Life Sciences Commons^™

Characterization And Management Of Auxin-Resistant Palmer Amaranth In Tennessee, Delaney C. Foster

Doctoral Dissertations

Palmer amaranth has a long history of evolving resistance to herbicides to the point it has become a significant row crop production obstacle. Cotton and soybean growers were offered new technologies in 2016, expanding in-crop herbicide options to include dicamba or 2,4-D. Within three years of commercialization, dicamba use in these crops increased ten-fold and growers began to report Palmer amaranth escapes in west Tennessee auxin-tolerant production systems. A survey of Palmer amaranth escapes in dicamba and 2,4-D-tolerant cotton and soybean fields in Tennessee was conducted in the fall of 2021 with the objective of determining if poor control was …

Evaluation Of Insecticide Resistance In Populations Of Tobacco Thrips, Frankliniella Fusca (Hinds), And Plant Density Effects On Thrips Injury To Cotton, Jessica L. Krob

Masters Theses

Two field studies were performed in Tennessee to evaluate the effects of plant density and seed spacing on thrips injury to upland cotton (Gossypium hirsutum L.). The plant density study consisted of seeding rate treatments that were low, normal, high, and very high, relative to university Extension recommendations. In the plant spacing study, treatments were implemented using nearly identical seeding rates but with relatively uniform seed spacing versus a clumped, “hill-dropped” spacing. In both studies, the seed was either treated with an insecticide (imidacloprid) and a fungicide or only with a fungicide. Due to variable environmental conditions, the results …

Improving Water And Plant Growth Regulator (Pgr) Management Practices In Cotton: Cultivar Physiological Responses And Pgr Rates, Kurt Wedegaertner

Masters Theses

Cotton (Gossypium hirsutum L.) is grown in an increasingly unpredictable climate and often under rainfed conditions. Without irrigation to alleviate common drought conditions, cultivar selection becomes a primary tool in mitigating the negative effects of water-deficit stress. Cultivars can differ in water use under water-limited environments, which can affect crop performance. Moreover, cotton management must involve balancing vegetative and reproductive growth through the use of plant growth regulators (PGR) due to the plant’s perennial growth pattern. The efficacy of PGRs are dependent on many variables including environmental conditions, irrigation, and genetics (cultivar). In 2020 and 2021, a series of …

Risk Management Potential Of Supplemental Irrigation For Cotton In A Sub-Humid Climate Under Climate Change, Wen Liu

Masters Theses

Adoption of supplemental irrigation to reduce cotton yield losses is a potential risk management strategy for farmers given increasingly frequent drought periods due to climate change. However, cotton farmers in the rolling landscape areas of the lower Mississippi River Basin (MRB) are concerned about whether an investment in supplemental irrigation is economically feasible. This study determined the impacts of the effects of risk exposure on optimal irrigation strategies for cotton production under climate change in West Tennessee. A crop simulation model was calibrated and validated using measured data from cotton irrigation experiments at Jackson, TN over three years (2006–2008). Simulated …

Fungicide Sensitivity Screening Of Corynespora Cassiicola In Us Soybean And Cotton, Tyler Miles Smith

Doctoral Dissertations

Target spot, caused by the fungus Corynespora cassiicola, is a foliar disease of cotton and soybean. Target spot has become a disease of concern in soybean and cotton production systems. Data for fungicide sensitivity and understanding potential impact on yield is lacking for C. cassiicola. Fungicide resistance is also a concern in C. cassiicola with the increase in resistant pathogens in soybean. With the lack of knowledge about baseline fungicide sensitivity and the concern of fungicide resistance the objectives of this study were: (i) to evaluate fungicide products and mixes in small plot soybean and cotton trials, (ii) …

Helicoverpa Zea (Boddie) (Lepidoptera: Noctuidae) Larval Distribution On Different Bt Technologies And Evaluating Cotton Plant Tissue Assays For Resistance Monitoring, Dawson David Kerns

