Hyperparastism and Biocontrol of Hedysarum mongolicum Rust by Sphaerellopsis filum

The hyperparasite Sphaerellopsis filum parasitizing on Hedysarum mongolicum rust (Uromyces hedysari-mongolici) forms conidia after 10 days at the temperature of 20 ℃ on PDA,and yellow white spore horn was also produced after 12 days.The teliospore and urediospore of U.hedysari-mongolici parasitized by S.filum faded colour,the cell wall destructed and the cell contents released in the late stage.The germination rate of parasitized teliospore lowered by 40%.To control H.mongolicum rust,the spore suspension of the hyperparasite was inoculated on uredium.The results of 3 years’ investigation in field showed that the degree of the rust infestation decreased with the increase of parasitization of S.filum in the forest.It seems that S.filum has good potential to be an effective biological control agent of the H.mongolicum rust.