About

Dave Stoltenberg is a professor in the Department of Plant and Agroecosystem Sciences at the University of Wisconsin-Madison. His research focuses on weed ecology and management, with particular emphasis on herbicide resistance in weeds such as giant ragweed, common waterhemp, and Palmer amaranth in Wisconsin. He investigates weed community dynamics and suppression in Kernza® intermediate wheatgrass systems, applying ecological concepts and principles to better understand cropping system services and tradeoffs through an agroecological approach. His work also includes studying weed community dynamics, suppression strategies, and mechanisms of herbicide resistance, contributing to sustainable weed management practices. In addition to his research, Stoltenberg is involved in classroom teaching, notably through the course Agronomy 300 Cropping Systems, which addresses environmental impacts, productivity, and profitability of Midwest crop production systems. His teaching emphasizes an agroecological approach, integrating ecological concepts to improve understanding of cropping system services and tradeoffs, including topics such as agricultural intensification, soil erosion, tillage systems, nutrient dynamics, water quality, crop rotation, and cropping system diversification. His contributions aim to enhance sustainable agricultural practices and weed management strategies within Midwest cropping systems.

Research topics

• Agronomy
• Biology
• Horticulture
• Ecology
• Genetics
• Chemistry
• Biochemistry
• Botany

Selected publications

• 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 access

  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

• Postemergence giant ragweed management as affected by soil and cover crop management, soybean planting time, and preemergence herbicide application

  Weed Technology · 2025-01-01 · 2 citations

  articleOpen access

  Abstract Early soybean planting and cover crop adoption in the U.S. Midwest prompt investigation into the impact of these practices on weed community dynamics and best management practices. While previous research has explored different aspects of giant ragweed control, the specific integration among soil management practices, including cover crop adoption, soybean planting timing, and herbicide use, has not been thoroughly investigated. This study assessed the effects of soil management, soybean planting time, and preemergence (PRE) herbicide application on giant ragweed control and soybean yield in Wisconsin and Nebraska in 2022 and 2023. The study included a factorial arrangement of four soil management treatments (conventional tillage, no-till, and fall-planted cereal rye early terminated and terminated at planting [planting green]), two soybean planting times, and two PRE herbicide treatments (PRE and no PRE). POST herbicides were applied when ∼50% of giant ragweed plants within each treatment reached ∼10 cm in height. In Nebraska, cereal rye and tillage treatments without a PRE had at least 67% lower giant ragweed density than no-till at POST. In no-till, densities were at least 60% lower with PRE compared to no PRE. In Wisconsin, cereal rye did not reduce giant ragweed density at POST compared to no-till, likely due to relatively low biomass accumulation. In contrast, delayed soybean planting reduced giant ragweed density for most treatments but lowered soybean yield in no-till and planting-green treatments. The PRE herbicides had either no effect or positive effects on reducing giant ragweed density and increasing soybean yield. Overall, this study suggests that soil management and soybean planting timing are crucial for effective giant ragweed management in Wisconsin, where biotypes with a long emergence window during the spring and summer are present, while in Nebraska, soil management and soybean planting timing are less critical due to giant ragweed biotypes with an early and short emergence window in the spring.

  PublisherOA PDFDOI

• Resistance to protoporphyrinogen oxidase inhibitors applied preemergence or postemergence to waterhemp (<i>Amaranthus tuberculatus</i>)

