Weed Science Commons^™

Impact Of Glufosinate On Sugarcane Yield And Yield Components When Applied Post-Directed And Its Efficacy In Controlling Emerged Itchgrass (Rottboellia Cochinchinensis), Warner R. Simon

LSU Master's Theses

Weed control is extremely important in the Louisiana sugarcane (Saccharum spp.) industry, as it is a perennial crop that grows back after each harvest. Fields are kept weed free using mechanical and chemical methods to prevent weed-crop competition and further establishment of weed populations. The weed itchgrass (Rottboellia cochinchinensis) has become problematic for Louisiana sugarcane producers. Sometimes, itchgrass can still emerge after farmers have made a pre-emergence (PRE) herbicide application. These weeds are usually controlled using the herbicide paraquat dichloride (paraquat) in post-emergence (POST) directed applications. In recent year, 2016-2024, the United States Environmental Protection Agency …

Impact Of Early-Season Postemergence Co-Applications Of Foliar And Residual Herbicides On Crop Injury, Growth, And Yield In 2,4-D- And Dicamba-Tolerant Cotton (Gossypium Hirsutum L.), Logan N. Vallee

LSU Master's Theses

Studies were conducted in 2021 through 2023 at the LSU AgCenter Dean Lee Research and Extension Center near Alexandria, LA to determine the sensitivity of 2,4-D- or dicamba- tolerant cotton (Gossypium hirsutum L.) to an early season application of a Group 15 and foliar-only herbicides. Both studies were randomized complete block designs with a two-factorial arrangement of treatments with four replications. In the dicamba-tolerant cotton study, Factor A consisted of no foliar-herbicide, dicamba alone, glyphosate alone, or dicamba plus glyphosate. Factor B consisted of either no Group 15 residual herbicide, acetochlor, or S-metolachlor. In the 2,4-D- tolerant cotton …

Halosulfuron Plus Prosulfuron And Propanil Interactions For Weed Control In Louisiana Rice Production, John A. Williams

LSU Master's Theses

A greenhouse study was conducted on November 18, and December 2, 2020 at Louisiana State University in Baton Rouge, Louisiana to evaluate the interaction between a pre-packaged mixture of halosulfuron plus prosulfuron mixed with propanil for alligatorweed control. Antagonism occurred when halosulfuron plus prosulfuron at 55 g ha-1 was mixed with propanil at 2,242 g ha-1 at all evaluation dates and antagonism was also observed with halosulfuron plus prosulfuron at 83 g ha-1 mixed with propanil at 2,242 g ha-1 at all evaluation dates except 14 DAT with observed controls of 69 to 77% compared with expected controls of 94 …

Containerized Satsuma Mandarin Production Under Protective Screens As A Management Strategy, Anna Timmerman

LSU Master's Theses

Many of the world’s citrus growing regions are experiencing challenges related to citrus greening, also known as Huanglongbing (HLB) caused by the presumed bacterial agent Candidatus Liberibacter spp. HLB is vectored by the Asian citrus psyllid (Diaphorina citri) and through propagation of infected citrus material. HLB impacts tree health as well as fruit development, ripening, and quality of the resulting citrus fruit, often leading to an unmarketable product. Producers are growing citrus in high density orchards underneath protective screening material that excludes the Asian citrus psyllid, preventing new HLB infections. Four ultra-high containerized tree spacings of 2 feet …

Evaluation Of Salvinia Weevil Establishment, Dispersal, And Environmental Pressures Impacting The Giant Salvinia Biological Control Program, Korey Danielle Pham

LSU Master's Theses

Giant salvinia (Salvinia molesta Mitchell), an invasive free-floating aquatic fern, invaded the Toledo-Bend reservoir along the Texas-Louisiana border in the 1990s. The rapid spread threatens critical ecosystems, economies, and cultural services by altering water quality, and impacting fishing, hunting, and navigation. To combat this issue, the LSU AgCenter has been rearing and distributing the salvinia weevil (Cyrtobagous salviniae Calder and Sands), which has demonstrated effectiveness in reducing giant salvinia populations within a matter of months to a few years. The first study assessed the impact of propagule pressure on salvinia weevil effectiveness in outdoor mesocosms and revealed that …

Louisiana Resident Perceptions On Invasive Aquatic Plant Species And Their Management, Anna Ribbeck

LSU Master's Theses

Determining the public perception of invasive species in Louisiana is an important tool to help shape and develop future management decisions, educational material and ultimately public policy. Therefore, the primary purpose of this study was to determine the perceptions of adult Louisiana residents regarding invasive aquatic plant species and their management. An online survey was used to collect data on registered Louisiana residential boaters’ perceptions towards invasive aquatic plants and their management. A postcard with a quick response code leading to the survey was mailed to 6,000 randomly selected Louisiana registered residential boaters. Of the 230 Louisiana registered boaters that …

Examination Of Pre-Emergence Control Of Johnsongrass In Sugarcane Seedlings, Carleton Baucum

