Identifying Disease in Georgia Alfalfa
Applied Research
Brennan Jackson
Gray
Abstract
Alfalfa (Medicago sativa) production is economically and nutritionally important to livestock and equine, but the management of alfalfa is more intensive than other forages. Georgia soils are typically lower in pH, and alfalfa requires a minimum of 6.5 pH in order to establish, grow, and promote nutrient intake from phosphorous and potassium applications. Soils with lower pH are at risk of aluminum toxicity. However, with Georgia’s higher humidity level than much of the rest of alfalfa production areas, disease is certainly a major concern. The three most popular varieties planted in Georgia are Bulldog 505, Bulldog 805, and Alfagraze 600RR. Bulldog 505 and Bulldog 805 exhibit resistance to Fusarium wilt and Phytophthora root rot. Alfagraze 600 RR exhibits resistance to nematodes, Phytophthora root rot, Fusarium wilt, Anthracnose, and Verticillium wilt.
Disease resistant varieties do alleviate some management to several major pathogens known to infect alfalfa. Three sites in Jones and Putnam County were scouted from September 2022 to March 2023. During this time, four diseases were observed and confirmed through microscopy which included common leaf spot (Pseudopeziza medicaginis), Stemphylium leaf spot (Stemphylium spp.), Rhizoctonia solani, and Leptosphaerulina leaf spot (Leptosphaerulina briosiana). Additionally, of the 1,339 plants evaluated during this period, 84% exhibited signs or symptoms of disease. Future research would include a comprehensive study of diseases in relation to alfalfa in Georgia in order to determine the feasibility or economic impact of control through chemical applications.
Poster has NOT been presented at any previous NACAA AM/PIC
This poster is being submitted for judging. It will be displayed at the AM/PIC if not selected as a State winner. The abstract will be published in the proceedings.
Click to view Poster
Authors: Brennan Jackson, Jean Williams-Woodward, Keith Fielder
-
Jackson, B. County Extension Agent, University of Georgia, Georgia, 31032
-
Williams-Woodward, J. Associate Professor, University of Georgia, Georgia, 30602
-
Fielder, K. County Extension Agent, University of Georgia, Georgia, 31024