|Johnson, Wiley - Carroll|
Submitted to: American Peanut Research and Education Society Abstracts
Publication Type: Abstract only
Publication Acceptance Date: 5/17/2001
Publication Date: 7/9/2001
Citation: Baughman, T.A., Dotray, P.A., Grichar, W.J., Johnson, W.C., Keeling, J.W., Lemon, R.G., Porter, B.L., Karnei, J.A., Besler, B.A., Brewer, K.D. 2001. Tolerance of peanut to glyphosate spot applications [abstract]. American Peanut Research and Education Society. 33:62. Interpretive Summary:
Technical Abstract: Trials were established in Texas (Flomot, Lamesa, and Yoakum) and Georgia (Tifton) to investigate the phytotoxic effects of glyphosate applied as a spot application in peanut. Glyphosate was applied as a 2% solution 2 weeks after crack (WAC), 4 WAC, 8 WAC, 10 WAC, 2+4 WAC, 2+8 WAC, 2+10 WAC, 4+8 WAC, 4+10 WAC, 2+4+8 WAC, and 4+8+10 WAC. Markers were established in the field to simulate weed populations. Markers were placed down the peanut row at 3 feet intervals. Glyphosate was applied as a single spot application to each marker at the various timings. Injury was observed in the form of chlorosis, necrosis, stunting, and stand reduction due to loss of peanut plants at all locations. The only treatments that reduce peanut yields were the 2 WAC and 4 WAC treatments at Flomot in 1999. Grades were reduced with all multiple applications except 2+4 and 2+8 WAC. Due to drought conditions, yield was not recorded at Flomot in 2000. However, similar peanut injury and stand reductions were observed. At Lamesa in 1999, yields were reduced with all multiple applications and the 2 WAC application. Grades were reduced with all multiple applications except 2+4 and 2+10 WAC. Yields were only reduced with the 2+10 WAC and 4+10 WAC treatments at Lamesa in 2000. Grades were reduced with all treatments except 4 WAC. Yields were not effected by any treatment at Yoakum in 1999. In 2000 at Yoakum, yields were reduced with all treatments except the 8 WAC and 2+8 WAC treatments. Grades were only reduced with the 2+10 WAC, 2+4+8 WAC, and 4+8+10 WAC treatments. Yields were reduced with all application timings at Tifton in 1999 and 2000. These trials indicated that severe injury and reductions in peanut yield and grade can occur from the use of glyphosate as a spot-application for weed control in peanut.