LSU Master's Theses

Sugarcane is susceptible to many diseases and insect pests; therefore, to maintain high sugar yield new varieties must be developed. Producing new varieties contributes to the overall crop success through enhanced yield, insect and/or disease resistance, cold tolerance, and ratooning ability. However, unlike conventional sugarcane, which is vegetatively propagated, new sugarcane varieties are produced from true seed. These seedlings are more susceptible to herbicidal injury and weed competition than conventional sugarcane. For sugarcane seedlings to succeed, weeds must be controlled therefore, the most effective herbicide program with regards to seedling safety must be implemented. The objectives of this research were …

Influence Of Planting Date, Maturity Group, Harvest Aids And Fungicide Application On Soybean (Glycine Max (L.) Seed Quality, Ana Priscila Campos

LSU Master's Theses

Field studies evaluated the influence of planting date, maturity group, and harvest timing on soybean yield and seed quality at the LSU AgCenter Northeast (NERS), Macon Ridge, and Dean Lee Research Stations in 2018-2020. In addition, the influence of harvest aid and fungicide application on seed quality impact from delayed harvest and environment was investigated at NERS in 2019 and 2020 in both field and environmentally controlled growth chambers. Soybean yield was maximized when maturity group IV and V soybean varieties were planted between Mid-April and Mid-May. Earlier and later planting dates did not result in maximized yield. Planting date …

Evaluation Of Metsulfuron-Methyl For Giant Salvinia (Salvinia Molesta) Control And Non-Target Species Sensitivity, William Prevost

LSU Master's Theses

The invasive aquatic fern giant salvinia (Salvinia molesta D.S. Mitchell) has been invading waterbodies across Louisiana and Texas since 1998. Recently, the non-aquatic herbicide metsulfuron-methyl was found to be highly efficacious against giant salvinia, but limited information is available on application techniques, use rates and concentrations, as well as its impact on non-target species. Therefore, a series of mesocosm experiments were conducted to further evaluate foliar and subsurface applications of metsulfuron against giant salvinia, as well as foliar applications of metsulfuron in combination with aquatic herbicides commonly used for giant salvinia control. When applied to the foliage of giant …

Cogongrass (Imperata Cylindrica (L.) Beauv.) In Louisiana: Cause And Consequence, Lorissa A. Radunzel-Davis

LSU Master's Theses

Cogongrass (Imperata cylindrica (L.) Beauv.), an invasive species from East Asia, is found worldwide and is problematic in several countries. In the United States, it grows primarily in the Southeast, reducing biodiversity by growing in dense patches and potentially causing mortality and reducing value of native and planted pinelands due to a high burning temperature. Using Lee Memorial Forest, a Louisiana State University AgCenter property in Washington Parish as a study site, this thesis explores cogongrass in Louisiana with emphasis on soil microbes and soil legacy effects on native plant species. Cogongrass populations at Lee Memorial Forest were more …

Strategies To Overcome Antagonism Of Quizalofop-P-Ethyl When Applied In Mixture With Other Herbicides, Lucas C. Webster

LSU Master's Theses

A field study was conducted in 2017 and 2018 at the LSU Agricultural Center H. Rouse Caffey Rice Research Station (RRS) near Crowley, LA. to evaluate the influence of different adjuvants in overcoming the antagonism of quizalofop when mixed with bispyribac in Louisiana rice production. The antagonism of quizalofop mixed with bispyribac plus HCOC at 14 DAIT was overcome with a neutral interaction observed at 28 DAIT for barnyardgrass control with an observed control of 91%, compared with an expected control of 97%. The addition of COC, SNS or HCOC into a mixture of quizalofop plus bispyribac provided synergistic or …

Determining Growth Characteristics And Control Programs For Nealley's Sprangletop (Leptochloa Nealleyi Vasey), Trace Buck

LSU Master's Theses

ABSTRACT

Research was conducted at the LSU AgCenter Dean Lee Research and Extension center near Alexandria, La in 2016 and 2017 to evaluate the growth characteristics and control of Nealley’s sprangletop. Nealley’s sprangletop is a relatively new weed with little research available to understand its growth habit and effective control strategies.

Nealley’s sprangletop undergoes a more drastic height increase of 212 to 742 mm, 4 to 6 WAE than Amazon sprangletop 377 to 612 mm in the same time frame. Averaged across harvest interval tiller and leaf number of Nealley’s sprangletop was approximately 50 and 40% less than Amazon sprangletop. …

Giant Salvinia, Salvinia Molesta (Salviniaceae): Evaluation Of Sub-Optimum Temperatures On Survival Of The Giant Salvinia Weevil, Cyrtobagous Salviniae (Coleoptera: Curculionidae) And Integration Of Management Practices With Aquatic Herbicides, Lauren W. Cozad

LSU Master's Theses

Salvinia molesta is one of the world’s worst aquatic weeds and has cost Louisiana nearly $7 million worth of damage and economic impact each year. While aquatic herbicides and the biological control agent, Cyrtobagous salviniae, are the most efficacious control methods, there are limitations with each technology. Therefore, studies were conducted to evaluate insect mortality at upper and lower lethal temperatures and investigate integrated pest management (IPM) with insects and herbicides. Three Louisiana populations of C. salviniae were tested to evaluate cold tolerance and found that at 0°C, the Bayou Nicholas population was 1.3- and 1.4-times more cold tolerant …