Masters Theses

Field trials were conducted in 2018 at the West Tennessee Research and Education Center (WTREC) in Jackson, TN and in 2019 at locations in College Station, TX, Tillar, AR, and Jackson, TN. Non-Bt, Cry1Ac + Cry1F, and Cry1Ac + Cry2Ab cotton varieties were either treated with an insecticide or left untreated. After five days, cotton plants were mapped for signs of bollworm, Helicoverpa zea (Lepidoptera: Noctuidae), feeding on floral structures (i.e., bolls, squares, flowers) and the physical presence of larvae. Bt technologies reduced the number of H. zea larvae and the amount of feeding injury, but no major differences in …

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 …

Long-Term Impacts Of Conservation Management Practices On Soil Carbon Storage, Stability, And Utilization Under Cotton Production In West Tennessee, Candace Brooke Wilson

Masters Theses

Biogeochemical cycling of soil carbon (C) is heavily influenced by conservation agricultural (CA) practices. This study examined SOC stability under three CA practices: reduced nitrogen (N) fertilizer application rate, cover cropping, and zero-tillage implemented for 31 years. Respiration rates measured from a 602-day incubation period were fitted to a double-pool first order exponential model of SOC decomposition. The active [respired] SOC pool showed distinct differences between applications of reduced (34N kg ha^-1 [-1]) and high fertilization rates (101N kg ha^-1) combined with tillage, and suggest that high fertilizer applications with conventional tillage allocated more C into a …

W291-B Diagnosing Suspected Off-Target Herbicide Damage To Cotton, G. Neil Rhodes Jr., Trevor D. Israel, Larry Steckel

Field & Commercial Crops

No abstract provided.

W291-A Preventing Off-Target Herbicide Problems In Cotton Fields, G. Neil Rhodes Jr., Trevor D. Israel, Larry Steckel

Field & Commercial Crops

No abstract provided.

Giant Ragweed (Ambrosia Trifida L.) Biology, Competition, And Control In Cotton (Gossypium Hirsutum L.), Kelly Anna Barnett

Doctoral Dissertations

The objectives of this research were to evaluate control options and investigate the biology and competitiveness of glyphosate-resistant (GR) giant ragweed in cotton. Our results determined that glufosinate followed by glufosinate, glufosinate plus pyrithiobac, and glufosinate plus fluometuron at 0.56 or 1.12 kg ai ha^-1 resulted in the highest level of visual control and the highest yield. However, glufosinate followed by glufosinate was the only treatment that resulted in the highest yield and > 90% control of GR giant ragweed.

The development of glufosinate-tolerant, 2,4-D tolerant, and dicamba-tolerant crops may provide growers with new opportunities for difficult-to-control weeds such as …

Locating The Variability Of Soil Water Holding Capacity And Understanding Its Effects On Deficit Irrigation And Cotton Lint Yield, Heath Adam Duncan

Masters Theses

Precision irrigation equipment such as variable-rate center pivots is readily available to Tennessee growers and producers; however, little research exists describing its application to cotton grown in Tennessee. In order to optimize the use of variable-rate irrigation equipment and water resources, two experiments were performed to determine (1) whether or not ground-penetrating radar (GPR) and electrical conductivity (EC) measurements can be used to delineate variable-rate irrigation zones and (2) examine the response of cotton lint yield to varying rates and duration of irrigation.

GPR and EC measurements were recorded, validated using soil cores, and used to identify the subsurface variability …

W288 Cotton Production In Tennessee, Christopher L. Main

Field & Commercial Crops

No abstract provided.

W287 Cotton Growth And Development, Christopher L. Main

Field & Commercial Crops

No abstract provided.

