Esper and the larvae of Brachy-meria agonoxenae Fullaway.

Key words: Etauuis aukeratia Staudinger, Nuclear polyhedrosis virus, Toxicity determination