Abstract: More than 200 specimens of plant seedling drop,root rot and sheath bling has been collected from 13 provinces(municipalities)and 58 districts(counties)from 1982-1995 in China. 162 strains of Rhizoctonia were identified by Ogoshi's strandard strains and the methods. These isolates were divided into multinucleates(R. solani), belonging to AG-1IA,AG-1IB,AG-1IC,AG-2-1,AG-2-2,AG-4 and AG-5 and binucleates(Rhizoctonia spp.)belonging to AG A, AG B(0),AG D,AG F,AG Gand AG K, respectively. The host plants of these isolates consist of 26 family,52 genera and 58 species. There was the evident of parasitic specifity for hosts in part AGs of Rhizoctonia . There was little difference of the identical AGstrains under the effect of temperature, while there was greater difference among the distinct AGs under the effect of temperature. The parasitic specifity for hosts in Rhizoctonia's AGs was distinctly affected by temperature changes.

Key words: Athetis lepigone, mitochondrial COI, haplotype, geographic population, genetic differentiation.