Having explored resistance issues with waterhemp and Palmer amaranth, let's turn our attention to discuss some control options for soybean in fields where resistance has been observed. The small-seeded weed is one of the toughest to control. Kyber ™ herbicide is the comprehensive solution to difficult-to-control weeds in soybean fields. Results from 2015 are described in the Crop News article, Manage waterhemp in soybean with layered residual herbicides. Waterhemp is a new, aggressive, glyphosate-resistant weed that has swept across the Midwest and made its way into Ontario and Quebec. For best control, apply a pre-emergence residual herbicide followed by post-emergence applications as needed throughout the growing season. Waterhemp resistance to HG 15 has not been confirmed yet in Iowa; however, it is important to proactively protect the value of these products for waterhemp control in soybean fields. Common waterhemp, giant ragweed, marestail (also commonly known as horseweed) and common lambsquarters are listed among the top problematic weeds for soybeans, according to weed experts in Illinois, Iowa, Kentucky and Minnesota. Early season competition from a heavy waterhemp infestation (more than 30 plants per square foot by the time they are 6 inches tall) can reduce corn yield by 15 percent. However, an increased selection pressure from these herbicides used in corn-soybean rotations has resulted in the evolution of HG 15 resistance in waterhemp populations, recently documented in Illinois. Links to this article are strongly encouraged, and this article may be republished Reducing application rates of these herbicides often results in reduced waterhemp control. Warrant is an acetochlor-based residual herbicide that can be applied post-emergence in soybean after soybeans are completely emerged, but before they reach R2 (initiation of flowering) growth stage. In an effort to use multiple effective SOAs to control waterhemp populations, we evaluated the performance of layering Group-14 Valor® SX followed by Group-15 Dual II Magnum. Figure 1. Control of waterhemp is best achieved with a two-pass herbicide program where the first pass is with a pre-emergence (PRE) soil applied herbicide and the second with a postemergent (POST) herbicide. With dwindling herbicide resources, there is a need to integrate non-chemical strategies into current weed management programs in soybean. Prior to the evolution of herbicide resistance in waterhemp, ALS-, PPO-, EPSPS- and GS-inhibiting herbicides controlled waterhemp postemergence in soybean. Although these three HG 15 herbicides provided 82% or more control 50% of the time, the lowest control fell below 50%. Not every product is suitable for every situation, and use of the correct application technique will ensure the best results. with Pre-emergence Herbicides in Soybean. Efficacy of HG 14 (flumioxazin), sulfentrazone) and HG 5 (metribuzin) on waterhemp control was also compared over the 5-year period. Say goodbye to Palmer amaranth. Use effective soil applied herbicides at planting. Waterhemp resistance to HG 15 has not been confirmed yet in Iowa, however it is important to proactively protect the value of these products for waterhemp control in soybean fields. Herbicide-resistant waterhemp is already problematic for soybean producers. Residual Control of Waterhemp . Every meeting I went to this winter, every conference I attended, and every farm magazine I picked up, Roundup-resistant weeds were there. 44 APPLICATION RESOURCES This guide is a comprehensive collection of recommended herbicide programs and options for soybeans, plus other valuable resources to aid in herbicide decision making. Include Group 15 herbicides in the both corn and soybean. A small number of weed species are resistant to multiple herbicides, leaving growers with very limited viable options for control. When soybean yields are at stake, trust in the power of Authority XL herbicide. His research program is focused on improved understanding of weed biology and ecology to develop effective, integrated weed management strategies in corn and soybean production systems of ... ISU Extension and Outreach The volume of inquiries about how to control large (taller than 12 inches) horseweed (a.k.a. In conventional or glyphosate-tolerant soybean: If Group 9 (e.g., glyphosate) resistance in waterhemp is known or suspected and there is no reason to believe the population is also resistant to Group 14 (e.g., PPO-inhibitors) herbicides, apply a Group 14 herbicide like Cobra®, Flexstar®, or Ultra Blazer® to waterhemp not more than 3 to 4 inches in height. This premix combines three modes of action, each effective individually, to control resistant weeds. The good news is these weeds are easy to control in corn. “You could use glyphosate, but resistance continues to increase every year. Waterhemp competing with soybeans at a farm in Seneca County, NY. As we finalize harvesting our crops, it’s important to properly map the fields infested with waterhemp and start developing an effective management plan for 2019. Planting in narrow rows to help soybeans, for example, outcompete the … Soybean fields with emerged waterhemp, where glyphosate has struggled in the past to control the weed, should receive priority for spraying. Among the HG 15 herbicides tested in soybean, pyroxasulfone provided the most consistent waterhemp control over the 5-year period (smaller size Box; Figure 1), with >95% control 50 percent of the time. The first true leaves of the waterhemp plant appear generally longer and more spear-shaped than other pigweeds. “The ALS inhibitors (Pursuit, Scepter) are almost completely ineffective against waterhemp in Illinois now,” Hager says. Apply in the spring to control tough weeds like marestail, waterhemp, lambsquarters and ragweed. “In today’s environment, there’s no such thing as an economic threshold for control of resistant weeds,” says Dr. Reid Smeda, University of Missouri weed scientist. Waterhemp control is an increasing challenge for soybean producers due to the evolution of multiple herbicide-resistant populations. It’s a premix of three herbicide sites of action aimed at managing problem soybean weeds including Palmer amaranth, waterhemp, and common ragweed. Boxes represent the middle 50% of the data. That ugly patch of weeds the combine just tore through is costing farmers money. Waterhemp is a late emerging weed, meaning that soil-applied herbicides should be applied 1 … HG 14 resistant is fairly common in Iowa fields, and while sulfentrazone and flumioxazin still have activity on resistant populations, it usually is shorter-lived than with susceptible populations. Group 14 herbicides are likely the best choice for POST-emergence control of glyphosate-resistant waterhemp in Roundup Ready soybeans. AVOID WATERHEMP: All three Indiana CCAs agree that planning, residual herbicides and a targeted postemergence approach can control waterhemp in soybeans next year. marestail) and waterhemp in soybean has remained consistent over the past 10 days. Season-long competition by waterhemp (more than 20 plants per square foot) has been shown to reduce soybean yield by 44%. In our research, we have observed less control of glyphosate-resistant waterhemp with tankmixes of glyphosate and fluthiacet (Cadet) or 2,4-DB compared with tankmixes of other PPO-inhibiting herbicides.
2020 soybean herbicides for waterhemp