Waterhemp Management in Soybeans Waterhemp Biology • Waterhemp gains a competitive advantage over several more aggressive summer annual weeds through the sheer number of plants that can infest an area. Results from 2015 are described in the Crop News article, Manage waterhemp in soybean with layered residual herbicides. Soybean fields with emerged waterhemp where glyphosate has struggled in the past should get top priority for spraying. This was followed by reports of 2,4-D ... help control late-emerging weeds in soybean. State & National Extension Partners. Prior to the evolution of herbicide resistance in waterhemp, ALS-, PPO-, EPSPS- and GS-inhibiting herbicides controlled waterhemp postemergence in soybean. Procedures: Objective 1. Efficacy of residual herbicides in a field varies from year to year due to environmental factors such as temperature and rainfall. Sulfentrazone (HG 14) and metribuzin (HG 5) provided more consistent (smaller size box) PRE waterhemp control compared to flumioxazin (HG 14) over the 5-year period. Waterhemp has been the most troublesome weed for soybean farmers for the last 10 years. Use effective soil applied herbicides at planting. Use full labeled rates; For postemergence treatments, make timely applications and apply to small pigweed (<4 inches tall). The only option is the use of a PPO-inhibiting herbicide such as Flexstar, Cobra, or Ultra Blazer although there are multiple known populations of PPO-resistant Palmer and waterhemp in the state of Kentucky. and Iowa State University Extension and Outreach. 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. Site A was in Seneca County, NY on a field of Odessa silt loam soil where waterhemp had survived various herbicide applications and produced seed in 2018. Although these three HG 15 herbicides provided 82% or more control 50% of the time, the lowest control fell below 50%. If applied too early, the control of Waterhemp declines. Slated for sale in November for the 2021 growing season, Kyber includes 3 herbicide sites of action—pyroxasulfone (Group 15), flumioxazin (Group 14) and metribuzin (Group 5). Multiple flushes of waterhemp can … The volume of inquiries about how to control large (taller than 12 inches) horseweed (a.k.a. Farmers should always use full, labeled rates and herbicides with multiple sites of action from different classes of chemistry. 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. Waterhemp control (% out of 100) with various preemergence (PRE) soybean herbicides New herbicide promises control of waterhemp. All rights reserved. Please visit our corn and soybean pages for information on a portfolio of products from Bayer to help you better manage weeds. Glyphosate-resistant waterhemp and Palmer amaranth are widespread and if they were not controlled early in the season, they can interfere with soybean harvest (Figure 1). Soybean fields with emerged waterhemp where glyphosate has struggled in the past should get top priority for spraying. Farmers who have soybean fields with heavy waterhemp pressure should consider applying HG 5 and HG 14-based PRE products as premixes or in combination with HG 15 to give more consistent early-season residual weed control and manage glyphosate- and PPO-resistant waterhemp. “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. Many of the other pre-emerge herbicides can be saved for post, just in case you need them. Waterhemp management in soybeans was a challenge for several farmers in 2018. Include Group 15 herbicides in the both corn and soybean. (800) 262-3804, Iowa State University PFR HERBICIDE STUDIES PG. According to the Purdue University Extension, in soybeans, 20 waterhemp plants per square foot can reduce yield by 44 percent. Boxes represent the middle 50% of the data. Herbicide-resistant waterhemp is already problematic for soybean producers. Weed control options in soybeans. With dwindling herbicide resources, there is a need to integrate non-chemical strategies into current weed management programs in soybean. “Zero tolerance for adding weed seed to the soil should be every farmer’s goal.”. Some herbicides perform better than others in variable environmental conditions. Apply in the spring to control tough weeds like marestail, waterhemp, lambsquarters and ragweed. the author is required. Diligent™ provides the defense you need, plus the flexibility to tank-mix with glyphosate and other residual herbicides. Layering herbicides for waterhemp control: Research on the effectiveness of this strategy in Minnesota soybean, including yield and control data. Ideally, a grower would use both a group 14 and a group 2 herbicide if the waterhemp is glyphosate-resistant to slow the selection pressure for multiple-resistant waterhemp. marestail) and waterhemp in soybean has remained consistent over the past 10 days. It’s a premix of three herbicide sites of action aimed at managing problem soybean weeds including Palmer amaranth, waterhemp, and common ragweed. without further permission if published as written and if credit is given to the author, Integrated Crop Management News, 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 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. Soon before or after soybean planting, apply a PRE residual herbicide with good activity on waterhemp. Waterhemp control is an increasing challenge for soybean producers due to the evolution of multiple herbicide-resistant populations. Protect your soybeans from waterhemp and other weeds with Diligent™ herbicide. Preemergence (PRE) soil residual herbicides serve as a foundation for managing waterhemp, but require follow-up treatments with effective postemergence (POST) products due to late-emerging plants. Soil-applied herbicide is the first chemical control step in protecting soybeans and corn from Waterhemp. 