Herbicidal activity and crop safety of Alternaria alternata DT-XRKA and Fusarium avenaceum DT-QKBD004A

Elsholtzia densa and Avena fatua are known as two of the most aggressive weeds, causing severe economic, environmental, human and animal health problems in China and around the world. In this study, seven strains of pathogenic fungi (i.e. DT-YSB1, DT-04A2, DT-DYLC, DT-XRKA, DT-08C, DT-14A2, and DT-QKBD004A) were isolated from weeds plants with infections symptoms. Pathogenicity test was performed and found that strain DT-XRKA exhibited strong herbicidal activity against E. densa, while strain DT-QKBD004A was highly pathogenic to A. fatua. On the basis of cultural, morphological and molecular characteristics, these two strains were identified as Alternaria alternata and Fusarium avenaceum, respectively. The safety assessment indicated that the spore suspension (10⁴ spore/ml) of strain DT-XRKA was generally safe for rapeseed, cabbage, tomato, cucumber, and pepper among the 12 tested crop species, though some non-target infections were observed. Strain DT-QKBD004A with same concentration was found to be safe for broad beans, corn, cabbage, tomato, cucumber, and pepper. Therefore, A. alternata and F. avenaceum can be selected for further studies to development mycoherbicides for control of these two weeds in rapeseed and broad bean fields.