About

Dr. Rodrigo Werle is an Associate Professor and Extension Cropping Systems Weed Scientist at the University of Wisconsin-Madison. His research and Extension program, known as WiscWeeds, focuses on integrated approaches to weed management in corn, soybean, and small grains within Wisconsin farm systems. His work emphasizes agroecologically-based strategies to promote sustainable weed management, protect water quality, enhance agroecosystem services, and increase food security. Dr. Werle's research also includes studying the biology and ecology of troublesome weed species and the distribution and management of herbicide-resistant weeds. He received his Bachelor of Science in Agronomy from São Paulo State University in Brazil, followed by a Master’s and Ph.D. in Agronomy with a specialization in Weed Science from the University of Nebraska-Lincoln. Prior to his current position, he served as an Assistant Professor and Cropping Systems Specialist at the University of Nebraska-Lincoln. Dr. Werle is actively involved in updating and developing weed management recommendations for Wisconsin growers, serving the agricultural community, and participating in programs such as herbicide evaluation. His contributions have been recognized through awards including the North Central Weed Science Society Outstanding Young Scientist Award in 2021 and the University of Wisconsin-Madison Alfred Toepfer Faculty Fellow Award in 2020-2021.

Research topics

• Agronomy
• Biology
• Environmental science
• Horticulture
• Ecology
• Soil science
• Animal science
• Biochemistry
• Chemistry
• Engineering

Selected publications

• Impact of application time on soil residual herbicide dissipation in early-planted soybean

  Weed Technology · 2026-01-01

  articleOpen accessSenior authorCorresponding

  Abstract In the Midwest United States, early soybean planting is becoming more common, but the implications for soil residual herbicide dissipation and optimal application time remain unclear. Earlier planting extends the interval between soil-residual herbicide application at planting and the onset and peak of weed emergence, potentially reducing efficacy through an extended window for dissipation. This study aimed to evaluate the dissipation and weed control efficacy of soil residual herbicides applied at different timings in early planted soybean crops under varying soil conditions. At Arlington, Wisconsin, which has a silt loam soil, herbicide concentrations when soil was sampled, 21 d after the fourth and final application of herbicides, which followed a series of treatments from planting to the V1 growth stage of soybean, were similar across application times, whereas at Brooklyn, Wisconsin, which has a sandy loam soil, herbicide concentrations were usually higher when herbicides were applied later. Despite these differences, weed density at postemergence was similar across application times within each site. However, an additional late postemergence herbicide application was necessary at Brooklyn following the earliest application times in 2022, indicating more rapid herbicide dissipation. Herbicide dissipation and efficacy varied by soil texture. In sandy soils, early applications may lead to reduced control of late-emerging weeds due to rapid dissipation. In contrast, finer-textured soils may allow for more flexible application timing. These insights support site-specific residual herbicide application strategies in early planted soybean systems.

  PublisherOA PDFDOI

• Evaluation of single versus multiple site of action preemergence herbicides for waterhemp and giant ragweed control in Wisconsin soybean

  Agrosystems Geosciences & Environment · 2026-01-09

  articleOpen access1st authorCorresponding

  Abstract The use of preemergence (PRE) herbicides with soil residual activity is recognized as an effective strategy for early‐season weed management in Midwest US soybean [ Glycine max (L.) Merr.] production. The efficacy of soybean PRE herbicides with single and multiple sites of action (SOAs), including acetolactate synthase (ALS), photosystem II, protoporphyrinogen oxidase (PPO), and very long‐chain fatty acid (VLCFA) inhibitors, was assessed in a randomized complete block design across 4 site‐years (Brooklyn‐2019, Fond du Lac‐2019, Lancaster‐2018, and Lancaster‐2019) for waterhemp [ Amaranthus tuberculatus (Moq.) J.D. Sauer] and three site‐years (Janesville‐2019, Janesville‐2020, and Janesville‐2021) for giant ragweed ( Ambrosia trifida L.) in Wisconsin. The data were pooled across site‐years, and the results are presented by species to highlight the most effective herbicide treatments across varying environmental conditions. Several single‐ and multiple‐SOA PRE herbicides from the photosystem II (PS II), PPO, and VLCFA groups effectively (>90%) controlled waterhemp at 21 and 42 days after treatment (DAT) and significantly reduced biomass (>86%) 42 DAT. Similarly, single ALS PRE herbicides group, as well as premixes containing ALS + PPO, ALS + PS II + PPO, and ALS + PPO + VLCFA, provided 79%–92% giant ragweed control at 21 and 42 DAT and reductions in biomass by 80%–95%. Our data show a positive correlation between biomass reduction and visual weed control assessments for both waterhemp and giant ragweed, suggesting that quality visual assessments can serve as a reliable proxy for evaluating PRE herbicide efficacy. Our results suggested that PRE herbicide containing two or three SOAs provided greater and more consistent control and biomass reduction of waterhemp and giant ragweed compared to single‐SOA PRE herbicides.

