On-Farm Evaluation of Reduced Rates of Prohexadione Calcium (Plant Growth Regulator) on Peanut.

Prohexadione Calcium is commonly used on Virginia type peanuts to manage their excessive vine growth and promote higher digger efficiency. However; minimal acres of runner type peanuts have Prohexadione Calcium applied due to their more compact growth habit. Vine growth of runner type cultivars have slowly changed in the last five years to have a more vigorous growth habit causing a renewed interest in growth regulators. Evaluations of runner cultivar response to reduced rates of Prohexadione Calcium were conducted in small plot and large on-farm strip trials in 2016 in Georgia. Application rates of Prohexadione Calcium at 7.25 oz/A (1X, Labeled), 5.44 oz/A (0.75X), 3.63 oz/A (0.5X), and an untreated check were evaluated on Georgia-12Y on the UGA Tifton Campu, Tifton, GA and on-Farm in Bulloch County, GA. Prohexadione Calcium at 5.44 oz/A (0.75X) and an untreated check was evaluated on Georgia-06G in Early County, Georgia. Applications were initiated when 50% of lateral vines from adjacent rows were touching. A second application was applied in 14 days after initial application. Cultivar and treatment responses were evaluated based on canopy growth, yield, and grade. All rates of Prohexadione Calcium significantly reduced canopy growth. Yield increased significantly for all rates compared to the untreated check with reduced rates performing similarly to the full rate.