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Articles 151 - 180 of 188

Full-Text Articles in Entomology

Phylogenetic Revision Of The Genus Mesynodites Reichardt (Coleptera: Histeridae: Hetaeriinae), Alexey K. Tishechkin Jan 2005

Phylogenetic Revision Of The Genus Mesynodites Reichardt (Coleptera: Histeridae: Hetaeriinae), Alexey K. Tishechkin

LSU Doctoral Dissertations

Mesynodites is the largest genus within the exclusively inquilinous (social insect-associated) histerid beetle subfamily Hetaeriinae (Insecta: Coleoptera: Histeridae). The 44 described species are systematically revised, and new taxa are described based on newly discovered species and the results of a cladistic analysis. The work was based on available type specimens representing 42 species and approximately 2500 specimens of non-type material. Phylogenetic hypotheses were based on maximum parsimony analysis of 150 morphological characters derived from a selection of Mesynodites species and representatives of related genera. This analysis confirmed that, in its current concept, Mesynodites is not a monophyletic taxon. Species included …

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Integrated Pest Management Of The Mexican Rice Borer In Louisiana And Texas Sugarcane And Rice, Francis P. F. Reay-Jones Jan 2005

Integrated Pest Management Of The Mexican Rice Borer In Louisiana And Texas Sugarcane And Rice, Francis P. F. Reay-Jones

LSU Doctoral Dissertations

Interactions between sugarcane, Saccharum spp., and the invasive species Mexican rice borer, Eoreuma loftini (Dyar), were evaluated in field experiments and in the greenhouse with rice, Oryza sativa L., as an additional host. By determining adult emergence holes together with percent bored internodes, a novel method for evaluating sugarcane cultivar resistance was developed. In 2001, LCP 85-384 had the greatest moth production per hectare, significantly higher (P ≤ 0.05) than HoCP 85-845. High levels of sodium and magnesium salt stress in the soil were associated with higher E. loftini injury in all cultivars except HoCP 91-555 and CP 70-321. Irrigation …

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Seasonal Abundance And Detection Of West Nile Virus In Ceratopogonids (Diptera: Ceratopogonidae) In East Baton Rouge Parish, Louisiana, Isidra Joselina Sabio Jan 2005

Seasonal Abundance And Detection Of West Nile Virus In Ceratopogonids (Diptera: Ceratopogonidae) In East Baton Rouge Parish, Louisiana, Isidra Joselina Sabio

LSU Master's Theses

The seasonal abundance and species composition of ceratopogonids (Diptera: Ceratopogonidae) in East Baton Rouge parish was described from light trap collections at 15 sites. A total of 4,968 collections were processed, and 48,667 ceratopogonids were collected from 20 November, 2002 through 25 November, 2004. Three genera of ceratopogonids (Forcipomyia Meigen, Atrichopogon Kieffer, and Culicoides Latrielle) and a total of 18 species of the genus Culicoides were identified. Ceratopogonids had distinctive spring and fall population peaks. Ceratopogonids were collected in every month during the study, with the exception of February 2004. These results suggest that certain species of Culicoides may …

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Liquid Feeding In The Red Imported Fire Ant, Solenopsis Invicta Buren (Hymenoptera: Formicidae), Kathryn Shea O'Brien Jan 2005

Liquid Feeding In The Red Imported Fire Ant, Solenopsis Invicta Buren (Hymenoptera: Formicidae), Kathryn Shea O'Brien

LSU Master's Theses

In order to accurately test liquid bait effectiveness in the lab, we determined that a starvation time of 96h is more appropriate than 72h of starvation time for laboratory fire ants (Solenopsis invicta Buren) to better simulate foraging ants in the field. Densities and viscosities of two commercial baits and 20% sugar water at 25C were measured then compared to amount of material consumed per ant at these physical properties. Mean densities of 20% sugar water, Dr. Moss, and Terro were 1.051, 1.287, and 1.354 g/mL, respectively, and viscosity of each bait treatment varied in the same order but more …

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Evaluation Of Selected Refuges In A Bollgard Cotton Production System: Heliothine Movement And Effects On Boll Injury, Rhett Hunter Gable Jan 2005

Evaluation Of Selected Refuges In A Bollgard Cotton Production System: Heliothine Movement And Effects On Boll Injury, Rhett Hunter Gable