  PublisherOA PDFDOI

• Targeted herbicide spraying systems: role of nozzle type, number of nozzle activation, nozzle orientation, and boom height on spray coverage and weed control

  Pest Management Science · 2026-02-21 · 1 citations

  articleOpen accessSenior authorCorresponding

  BACKGROUND: Differences in ground-based sprayer setup within targeted herbicide application systems can influence spray coverage and herbicide efficacy. This research aimed to improve understanding of how these factors affect spray coverage and weed control using complementary field and controlled-environment experiments. RESULTS: ), TP40015E and DG80015 nozzles produced similar spray coverage (25%). A 53 cm boom height provided greater spray coverage under both no-wind (52%) and wind (32%) conditions compared to 76 cm (41% no-wind versus 18% with wind; Study 2). Multiple-nozzle activation resulted in higher spray coverage than a single-nozzle activation under no-wind (58% versus 36%) and wind (29% versus 19%) conditions. Multiple nozzles also resulted in greater weed control (> 92%) and biomass reduction (95%) than single-nozzle activation (78% control and 87% biomass reduction; Study 3). Under no-wind conditions, conventional 0° and 30° rearward inclined nozzle orientations provided comparable spray coverage (≥ 42%) and did not differ in weed control or biomass reduction. In contrast, under wind conditions, the 30° rearward inclined orientation resulted in the lowest spray coverage (16%; Study 5). CONCLUSION: Regardless of boom height, nozzle orientation, and wind, activation of multiple nozzles resulted in better spray coverage and weed control than single nozzle activation. © 2026 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

  PublisherOA PDFDOI

• Target‐site and non‐target‐site mechanisms confer multiple herbicide resistance in waterhemp ( <scp> <i>Amaranthus tuberculatus</i> </scp> ) accessions from Wisconsin

  Pest Management Science · 2026-03-02

  articleOpen accessSenior authorCorresponding

  BACKGROUND: A preliminary screening identified a multiple herbicide-resistant waterhemp, Amaranthus tuberculatus (Moq.) Sauer, accession (A101) exhibiting resistance to 2,4-D and atrazine despite no prior exposure to these herbicides. Therefore, our objective was to characterize resistance to 2,4-D, atrazine, glyphosate, fomesafen, and mesotrione in A101, along with two additional multiple herbicide-resistant accessions (A75 and A103). RESULTS: A101 exhibited low to medium levels of resistance to all five herbicides evaluated (ranging from 1.8-fold for mesotrione to 8.5-fold for fomesafen). Both A75 and A103 also had multiple resistance to glyphosate and atrazine, with A75 and A103 additionally resistant to 2,4-D and fomesafen, respectively. Amplification of EPSPS and the P106S substitution accounted for some of the glyphosate resistance, and some of the fomesafen resistance was explained by the G210 deletion in the target enzyme. Moreover, the use of cytochrome P450 monooxygenases (P450s) and glutathione S-transferases (GSTs) inhibitors indicated that non-target-site resistance (NTSR) mechanisms also contribute to at least some of the resistance traits. CONCLUSION: Metabolic resistance to 2,4-D and atrazine suggests that the use of other herbicides may have contributed to the selection of enhanced P450s and GSTs activity in A101 accession. To our knowledge, this is the first report of P450s associated with atrazine resistance in A. tuberculatus globally. A101 is the first confirmed case of A. tuberculatus resistance to hydroxyphenyl pyruvate dioxygenase inhibitors in Wisconsin, exhibiting a low-level resistance likely associated with P450s and GSTs activity. Our results suggest the coexistence of target-site resistance and NTSR mechanisms associated with glyphosate resistance in A101. © 2026 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

