Control of Glyphosate-Resistant Giant Ragweed in Winter Wheat

Abstract

Four field experiments were conducted over a 2-yr period (2012 and 2013) in winter wheat to evaluate POST herbicides for the control of glyphosate-resistant (GR) giant ragweed. POST herbicides were evaluated for winter wheat injury and GR giant ragweed control, population density, and aboveground biomass. The herbicides used in this study provided 54 to 90% and 51 to 97% control of GR giant ragweed at 4 and 8 wk after treatment (WAT), respectively. At 8 WAT, auxinic herbicide treatments or herbicide tank mix/premix treatments that contained auxinics provided 78 to 97% control of GR giant ragweed. Reductions in GR giant ragweed population density and aboveground biomass were 62 to 100% and 83 to 100%, respectively, and generally reflected the level of control. The results of this research indicate that Ontario, Canada, corn and soybean growers should continue to incorporate winter wheat into their crop rotation as one component of an integrated weed management (IWM) strategy for the control of GR giant ragweed.

Cropping System Redesign for Improved Weed Management: A Modeling Approach Illustrated with Giant Ragweed (Ambrosia trifida)

“…In 2017, alfalfa occupied 49% of the forage crop area in the states of Illinois, Indiana, Iowa, Minnesota, Nebraska, Ohio, South Dakota, and Wisconsin [27]. The use of winter cereals, like rye, and perennial forages, like alfalfa, appears to offer considerable opportunities to suppress populations of giant ragweed, due to differences in phenology and crop-specific mowing and herbicide regimes [17,32,42]. Additionally, because alfalfa is a perennial species that may remain in a field for forage harvesting for varying lengths of time after planting, modeling its use in different rotations provided an opportunity to investigate the weed-related effects of altering planting patterns without a concomitant increase in crop species richness.…”

“…Based on data from Mahoney et al [42], we set survival of giant ragweed seedlings in rye, due to herbicide application or cultivation, at 10% (i.e., control efficacy was 90%). Survival of giant ragweed seedlings growing with alfalfa was set at 0, due to the multiple mowing operations associated with hay harvests.…”

“…Our first-order analyses assumed a high level of giant ragweed control efficacy in rye (90%), based on results obtained by Mahoney et al [42] with herbicides applied to winter wheat. Because levels of weed control using cultivation equipment can be considerably lower than with herbicides [6], we conducted a sensitivity analysis to determine the effects of varying levels of giant ragweed control in rye.…”

Certified Crop Advisors’ Perceptions of Giant Ragweed (Ambrosia trifida) Distribution, Herbicide Resistance, and Management in the Corn Belt

“…Prevention of early giant ragweed germination by cover crops or cereal grains could promote decay of nongerminated or dormant giant ragweed seeds in soil over the summer months. Winter cereal grains or cover crops would also provide multiple chemical or mechanical control options for giant ragweed control (Mahoney et al 2015). The effect of cover crops and cereal grains on late-vs. early-emerging giant ragweed populations warrants investigation.…”

Pollen-mediated gene flow and transfer of resistance alleles from herbicide-resistant broadleaf weeds

“…It is widely distributed in the United States, primarily in the eastern Corn Belt, and in southern Canada (Bassett and Crompton 1982) and in several countries in Asia and Europe (Makra et al 2015). Giant ragweed is an economically important weed because of its allergenic pollen and its competitiveness with agronomic crops, including corn, soybean, and wheat (Ganie et al 2016;Mahoney et al 2015). Early emergence, rapid growth rate, and a high leaf-area index enable giant ragweed to assume a dominant role in the plant community; it often becomes invasive, reducing species diversity in the infested landscape (Abul-Fatih and Bazaz 1979a).…”