Entomology Commons^™

Canopy Arthropod Responses To Catastrophic Wind Disturbances In Gulf Coast And Caribbean Forests, Manoj Pandey

LSU Doctoral Dissertations

Hurricanes are major natural disturbances and integral components of forest disturbance regimes globally. The frequency and intensity of hurricanes are predicted to increase in the future due to global warming. The altered hurricane regime, along with direct effects of climate change on arthropod populations and communities, has the capacity to endanger the critical ecosystem processes and services provided by forest canopies. Therefore, it is crucial to understand the responses of forest fauna to disturbances such as hurricanes. This dissertation is aimed at understanding the short-term and long-term effects of hurricanes on canopy arthropods to improve predictions of the consequences of …

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 …

Improving The Deployment Of Insecticidal Seed Treatments In Louisiana Rice In Accordance With Integrated Pest Management, Megan Marie Mulcahy

LSU Doctoral Dissertations

Lissorhoptrus oryzophilus Kuschel (Coleoptera: Curculionidae), is the most destructive insect pest of rice in the United States. Lissorhoptrus oryzophilus larvae feed on rice roots, reducing yields by up to 25 %. Lepidopteran stem borers, in the family Crambidae, are also economically important pests of rice in Louisiana.

Currently, insecticidal seed treatments are used throughout the U.S. Mid-south rice industry to prophylactically control L. oryzophilus. Chlorantraniliprole seed treatments are also effective against stem borers. Thus, insecticidal seed treatments are used on >80 % of Louisiana rice acreage. Although seed treatments reduce damage inflicted by these pests, they are applied preventatively …

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 …

Investigating Plant Tolerance For The Management Of Insect Pests In Rice, James Michael Villegas

LSU Doctoral Dissertations

The rice water weevil, Lissorhoptrus oryzophilus Kuschel (Coleoptera: Curculionidae), is the most destructive and widespread insect pest of rice (Oryza sativa L., Poaceae) in the USA. This insect poses a global threat to rice production, having invaded rice-producing regions of Asia and Europe. Moreover, lepidopteran stemborers, particularly the invasive Mexican rice borer, Eoreuma loftini (Dyar) (Lepidoptera: Crambidae), are increasingly becoming problematic in Louisiana rice. Although insecticidal seed treatments have been widely used against weevils and stemborers, alternative management strategies are needed. Plants possess defense-related traits that both reduce injury from herbivores (resistance) and the amount of yield loss per …

Resistance Allele Frequencies To Cry1ab And Vip3aa20, And Performance Of Cry1a.105/Cry2ab2 Susceptible And Single/Dual-Gene Resistant Corn Earworm On Non-Bt And Low Concentrations Of Bt Diet, Shucong Lin

LSU Master's Theses

Corn earworm, Helicoverpa zea (Boddie), is an important agricultural pest and a target species of Bt corn and Bt cotton. Recently, this pest in the U.S. has developed resistance to Cry1/Cry2 corn and cotton. The objectives of this study were to 1) estimate the frequencies of resistance allele to Cry1Ab and Vip3Aa20 proteins in Louisiana populations of H. zea; 2) determine if Cry1A.105/Cry2Ab2 single/dual-gene resistance in H. zea is associated with fitness costs; and 3) investigate the effect of three low concentrations of mixed Cry1A.105/Cry2Ab2 proteins on the growth, development, and reproduction of two known Bt-susceptible strains and six …

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 …

Characterizing The Epidemiology Of Bluetongue And Epizootic Hemorrhagic Disease Virus In Louisiana, Michael Edward Becker

LSU Doctoral Dissertations

Bluetongue virus (BTV) and Epizootic Hemorrhagic Disease Virus (EHDV) are arthropod-borne viruses (Reoviridae; Orbivirus) transmitted by biting midges in the genus Culicoides. These viruses cause hemorrhagic disease and induce serious morbidity and mortality rates in wild and captive deer. Cattle are normally asymptomatic but serve as the reservoir/amplifying host for these viruses and play an important role in the transmission cycle. The objectives of this study were to characterize the epidemiology of these viruses as they relate to white-tailed deer and cattle, evaluate different trap types for collecting Culicoides midges, and determine if these viruses can be detected …