  PublisherDOI

• Dicamba-based preemergence herbicide tank mixtures improved residual weed control in dicamba-resistant soybean

  Frontiers in Agronomy · 2025-04-09 · 4 citations

  articleOpen access

  In February 2024, the United States Environmental Protection Agency (EPA) vacated the registrations of dicamba products for over-the-top applications on dicamba-resistant cotton and soybean following a court ruling. This decision has raised significant concerns among United States farmers, who now have limited chemical options to manage tough-to-control weeds. However, the risk of off-target dicamba movement to sensitive plants remains a critical issue. If permitted in the future, applying dicamba as a preemergence (PRE) treatment, tank-mixed with other soil residual herbicides, could help reduce off-target movement while preserving its utility for managing problem weeds. Field experiments were conducted in 2022 and 2023 in Minnesota and North Dakota, and in 2021 and 2022 in Wisconsin, to evaluate the effectiveness of dicamba-based PRE herbicide mixtures in soybean. Across all site-years, dicamba tank mixed with other soil residual herbicides provided better control of targeted weed species at 21 d after treatment (DAT) compared to applying the residual herbicides alone. In Minnesota, dicamba-based herbicide tank mixes provided an average waterhemp control of 72%, compared to 59% for treatments without dicamba at 21 DAT. Similarly, in North Dakota, waterhemp control at 21 DAT improved from 74% with residual herbicides alone to 97% when tank mixed with dicamba. In Wisconsin, dicamba-based tank mixes resulted in 96% control of common ragweed and 83% of velvetleaf, versus 83% and 73% for those species, respectively, without dicamba. At the Minnesota site, adding dicamba to residual herbicides improved common lambsquarters and giant ragweed control by 17% and 20%, respectively, and their densities were reduced by at least 50%. At the North Dakota site, kochia control was improved by 23% with dicamba PRE. The results from this research outlined the effectiveness of PRE application of dicamba tank mixed with other residual herbicides for effective weed management in the Upper Midwest.

  PublisherOA PDFDOI

• Termination strategies for high biomass cereal rye cover crop in soybean planting green systems

  Agrosystems Geosciences & Environment · 2025-07-09

  articleOpen accessSenior authorCorresponding

  Abstract Weed management programs utilizing high‐biomass cereal rye ( Secale cereale L.) cover crop in Wisconsin soybean [ Glycine max (L.) Merr.] production systems are increasing in popularity. Much of this method's success depends on effective cereal rye termination and environmental conditions in the spring. A randomized complete block design field experiment was conducted in 2021 and 2022 at the University of Wisconsin‐Madison Arlington Agricultural Research Station in southern Wisconsin designed to determine the efficacy of chemical (glyphosate, clethodim, and quizalofop‐P‐ethyl) and mechanical (McFarlane roller‐crimper) techniques and combinations thereof for termination of high biomass cereal rye cover crop and their impact on yield in planting green soybean systems. The control treatment was glyphosate applied pre‐plant (preplant control). Glyphosate‐containing treatments were the most effective in percent control of terminated cereal rye 21 days after soybean planting in both years (2021: &gt;98%, 2022: &gt;99%) compared to roller‐crimping (2021: &lt;49%, 2022: &gt;96%), the ACCase inhibitors clethodim and quizalofop‐P‐ethyl (2021: &lt;29%, 2022: &lt;85%), roller‐crimper + clethodim (2021: &lt;66%; 2022: 99%), and roller‐crimper + planting green quizalofop‐P‐ethyl (2021: &lt;63%). Soybean stand densities in planting green clethodim (&lt;27%) and planting green quizalofop‐P‐ethyl (&lt;18%) treatments were less than the pre‐plant control in both years. Soybean stand density was not affected by other treatments. Soybean yields in both years were greater in the pre‐plant control treatment (2021: 5454 kg ha −1 and 2022: 3912 kg ha −1 ) than other treatments except for the roller‐crimper + planting green glyphosate treatment (2021: 5137 kg ha −1 and 2022: 3541 kg ha −1 ). Planting green glyphosate, roller‐crimper, and all chemical + mechanical combinations did not differ from each other in yield for 2022. This study found that roller‐crimper + planting green glyphosate was equivalent to the pre‐plant control, and both were followed by planting green glyphosate as the best termination techniques for controlling a high biomass cereal rye cover crop and protecting yield potential in planting green soybean systems.

