Causes of cotton Fusarium wilt outbreaks in Georgia

Authors: Bell, Alois - Al; KEMERAIT, ROBERT - Texas A&M University; ORTIZ, CARLOS - Texas A&M University; PROM, SANDRIA - Texas A&M University; Quintana, Jose; NICHOLS, ROBERT - Cotton, Inc; Liu, Jinggao

Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Abstract Only
Publication Acceptance Date: 11/5/2016
Publication Date: 2/1/2017
Citation: Bell, A.A., Kemerait, R.C., Ortiz, C.S., Prom, S., Quintana, J., Nichols, R.L., Liu, J. 2017. Causes of cotton Fusarium wilt outbreaks in Georgia [abstract]. Proceedings of the National Cotton Council Beltwide Cotton Conferences, January 4-6, 2017, Dallas, Texas. p. 162.

Interpretive Summary:

Technical Abstract: Severe outbreaks of Fusarium wilt of cotton in Georgia since 2011 raised concerns about the genotypes of the causal pathogen Fusarium oxysporum. We isolated 492 F. oxysporum isolates from 107 wilted plants collected from 7 fields in 5 counties and determined their population structure utilizing vegetative complementation tests and DNA sequence analysis. Eight VCGs, VCG0111 (race 1), VCG0112 (race 2), VCG01117B, VCG01117C, VCG01118, VCG01119 (race 8), VCG01120 and VCG01121, were found and their phylogenic relationships determined. VCG01121 has never been reported before and was the major VCG in Georgia. This VCG was especially prominent in Berrien County, the center of the outbreaks. Two pathogenicity tests that can distinguish vascular competent isolates from root-rot pathotype isolates were used to characterize the 8 VCGs. All 8 VCGs were the vascular competent pathotype and required root-knot nematode to cause severe wilt. Therefore, use of nematode resistance cultivars is the most viable approach to control the disease in Georgia.