Author:
Marple Molly E.,Al-Khatib Kassim,Shoup Douglas,Peterson Dallas E.,Claassen Mark
Abstract
Field experiments were conducted at Manhattan and Hesston, KS, in 2004, and at Manhattan, KS, in 2005, to evaluate cotton response to seven hormonal-type herbicides. Herbicides 2,4-D amine, 2,4-D ester, clopyralid, picloram, fluroxypyr, triclopyr, and dicamba were each applied at 0, 1/100, 1/200, 1/300, and 1/400 of the herbicide use rates on cotton in the six- to eight-leaf stage. Herbicide use rates were 210 and 280 g ae/ha for fluroxypyr and clopyralid and 561 g ae/ha, for 2,4-D amine, 2,4-D ester, dicamba, picloram, and triclopyr. At 14 d after treatment (DAT), all herbicides caused leaf cupping and epinasty, except triclopyr and clopyralid, which caused severe bleaching and chlorosis. The order of visual injury ratings was 2,4-D ester > 2,4-D amine > picloram > dicamba > fluroxypyr > triclopyr > clopyralid. By 56 DAT, slight injury symptoms were observed on plants treated with all herbicides, except all rates of 2,4-D, from which symptoms were severe. All rates of 2,4-D and the highest rate of picloram caused more than 60% flower abortion. Ranking of fiber yield reduction after herbicide treatment was 2,4-D ester > 2,4-D amine > picloram > fluroxypyr > dicamba > clopyralid > triclopyr. This research demonstrated that cotton is extremely susceptible to simulated drift rates of 2,4-D and picloram, whereas clopyralid and triclopyr caused early injury, with minimal effect on cotton yield.
Publisher
Cambridge University Press (CUP)
Subject
Plant Science,Agronomy and Crop Science
Reference34 articles.
1. Contamination of Cotton Fields by 2,4‐d or Hormone‐Type Weed Sprays
1
2. Stinger® herbicide, EPA Registration No. 62719-73, Dow AgroScience, Indianapolis, IN 46268-1189.
3. Rawson J. E. and Schrodter G. N. 1981. Preliminary study of the effects of simulated herbicide drift on cotton toxicity, residues. Proc. Aust. Weed Conf. 6:137–138.
4. Def 6® herbicide, EPA Registration No. 264-730, Bayer Crop Science, RTP, NC 27709.