Efficacy testing of five fungicides against the pathogen of yellow stunt and root rot of Astragalus adsurgens in laboratory

Embellisia astragali is a stong and virulent pathogen that develops within milk vetch (Astragalus adsurgens).So far no research had been conducted on chemical controlling for this serious disease. This study assessed the efficacy of five fungicides on E.astragalus through inhibitory tests for colonal growth, spore germination and hypha elongation. The results showed that five tested fungicides all had reflected the colonal growth, spore germination and hypha elongation of E.astragalus partly. The order of concentration for 50% of maximal effect (EC50) was chlorothalonilmetalaxylmancozebThiophanate-methyltriadimefon within above 3 tests, the EC50 of chlorothalonil on colonal growth, spore germination and hypha elongation was 0.028, 0.03 and 0.04 g·L-1 respectively, the EC50 of triadimefon was 0.46, 0.48 and 0.21 g·L-1 respectively.