Frequency of fungi associated with strawberry dry wilt and in vitro antagonistic impact of Trichoderma harzianum and Bacillus subtilis

Objective: To determine the frequency of fungi associated with strawberry dry wilt and to evaluate the antagonistic impact of Trichoderma harzianum and Bacillus subtilis. Design/Methodology/Approach: Three sampling sessions were conducted in strawberry plantations in the Zamora Valley to isolate and identify fungi associated with strawberry dry wilt and to determine their frequency. In vitro antagonism tests were performed between Trichoderma harzianum, Bacillus subtilis, and fungi isolated from strawberry plants showing wilt symptoms. Additionally, the percentages of mycelial growth inhibition were determined. Results: Six fungi were isolated from diseased plants showing wilt symptoms. The most frequent fungi were: Neopestalotiopsis sp. (54.7%), Fusarium oxysporum (50.6%), and Rhizoctonia solani (40.5%). Trichoderma harzianum inhibited >90% of the radial growth of Rhizoctonia solani mycelia, of Cylindrocarpon sp., >80% of Fusarium solani, and F. oxysporum mycelia, and 77.7% of Neopestalotiopsis sp. mycelia. Bacillus subtilis recorded the highest antagonism against Rhizoctonia solani (57%). Study Limitations/Implications: This research faced no limitations. Findings/Conclusions: In vitro tests determined that Trichoderma harzianum can inhibit the mycelial growth of fungi associated with strawberry dry wilt. Bacillus subtilis had a lower capacity to inhibit the mycelial growth of the confronted fungi than Trichoderma harzianum; however, it was the most effective bacterium against Rhizoctonia solani.