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Susceptibility Of Spodoptera Frugiperda Populations In The Southern Region Of The U.S. To Common Bt Proteins And Performance Of A Dual-Gene Resistant Helicoverpa Zea Strain On Common Pyramided Bt Corn Traits, Tiago H. Da Silva

LSU Master's Theses

The fall armyworm (Spodoptera frugiperda) and corn earworm (Helicoverpa zea) are two polyphagous pests that, in the Americas, are targeted by transgenic corn and cotton expressing Bacillus thuringiensis (Bt) proteins. A previous study during 2011-2013 demonstrated practical resistance to Cry1F corn in S. frugiperda in the southeastern seaboard of the U.S., while resistance of H. zea to Bt corn and cotton containing cry1A and cry2A genes has widely occurred in the U.S. The first objective of this study was to investigate the current susceptibility status to four Bt proteins commonly expressed in Bt corn plants, including …

Investigating The Potential Role Of Termites As Pathogen Vectors In The Decline Of Ironwood Trees (Casuarina Equisetifolia) In Guam, Garima Setia

LSU Master's Theses

Termites have been found associated with the decline of Casuarina equisetifolia (ironwood), an important agro-forestry species in Guam. While the ironwood tree decline (IWTD) was first reported in 2002, its association with termites as well as with bacteria Ralstonia solanacearum and Klebsiella species (K. oxytoca and K. variicola) was determined in 2010 and 2012 respectively. In 2019, the termite species attacking the ironwood trees were identified as Nasutitermes takasagoensis, Coptotermes gestroi, and Microcerotermes crassus. However, the role of termites in IWTD is not known. Since termites are repositories of bacteria and consume wood, termite foragers might …

Review Of Structural Color In The Genus Chrysochroa Dejean, 1833 (Coleoptera: Buprestidae), Able Chow

LSU Master's Theses

The jewel beetles, (Coleoptera: Buprestidae Leach, 1815), is the eighth most speciose coleopteran family, with the majority of its members possessing diverse bright, saturated structural coloration of multilayer origin. This study focuses on the genus Chrysochroa Dejean, 1833, which includes some of the most brilliantly and charismatically colored buprestid species. While members of Chrysochroa are prised by entomologists amateurs and professional and are well-represented in museum collections, the evolution and ecology of their structural color remain underexplored. Twenty-eight select taxa including exemplars from all 13 subgenera of Chrysochroa were investigated to provide an overview of the objective optical properties and …

Defining Toxicological Endpoints Of Aphis Gossypii Feeding, Flinn O'Hara

LSU Master's Theses

The cotton aphid, Aphis gossypii Glover (Hemiptera: Aphididae), is a destructive agricultural pest, due to photosynthate removal and plant virus transmission. This project consisted of two main goals. First, we employed toxicity bioassays and electrical penetration graph (EPG) methodology to quantify changes to feeding behavior and toxicity of A. gossypii after exposure to commercialized aphicides. Commercialized aphicides containing flupyradifurone, sulfoxaflor, thiamethoxam, thiamethoxam + lambda cyhalothrin, and bifenthrin induced > 90% aphid mortality within 4 hours of exposure. This was supported by our EPG results that showed a significant reduction in the proportion of aphids that continued to probe on cotton 4 …

Identifying The Components Of A Hemp (Cannabis Sativa L.) (Rosales: Cannabaceae) Integrated Pest Management Program In Louisiana, Nathan C. Arey

LSU Master's Theses

Hemp, Cannabis sativa (L.) (Rosales: Cannabaceae), is defined as a plant in the genus Cannabis with a delta-9 3 tetrahydrocannabinol (THC) concentration of not more than 0.3% on a dry weight basis. Domestic acreage of this crop has increased in response to the ratification of the Agricultural Act of 2014 and the Agricultural Improvement Act of 2018. In 2021, 21,915 hectares of hemp were planted in the United States with a production value of $712 million. There is a current lack of literature on insect related research in this reemerging crop system in the state of Louisiana. Therefore, this present …

Understanding The Horse Fly Species And Species Relations Of The Tabanus Nigrovittatus Complex Along Coastal Louisiana, Darrius M. Davis

LSU Master's Theses

The Dipteran family Tabanidae is among the most diverse families of insects that is comprised of approximately 144 genera with 4455 described species (Pape et al. 2011). Members of the family Tabanidae have been studied for well over 100 years in Louisiana. Hine (1906, 1907) conducted the first surveys of the members of the tabanid family and noted the presence of 14 species. Jones and Bradley (1923) supplemented Hine’s observations with their own inventory of horse flies across four parishes and found an additional 14 species that were not recorded by Hine. Subsequently, Tidwell (1970, 1973) conducted a survey of …

