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Effect Od Different Sources And Application Rates Of Sulfur On Corn And Soybean Production Systems In Louisiana, Diego Mayorga Valladares
Effect Od Different Sources And Application Rates Of Sulfur On Corn And Soybean Production Systems In Louisiana, Diego Mayorga Valladares
LSU Master's Theses
Sulfur (S) is a structural component of amino acids such as cysteine and methionine and is involved in important functions within the plant like photosynthesis, carbon and nitrogen metabolism, protein synthesis of oils, and detoxification mechanisms. Sulfur deficiency in crops has intensified around the world. Some of the reasons are improvement in controlling SO2 emissions from industries, growing usage of high analysis S-free fertilizers and augmented cropping intensity. Sulfur fertilization has become an important factor in crop production systems and fertilization guidelines for S need to be up-to-date to improve use efficiency and compensate for rising prices of fertilizers. …
Re-Evaluation Of Late Season Action Thresholds And The Effect Of Seed Treatments On Early Season Colonization Of Threecornered Alfalfa Hopper, Spissistilus Festinus (Say), In Louisiana Soybean, Glycine Max (L) Merr, Tyler Ray Tagle Musgrove
Re-Evaluation Of Late Season Action Thresholds And The Effect Of Seed Treatments On Early Season Colonization Of Threecornered Alfalfa Hopper, Spissistilus Festinus (Say), In Louisiana Soybean, Glycine Max (L) Merr, Tyler Ray Tagle Musgrove
LSU Master's Theses
Soybean, Glycine max (L.) Merr, is considered the most economically important oil and feed crop in the US and is grown on nearly 35,000,000 ha on an annual basis. Factors that limit yield include weed pressure, disease infection, and of particular interest to entomologists, insect herbivory. Soybean is targeted by a range of above and below ground pests which are primarily controlled by insecticides. Neonicotinoids are a recently popularized insecticide class that when applied as a seed treatment, can provide protection from early season pests. The most economically significant early season pest is threecornered alfalfa hopper, Spissistilus festinus (Say), whose …
Impact Of New Technologies On Weed Control In Louisiana Rice Production, David C. Walker
Impact Of New Technologies On Weed Control In Louisiana Rice Production, David C. Walker
LSU Doctoral Dissertations
Field studies were conducted in 2018-2021 at the LSU Agricultural Center’s H.R. Caffey Rice Research Station (RRS) near Crowley, LA, and the Dean Lee Research and Extension Center (DLREC) near Alexandria, LA to evaluate off-target florpyrauxifen movement on soybean. Soybean was treated with florpyrauxifen at the V4-V5 or R1-R2 growth stages. Soybean injury was evaluated at 1, 7, 14, and 28 days after treatment (DAT) and soybean plant height (cm) was recorded at 7, 14, and 28 DAT. At soybean maturity, yield and individual yield components were subjected to regression analysis to describe the relationship between florpyrauxifen rate and soybean …
Influence Of Planting Date, Maturity Group, Harvest Aids And Fungicide Application On Soybean (Glycine Max (L.) Seed Quality, Ana Priscila Campos
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 …
Cover Cropping In Soybean-Corn Rotation System: Economic, Agronomic, And Soil Fertility Impact, Jose Rodolfo Mite
Cover Cropping In Soybean-Corn Rotation System: Economic, Agronomic, And Soil Fertility Impact, Jose Rodolfo Mite
LSU Doctoral Dissertations
Planting winter-annual cover crops prevent soil erosion, reduces water runoff, and improves soil structure and soil quality. This research was conducted from 2017 to 2019 to evaluate the nutrient turnover of different species of cover crops in soils under different row crop production systems in Northeast and Central Louisiana. In Northeast Louisiana (Site 1, 2, and 3), treatments (cover crops and no cover crop) were arranged in a strip trial with three replications. At the Ben Hur Research Station, the treatments included three planting dates (September, October, and November) with [7 kg ha-1 of phosphorus (P) and potassium (K)] …
Evaluation Of Soil Type And Seeding Rate On Winter Cover Crop Species In A Soybean Production System, Donna S. Morgan
Evaluation Of Soil Type And Seeding Rate On Winter Cover Crop Species In A Soybean Production System, Donna S. Morgan
LSU Doctoral Dissertations
The integration of winter annual cover crops into a cropping system can potentially improve soil health and crop production, however, the impact of variables such as seeding rates, across two very different soil types, has not been well documented. A two-year study was conducted at the Dean Lee Research Station and Extension Center in Alexandria, Louisiana to evaluate the effects of cover crop seeding rate and soil type on cover crop biomass, weed suppression, soil fertility, and soybean (Glycine max L) growth and yield. Analysis of potential economic impacts was also performed to estimate financial net returns for three …
