UW-Madison Open Dissertations and Theses

Management of Popillia japonica (Coleoptera: Scarabaeidae) with Reduced Pesticide and Biological Control in Midwest Vineyards

2026-05-23T12:26:04Z

Management of Popillia japonica (Coleoptera: Scarabaeidae) with Reduced Pesticide and Biological Control in Midwest Vineyards Parkanzky, Emilie Popillia japonica Newman (Coleoptera: Scarabaeidae), is an economically important pest of many crop and ornamental plants. The adult beetle is the most substantial defoliator of grape in the upper Midwest region. With alternative management options resulting in insufficient population reduction, current management practices rely on broadcast insecticide applications targeting adults on foliage, that are hazardous to the environment, non-target organisms, and farm workers. Perimeter-focused management targets the borders of crop plots for pest control with use of a killing agent, preventing incoming economically damaging insects from entering an interior. Attract-and-Kill (A&K) strengthens the edge-effect leveraged in perimeter-focused management by integrating the use of pest-specific, semiochemical attractant lures with the killing agent on a substrate. The objectives of this study were to assess the impact of A&K and Perimeter Spray applied to grape block perimeters on 1) P. japonica adult abundance and 2) grape foliar injury, compared to grower standard broadcast pesticide programs. In the A&K treatment, commercial lures were deployed along the perimeter of the plot. In the combined A&K and Perimeter Spray plots, a border application of Sevin XLR PLUS (carbaryl) was applied every 15-18 days. Grower Standard plots followed the pesticide schedule selected by each grower, typically involving one to four full block insecticide applications across the growing season. Across two growing seasons (2024-2025), beetle abundance and defoliation did not differ significantly among treatments. A&K and Perimeter Spray performed comparably to each other and to the grower standard while reducing treated surface area by 88% and application time by 78%, demonstrating that the Perimeter Spray provided the most cost-effective option with an 88% reduction in cost relative to the Grower Standard. Evaluating the potential of A&K and Perimeter Spray as reduced input management tools will help Wisconsin grape growers consider practices that maintain pest suppression while lowering environmental impacts, direct costs and reliance on broadcast applications.

EVALUATING SYNERGISTIC POSTEMERGENCE CORN HERBICIDE TANK MIXES FOR BROAD-SPECTRUM TROUBLESOME WEED CONTROL IN WISCONSIN ATRAZINE-PROHIBITED AREAS

2026-05-23T12:26:03Z

EVALUATING SYNERGISTIC POSTEMERGENCE CORN HERBICIDE TANK MIXES FOR BROAD-SPECTRUM TROUBLESOME WEED CONTROL IN WISCONSIN ATRAZINE-PROHIBITED AREAS Zhu, Daniel Qiran Atrazine is a staple herbicide in corn (Zea mays L.) production, however, due to ground water contamination concerns, atrazine has become prohibited in Wisconsin on approximately 490,000 ha of cropland. This eliminates a cost-effective, broad-spectrum, and strong tank-mix partner from many herbicide portfolios and increases the reliance on alternatives like mesotrione amid rising herbicide resistance reports. Understanding the value of atrazine, what growers can do in lieu of atrazine, and how to steward alternatives to atrazine is critically important for growers in atrazine prohibition areas. Thus, this thesis aims to evaluate the stakeholder perception of access to atrazine, explore the efficacy of atrazine alternative tank mixes, and understand the potential to combat resistant weeds in order to steward important chemistries such as mesotrione. Of a survey of 42 Wisconsin stakeholders documenting herbicide programs, it was found that the average herbicide costs were similar, but perceived weed control satisfaction was lower inside atrazine prohibition areas compared to outside (Chapter 1). Atrazine (a photosystem II- inhibitor) is an important tank-mix partner for many herbicides but especially for mesotrione due to a synergistic interaction between photosystem II-inhibitors and mesotrione that enhances weed control. Loss of access to atrazine eliminates stakeholders’ ability to leverage this interaction and consequently increases the reliance on solo mesotrione applications. Examination of atrazine alternative Photosystem II-inhibitors tank mixed with mesotrione found that bromoxynil + mesotrione synergistically delivered effective (>90%) on both waterhemp (Amaranthus tuberculatus [Moq.] Sauer) and giant ragweed (Ambrosia trifida L.), the most troublesome broadleaf weeds in Wisconsin (Chapter 2), however, struggled to control grass weed species. Subsequent studies were aimed at bolstering bromoxynil + mesotrione broadleaf targeting tank mixes with addition of grass targeting postemergence herbicide such as glyphosate or nicosulfuron. These studies revealed that in general, addition of glyphosate or nicosulfuron to bromoxynil + mesotrione will deliver effective control of grasses, however, species-specific antagonistic interactions can decrease grass control (Chapter 3). Stakeholders desiring to avoid such tank mixtures may use this document as a guide. Finally, amid reports of metabolically atrazine and mesotrione resistances in Wisconsin, controlled environment studies were conducted to understand the role of synergistic tank mixing in mitigating resistance. It was found that the complementary action of either atrazine or bromoxynil mixed with mesotrione was able to consistently and synergistically deliver effective weed control of metabolically multiple herbicide resistant waterhemp plants as long as applications were timely (plants < 10 cm; Chapter 4). Therefore, synergistic tank mixing is an effective tool for optimizing weed control and potentially for mitigating the evolution of resistance. Nonetheless, understanding the implications of synergistic postemergence tank mixing is fundamental for stakeholders raising corn in atrazine prohibition areas to optimize weed control and to promote the stewardship of mesotrione.

