Evaluation of fungicide seed treatments on alfalfa in western Kentucky, 2020.

Plots were established at the University of Kentucky Research and Education Center (UKREC) in Princeton. The previous crop was soybeans. Field tillage, fertilizer, and weed control were managed according to standard practices. The alfalfa cultivar Algonquin was drilled on a 7-in. row spacing at a rate of 15 lb seed/A on 3 Apr using a modified plot-sized drill. Fungicide seed treatments were applied using a batch seed treater prior to planting. Alfalfa stands were measured in each plot on 4 Jun, at the second trifoliate growth stage, by arbitrarily selecting two 1 sq ft areas within each plot and counting the total number of alfalfa plants in each square. The center 5 ft of each plot was harvested with a small plot harvester on 18 Aug to determine yield and forage quality. Neutral detergent fiber (NDF), and acid detergent fiber (ADF) were determined using near infrared reflectance spectroscopy.

The trial location experienced below average temperatures in April and May which delayed emergence and impacted stand and plant growth. Alfalfa growth was slower than expected with only one harvest possible. The fungicide treatments significantly improved stands. Rizolex + Apron XL resulted in a greater plant population compared to other treatments and the non-treated control. Apron XL alone also resulted in greater population than the non-treated control. The fungicide treatments did not significantly affect dry matter yield or forage quality as measured by NDF and ADF.

~Chris Teutsch and Kiersten Wise