First report of maize ear rot caused by Fusarium sporotrichioides in China.
In September and October 2018, a survey to determine population structure and composition of Fusarium spp. causing maize ear rot was conducted in 26 cities or counties in Heilongjiang Province, the largest maize planting area in China. Disease incidence was 5-25% at individual fields. Rotten ears or kernels covered with white, pink, or salmon mold were collected. Fusarium spp. were identified by morphological characteristics and specific PCR amplification and then confirmed by DNA sequence comparison of the partial translation elongation factor-1α, β-tubulin and mitochondrial small subunit genes. Twelve Fusarium spp. were identified; F. verticillioides and F. graminearum species complex were the predominant causal agents. Several isolates from Anda were identified as F. sporotrichioides based on morphological and molecular characteristics, which was further confirmed by pathogenicity tests. F. sporotrichioides was previously reported associated with head blight of wheat, root rot of Erigeron breviscapus, wilt of lavender, and foliar spot on forage corn. It was also reported to cause maize ear rot in Poland and Tanzania. F. sporotrichioides can produce trichothecene mycotoxins (T-2/HT-2 toxins) that cause toxicosis in animals and humans. This is thought to be the first report of F. sporotrichioides causing maize ear rot in China.