Aphid Herbivory On Industrial Hemp, Cannabis Sativa L., And The Impact Of Plant-Soil Feedbacks On Hemp Performance In Louisiana, Alex Leede

LSU Master's Theses

Industrial hemp, Cannabis sativa L., is defined as having less than 0.3% delta-9-tetrahydrocannabinol by dry weight. It can be grown for fiber, food, oil, and cannabinoids. As a newly legalized crop, little research exists regarding the cultivation or pest management practices in Louisiana. The versatility of industrial hemp may allow for substantial future production in Louisiana. This project set out to understand the impact of previous crops on hemp performance and soil microbial communities. Soybean, Glycine max L. (Merr), grain sorghum, Sorghum bicolor (L.) Moench, and sweetpotato, Ipomeae batatas (L.) Lam, were selected as soil conditioning crops because they are …

Soil Moisture Mediated Behavioral And Physiological Alterations Of Coptotermes Formosanus And Reticulitermes Flavipes (Blattodea: Rhinotermitidae), Steven J. Richardson

LSU Master's Theses

Substrate moisture is a critical environmental factor for the survival and behavior of subterranean termites (Blattodea: Rhinotermitidae). The invasive Formosan subterranean termite (Coptotermes formosanus) and the native eastern subterranean termite (Reticulitermes flavipes) co-occur in the southeastern United States, but C. formosanus is predominant in subtropical and R. flavipes is more common in temperate regions. The difference in their geographic distributions is largely attributed to their different behavioral and physiological ecology. While ample research has been done on foraging behavior of the two species, there was no empirical evidence for the effects of constant soil moisture on …

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 …

Revealing The Native Status Of Conyza Bonariensis: Specialization Of Insect Herbivores Associated With Conyza And Erigeron Spp. (Asteraceae) In Louisiana, Texas, And Mississippi, Carlos Wiggins

LSU Master's Theses

Flaxleaf fleabane [Conyza bonariensis (L.) Cronquist] (Asterales: Asteraceae) is an annual herb which grows up to 1.0 m in height and is native to South America. Due to introduction and subsequent development of herbicide resistance, C. bonariensis has become a major agricultural weed in Australia. The purpose of this study was to catalog herbivorous insects associated with local populations of C. bonariensis in Louisiana, Texas and Mississippi in order to establish comparisons with the Australian fauna and identify potential biological control agents. Leaves, roots, stems, and flowers of C. bonariensis were inspected for signs of insects and pathogens. Results …

Response Of Roseau Cane (Phragmites Australis) To Two Biotic Stresses: Hyalopterus Pruni And Bipolaris Yamadae, Heather E. Cizek

LSU Master's Theses

Roseau cane (Phragmites australis) is considered an invasive plant because of its ability to replace native plant species. However, in Louisiana it plays an important role protecting coastal infrastructure and being part of the marsh ecosystem in the lower Mississippi River Delta. In recent years, Roseau cane has been affected by a die-off, a problem that has also been reported in some European countries. Possible biotic and abiotic factors that have been associated with the die-off include scale insects, climate change, pollution, salinity levels, and pathogens.

In this research, the individual and combined effect of a foliar disease …

Regional Expansion And Evaluation Of Potential Chemical Control For Invasive Apple Snails (Pomacea Maculata) In Southwest Louisiana, Julian M. Lucero

LSU Master's Theses

The integration of monitoring and chemical control is an efficient strategy for managing invasive apple snails, Pomacea maculata, in the rice (Oryza sativa L.) and crawfish systems of southwest Louisiana. However, their current distribution, expansion rates, and susceptibility to chemical control methods in this area are not well known. This study evaluated the expansion of P. maculata in southwest Louisiana and assessed potential chemical control for P. maculata among toxicity assays using various application rates. The effects of potential chemical control were also assessed on a non-target species, the red swamp crawfish (Procambarus clarkii). P. maculata …

Characterization Of Resistance To Two Crambid Stem Borers Among Louisiana Sugarcane Cultivars, Leonardo D. Salgado

