How an herbicide can affect plant diseases in a crop rotation program? A case study on Othello® OD

Herbicides can play an essential role in crop rotation programs' integrated management of plant diseases. Trichoderma species are major biological control fungi (BCF) used in agriculture. This study examined the effect of the herbicidal product Othello® OD on the in vitro growth of T. asperelloides, as well as some phytopathogenic fungi (Bipolaris sp., Fusarium graminearum, F. oxysporum, and Rhizoctonia solani). The poisoned food method was utilised with potato dextrose agar as the basal medium. The plates were then incubated at 26 °C in the dark. Results showed that all tested fungi were statistically similar in their sensitivity to the herbicide Othello® OD. Despite this, the significantly higher growth rate of T. asperelloides compared to the other tested fungi and its negligibly low sensitivity to Othello® OD suggests the potential of using the herbicidal product and T. asperelloides for managing essential diseases in a crop rotation program. The alignment of acetolactate synthase amino acid sequences using COBALT tool obtained a tree with 17 nodes separating the three fungal groups. The acetolactate enzymes of Bipolaris oryzae and B. sorokiniana were similar enough to form a unique group, indicating that they may be considered distinct species. In the second group, the enzyme of Fusarium oxysporum was more identical to that of T. asperelloides than F. graminearum. The third group only included enzymes from R. solani isolates.