Determining Exposure to Auxin-Like Herbicides. I. Quantifying Injury to Cotton and Soybean

Abstract

Crop injury caused by drift of auxin-like herbicides has been a concern since their development. Research was conducted to describe a method of quantifying injury from auxin-like herbicides as a first step in determining crop damage. Reduced rates of 2,4-D, dicamba, and triclopyr were applied to cotton and soybean plants in the three- to six-leaf stage in field and greenhouse studies. Injury to leaves and stems were evaluated separately, and the values were combined so that one injury estimate was obtained for each individual plant rated. Injury symptoms were typical for auxin-type herbicides and ranged from slight bending of stems or petioles and wrinkled leaves to necrosis. Specific descriptions of leaf and stem injury levels were used to describe plant injury consistently. These descriptions were very detailed for the lower injury levels, but the characterizations became more general as the injury increased because of the prominence of factors such as necrosis. The injury evaluation method provided repeatable results for each herbicide and herbicide rate used. This injury evaluation method has many possible uses in auxin-like herbicide research and lays the foundation for forecasting the impact of early-season injury to cotton and soybean yield.

Evaluation of 2,4-D-Choline Based Herbicide Systems in 2,4-D Tolerant Soybean (<i>Glycine max</i> L.)

“…Nozzles that produce coarser size droplets will minimize 2,4-D particle drift and subsequent injury to sensitive crops in adjacent fields [23]. However, application instruction, including nozzle types, time of day of application along with other ways to mitigate drift injury are accompanied with the new herbicides technologies to help reduce misuse by growers and commercial applicators [22].…”

Mapping-by-sequencing of Ligon-lintless-1 (Li 1 ) reveals a cluster of neighboring genes with correlated expression in developing fibers of Upland cotton (Gossypium hirsutum L.)

“…The Li 1 vegetative phenotypes mimic the exposure of cotton to low dosages of 2,4-D, a synthetic auxin herbicide, which has long been used to identify mutants of polar auxin transport (Bennett et al 1996;Sciumbato et al 2004). Injury to cotton plants by low dosages of auxin-type herbicides is characterized by bending and twisting of stems and wrinkling of leaves, although fiber length is not affected (Sciumbato et al 2004;Smith and Wiese 1972). However, transgenic over-expression of auxin synthesis during lint fiber initiation resulted in an increase in lint yield (Zhang et al 2011).…”

Efficacy of 2,4-D, Dicamba, Glufosinate and Glyphosate Combinations on Selected Broadleaf Weed Heights

“…Dicamba and 2,4-D, although widely used, have long been scrutinized by regulators because of potential injury to off target plants caused by herbicide volatilization [6]; however, the release of new low volatility formulations of dicamba and 2,4-D has addressed most of those concerns [7] [8] [9] [10] [11]. Recently, attention has been drawn to new formulations of dicamba and 2,4-D herbicides due to the release of the 2,4-D and dicamba tolerant soybean and cotton technologies that will assist in the management of difficult-to-control glyphosate-resistant Palmer amaranth (Amaranthus palmeri S.…”