LSU Master's Theses

Cultivar resistance is a key management strategy for the stem borer complex (Lepidoptera: Crambidae) in Louisiana sugarcane, but mechanisms of resistance are not well understood. This research evaluated the potential mechanisms of cultivar resistance to Diatraea saccharalis and Eoreuma loftini among commercial sugarcane cultivars and experimental clones through a series of field screenings, greenhouse trials, and diet incorporation assays. The stem borer resistant standard HoCP 85-845 and cultivar L 01-299 were among the cultivars with the lowest borer injury levels in both field and greenhouse trials. Cultivars HoCP 00-950, L 12-201, and HoCP 14-885 were among the most heavily injured …

Mosquito Distribution And Stoichiometric Analysis Between Open And Closed Canopies In New Orleans Cemeteries, Rachel Rogers

LSU Master's Theses

Cemetery vases represent an important container habitat for mosquito larvae. Some species, like, Aedes albopictus and Aedes aegypti, prefer container habitats, whereas others, like Culex quinquefasciatus, will opportunistically use containers. In New Orleans, these three medically important vector species (Ae. albopictus Ae. aegypti, and Cx. quinquefasciatus) co-occur, despite a demonstrated competitive advantage of Ae. albopictus to the other two. Here we test the hypothesis that canopy cover from trees could be a mediating factor in driving mosquito assemblages in New Orleans, by influencing food sources, and the microclimate experienced by mosquito larvae. Samples from seven …

Insecticide Resistance Management Approaches And Naturally Derived Toxicants For The Control Of Fall Armyworm, Spodoptera Frugiperda, Sarah Mccomic

LSU Master's Theses

Spodoptera frugiperda, the fall armyworm (FAW), is a major agricultural pest causing billions of dollars in damage annually to staple crops. Agricultural losses stemming from this pest continues to increase as resistance to commercialized insecticide classes evolves and spreads. Considering this, novel chemistries with new modes of action as well as novel resistance management strategies need to be developed to achieve continued control of FAW populations. This project consisted of two main goals. First, we aimed to develop a neurophysiological assay to enable a more precise understanding of pyrethroid and organophosphate resistance at the level of the nerve. We …

The Collection Of Baseline Data On Insect And Plant Communities Across Multiple Salinity Zones Within Louisiana's Tidal Marshes, Benjamin G. Aker

LSU Master's Theses

Tidally influenced coastal marshes provide numerous important ecosystem services, but these habitats are experiencing extreme habitat loss. Louisiana’s coastal marshes in particular are vulnerable to land loss resulting from both anthropogenic and natural causes, but especially to subsidence and relative sea-level rise. In response, the Louisiana Coastal Restoration and Protection Authority has outlined and is currently implementing the largest ever attempt at habitat restoration. A major component of this habitat restoration attempt is the use of freshwater and sediment diversions to increase the input of low salinity water, sediment, and nutrients needed to slow marsh loss and build land. Coastal …

Ecology Of The Roseau Cane Scale (Nipponaclerda Biwakoensis, Hemiptera: Aclerdidae) In Coastal Louisiana, Leslie Alejandra Aviles Lopez

LSU Master's Theses

Common reed, Phragmites australis, is the dominant plant in the Mississippi River Delta (MRD), Louisiana. Phragmites australis stands reduce soil erosion from wave action, protect the oil infrastructure, and freshwater habitats. In the fall of 2016, widespread reed die-backs in the MRD were associated with outbreaks of an invasive scale Nipponaclerda biwakoensis (Hemiptera: Aclerdidae). Due to the recent detection of the scale, there was limited knowledge of its ecology in the adventive range, and its impacts on P. australis lineages. Therefore, the objectives of my thesis were to determine (1) the host specificity of the N. biwakoensis in important economic …

Impacts Of Commercial Biopesticides On Crapemyrtle Bark Scale (Acanthococcus Lagerstroemiae) And Beneficial Insects, Giovana Matos Franco

LSU Master's Theses

The crapemyrtle bark scale (CMBS), Acanthococcus lagerstroemiae (Kuwana) (Hemiptera: Eriococcidae), is an important pest of crapemyrtles, Lagerstromia spp. (Myrtales: Lythraceae) since its damage results in an unpleasant aesthetic. Current CMBS management methods depend heavily on pesticides which impact on beneficial insects. Biopesticides show potential for pest control, host specificity, and low impact towards non-target organisms. The objectives of my thesis were to determine (1) if biopesticides are effective against CMBS infestations when applied in different seasons, and (2) their effects towards coccinellids known to attack CMBS.

