Poster: Biology & Disease Mgmt: Mycology
Characterizing Fusarium species infecting corn roots in South Dakota
A. ADHIKARI (1), P. Okello (1), B. Kontz (1), M. Dunbar (1), A. Varenhorst (2), F. Mathew (2) (1) South Dakota State University, U.S.A.; (2) South Dakota State University, U.S.A.
There are multiple Fusarium spp. that are associated with root diseases on corn, Zea mays, in the United States. However, the importance of Fusarium associated with root disease of corn in South Dakota, is still unknown. In 2015, a survey of 50 corn fields from 23 counties in South Dakota, was conducted to characterize the Fusarium spp. associated with root diseases of corn. A total of 250 samples (5 plants per field) were collected between V1 (first leaf) to V3 (third leaf) growth stages. Root pieces from each sample were surface sterilized and placed on potato dextrose agar (PDA) for 7 to 10 days at 25°C under 12 hour fluorescent light/dark conditions. Isolates of Fusarium were hyphal-tipped, cultured, and then identified microscopically based on colony growth and spores produced on PDA. Representative Fusarium isolates were confirmed by sequencing of the translation elongation factor (EF1-α) gene region. At least seven Fusarium spp. were identified. Fusarium graminearum and F. oxysporum were the most frequently recovered (≥20%) Fusarium spp. from the corn roots. In the aggressiveness study to compare Fusarium isolates in the greenhouse, significant differences in aggressiveness (P ≤ 0.05) was observed among the Fusarium spp. with the most aggressive isolates being F. graminearum (FG13) and F. acuminatum (FA8). Results from this research will help us develop disease management strategies for corn farmers in South Dakota to maximize their yield.