Cotton (Gossipium Hirsutum L.) Response To Irrigation And Environment In A Short Season Climate, Matthew Scott Wiggins

Masters Theses

Research was conducted in 2010 and 2011 at the West Tennessee Research and Education Center in Jackson, TN to investigate water deficit and irrigation response in cotton to provide a better understanding of physiological growth changes and yield impact on the crop grown in soils of varying depth to a sandy layer. The deep soil yielded more vegetative mass when compared with the shallower soil. This is also true when applying higher rates of irrigation where plants grew two more nodes of growth and 15.2 centimeters of plant height. Time to cotton maturity was delayed seven days in the deep …

W221-Mid-South Multi-State Evaluation Of Treatment Thresholds For Tarnished Plant Bug In Pre-Flowering Cotton, The University Of Tennessee Agricultural Extension Service

Field & Commercial Crops

Prior to bloom, the primary hemipteran pest of cotton in the Mid-South is the tarnished plant bug (TPB). Cotton fleahopper and clouded plant bug are other hemipteran pests that are occasionally observed. These pests reduce yields by feeding on squares (flower buds), which often shed. Mid-sized or larger squares may not shed, but feeding injury is generally evident in the form of yellow staining on the surface of the square and damaged anthers in flowers (i.e., dirty blooms). Square loss can delay maturity and sometimes reduce yield. Delays in crop maturity, even when not causing yield loss, can increase mid-and …

W111-Cotton Insects:Slugs And Snails, The University Of Tennessee Agricultural Extension Service

Field & Commercial Crops

No abstract provided.

W110-Cotton Insects: Clouded Plant Bug, The University Of Tennessee Agricultural Extension Service

Field & Commercial Crops

No abstract provided.

W075-Cotton Defoliation Timing, The University Of Tennessee Agricultural Extension Service

Field & Commercial Crops

Defoliation is an often-overlooked process that, if done properly, can pay large dividends. Defoliation is relatively easy in some situations and extremely difficult in others. Defoliation is the application of chemicals to encourage or force cotton leaves to drop from the plant, allowing harvest of the crop in a timely manner. Proper defoliation requires a balancing act between killing the leaves too quickly or not affecting the leaf at all. Successful defoliation requires that the leaf must stay alive long enough to begin the formation of an abscission zone, resulting in leaf drop. Killing the leaf too rapidly results in …

W074-Managing Late-Planted Cotton, The University Of Tennessee Agricultural Extension Service

Field & Commercial Crops

Traditionally, cotton planting in Tennessee starts near the end of April and continues until mid-May, with the bulk of the cotton planted during the first and second weeks of May. Oftentimes, producers are forced to plant outside of these recognized windows. Although Tennessee has recently experienced longer than normal growing seasons and higher than average DD-60 accumulation, long-term historical data shows that in 50 percent of the last 30 years, a killing freeze could occur during the second and third weeks of October (Table 1). Fortunately, early-maturing varieties, Bt cotton for worm control and boll weevil eradication allow for a …

W073-Making Cotton Replant Decisions, The University Of Tennessee Agricultural Extension Service

Field & Commercial Crops

Each year, many producers are forced to replant cotton due to adverse conditions. Replant decisions are often the most difficult decisions to make, so second-guessing is very common. This publication is intended to aid in your replant decision-making.

W035-Cotton Insects: Spider Mites, The University Of Tennessee Agricultural Extension Service

Field & Commercial Crops

No abstract provided.

W034-Cotton Insects: Loopers, The University Of Tennessee Agricultural Extension Service

Field & Commercial Crops

No abstract provided.

W033-Cotton Insects: Fall Armyworm, The University Of Tennessee Agricultural Extension Service

Field & Commercial Crops

No abstract provided.

W032-Cotton Insects_Cutworms, The University Of Tennessee Agricultural Extension Service

Field & Commercial Crops

No abstract provided.

W031-Cotton Insects: Tobacco Budworm, The University Of Tennessee Agricultural Extension Service

Field & Commercial Crops

No abstract provided.

W030-Cotton Insects: Bollworm, The University Of Tennessee Agricultural Extension Service

Field & Commercial Crops

No abstract provided.

W029-Cotton Insects: Beet Armyworm, The University Of Tennessee Agricultural Extension Service

Field & Commercial Crops

No abstract provided.

W028-Cotton Insects: Cotton Aphid, The University Of Tennessee Agricultural Extension Service

Field & Commercial Crops

No abstract provided.

W027-Cotton Insects: Stink Bugs, The University Of Tennessee Agricultural Extension Service

Field & Commercial Crops

No abstract provided.