  Weed Science · 2025-01-01 · 3 citations

  articleOpen access

  Abstract In Wisconsin, herbicide resistance in waterhemp [ Amaranthus tuberculatus (Moq.) Sauer] has been confirmed to five herbicide sites of action, including protoporphyrinogen oxidase (PPO) inhibitors. Following a report of a suspected PPO inhibitor–resistant A. tuberculatus population (A92 accession), our objective was to characterize resistance to PPO inhibitors applied preemergence or postemergence to this accession, along with two PPO inhibitor–susceptible control accessions (A66 and A82). We hypothesized that PPO-inhibitor resistance in A92 was driven by target site–resistance mechanisms. According to our results, the A92 accession is resistant to sulfentrazone (3.1-fold; P-value = 0.0278) and fomesafen (3.1-fold; P-value = 0.0745) preemergence and to lactofen (18.6-fold; P-value = 0.0003) and fomesafen (5.9-fold; P-value &lt;0.0001) postemergence. Resistance to PPO inhibitors was not explained by the presence of any known target-site mutations in PPX1 or PPX2 genes. Our study represents the first confirmed case of an A. tuberculatus accession resistant to PPO inhibitors applied preemergence in Wisconsin. Consistent with previous research, our results demonstrate that the A92 accession, compared with control accessions, is less sensitive to fomesafen regardless of the application timing. Further research is necessary to identify other potential PPO-inhibitor resistance mechanisms in the A92 accession, including potential non–target site resistance mechanisms associated with cytochrome P450 monooxygenases or glutathione S -transferases.

  PublisherOA PDFDOI

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

  Agrosystems Geosciences & Environment · 2025-07-09

  articleOpen access

  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

• Managing nitrogen fertility and stand density for sustaining Kernza intermediate wheatgrass yields

  Crop Science · 2025-09-01

  articleOpen access

  Abstract Kernza intermediate wheatgrass (IWG) [ Thinopyrum intermedium (Host) Barkworth &amp; D.R. Dewey] is a promising perennial grain and forage crop, but experiences grain yield decline, potentially due to limited nitrogen (N) and stand overcrowding. We evaluated the effects of N fertilization and stand thinning on grain and forage yield, weed biomass, thousand‐kernel weight (TKW), and harvest index (HI). We used a full factorial design with N rates of 0, 75, and 150 kg N ha −1 and thinning intensities of 0%, 25%, 38%, or 50% stand density reduction via banded herbicide at two locations in Wisconsin over 2 years. Fertilization and thinning did not interact. Grain yields increased with N fertilization except at Madison in Year 2. At Lancaster, grain yield increased from 293 with no N to 497 and 701 kg ha −1 with 75 and 150 kg N ha −1 , respectively, across years. At Madison, grain yield increased only in Year 1. Forage mass also increased with N at both sites except Madison in Year 2. At Lancaster, forage mass ranged from 4016 to 6500 kg ha −1 across years and N rates. TKW and HI increased with N at both sites, except at Madison in Year 2. Weed biomass was unaffected by treatments. Thinning had no effect on grain yield at Lancaster in Year 1, but in Year 2, grain yield increased from 368 to 505 kg ha −1 with 50% thinning. These results suggest that applying 75 kg N ha −1 is important for maintaining IWG productivity and that thinning can help sustain grain yield in older stands.

  PublisherOA PDFDOI

• Forage boost or grain blues? Legume choices shape Kernza intermediate wheatgrass dual-purpose crop performance

  Field Crops Research · 2024-08-01 · 9 citations

  articleOpen access

  Kernza intermediate wheatgrass is a new perennial grain crop with the potential to produce high nutritive value forage when intercropped with legumes. Understanding the potential benefits of intercropping systems requires considering the interaction between different legume species intercropped, intermediate wheatgrass row spacing, and environments encompassing spatial and temporal variation. We aimed to evaluate the effect of these factors on the biomass allocation to harvestable (grain, intermediate wheatgrass forage, legume forage) and non-harvestable (weed biomass) outputs. In four environments, given by the combination of two sites (Wisconsin, USA) and two establishment years, we sowed intermediate wheatgrass in two row spacings in eight cropping systems: three intermediate wheatgrass monocultures [control without N fertilization, intermediate wheatgrass fertilized with 45 or 90 kg N ha−1 as urea], and four intermediate wheatgrass-legume intercrops (intermediate wheatgrass with alfalfa, Berseem clover, Kura clover, or red clover). We evaluate grain yields, intermediate wheatgrass and legume forage, and weed biomass over three consecutive years. Our results suggest that intercropping legumes does not affect Kernza grain yield in the first grain production year, which is the year with the highest yield potential. In subsequent production years, grain yields were lower in red clover intercrops than in intermediate wheatgrass monoculture control or fertilized, depending on the environment. Among the legumes tested in our study, red clover and alfalfa were suitable for increasing total biomass production in most of the environments and red clover reduced weed biomass compared to intermediate wheatgrass monocultures. Our results encourage intercropping legumes with intermediate wheatgrass because of the increase in forage yield and quality. These benefits can compensate for lower Kernza grain yields commonly observed in the second and third production years. Our study provides valuable insights into the intermediate wheatgrass potential as a dual-use crop for grain and forage production. Improving our understanding of the factors that influence grain yield and forage production such as post-harvest management, multiple forage harvests or grazing, may optimize the productivity and sustainability of these cropping systems.

