Control of Volunteer Glyphosate-Resistant Corn (Zea mays) in Glyphosate-Resistant Soybean (Glycine max)

Abstract

Volunteer corn in soybean can reduce yields, interfere with harvest, and cause unacceptable levels of contamination by its presence in the harvested soybean. In Ontario, soybean frequently follow corn in rotation. The use of glyphosate-resistant corn and soybean varieties has increased dramatically in Ontario. Field studies were conducted at two locations in southwestern Ontario to determine whether quizalofop-p-ethyl, clethodim, and fenoxaprop-p-ethyl can be tank mixed with glyphosate to provide effective control of volunteer glyphosate-resistant corn in glyphosate-resistant soybean. Soybean plots were overseeded with glyphosate-resistant corn and treatments consisting of glyphosate applied alone and tank mixed with full and reduced rates of each graminicide with and without a recommended surfactant. Tank mixing the graminicides and adjuvants with glyphosate did not affect glyphosate weed control or crop tolerance. Use of a recommended adjuvant significantly improved the effectiveness of the graminicides, particularly when reduced rates were applied. Quizalofop-p-ethyl was the most effective graminicide for controlling glyphosate-resistant volunteer corn, followed by clethodim and fenoxaprop-p-ethyl.

Glyphosate tolerant volunteer corn control at two development stages

“…Blackshaw et al (2006) found antagonism in the mixture of clethodim-D amine + 2.4 (30 + 420 g ha -1 ) and quizalofop-P-D amine + 2.4 (36 + 420 g ha -1 ) through the lowest volunteer AC Barrie wheat biomass reduction, compared with graminicides individual applications, as well as the amine formulation provided the Glyphosate tolerant volunteer corn controle at two development stages highest antagonism to the formulation of 2,4-D on ester herbicide mixture. Tables 2 and 3. It can be checked, for the V 5 , that haloxyfop and clethodim applied alone or in mixture with 2,4-D and fluroxypyr showed maximum control between 31.7 and 38.7 DAA, with the exception of haloxyfop mixture + 2 4-D (670 + 25 g ha -1 ), that would take 57.8 DAA to promote satisfactory control (80.2%).…”

“…The soil was classified as eutroferric Red Latosol, in a clayey texture (Embrapa, 1999). The soil chemical analysis result presented the following characteristics: pH (CaCl 2 ) = 5.68; organic matter = 19.2 g dm -3 ; phosphorus = 26.44 mg dm -3 ; H+Al = 3.03 cmol c dm -3 ;…”

“…Unlike conventional maize hybrids, glyphosate does not control volunteer plants derived from tolerant hybrids efficiently (Deen et al, 2006).…”

“…Thus, the degree of interference exerted by glyphosate tolerant corn volunteer plants can reach yield losses rates of 23% in corn, 18% in soybean, 19% in sugar beet and 8% in the production of cotton fibers (Thomas et al, 2007;Marquardt et al, 2012b;Kniss et al, 2012). Therefore, the use of tank mixtures with ACCase inhibitors graminicides can be an excellent alternative in desiccation handling and post-emergence of transgenic soybean (Deen et al, 2006;Maciel et al, 2013).…”

Genetic use restriction technologies and possible applications in the integrated pest management

“…An example of this problem is the effect of volunteer GR corn on GR soybean crop, or vice versa, because the herbicide used in both crops is glyphosate. In that situation, the use of other herbicides or control method to replace glyphosate is required to control the volunteer transgenic plants (DEEN et al, 2006;BOND & WALKER, 2009). However, several herbicide resistance genes have been stacked into the same crop genotype, reducing herbicide options for the management of volunteer plants (SOLTANI et al, 2014).…”