This paper deals with the transfer method and mechanism of hypovirulence factors; the mixed system of virulent and hypovirulent strains; the super microcosmic structure and physiological characters in the two kinds of hyphae.

• 本文阐述了弱毒因子的传递方式、理，强、毒菌系混合体系，两类菌丝的超微结构以及生理特性。