Banca de DEFESA: LUMA LORENA LOUREIRO DA SILVA RODRIGUES

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
DISCENTE : LUMA LORENA LOUREIRO DA SILVA RODRIGUES
DATA : 19/05/2026
HORA: 11:00
LOCAL: Zoom
TÍTULO:

WISCONSIN WATERHEMP RESISTANCE: TEMPORAL TRENDS, APPLICATION TIMING, AND RAPID DETECTION APPROACHES

PALAVRAS-CHAVES:

Amaranthus tuberculatus; multiple resistance; postemergence; preemergence; dose-response; agar-based assay; Wisconsin

PÁGINAS: 98
RESUMO:

GENERAL ABSTRACT

Waterhemp [Amaranthus tuberculatus (Moq.) Sauer] is among the most economically significant and challenging weed species in corn and soybean production systems in the Midwestern United States. This species exhibits confirmed resistance to eight herbicide sites of action (SOA) and widespread multiple resistance throughout the region. In Wisconsin, statewide resistance screenings have identified resistance to ALS, PSII, EPSPS, PPO, and HPPD inhibitors, with the resistance landscape evolving rapidly. To address critical knowledge gaps in herbicide resistance of Wisconsin waterhemp, three complementary studies were conducted. The first study compared the response of Wisconsin waterhemp accessions collected in 2023 to commonly used postemergence (POST) and preemergence (PRE) herbicides against baseline data from 2018. Results documented increase in survival following POST applications of 2,4-D, atrazine, dicamba, fomesafen, and mesotrione over five years, as well as declining PRE efficacy of atrazine and fomesafen. Glufosinate provided complete control across all accessions. The second study evaluated resistance to multiple SOAs in selected accessions through greenhouse dose-response experiments under both POST and PRE application timings. This study confirmed widespread resistance to 2,4-D, atrazine, fomesafen, and mesotrione, and reported the first documented cases of Group 15 (S-metolachlor) resistance in Wisconsin waterhemp. Resistance to fomesafen was consistently expressed across both application timings, while mesotrione resistance showed reduced magnitude under PRE application, indicating growth-stage-dependent expression. The third study developed and validated an agar-based Petri dish assay for resistance detection across five herbicide SOAs. This assay demonstrated strong correlations with conventional pot-based bioassays for fomesafen, S-metolachlor, and mesotrione, confirming its reliability, cost-effectiveness, and rapidity as an alternative for large-scale resistance monitoring. Collectively, these studies provide an integrated foundation for understanding waterhemp resistance dynamics in Wisconsin and support the development of more effective and sustainable integrated weed management strategies to address the ongoing evolution of herbicide resistance in corn and soybean production systems.

MEMBROS DA BANCA:
Presidente - 2213033 - DANIEL VALADAO SILVA
Externo à Instituição - CAIO AUGUSTO DE CASTRO GROSSI BRUNHARO
Externo à Instituição - RODRIGO WERLE
Externa à Instituição - TATIANE SEVERO SILVA
Externo à Instituição - VICTOR HUGO VIDAL RIBEIRO