29: 716–729. Treating new infestations early reduces waterhemp establishment, prevents seed production and greatly improves control. New this year, we’ve added Include Group 15 herbicides in the both corn and soybean. Use effective soil applied herbicides at planting. 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. Other control practices farmers may use include crop rotation, planting cover crops and using diversified weed management programs. 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 economic threshold recommendation is no longer enough. Copyright © 2020 Iowa State University of Science and Technology. For further information on resistance confirmed by state, visit the International Survey of Herbicide Resistant Weeds. Reducing application rates of these herbicides often results in reduced waterhemp control. Think about waterhemp, lambsquarters, common ragweed, giant ragweed, palmer pigweed, velvetleaf, and marestail. (And common ragweed. This premix combines three modes of action, each effective individually, to control resistant weeds. Purdue Extension also found a similar impact on corn yield. The volume of inquiries about how to control large (taller than 12 inches) horseweed (a.k.a. Farmers also can use several cultural practices to control waterhemp. ( Sonja Begemann ) Waterhemp, Palmer amaranth, redroot pigweed—these words in agriculture are nearly synonymous with … Nicholas J. Arneson, Daniel H. Smith, Ryan DeWerff, Maxwel Coura Oliveira, and Rodrigo Werle. 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. This strategy will aid in delaying emergence of waterhemp until soybean canopy closure when the crop will be more competitive, thereby reducing selection pressure on POST herbicides and reducing crop-weed competition and protecting against soybean yield losses. The small-seeded weed is one of the toughest to control. That ugly patch of weeds the combine just tore through is costing farmers money. Think about waterhemp, lambsquarters, common ragweed, giant ragweed, palmer pigweed, velvetleaf, and marestail. Waterhemp competing with soybeans at a farm in Seneca County, NY. Never apply glyphosate alone to emerged pigweed Those populations were resistant to one or more of these products including s-metolachlor, dimethenamid-P, pyroxasulfone, and acetochlor. 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. Time of application is very important. To evaluate the performance of commonly used HG 15 herbicides (pyroxasulfone, S-metolachlor, dimethenamid-P, and acetochlor) on waterhemp in Iowa soybean fields, an analysis on weed control data collected from herbicide evaluation trials was conducted by the Weed Science program at Iowa State University Research Farms from 2015 to 2019. Waterhemp is a late emerging weed, meaning that soil-applied herbicides should be applied 1 … These herbicides have been extensively used for postemergence waterhemp control in soybeans with generally good results. Postemergence Herbicides for Soybeans. Got waterhemp? A single plant can produce a quarter-million seeds, which can remain viable for up to four years in the soil. Scenario 3: RR2Xtend Soybeans are emerged and Palmer/Waterhemp are emerged. If you’re a soybean grower, you really have only four classes of postemergence herbicides to throw at waterhemp. The answer can be summarized as follows: there are NO postemergence herbicides that will consistently control these very large weeds in soybean,… The first true leaves of the waterhemp plant appear generally longer and more spear-shaped than other pigweeds. The main reason we like the combination we listed is the weed control is superior to anything else. • Why use a full rate instead of a reduced (“setup”) rate? For soybeans, customers should consider using Kyber™ herbicide, Sonic ® herbicide and Trivence ® herbicide. A follow-up application of HG 15 is recommended at the POST timing as part of a layered residual program in soybean. 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. By Brian Hefty Everyone is talking about Roundup-resistant weeds. Efficacy of residual herbicides in a field varies from year to year due to environmental factors such as temperature and rainfall. 