Evaluation of the biocontrol potential of the fungus Botrytis euroamericana strain HZ-011 for herbicidal activity

Abstract

Background: Weeds in farmland seriously threaten crop yield and cause huge economic losses. Due to the extensive use of chemical herbicides, a series of problems have been arisen, such as environmental pollution, soil degradation and pesticide residues. To assess the herbicidal activity, crop safety, taxonomic identity and infection process of strain HZ-011, the methods of inoculation on detached leaves in vitro and pot plants in vivo, as well as scanning electron microscopy, were used in this study. Results: The results indicated that strain HZ-011 had pathogenic effects on detached leaves of four weeds, including Amaranthus retroflexus Linn., Elsholtzia densa Benth., Malva crispa Linn. and Chenopodium album Linn. in vitro. Strain HZ-011 also showed high pathogenicity to C. album and A. retroflexus in vivo, in which the pathogenicity rates were 100%, meaning all plants died after 7 days in the pot test, while the pathogenicity rates for E. splendens and M. crispa were 60.00 and 29.60%, respectively. This strain was safe for local crops, including Vicia faba Linn., Pisum sativum Linn., Brassica napus Linn., Hordeum vulgare Linn. and Triticum aestivum Linn. Strain HZ-011 was identified as the fungus Botrytis euroamericana based on its morphology, molecular biology and a constructed phylogenetic tree. The infection process of B. euroamericana HZ-011 in C. album was studied by plant histopathological observations after pathogen infection. This procedure showed that the mycelium of strain HZ-011 invaded C. album tissues from the stomata, infected and propagated within the tissues, and the spores produced further damage in the C. album tissues and lesions occurred on the surfaces of C. album leaves. Conclusion: These tests provide a basis for fungus B. euroamericana HZ-011 as a potential microbial herbicide.