To test the efficacy of selected biopesticides, treatments were delivered to potted plants or …

Larval Survival And Movement Of The Fall Armyworm And Corn Earworm (Lepidoptera: Noctuidae) In Seed Blends Of Non-Bt And Pyramided Bt Corn: Implications For Resistance Management, Marcelo Dimase

LSU Master's Theses

A seed blend refuge has been used in the U.S. Corn Belt for Bt corn insect resistance management (IRM). The fall armyworm, Spodoptera frugiperda (F.), and corn earworm, Helicoverpa zea (Boddie) are major target pests of Bt corn in the Americas. One major concern for the use of a seed blend refuge is that larval movement of insects among non-Bt and Bt plants could affect its efficacy for resistance management. To address this concern, field and greenhouse trials were conducted to determine 1) if seed blend refugia could provide comparable levels of susceptible S. frugiperda (aabb) as structured refugia and …

The Effects Of Oral And Venereal Transmission Of Deformed Wing Virus On Honey Bee (Apis Mellifera) Queen And Colony Health, Sarah Lang

LSU Master's Theses

Honey bees are important pollinators necessary for the production of many foods. Managed honey bee colonies have been experiencing high levels of colony loss over the last decade due to a combination of different factors. Parasites, pathogens, and queen failure are repeatedly reported as major causes for colony loss, but there is little research exploring the relationship between honey bee viruses and queens. Deformed wing virus, a major honey bee virus, has a worldwide distribution, is extremely prevalent, and can infect all castes and life stages. Honey bee queens can be infected with the virus through multiple transmission routes …

Influence Of The Annual Flood Pulse Of The Atchafalaya River And Updates On The Ecology Of Floodplain Aquatic And Semi-Aquatic Hemiptera And Their Associates, Patricia Ls Wooden

LSU Master's Theses

Understanding the biodiversity of insects in an area provides key insights into the health and uniqueness of an ecosystem. Here we increase the breadth of knowledge of Louisiana aquatic Hemiptera through field and natural history collection research. The Atchafalaya River floodplain is variably inundated throughout the course of the year, peaking with the spring flood pulse, resulting in spatiotemporally dynamic habitats for aquatic organisms. Buffalo Cove Water Management Unit (BC) is within the river system, whereas Lake Fausse Pointe (LFP) has been leveed from the influence of the river for over 50 years. We collected aquatic macroinvertebrates with quatrefoil light …

Determining The Presence Or Absence Of Euscepes Postfasciatus In Haiti And Use Of Molecular Markers For The Distinction Of Cylas Formicarius Elangantulus Biotypes, Marie Rachele Lexidort

LSU Master's Theses

Cylas formicarius elegantulus (Summers) and Euscepes postfaciatus (Fairmaire) are the most destructive sweetpotato weevils in the Caribean Basin. However, damage occurring in sweetpotato production in Haiti is attributed to C. formicarius (S), since it is known to be the most prevalent species while, conflicting information is available pertaining to the occurrence of the E. postfaciatus (F). This study was conducted in the summer of 2018 to determine the presence or absence of E. postfaciatus (F) in Haiti. 98 weevil samples from field (70% ) and infested sweetpotato roots from field and regional markets were collected (30%) in the most relevant …

The Role Of Atp-Sensitive Inward Rectifier Potassium Channels In The Regulation Of Reactive Oxygen Species In The Western Honey Bee, Apis Mellifera L., Christopher J. Fellows

LSU Master's Theses

Colonies of managed honey bees are annually being lost at an unsustainable rate, partly due to reduced immunocompetence that leads to acute viral outbreaks and mortality. To aid in restoring honey bee health despite the myriad of environmental stressors, this thesis focuses on identifying novel physiological pathways that can mitigate virus-mediated mortality through increased immune function. Previous work has demonstrated that a family of potassium ion channels, termed K_ATP channels, mediate the survival of honey bees during infection from a model virus, suggesting K_ATP channels may drive antiviral immunity. Interestingly, these channels have been linked to the regulation …

Physiological Characterization Of Inward Rectifier Potassium (Kir) Channels In Insect Neural Systems, Rui Chen

LSU Master's Theses

A complete understanding of the physiological pathways critical for proper function of the insect nervous system is still lacking. The recent development of potent and selective small-molecule modulators of insect inward rectifier potassium channels has enabled the interrogation of the physiological role and toxicological potential of Kir channels within various insect tissue systems. Therefore, we aimed to highlight the physiological and functional role of neural Kir channels in the central nervous system, muscular system, and neuromuscular system through pharmacological and genetic manipulations. Our data provide significant evidence that Drosophila neural systems rely on the inward conductance of K+ ions for …