2150 Beardshear Hall This is really a worst-case scenario as herbicide options are limited to none. Seedlings are hairless and have leaves that look waxy or glossy. Marvel™ herbicide protects soybean yields with superior postemergence control of glyphosate-resistant weeds and broad-spectrum control of other key weeds, including waterhemp, Palmer amaranth/Palmer pigweed, lambsquarters, morningglories and velvetleaf. Waterhemp can grow at the incredible rate of 1 to 1 1/4 inches per day, so timely herbicide application is critical. Waterhemp: Best=Flexstar, 2=Marvel (Flexstar/Cadet premix), ... Darren and I have put together the best weed control programs in corn, soybeans, and wheat for all the weeds I have listed above, as well as many more. Planting in narrow rows to help soybeans, for example, outcompete the … Although flumioxazin was very effective on waterhemp (>95% control 50% of the time), control fell below 60% in one out of the five years. For best control, apply a pre-emergence residual herbicide followed by post-emergence applications as needed throughout the growing season. A description of herbicide resistance in Illinois waterhemp populations, along with postemergence herbicide options to control waterhemp, follows. Subscribe to receive email alerts when new information is posted. “If left untreated, it will compete with soybeans all season long, and can reduce yield by 44%,” said Jeff Stachler, OSU Extension Educator in Auglaize County, and Weed Specialist. For the complete report, see Managing Waterhemp in Soybean with Layered Residual Herbicides - A Strategy for Controlling ALS and Glyphosate Resistant Waterhemp in Minnesota, 2015 and 2016. A single plant can produce a quarter-million seeds, which can remain viable for up to four years in the soil. In Illinois, Iowa, Missouri and other areas across the Corn Belt, there is documented waterhemp resistance to ALS inhibitors (Group 2), PPO inhibitors (Group 14), glyphosate (Group 9), triazines (Group 5) and HPPD inhibitors (Group 27). contained within may not be the most current and accurate depending on when it is accessed. Kyber ™ herbicide is the comprehensive solution to difficult-to-control weeds in soybean fields. Weed control options in soybeans. Site A was in Seneca County, NY on a field of Odessa silt loam soil where waterhemp had survived various herbicide … 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. If applied too early, the control of Waterhemp declines. Some of those include: 1. Bayer has a broad herbicide portfolio to combat tough-to-control and resistant weeds. Never apply glyphosate alone to emerged pigweed Waterhemp requires more than twice as many growing degree days to reach 50% emergence as giant foxtail or velvetleaf (Figure 1), resulting in much of the population emerging after mid-June. Postemergence Herbicides for Soybeans. Before applying any herbicide, please read the entire label for the best possible results and to confirm that the product is effective on the weeds you wish to control. With increasing frequency of wet springs, as in 2019, some PRE herbicides break down early in the season resulting in inadequate residual control of waterhemp, a scenario that imposes a greater selection pressure on POST products. Not every product is suitable for every situation, and use of the correct application technique will ensure the best results. 04 APPLICATION TIMING AND CUTOFFS PG. The blue line within each plot represents the median of data, while the diamond represents the average percent control over the 5-year period. Season-long competition by waterhemp (more than 20 plants per square foot) has been shown to reduce soybean yield by 44%. Waterhemp can grow at the incredible rate of 1 to 1 1/4 inches per day, so timely herbicide application is critical. As we get close to soybean harvest, some herbicides can be applied as harvest aids (desiccant) to desiccate weeds and improve harvest operation. “The ALS inhibitors (Pursuit, Scepter) are almost completely ineffective against waterhemp in Illinois now,” Hager says. Marvel™ herbicide protects soybean yields with superior postemergence control of glyphosate-resistant weeds and broad-spectrum control of other key weeds, including waterhemp, Palmer amaranth/Palmer pigweed, lambsquarters, morningglories and velvetleaf. CONTROL IN SOYBEAN. DiFlexx herbicide controls tough weeds including Palmer amaranth, waterhemp, ragweed and lambsquarters, plus over 100 more annual and perennial weeds in corn. Waterhemp is a new, aggressive, glyphosate-resistant weed that has swept across the Midwest and made its way into Ontario and Quebec. Soybean fields with emerged waterhemp where glyphosate has struggled in the past should get top priority for spraying. Each is a "contact" herbicide, so thorough coverage of the target vegetation is essential for good control. The lowest level of control with pyroxasulfone was 88% at three weeks after application. The good news is these weeds are easy to control in corn. And waterhemp.). Several management considerations need to be addressed with The most troublesome multiple-resistant weeds for North American crop production are 2 pigweed species, common waterhemp and Palmer amaranth. Group 14 herbicides are likely the best choice for POST-emergence control of glyphosate-resistant waterhemp in Roundup Ready soybeans. Box and whisker plots showing the variability in waterhemp control at 3 weeks after application of key PRE-emergence herbicides used in soybean over the last five years (2015-2019) in trials conducted by the ISU Weed Science program at the Research Farms. DiFlexx ® DUO DiFlexx DUO is the ideal combination of HPPD herbicide and dicamba, plus a highly effective CSI safener from Bayer that controls grass and broadleaf weeds. “The ALS inhibitors (Pursuit, Scepter) are almost completely ineffective against waterhemp in Illinois now,” Hager says. Although there are many ways weeds escape control in crop fields, one of the leading causes of waterhemp control failures is emergence of plants following postemergence herbicide (POST) treatments. Every meeting I went to this winter, every conference I attended, and every farm magazine I picked up, Roundup-resistant weeds were there. With dwindling herbicide resources, there is a need to integrate non-chemical strategies into current weed management programs in soybean. Waterhemp is a late emerging weed, meaning that soil-applied herbicides should be applied 1 … Waterhemp control was more variable (bigger size boxes) with s-metolachlor, dimethenamid-P, and acetochlor. of waterhemp resistant to metolachlor and other Group 15 herbicides. We have, however, seen the development of new soybeans with herbicide-resistant traits. Use Group 14 (PPO) in soybean followed by Group 27 (HPPD) in corn. Proliferation of resistant waterhemp can be managed by accurate weed identification and regular scouting. 