Developing Management Strategies For Taproot Decline, Xylaria Sp., In Soybean, Myra Purvis
Developing Management Strategies For Taproot Decline, Xylaria Sp., In Soybean, Myra Purvis
LSU Master's Theses
Soybean (Glycine max) is one of the most important oilseed crops in the world. Taproot decline is a recently discovered disease caused by Xylaria sp., a novel species located within the Xylaria arbuscula aggregate. Foliar symptoms include interveinal chlorosis and necrosis, and upon further investigation, there are often dead plants adjacent within the row. Many other soybean diseases have similar foliar symptoms; therefore, more examination is usually required for proper identification. Soybean debris from previous years is suspected to be the primary source of inoculum. Plants may be infected at any point during the growing season, often …
Soybean Response To Dicamba: Associated Injury Criteria And Development Of A Model To Predict Yield Loss, Matthew Ryan Foster
Soybean Response To Dicamba: Associated Injury Criteria And Development Of A Model To Predict Yield Loss, Matthew Ryan Foster
LSU Doctoral Dissertations
In research conducted using indeterminate soybean [Glycine max (L.) Merr.], fourteen injury criteria observed following dicamba at 0.6 to 280 g ae ha-1 (1/1000 to ½ of 560 g ha-1 use rate) were rated using a scale of 0= no injury, 1= slight, 2= slight to moderate, 3= moderate, 4= moderate to severe, and 5= severe. Greatest crop injury 15 d after treatment (DAT) was observed following dicamba applied at 0.6 to 4.4 g ha-1 at V3/V4 for upper canopy pale leaf margins (3.8 to 4.2) and at R1/R2 for terminal leaf cupping (4.1 to 5.0) …
Distinguishing Isolates Of Rotylenchulus Reniformis Endemic In Louisiana On The Basis Of Root-Associated Females And Egg Masses, Benjamin Mcinnes
Distinguishing Isolates Of Rotylenchulus Reniformis Endemic In Louisiana On The Basis Of Root-Associated Females And Egg Masses, Benjamin Mcinnes
LSU Master's Theses
The reniform nematode Rotylenchulus reniformis is a major pathogen of soybean and cotton in Louisiana. Previous studies have shown that populations of reniform nematode throughout the southern United States vary in reproduction and pathogenicity. Limited studies have been conducted to evaluate the reproduction and pathogenicity of populations of R. reniformis endemic in Louisiana. Studies with isolates of the nematode from eight cotton-producing parishes focused solely on reproduction of the root-associated infective and swollen female life stages with and without attached egg masses on the cotton genotypes MT2468 Ren3, M713 Ren5, and Stoneville 4946GLB2 and the soybean genotypes PI 548316, PI …
The Roles Of Avr4 In Fungal Virulence,Cercosporin Biosynthesis And Its Potential Use In Host Induced Gene Silencing For Controlling Cercospora Leaf Blight Disease Of Soybeans, Josielle Santos Rezende
The Roles Of Avr4 In Fungal Virulence,Cercosporin Biosynthesis And Its Potential Use In Host Induced Gene Silencing For Controlling Cercospora Leaf Blight Disease Of Soybeans, Josielle Santos Rezende
LSU Doctoral Dissertations
The AVR4 effector, secreted by Cladosporium fulvum, has been demonstrated to be involved in pathogen virulence. Recent studies further demonstrated that Avr4 is highly conserved among several Cercospora species, indicating a potential important role of this gene in fungal virulence. Therefore, investigation to determine whether this fungal effector gene is present in Cercospora cf. flagellaris (previously known as C. kikuchii), the causal agent of soybean cercospora leaf blight (CLB) disease, and whether it plays any role in CLB disease development, is of great interest. In the present study, the Avr4 gene from C. cf. flagellaris was cloned and mutants lacking …
Documentation Of Siderophore Activity, Metal Binding, And Its Effect On Symptomatology Of Cercospora Leaf Blight Caused In Soybean By Cercosporin From Cercospora Cf. Flagellaris, Brian Michael Ward
Documentation Of Siderophore Activity, Metal Binding, And Its Effect On Symptomatology Of Cercospora Leaf Blight Caused In Soybean By Cercosporin From Cercospora Cf. Flagellaris, Brian Michael Ward
LSU Doctoral Dissertations
Cercospora leaf blight of soybean (Glycine max) is a serious problem in the mid-south of the United States and is present in most soybean-growing regions of the world. The causal organisms, Cercospora kikuchii, C. cf. flagellaris and C. cf. sigesbeckiae, utilize the photo-activated toxin cercosporin as the primary pathogenicity factor. The disease has historically been understood to progress from a purpling or bronzing of the leaves to a blight in which tissue dies. Previous literature showed possible binding of cercosporin to metals and previous work in our group showed possible use of minor element nutrition in the plant to reduce …