Mosquito Image Classification Using Convolutional Neural Networks, Sumanth Vissamsetty

LSU Master's Theses

Human life has always been affected by insects, especially mosquitoes, since it's early beginnings. This pesky insect acts as a vector that transmit pathogens through feeding on our blood, spreading life-threatening diseases like Zika Virus, Malaria, Dengue fever, Chikungunya and more. It is important to prevent these mosquitoes from harming humans and one way to do so is to control the mosquito population, or mosquito abatement as it is commonly known. It is important to note that not all mosquitoes are the same and each of them live, reproduce and attack in their own unique way. Hence it is crucial …

Effects Of Dietary Sugars And Sugar Alcohols On Mortality And Thermal Tolerance In Culex Quinquefasciatus And Aedes Aegypti, Madeleine Chura

LSU Master's Theses

Aedes aegypti (L. 1762), the yellow fever mosquito, and Culex quinquefasciatus Say 1823, the southern house mosquito, are prevalent in tropical and subtropical areas worldwide and are responsible for the spread of a number of devastating diseases to humans and livestock. The development of new control methods, as well as continued study of mosquito biology, is vital for improving human health. This study aimed to examine the efficacy of sugar alcohols as a novel means for mosquito control, as well as how sugar alcohols and other factors are involved in thermal tolerance in mosquitoes.

No-choice tests with the sugar alcohols …

The Effects Of Juvenile Exposure To Sub-Lethal Concentrations Of Pesticides On The Adult Reproductive Biology Of The Male Southern House Mosquitoe, Culex Quinquefasciatus, Shiloh Dean Judd

LSU Master's Theses

Mosquitoes transmit pathogens capable of causing significant diseases, the worst of which can permanently disfigure or kill. Mosquito control efforts can be strengthened by better understanding all aspects of mosquito biology, but there is deficient information regarding sperm production in male mosquitoes. Understanding the sperm production and capacity of vector species may reveal new control strategies.

The goal of this research was to determine if larval exposure to sub-lethal concentrations, defined as killing less than half of the sample population, of pesticides negatively impacts the adult male reproductive health of the southern house mosquito, Culex quinquefasciatus Say. This study quantified …

Ecology Of Emerald Ash Borer (Agrilus Planipennis: Buprestidae) In Louisiana, Balwinder Kaur

LSU Master's Theses

In 2015, emerald ash borer (EAB) was detected in North Louisiana (LA). There is no information on wood inhabiting insects of green ash (Fraxinus pennsylvanica Marshall) trees, phenology and parasitoid establishment in LA. The first objective of the study was to quantify the insect assemblages and to compare their diversity, abundance and evenness within the epicenter of the EAB infestations in North LA including regions in Central and South LA where EAB has not been detected yet. We established four treatments, based on log diameter: small and large; and log condition: dead and live for green ash. All the …

Residual Effects Of Termiticides On Mortality Of Formosan Subterranean Termites, Coptotermes Formosanus Shiraki, In Substrates Subjected To Flooding, Rajani Sapkota

LSU Master's Theses

Formosan subterranean termites (Coptotermes formosanus Shiraki) are one of the most important economic insects in the Southern US since they cause severe and costly damage to properties. Soil treatment with termiticides is the most widely used and reliable method for termite prevention, but their efficacy after a home floods, an all too common event for a homeowner in recent years, has prompted many pest control companies to suggest a new treatment is necessary. This can be expensive and possibly unnecessary. However, several factors such as termiticide water solubility and binding properties, soil type and soil leachability and the inherent …

Susceptibility Of Field-Collected Pupations Of The Corn Earworm, Helicoverpa Zea (Boddie) (Lepidoptera: Noctuidae) From Three Southern States Of The U.S. To Cry1a.105 And Cry2ab2 Proteins, Gagandeep Kaur

LSU Master's Theses

The corn earworm (CEW), Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), is a major target pest of pyramided Bt corn and Bt cotton in the U.S. In 2016 and 2017, notable corn ear damage and larval survival of CEW were observed on pyramided Cry1A.105/Cry2Ab2 corn in some fields in northeast Louisiana. The objectives of this study were 1) to determine if the ear damage and larval survival observed in the area were due to resistance development to the Bt proteins in the plants, and 2) if resistance had occurred, to determine the approximate distributions of the resistance in the southern region of …