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. 42 PLANT-BACK RESTRICTIONS PG. Palmer amaranth and waterhemp have an amazing ability to develop resistance to herbicides. 3 Due to its genetic variability, wide emergence window, vigorous growth potential, and prolific seed production, waterhemp has become a troublesome weed in Use Group 14 (PPO) in soybean followed by Group 27 (HPPD) in corn. 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. This article was originally published on April 17, 2020. Waterhemp competing with soybeans at a farm in Seneca County, NY. Take Home Message. For best control, apply a pre-emergence residual herbicide followed by post-emergence applications as needed throughout the growing season. Group 14 herbicides are likely the best choice for POST-emergence control of glyphosate-resistant waterhemp in Roundup Ready soybeans. Two trial sites were established. This premix combines three modes of action, each effective individually, to control resistant weeds. Extend weed spectrum and burndown when weeds have already emerged by adding to Roundup herbicide or 2,4-D LVE. Group 15 herbicides (HG 15) are commonly used for PRE waterhemp control. It is highly unlikely that a one pass, preemergence herbicide application will provide adequate control of resistant tall waterhemp in soybeans. Kyber ™ herbicide is the comprehensive solution to difficult-to-control weeds in soybean fields. Waterhemp control (% out of 100) with various preemergence (PRE) soybean herbicides It can be applied at 1.25 to 2 quarts per acre, depending on soil texture and organic matter content. The use of PRE-emergence herbicides is a foundation for waterhemp control in soybeans. Soybean fields with emerged waterhemp, where glyphosate has struggled in the past to control the weed, should receive priority for spraying. The impact of waterhemp on soybean yields is very real. To evaluate the performance of commonly used HG 15 herbicides (pyroxasulfone, S-metolachlor, dimethenamid-P, and acetochlor) on waterhemp in Iowa soybean fields, an analysis on weed control data collected from herbicide evaluation trials was conducted by the Weed Science program at Iowa State University Research Farms from 2015 to 2019. soybean herbicides in Roundup Ready (RR) or conven-tional soybean systems. Authority Edge has “You could use glyphosate, but resistance continues to increase every year. Figure 1. Palmer amaranth and waterhemp have an amazing ability to develop resistance to herbicides. The first step is to verify you’re actually dealing with waterhemp. Group 14 herbicides are likely the best choice for POST-emergence control of glyphosate-resistant waterhemp in Roundup Ready soybeans. Prashant Jha is an Associate Professor and Extension Weed Specialist with the Department of Agronomy at ISU. Protect Your Almonds Against Nematodes with Velum One, Protect Your Potatoes Against Nematodes with Velum Prime, International Survey of Herbicide Resistant Weeds, Six Questions to Ask Yourself when Developing Your Weed Control Program, Identifying Pigweed and Keeping Resistance at Bay. Soybean Pest Beat: Here are tips to get a plan rolling to control waterhemp in 2021. Group 14 herbicides are likely the best choice for post-emergence control of glyphosate-resistant waterhemp in Roundup Ready soybeans. First true leaves appear generally longer and more spear-shaped than other pigweeds. 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. marestail) and waterhemp in soybean has remained consistent over the past 10 days. Herbicide-resistant waterhemp is already problematic for soybean producers. To preserve the value of POST herbicides, the main goals of a PRE product are to reduce the density and size of weeds at the time of POST herbicide application. Waterhemp is an annual weed with enormous genetic diversity. Two trial sites were established. with Pre-emergence Herbicides in Soybean. ( Sonja Begemann ) Waterhemp, Palmer amaranth, redroot pigweed—these words in agriculture are … Figure 1. New herbicide promises control of waterhemp. 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. Say goodbye to Palmer amaranth. These herbicides have been extensively used for postemergence waterhemp control in soybeans with generally good results. Control waterhemp before it reaches 4 inches in height to achieve timely and effective herbicide application. The small-seeded weed is one of the toughest to control. Use full labeled rates; For postemergence treatments, make timely applications and apply to small pigweed (<4 inches tall).
2020 soybean herbicides for waterhemp