| Summary: | Alfalfa Fusarium Root Rot (AFRR) is a serious soil-borne disease with a complex pathogenicity. Diseased samples suspected of AFRR were collected from Hohhot, Ordos, Hulunbeier, Chifeng, and Bayannur in Inner Mongolia, China, leading to 317 isolates. The isolates were identified as <i>Fusarium acuminatum</i>, <i>F. solani</i>, <i>F. equiseti</i>, <i>F. incarnatum</i>, <i>F. oxysporum</i>, <i>F. avenaceum</i>, <i>F. verticillioides</i>, <i>F. proliferatum</i>, <i>F. falciforme</i>, <i>F. tricinctum</i>, <i>F. virguliforme</i>, and <i>F. redolens</i>, and the results of pathogenicity testing showed that 12 <i>Fusarium</i> species could cause alfalfa root rot. Among these, <i>F. verticillioides</i>, <i>F. falciforme</i>, and <i>F. virguliforme</i> have not previously been reported to cause AFRR in China. Although the population structure of the pathogens differed in different regions, the dominant pathogenic species was <i>F. acuminatum</i>. Fungicide toxicity tests showed that seven fungicides inhibited <i>F. acuminatum</i>, of which fludioxonil, kresoxim-methyl, and triadimefon were found to be strongly toxic towards <i>F. acuminatum</i> with EC<sub>50</sub> values of 0.09, 2.28, and 16.37 μg/mL, respectively, suggesting that these could be used as alternative fungicides for the control of AFRR. The results of this study can provide a theoretical basis for exploring the occurrence and epidemiology of alfalfa root rot and strategies for its control.
|
|---|