  PublisherDOI

• Resistance to protoporphyrinogen oxidase inhibitors in giant ragweed (<i>Ambrosia trifida</i>)

  Pest Management Science · 2024-08-05 · 12 citations

  articleOpen access

  BACKGROUND: Giant ragweed (Ambrosia trifida L.) is one of the most troublesome weed species in corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] cropping systems. Following numerous reports in 2018 of suspected herbicide resistance in several Ambrosia trifida populations from Wisconsin, our objective was to characterize the response of these accessions to acetolactate synthase (ALS), enolpyruvyl shikimate phosphate synthase (EPSPS), and protoporphyrinogen oxidase (PPO) inhibitors applied POST. RESULTS: Four accessions (AT1, AT4, AT6, and AT10) exhibited ≥ 50% plant survival after exposure to the cloransulam 3× rate. Two accessions (AT8 and AT10) and one accession (AT2) exhibited ≥ 50% plant survival after exposure to glyphosate and fomesafen 1× rates, respectively. The AT10 accession exhibited multiple resistance to cloransulam and glyphosate. The AT12 accession was 28.8-fold resistant to fomesafen and 3.7-fold resistant to lactofen. A codon change in PPX2 conferring a R98L substitution was identified as the most likely mechanism conferring PPO-inhibitor resistance. CONCLUSION: To our knowledge, this is the first confirmed case of PPO-inhibitor resistance in Ambrosia trifida globally and we identified the genetic mutation likely conferring resistance. Proactive and diversified integrated weed management strategies are of paramount importance for sustainable long-term Ambrosia trifida management. © 2024 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

  PublisherOA PDFDOI

• Cereal rye biomass effects on giant ragweed suppression inform management decisions

  Agrosystems Geosciences & Environment · 2024-12-30 · 1 citations

  articleOpen access

  Abstract Giant ragweed ( Ambrosia trifida L.) has become one of the most troublesome weeds across the US Midwest partially due to its early emergence, high competitiveness, and herbicide resistance evolution. This study aimed to determine the amount of cereal rye ( Secale cereale L.) biomass needed to suppress giant ragweed establishment and growth. The study was conducted in 2022 and 2023 at the Rock County Farm near Janesville, WI, in naturally infested giant ragweed fields. At establishment, the research site was tilled to remove weed biomass and crop residue, followed by placement of eight cereal rye biomass treatments: 0, 0.6, 1.2, 2.4, 4.8, 7.2, 9.6, and 12.0 Mg ha −1 . Cereal rye biomass was collected from a fall‐seeded cover‐cropped field, oven‐dried until constant mass, and evenly spread on the surface of each plot based on respective rates. Data were collected 42 days after study establishment, consisting of giant ragweed plant height, density, and dry biomass. Results showed that 3.8 and 4.8 Mg ha −1 of cereal rye biomass reduced giant ragweed biomass and density by 50%, respectively, compared to the no‐biomass treatment. Maximum giant ragweed height reduction in this study was 40% compared to the no‐biomass treatment. Our results show that cereal rye cover crop biomass was effective in suppressing giant ragweed establishment and growth with a minimum of 3.8 Mg ha −1 cereal rye biomass for &gt;50% suppression of giant ragweed establishment and growth. These results quantify the relationship between cereal rye dry biomass and the suppression of giant ragweed, and can support grower decision‐making for timing of cereal rye termination.