Effects Of Minor Elements On Cercospora Kikuchii, Cercospora Leaf Blight And Rust On Soybeans, Brian Michael Ward
Effects Of Minor Elements On Cercospora Kikuchii, Cercospora Leaf Blight And Rust On Soybeans, Brian Michael Ward
LSU Master's Theses
Soybean (Glycine max) is one of the most widely grown crops in the world. Many pathogens attack soybeans, but of particular importance to tropical and subtropical areas such as Louisiana is Cercospora leaf blight (CLB). This disease is caused by the fungus Cercospora kikuchii and favored by high temperatures. This fungus utilizes a toxin, cercosporin, as its primary pathogenicity factor. Soybean rust (SBR), caused by Phakopsora pachyrhizi, is another common disease that occurs in Louisiana under cooler environmental conditions of spring and fall. Both diseases occur regularly in Louisiana and may result in severe yield losses. Cercospora kikuchii has recently …
Sensitivity And Resistance Of Cercospora Kikuchii, Causal Agent Of Cercospora Leaf Blight And Purple Seed Stain Of Soybean, To Selected Fungicides, Paul Patrick Price, Iii
Sensitivity And Resistance Of Cercospora Kikuchii, Causal Agent Of Cercospora Leaf Blight And Purple Seed Stain Of Soybean, To Selected Fungicides, Paul Patrick Price, Iii
LSU Doctoral Dissertations
ABSTRACT Isolates of Cercospora kikuchii, the causal agent of Cercospora leaf blight (CLB) and purple seed stain (PSS), were used to determine baseline sensitivities to selected quinone outside inhibitor (QoI) and demethylation inhibitor (DMI) fungicides by conducting radial growth assays on fungicide-amended media. The effective concentration to inhibit 50% radial growth (EC50) for each isolate was calculated by linear interpolation of the dose-response relationship. All baseline distributions were non-normal with outliers towards the less sensitive ends of the spectra, and median EC50 values for azoxystrobin, pyraclostrobin, trifloxystrobin, flutriafol, propiconazole, and tetraconazole were 0.081, 0.013, 0.012, 0.273, 0.143, 1.47 µg/ml, respectively. …
Simplicillium Lanosoniveum, A Mycoparasite Of Phakopsora Pachyrhizi And Its Use As A Biological Control Agent, Nicole A. Ward
Simplicillium Lanosoniveum, A Mycoparasite Of Phakopsora Pachyrhizi And Its Use As A Biological Control Agent, Nicole A. Ward
LSU Doctoral Dissertations
In 2007, a filamentous fungus was recovered from sori of soybean rust (SBR), caused by Phakopsora pachyrhizi, collected from Louisiana and Florida. This fungus was identified as Simplicillium lanosoniveum on the basis of ITS sequence data and morphological traits. Simplicillium lanosoniveum was found coiling within sori and around urediniospores and showed a trophic attraction to rust sori, extending from sorus to sorus. In co-inoculated soybean leaves, the fungus did not grow or establish on leaf surfaces until sori erupted. Similarly, S. lanosoniveum colonized within 3 days and sporulated within 4 days on leaves showing disease symptoms. In field studies, when …
The Influence Of Morningglory (Ipomoea Lacunosa), Hemp Sesbania (Sesbania Exaltata), And Johnsongrass (Sorghum Halepense) On Reproduction Of Rotylenchulus Reniformis On Cotton Gossypium Hirsutum L. And Soybean Glycine Max. (L.) Merrill, Michael John Pontif
LSU Doctoral Dissertations
Microplot studies were conducted to evaluate the effects of cotton (LA. 887), soybean (Pioneer 96B21), and three endemic weed species, pitted morningglory (Ipomoea lacunosa), hemp sesbania (Sesbania exaltata), and johnsongrass (Sorghum halepense), on reproduction of the reniform nematode, (Rotylenchulus reniformis). Over two microplot trials the co-culture of cotton with any of the three weeds suppressed numbers of reniform nematode juveniles in soil. When grown singly, reniform nematode reproductive values after 60 days on cotton averaged 69.0, while those for morningglory, hemp sesbania, and johnsongrass averaged 42.0, 23.5, and 18.0, respectively. Reproductive values for cotton co-cultured with morningglory averaged 38.7. Those …
Cercospora Leaf Blight Of Soybean: Pathogen Vegetative Compatibility Groups, Population Structure, And Host Resistance, Guohong Cai
LSU Doctoral Dissertations
Nitrogen nonutilizing mutants were used to assess vegetative compatibility of 58 isolates of Cercospora kikuchii, 55 of which were isolated from soybean plants in Louisiana. Only 16 of 56 self-compatible isolates were assigned to six multi-member vegetative compatibility groups (VCGs), 01-06, with two or three isolates in each VCG. The other 40 isolates were not vegetatively compatible with any isolates other than themselves. All six multi-member VCGs contained isolates from different soybean cultivars, and three included isolates from different locations. Only one VCG included isolates both from soybean leaves and from seeds, while two and three multi-member VCGs included isolates …