Study on the Identification, Biological Characteristics, and Fungicide Sensitivity of the Causal Agent of Strawberry Red Core Root Rot

Strawberry red core root rot disease affects the growth and yield of strawberry (Fragaria ananassa Duch), which leads to economic losses in China. The study employed a tissue separation method to isolate and identify the causal agent responsible for strawberry red core root rot. This was achieved by the observation of its morphological characteristics, sequencing analyses, and pathogenicity tests. The sensitivity of five chemical fungicides against the two species of Fusarium was determined using the mycelial growth rate method, and the biological characteristics of the two species were examined. The pathogens were identified as Fusarium solani and Fusarium oxysporum. The optimal conditions for the mycelial growth of F. solani and F. oxysporum were determined to be potato sucrose agar at 25 °C and pH 6, and potato dextrose agar at 30 °C and pH 8, respectively, with a 24:24 light cycle. The most suitable carbon and nitrogen sources for the mycelial growth of F. solani were sucrose and sodium nitrate (NaNO3), while for F. oxysporum, they were glucose and peptone. A fungicide sensitivity test indicated that Prochloraz had a good inhibitory effect on the growth of F. solani and F. oxysporum with EC50 values of 0.088 mg L−1 and 0.162 mg. The growth inhibition effect of Azoxystrobin to F. solani and Carbendazim to F. oxysporum was not obvious. This study provides a theoretical basis for further research on strawberry red core root disease and its prevention.