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A Bioassay To Determine Poa Annua Responses To Indaziflam, Benjamin D. Pritchard

Masters Theses

Herbicide resistance within Poa annua is widespread in managed turfgrass systems. In 2020, a P. annua collection from a golf course in the southeastern United States was reported to be resistant to indaziflam as well as six other mode-of-action groups. Considering P. annua is the most troublesome weed in turfgrass, a bioassay to screen other collections with putative indaziflam resistance is needed. A dose-response experiment was conducted with ten concentrations of indaziflam (0, 250, 500, 750, 1000, 1250, 1500, 2000, 4500, and 9000 pM) in Gelrite® culture during 2021 and 2022. An herbicide-susceptible (S1) collection of P. annua, a …

Scope And Influence Of Enhanced Triazine Degradation In U.S. Soils, Ethan Trent Parker

Doctoral Dissertations

The triazines are one of the most widely used herbicide classes ever developed, and play a role in managing herbicide-resistant weed populations in sustainable agricultural production systems. The triazines are traditionally valued for their persistence and season-long weed control in over 50 crops including corn, soybeans, wheat, and vegetables. The literature suggests that atrazine, the most widely used triazine, may no longer remain persistent in soils due to enhanced microbial degradation. Experiments examined the rate of degradation of atrazine and two other triazine herbicides: simazine and metribuzin in both atrazine adapted and non-adapted soils from across the United States. Additional …

Potential Interaction Between Pre- And Post-Emergence Herbicides And The Efficacy Of Insecticide And Fungicide Seed Treatments In Cotton, Cory Joseph Vineyard

Masters Theses

An apparent reduction in the performance of neonicotinoid seed treatments in controlling thrips, especially in cotton, has been observed, which has coincided with the increased use of both pre- and post-emergence herbicides to control glyphosate-resistant weeds. The objective of this research was to evaluate the potential interactions of both pre- and post-emergence herbicides on the efficacy of insecticide and fungicide seed treatments in cotton

Aldicarb along with imidacloprid and thiamethoxam seed treatments reduced thrips numbers compared with non-treated seed. However, thiamethoxam did not provide effective control. Some pre-emergence herbicide treatments reduced plant health. While there was evidence that thrips injury …

Influence Of Aminocyclopyrachlor Plus Metsulfuron On Seedhead Development And Forage Quality In Tall Fescue, Trevor Davis Israel

Doctoral Dissertations

This research quantified the level of seedhead suppression, injury, total ergot alkaloid changes, and forage quality changes in endophyte-infected tall fescue resulting from spring applications of aminocyclopyrachlor (ACP) plus metsulfuron (MET). Results indicated that ACP plus MET reduced tall fescue seedhead density 53 to 55% but also reduced yield 39 to 51% at spring harvest. ACP plus MET also reduced total ergot alkaloid concentration 28 to 34% and improved crude protein (CP) and relative forage quality (RFQ).

This research also determined the impact of ACP plus MET application timing and rate on tall fescue injury and weed control. Spring and …