Studies on screening of antifungal plants and antifungal activities of Glycyrrhiza uralensis against five phytopathogens.

In order to find new fungicides,antifungal activities of 17 plant extracts against Peronophythora litchi were determined by using mycelial growth rate method.The main results were as follows: after 7 days' treatment with a dry-powder mass concentration of 10 mg/mL,the methanol extracts of Polygonum lapathifolium and Camellia oleifera showed inhibition rates of 74.37% and 77.02%,respectively,while the methanol extract of Glycyrrhiza uralensis(root) showed inhibition rates of 97.83% at the same test mass concentration;extraction ratio reached 20.80% by using methanol to extract Glycyrrhiza uralensis(root) and it showed inhibition rates of 63.84% and 80.68% on P.litchi with dry-powder mass concentrations of 1.0 and 5.0 mg/mL,respectively,and the median inhibitory mass concentration was 0.47 mg/mL against the germination of sporangia of P.litchi.The median inhibitory mass concentration against P.litchi,Phytophthora capsici,Colletotrichum gloeosporioides,Fusarium oxysporum f.sp.cubense,and Cladosporium herbarum was 0.62,0.89,9.70,6.42 and 4.53 mg/mL,respectively.These results suggest that the methanol extract of G.uralensis(root) has good antifungal activity,and it is expected to develop into a new fungicide with further research.