From Fatty Acid Oxidation to Triacylglycerol Resynthesis: Convergent PPAR Signaling in Six Murine Models of Lipid Metabolism

2026-05-23T12:26:02Z

From Fatty Acid Oxidation to Triacylglycerol Resynthesis: Convergent PPAR Signaling in Six Murine Models of Lipid Metabolism Tu, Andrew The intestinal epithelium simultaneously performs nutrient absorption, pathogen defense, hormone signaling, barrier maintenance, and rapid self-renewal along a crypt-villus axis, all while responding to changing nutrient conditions. Nutrient absorption is no easy task; lipid absorption alone requires coordinate uptake at the apical membrane, intracellular re-esterification, lipid remodeling, chylomicron packaging, and basolateral export. This thesis examines how genetic perturbation of intestinal lipid handling reorganizes the enterocyte transcriptional response and asks whether mechanistically distinct disruptions converge on a shared downstream program. Six conditional knockout mouse models spanning three mechanistic classes were profiled across single-cell RNA-sequencing and bulk RNA-sequencing: intestine-specific Cpt1a-(Cpt1iKO), Cpt2- (Cpt2iKO), and Cpt1a/Cpt2-double (C12iKO) knockouts block long-chain mitochondrial fatty acid oxidation at successive carnitine-shuttle steps; intestine-specific Pex5 knockout impairs all peroxisomal function, including beta-oxidation of very-long-chain fatty acids; and disruption of Mogat2, globally (Mogat2–/–) or intestine-specifically (Mogat2iKO), removes the rate-limiting enzyme for monoacylglycerol-to-diacylglycerol resynthesis in the intestinal absorptive pathway. This thesis is organized around comparing the use of bulk and single-cell RNA-sequencing as complementary lenses, addressing different biological questions regarding the same biological system. Chapter 1 introduces the current understanding of intestinal lipid metabolism along the crypt-villus axis. Chapter 2 establishes the statistical power and resolution that make each technology suited to address different questions. A novel observation is that monoacylglycerol lipase (Mgll) transcript is found not in enterocytes but in vascular and lymphatic endothelium implicating its function in the intestine. Conversely, single-cell sparsity prevents the cross-dataset convergence detection that bulk RNA-sequencing replication enables. Chapter 3 then applies single-cell resolution to build on the previous work studying absorptive enterocyte zonation and transdifferentiation along the villus. Using our Cpt2iKO, Mogat2iKO, and Mogat2–/–models, we showed that PPAR target activation is convergent and zonation dependent across Cpt2iKO, Mogat2iKO, Mogat2–/–, and fasted animals, mirroring the elevated and earlier expression of lipid metabolism genes under high-fat high-sugar diet, as previously reported in literature. We also report an IL-22/Reg3 antimicrobial axis which dissociates between Mogat2iKO and Mogat2–/– under high-fat diet using intercellular cell signaling analysis with our single-cell data. Chapter 4 then applies bulk replication to the convergence question across all six knockout panels, showing that PPAR target gene activation is shared across lipid pathway manipulations, and that this convergence is captured at the network level by a weighted gene co-expression module. Finally, Chapter 5 builds on the characterizations we performed to propose research questions that might be answered with additional experiments. An accompanying methodological appendix documents the AI-augmented bioinformatic workflow as well as the current state of AI in bioinformatics, pitfalls, and methods to overcome current limitations.

Assessing the efficacy of softwood-derived biochar in the remediation of dicamba-based herbicides in agroecosystems

2026-05-23T12:26:01Z

Assessing the efficacy of softwood-derived biochar in the remediation of dicamba-based herbicides in agroecosystems Muhr, Benjamin Dicamba is a widely used auxinic herbicide in the United States whose environmental mobility raises concern for off-target transport and damage to susceptible plant species in the environment. Biochar has been proposed as a soil amendment capable of reducing dicamba movement through sorption, but sorption behavior and efficacy can vary greatly with biochar physiochemical properties dependent on feedstock sources and the temperature at which it is pyrolyzed, as well as the formulations of dicambic herbicides used. This thesis evaluated the sorption of pure dicamba, dicamba-dimethylamine (DMA), dicamba-diglycolamine (DGA), and two commercially available dicamba-based herbicide formulations to a sandy loam soil and to softwood biochars pyrolyzed at 350, 450, and 550 °C. The objectives were to determine how biochar pyrolysis temperature affects dicamba retention, to compare the sorption behavior of acid and salt formulations, and to identify which sorbent is most effective for environmental remediation applications. Batch sorption experiments were conducted across a range of concentrations in a dilution series. They were quantified using HPLC with a Diode Array Detector (DAD) and interpreted using linear, Freundlich, and Langmuir isotherm models. For pure dicamba, sorption described by the linear isotherm model indicated relatively constant partitioning across the tested concentration range and no strong evidence of sorbent saturation. Among all sorbents, the 550 °C biochar exhibited the highest partition coefficient and the greatest overall sorption efficacy, indicating the strongest affinity for dicamba and the earliest onset of differential partitioning relative to soil and lower-temperature biochars. The 350 °C and 450 °C biochars showed sorption behavior that was not substantially different from unamended sandy loam soil, suggesting that lower-temperature pyrolysis did not meaningfully enhance dicamba retention.