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 …

Taxonomy And Systematics Of The New Zealand Pselaphini (Coleoptera: Staphylinidae: Pselaphinae), Brittany Elin Owens

LSU Doctoral Dissertations

The New Zealand (NZ) Pselaphini was revised at the species level, a phylogenetic analysis was performed using morphological data, and first steps were taken towards the construction of a molecular analysis of the tribe. Eight new genera and 33 new species were discovered from specimens collected from the NZ mainland, offshore islands, Chatham Islands and the Subantarctic Islands. Of the 13 species originally described in the genus Pselaphus by Thomas Broun during the late 19^th and early 20^th centuries, all were either reassigned to the genera Pselaphaulax and Pselaphogenius, or were placed into new genera. Three names …

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 …

Effects Of Virus Infection And Volatiles On Aphid Virus Vector Behavior On Sweetpotato, John Lawrence Dryburgh

LSU Doctoral Dissertations

Sweetpotato is affected by a wide variety of viruses worldwide, which can cause yield losses of up to 90%. Many of these viruses are transmitted by aphids in a non-persistent manner. Non-persistent viruses are acquired and transmitted within minutes, and thus conventional control, such as insecticides, are ineffective. Altering aphid movement and feeding behavior may affect the rate of virus transmission. One potential method to alter aphid behavior is volatile organic compounds (VOC), including volatiles emitted by virus infected plants, plant hormones, and commercial control agents. Aphid movement near sweetpotato fields was monitored to determine trends throughout the growing season. …

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 …

Effects Of Plant Viruses On Vectors And Non-Vector Herbivores In Three Different Pathosystems, Sunil Paudel

LSU Doctoral Dissertations

Plant viruses are an important component of agro-ecosystems and the knowledge of impacts they can cause on their hosts, and on different vectors and non-vector herbivores associated with the hosts, is very crucial in devising sound management strategies for virus disease and vector control in the landscape. The interactions between these components, however, are difficult to predict and vary according to the system under investigation. In order to understand some of these interrelationships, different sets of experiments were carried out in three different pathosystems to look at the impacts of plant viruses on vector and non-vector herbivores. Firstly, in Sorghum …

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 Tripartite Interaction Between Arbuscular Mycorrhizal Fungi, Rice, And Insects, Lina Bernaola Alvarado

LSU Doctoral Dissertations

Losses caused by pests remain an important limitation to achieving high rice yields in the United States. Arbuscular mycorrhizal fungi (AM fungi) are able to modify plant physiology by increasing plant growth or inducing defense responses against insect herbivores. However, studies of the role of AM fungi in agroecological factors, including natural occurrence, plant resistance, soil dependency, and plant tolerance, with specific regards to pests that feed on rice plants have not been conducted before. A three-year study revealed natural occurring colonization by AM fungi on rice roots sampled in four rice-producing areas in the southern United States. Overall, rice-AM …

Intraguild Predation: Interactions Between Predators, Pathogens, And Their Shared Resources In Crop Pest Communities, Andrew Jason Flick

LSU Doctoral Dissertations

Crop pest management requires an understanding of the complex interactions among pest species that potentially damage crop yield and species that may be crucial for controlling pest species outbreaks. For example, predators, parasitoids, and pathogens are constantly interacting via their shared prey or hosts. Predators may prefer infected prey, which can be easier to catch; however, infected prey may be less nutritious or even lethal for predators. These interactions then dictate the short-term dynamics of host and pathogen as well as between prey and predator. "How these dynamics change as the species in the system change either empirically or theoretically?" …

Induced Resistance In Rice, Oryza Sativa, To Herbivores In The Southern United States, Emily Clare Kraus

LSU Doctoral Dissertations

The effects of herbivory and chemical applications as potential inducers of resistance to herbivores in rice, Oryza sativa L., were explored through a series of field, greenhouse, and laboratory experiments. Studies were conducted to investigate the preference and performance of several herbivore pests of rice with a focus on, Lissorhoptrus oryzophilus Kuschel, the rice water weevil (RWW), under conditions where rice plants had been stressed by previous herbivory or chemical applications. The effects of defoliation by Spodoptera frugiperda (J.E. Smith), the fall armyworm, on resistance and tolerance of rice to RWW under field conditions were examined. Herbivory by fall …

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 …