  PublisherOA PDFDOI

• Stakeholder assessment of weed management practices and perceptions of targeted spraying technologies in corn-soybean systems

  Frontiers in Agronomy · 2025-07-03 · 3 citations

  articleOpen accessSenior authorCorresponding

  Introduction Understanding regional weed control practices and stakeholder perspectives is essential to guide the development and adoption of novel weed management technologies. This survey aimed to evaluate chemical weed control practices, major weed escapes, and stakeholder perceptions of targeted spraying technologies in corn and soybean cropping systems across the U.S. Midwest. Methods A survey was conducted from fall 2021 to spring 2022 in corn ( Zea mays L.) and soybean [ Glycine max (L.) Merr.] cropping systems across the Western U.S. Midwest Region (WUMR: Kansas and Nebraska) and the Eastern U.S. Midwest Region (EUMR: Illinois, Minnesota, and Wisconsin). It assessed currently adopted herbicide programs, end-of-season weed escapes, and awareness of targeted spraying technologies among growers, advisors, and applicators. Results Survey responses (128 participants) indicated that over 50% of growers used a two-pass herbicide application program [preemergence (PRE) followed by postemergence (POST) with layered residual] in soybean and corn across both regions in 2021. The top weed escapes in WUMR corn fields were Palmer amaranth ( Amaranthus palmeri S.Wats.), waterhemp [ Amaranthus tuberculatus (Moq.) J.D.Sauer], and foxtail species ( Setaria spp.), while for soybean fields, Palmer amaranth, waterhemp, and volunteer corn were most common. Conversely, EUMR respondents primarily reported foxtail spp., waterhemp, and giant ragweed ( Ambrosia trifida L.) escapes in corn and waterhemp, giant ragweed, and volunteer corn in soybean fields. Over 49% of respondents believe that novel targeted spraying technologies could help control late season weed escapes. However, more than 75% are unsure whether these technologies will be adopted in the operations they manage in the future, with 48% indicating the need of more information to support their decision. The survey results showed a greater reliance on commercial applicator services in the EUMR than WUMR, highlighting the potential role of commercial applicators in advancing effective herbicide strategies and targeted spraying technologies adoption while reducing the need for farmers to invest in new equipment within the EUMR region. Discussion This survey highlights substantial opportunities for targeted herbicide application technologies research and outreach education involving regulatory agencies, spray manufacturers, chemical companies, decision influencers, University Extension and other parties.

  PublisherOA PDFDOI

• Influence of glufosinate mixtures on waterhemp control and soybean canopy and yield

  Weed Technology · 2025-01-01 · 2 citations

  articleOpen accessSenior authorCorresponding

  Abstract Glufosinate serves as both a primary herbicide option and a complement to glyphosate and other postemergence herbicides for managing herbicide-resistant weed species. Enhancing broadleaf weed control with glufosinate through effective mixtures may mitigate further herbicide resistance evolution in soybean and other glufosinate-resistant cropping systems. Two field experiments were conducted in 2020 and 2021 at four locations in Wisconsin (Arlington, Brooklyn, Janesville, and Lancaster) and one in Illinois (Macomb) to evaluate the effects of postemergence-applied glufosinate mixed with inhibitors of protoporphyrinogen oxidase (PPO) (flumiclorac-pentyl, fluthiacet-methyl, fomesafen, and lactofen; Group 14 herbicides), bentazon (a Group 6 herbicide), and 2,4-D (a Group 4 herbicide) on waterhemp control, soybean phytotoxicity, and yield. The experiments were established in a randomized, complete block design with four replications. The first experiment focused on soybean phytotoxicity 14 d after treatment (DAT) and yield in the absence of weed competition. All treatments received a preemergence herbicide, with postemergence herbicide applications occurring between the V3 and V6 soybean growth stages, depending on the site-year. The second experiment evaluated the effect of herbicide treatments on waterhemp control 14 DAT and on soybean yield. Lactofen, applied alone or with glufosinate, produced the greatest phytotoxicity to soybean at 14 DAT, but this injury did not translate into yield loss. Mixing glufosinate with 2,4-D, bentazon, and PPO-inhibitor herbicides did not increase waterhemp control, nor did it affect soybean yield compared to when glufosinate was applied alone, but it may be an effective practice to reduce selection pressure for glufosinate-resistant waterhemp.

