pnut pnut Peanut Science 0095-3679 0095-3679 American Peanut Research and Education Society 10.3146/i0095-3679-24-2-8 Peanut Response to Ethalfluralin: Rates and Methods of Application1 W. C. Johnson III *, D. L. Colvin , G. R. Wehtje , T. A. Littlefield , and B. G. Mullinix Jr. 2 Res. Agron., USDA-ARS, P.O. Box 748, Tifton, GA; Prof., Univ. of Florida; Prof., Auburn Univ.; Grad. Res. Asst., Univ. of Florida; and Agric. Res. Statistician, Coastal Plain Exp. Stn., Tifton, GA 31793-0748

1 Cooperative investigations of the USDA-ARS, Univ. of Florida, Auburn Univ., and Univ. of Georgia. All programs and services of the USDA-ARS, Univ. of Florida, Auburn Univ., and the Univ. of Georgia are offered on a nondiscriminatory basis without regard to race, color, national origin, religion, sex, age, marital status, or handicap.

 *Corresponding author (e-mail: cjohnson@tifton.cpes.peachnet.edu). 7 1997 24 2 101 104 American Peanut Research and Education Society 1997 American Peanut Research and Education Society Abstract

Studies were conducted in 1994 and 1995 at Headland, AL, Gainesville, FL, and Tifton, GA to quantify peanut injury by ethalfluralin applied preplant incorporated (PPI) or preemergence (PRE) at 0.0, 0.6, 1.1, 2.2, and 4.5 kg ai/ha. Parameters most sensitive to ethalfluralin injury were pod biomass and yield, while time of emergence, stand, canopy width, and foliar biomass were less sensitive. Ethalfluralin was generally more injurious when applied PPI than PRE, especially when rates were ≥ 2.2 kg/ha. At these rates, pod formation was inhibited and yields were reduced with little corresponding effect on vegetative growth. These data show ethalfluralin can be safely applied either PPI or PRE to peanut at rates ≤ 1.1 kg/ha.

 Key Words Arachis hypogaea L; , herbicide phytotoxicity; , peanut injury