AUTHOR=Li Xiaojiao , Leng Jinsong , Yu Longfeng , Bai Haidong , Li Xiaojun , Wisniewski Michael , Liu Jia , Sui Yuan 

TITLE=Efficacy of the biocontrol agent Trichoderma hamatum against Lasiodiplodia theobromae on macadamia

JOURNAL=Frontiers in Microbiology

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2022.994422

DOI=10.3389/fmicb.2022.994422

ISSN=1664-302X

ABSTRACT=<p>Macadamia (<italic>Macadamia integrifolia</italic>) trees are an important source of revenue in rainforest ecosystems. Their nuts are rich in vitamins, minerals, fiber, antioxidants, and monounsaturated oils. The fungus <italic>Lasiodiplodia theobromae</italic>, however, is a major disease problem, causing kernel rot and other disease symptoms. In the present study, a dual confrontation assay was used to evaluate the inhibitory effect of an endophytic strain of <italic>Trichoderma hamatum</italic> C9 from macadamia root against <italic>L. theobromae</italic>. Volatiles and cell-free culture filtrate of <italic>T. hamatum</italic> were also used to assess their antifungal activity against <italic>L. theobromae</italic>. Results suggested that <italic>T. hamatum</italic> exhibited a significant inhibitory effect against <italic>L. theobromae in vitro</italic>. Further results of a biocontrol assay indicated that a spray treatment of <italic>T. hamatum</italic> conidial suspension significantly decreased the size of lesions caused by artificially inoculated <italic>L. theobromae</italic> on macadamia leaves, as well as the disease index in young trees inoculated with <italic>L. theobromae</italic>, relative to sterile water controls. Collectively, our findings indicate that <italic>T. hamatum</italic> C9 represents a potential biocontrol agent that can be used to manage <italic>L. theobromae</italic> on macadamia.</p>