  PublisherOA PDFDOI

• Nitrogen fertilizer equivalence of red clover when inter‐seeded into corn

  Agronomy Journal · 2025-07-01

  articleOpen access

  Abstract Inter‐seeding red clover ( Trifolium pratense L.) provides an alternative method to incorporate cover crops into continuous corn ( Zea mays L.) in the Upper US Midwest. Red clover is a leguminous cover crop that can grow in low‐radiation environments and is winter hardy. Systems with red clover have demonstrated improved corn yield and a fertilizer N equivalence but understanding these effects with inter‐seeding warrants further investigation. The objectives of this study were to determine the effect of inter‐seeding red clover on (i) plant‐available N during and after red clover decomposition, (ii) optimum N rates for corn, and (iii) corn yields. The experimental design was a randomized, complete block‐split plot design, with cover crop as the main plot factor (treatments with and without inter‐seeded red clover) and N‐rate as a split‐plot factor (N‐rates between 0 and 315 kg‐N ha −1 in 45 kg‐N ha −1 intervals). Quadratic plateau response curves with a bootstrapping technique were used to determine differences in optimum N rate among treatments. Corn yields were evaluated with or without red clover inter‐seeded following the first inter‐seeding year. Red clover accumulated biomass values of 50 kg ha −1 up to 300 kg ha −1 pre‐termination when inter‐seeded with corn at the V4–V5 growth stage without detriment to yield. Corn yield was improved with clover treatments in one of four site years tested, resulting in a (15–17 kg ha −1 ) lower N requirement that year. Overall, our results indicate that inter‐seeding red clover into continuous corn did not provide an agronomically meaningful nitrogen fertilizer equivalence to the cropping system.

  PublisherOA PDFDOI

• Comparing agronomic performance of industrial hemp varieties for suitable production in the United States

  Agronomy Journal · 2025-01-01 · 6 citations

  articleOpen access

  Abstract Industrial hemp ( Cannabis sativa L.) is an ancient crop used throughout history for fiber, oilseed, and therapeutic compounds. Hemp varieties were cultivated across diverse environments in the United States, but knowledge of those agronomic practices along with genetic resources was lost during a period in which cultivation of cannabis was prohibited. Therefore, regional performance evaluations of hemp varieties for crop performance coupled with scientific communication of outcomes to the public are crucial for hemp's development as an agricultural commodity. Objectives for this research were to evaluate relative yields of industrial hemp varieties grown across the United States and link their suitability for commercial production across locations. A national collaboration established variety trials containing seven industrial hemp varieties planted across 14 locations (36°–48° N latitude and 72°–110° W longitude) over a 3‐year period. Crop dry straw yield and seed yield increased from the averages of 1600 and 700 kg ha −1 in Year 1 to 2400 and 1150 kg ha −1 in Year 2, and 3050 and 815 kg ha −1 in Year 3, respectively. The varieties Anka and X‐59 performed best in Vermont and Virginia, where seed yields consistently exceeded 1100 kg ha −1 ; however, no single variety performed above average across all sites. Overall, this assessment identified two industrial hemp varieties suitable for commercial production in specific sites and highlighted the importance for hemp breeders to investigate variety × location × year interactions when developing improved varieties to best capture site‐specific productivity.

  PublisherOA PDFDOI

Frequent coauthors

• Maxwel C. Oliveira

  University of Wisconsin–Madison

  32 shared

• Nicholas J. Arneson

  University of Wisconsin–Madison

  29 shared

• John L. Lindquist

  University of Nebraska–Lincoln

  15 shared

• Ryan P. DeWerff

  University of Wisconsin–Madison

  13 shared

• Shawn P. Conley

  University of Wisconsin–Madison

  11 shared

• Amit J. Jhala

  University of Nebraska–Lincoln

  10 shared

• José J. Nunes

  University of Wisconsin–Madison

  9 shared

• Greg R. Kruger

  9 shared

Awards & honors

• North Central Weed Science Society, Outstanding Young Scient…
• University of Wisconsin-Madison, Alfred Toepfer Faculty Fell…
• Wisconsin Association of County Agricultural Agents, Second…
• Weed Science Society of America, Outstanding Graduate Studen…
• University of Nebraska-Lincoln Dean’s Fellowship (2014-2015…