  PublisherOA PDFDOI

• Synthetic auxin herbicides do not injure intermediate wheatgrass or affect grain yield

  Weed Technology · 2023-10-01 · 4 citations

  articleOpen accessSenior authorCorresponding

  Abstract Intermediate wheatgrass (IWG) is a cool-season perennial grass developed as a dual-purpose grain and forage crop. One barrier to adopting this crop is a lack of information on the effects of herbicides on IWG for grain production. An experiment was conducted to evaluate herbicide effects on IWG grain yield, crop injury, and weed control over 2 yr (2019 to 2021) at sites in Wisconsin, Minnesota, New York, and North Dakota. This evaluation included broadleaf herbicides registered for use on wheat: 2,4-D amine, clopyralid, MCPA, and a mixture of clopyralid + MCPA (all are categorized as Group 4 herbicides by the Weed Science Society of America). Each herbicide or mixture was applied at 1× and 2× the labeled wheat application rate to newly planted and established (1- to 5-yr-old) IWG stands in the fall or spring. Herbicides were applied during IWG tillering or jointing stages in the fall or during the jointing stage in the spring. Across site years, application timing, herbicide, and application rate showed no effect on IWG grain yield or plant injury. Broadleaf weed control ranged from 71% to 92% across herbicide treatments relative to the nontreated check at the Wisconsin site, whereas weed control at the Minnesota site was variable among treatments. At the New York site, herbicides were equally effective for broadleaf weed suppression, whereas weed pressure was very low at the North Dakota site and treatments did not affect weed cover. The results show that newly planted and established stands of IWG are tolerant to the synthetic auxin herbicides 2,4-D amine, clopyralid, and MCPA when applied during tillering or jointing in the fall or during jointing in the spring. Synthetic auxins represent a potentially useful tool for weed control in IWG cropping systems, especially for problematic broadleaf weed species.

  PublisherOA PDFDOI

• Forage harvest management impacts “Kernza” intermediate wheatgrass productivity across North America

  Agronomy Journal · 2023-06-07 · 32 citations

  articleOpen access

  Abstract Intermediate wheatgrass [IWG, Thinopyrum intermedium (Host) Barkworth &amp; D.R. Dewey, trade name Kernza] is a widely adapted, cool‐season forage grass, actively bred for perennial grain production. Most of IWG's net primary productivity is directed to nonreproductive structures, so dual‐use strategies to harvest both grain and forage represent a potentially viable pathway to increase its productivity and profitability. We conducted a 3‐year trial at nine diverse environments across North America to evaluate grain and forage yields and forage nutritive value of an early IWG breeding line under contrasting forage harvest managements. These included control (no forage harvest), summer forage harvest immediately after grain harvest, and summer forage harvest with spring or fall forage harvests. Across all sites, IWG grain yields averaged 745, 296, and 221 kg ha −1 for the first, second, and third years, respectively. Grain yields were influenced more by stand age than site. Summer forage mass after grain harvest averaged 6.0, 4.5, and 5.7 Mg ha −1 respectively for the first 3 years. Forage mass was less influenced by stand age, and more by site and forage harvest frequency. Fall forage harvest increased grain yields while spring forage harvests decreased grain yields and both treatments increased total relative feed nutritive values. Collectively, our results demonstrate that harvesting forage can improve both grain yield and forage nutritive values. Farmers growing IWG as a perennial grain can benefit from dual‐use management by harvesting both grain and forage.

  PublisherOA PDFDOI

Frequent coauthors

• Chris M. Boerboom

  University of Wisconsin–Madison

  16 shared

• Rodrigo Werle

  University of Wisconsin–Madison

  9 shared

• Shawn P. Conley

  University of Wisconsin–Madison

  8 shared

• Nicholas J. Arneson

  University of Wisconsin–Madison

  7 shared

• Larry K. Binning

  7 shared

• Valentín Picasso

  University of Wisconsin–Madison

  7 shared

• Dean S. Volenberg

  University of Missouri

  6 shared

• Maxwel C. Oliveira

  University of Wisconsin–Madison

  6 shared

Education

• Ph.D., Plant Pathology

  University of Wisconsin-Madison

  1990

• M.S., Plant Pathology

  University of Wisconsin-Madison

  1986

• B.S., Botany

  University of Wisconsin-Madison

  1982