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ARS Home » Southeast Area » Stoneville, Mississippi » Crop Genetics Research » Research » Publications at this Location » Publication #339138

Research Project: Development and Characterization of Soybean Germplasm, Curation of Stored Accessions, and Regional Evaluations of New Genotypes

Location: Crop Genetics Research

Title: First report of root rot of cowpea caused by Fusarium equiseti in Georgia in the United States

Author
item Yonggang, Li - Northeast Agricultural University, China
item Zhang, Siqi - Northeast Agricultural University, China
item Xu, Lankun - Northeast Agricultural University, China
item Li, Shuxian
item Ji, Pingsheng - University Of Georgia

Submitted to: Plant Disease
Publication Type: Research Notes
Publication Acceptance Date: 5/22/2017
Publication Date: 8/15/2017
Citation: Li, Y., Zhang, S., Xu, L., Li, S., Ji, P. 2017. First report of root rot of cowpea caused by Fusarium equiseti in Georgia in the United States. Plant Disease. DOI: 10.1094/PDIS-03-17-0358-PDN.

Interpretive Summary: Cowpeas are one of the most important food crops widely grown in the southern United States. In May of 2015, root rot was observed on cowpea in Tift County, Georgia. The disease occurred on approximately 10% of cowpea plants in 2 fields. Symptoms appeared as sunken reddish brown lesions on roots and stems under the soil line, some roots became dark brown and rotted, and infected plants eventually wilted and died. A fungus was isolated and identified as Fusarium equiseti based on its structure and DNA sequences. In greenhouse tests, all plants treated with the fungus showed disease symptoms, while non- treated plants were healthy. This is the first report confirming F. equiseti causing root rot on cowpea in the United States. Cowpea is an important vegetable crop in Georgia and occurrence of the new disease caused by F. equiseti needs to be properly managed to reduce yield loss.

Technical Abstract: Root rot was observed on cowpea in Tift County, Georgia, in May of 2015. The disease occurred on approximately 10% of cowpea plants in 2 fields (2 ha). Symptoms appeared as sunken reddish brown lesions on roots and stems under the soil line, secondary roots became dark brown and rotted, and infected plants eventually wilted and died. A fungus was isolated and identified as Fusarium equiseti based on morphological characteristics. Sequences of the internal transcribed spacer regions of rDNA (ITS1-5.8S-ITS4) showed 99% identical to an F. equiseti isolate (GenBank accession no. KJ412501). Results from pathogenicity tests in greenhouse showed that all inoculated seedlings showed symptoms identical to those observed in the field 8 days after inoculation. No disease occurred on the control cowpea plants treated with sterile distilled water. The fungus was reisolated from the diseased root and confirmed to be F. equiseti based on morphological characteristics and ITS sequence analysis. To our knowledge, this is the first report confirming F. equiseti causing root rot on cowpea in the United States. Cowpea is an important vegetable crop in Georgia and occurrence of the new disease caused by F. equiseti needs to be properly managed to reduce yield loss.