Biological characteristics and fungicides screening in vitro of Fusarium zanthoxyli，the pathogen causing stem canker in prickly ash

Stem canker, caused by Fusarium zanthoxyli X. Zhou, T. Aoki, O'Donnell & Z.M. Cao, seriously affects the growth and yield of prickly ash. This study aims to explore the biological characteristics of F. zanthoxyli and screen the effective fungicides, thereby providing a theoretical basis for the prevention and control for stem canker of prickly ash. The results showed that the growth rate of F. zanthoxyli was the fastest on carrot agar（CA）, with a colony growth rate of 4.37 mm/d. F. zanthoxyli mainly produced microconidia in different solid and liquid media, and the optimal growth temperature for F. zanthoxyli was 25℃. Three light treatments did not significantly affect the colony growth rate, but the full dark treatment is conducive to the spore production of the F. zanthoxyli in the CA liquid medium. The virulence of 17 fungicides against F. zanthoxyli was determined by colony growth rate method. Among biofungicides, 3% polyoxin exhibited the most pronounced antifungal activity, with an EC₅₀ value of 0.28 mg/L. For single-component chemical fungicides, 50% carbendazim, 10% difenoconazole and 50% thiophanate-methyl demonstrated superior efficacy, recording EC₅₀ values of 0.61, 1.02 and 2.90 mg/L, respectively. Regarding formulated chemical fungicides, 72% cymoxanil·mancozeb and 30% pyraclostrobin·tebuconazole showed notable inhibitory effects, with EC₅₀ values of 1.23 and 1.44 mg/L in sequence.