LSU Master's Theses

During 2001-2003, distribution of heliothine- (bollworm, Helicoverpa zea [Boddie], and tobacco budworm, Heliothis virescens [F.]) injured bolls in a transgenic Bacillus thuringiensis Berliner (Bt) Bollgard® and non-Bt refuge cotton system was evaluated in several experiments. Heliothine-damaged bolls were significantly higher and seedcotton yields were lower in the non-Bt refuge than in the Bollgard® areas of fields. The highest probability in occurrence of damaged bolls was at sites near the center of the non-Bt refuge. Number of damaged bolls and probability values describing occurrence decreased from the center of the refuge to sites near the interface (adjacent rows) of the non-Bt …

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Evaluation Of Vetiver Oil And Alate Biology As Preventative Measures Against The Formosan Subterranean Termite, Coptotermes Formosanus Shiraki (Isoptera: Rhinotermitidae), Karen Elizabeth Nix Jan 2005

Evaluation Of Vetiver Oil And Alate Biology As Preventative Measures Against The Formosan Subterranean Termite, Coptotermes Formosanus Shiraki (Isoptera: Rhinotermitidae), Karen Elizabeth Nix

LSU Master's Theses

The Formosan subterranean termite, Coptotermes formosanus Shiraki, is responsible for over $1 billion in property damage, repairs, and control in the United States. Presently, control of this exotic pest depends mainly on chemical methods. There is an increasing interest in using natural products in pest control because of their low mammalian toxicity and environmental safety. Chemical components of the roots of vetiver grass, Vetiveria zizanioides (L.) Nash, have shown to be effective repellents and toxicants to Formosan subterranean termites. Objectives of this research were to evaluate: 1) vetiver grass root growth and its oil distribution; 2) vetiver oil, nootkatone, and …

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Evaluation Of Beauveria Bassiana And Host Plant Resistance For The Management Of Rice Stink Bug In Rice Agro-Ecosystem, Dilipkumar Thakorbhai Patel Jan 2005

Evaluation Of Beauveria Bassiana And Host Plant Resistance For The Management Of Rice Stink Bug In Rice Agro-Ecosystem, Dilipkumar Thakorbhai Patel

LSU Master's Theses

Isolates of Beauveria bassiana (Balsamo) Vuillemin were tested for biological control of rice stink bug, Oebalus pugnax (Fab.), in the laboratory, in small-plot field experiments compared with conventional insecticides, and in a large-plot experiment to determine the spread and persistence of the fungus. The soil-derived isolate LRC28 was more virulent to O. pugnax adults than the rice stink bug-derived isolate RSB in a laboratory experiment. The fungal isolates did not differ from one another in reducing insect numbers or in infecting rice stink bugs in the small-plot experiments. A single application of B. bassiana reduced rice stink bug nymphs on …

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Revision Of Pocadius Erichson (Coleoptera: Nitidulidae), Andrew R. Cline Jan 2005

Revision Of Pocadius Erichson (Coleoptera: Nitidulidae), Andrew R. Cline

LSU Doctoral Dissertations

A revision of Pocadius Erichson (Coleoptera: Nitidulidae) was completed. A total of 46 species were (re)described, including 25 new species, a key to species constructed, and phylogenetic analysis performed. Taxonomic changes, including nomenclatural emendations, reinstatement of species, and description of new taxa, within this dissertation do not constitute formal changes as defined by the International Code of Zoological Nomenclature. Illustrations of the genitalia, key characters, and dorsal habitus of species are provided. The phylogeny demonstrates a monophyletic Pocadius. The phylogeny suggests a Palearctic origin of the genus with subsequent speciation into the Old World tropics and New World. Host specialization …

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Faunal Succession Of Necrophilous Insects Associated With High-Pofile Wildlife Carcasses In Louisiana, Erin Jean Grindley Watson Jan 2004

Faunal Succession Of Necrophilous Insects Associated With High-Pofile Wildlife Carcasses In Louisiana, Erin Jean Grindley Watson

LSU Doctoral Dissertations

The same entomological criteria used in estimating time of death for humans are applicable for deceased wildlife. Necrophilous insects associated with animal carcasses can provide wildlife law enforcement with valuable information necessary for postmortem interval estimation, and ultimately, to incriminate poachers. The purpose of this research was twofold: to establish species composition, faunal succession patterns, and species and life stage interactions of necrophilous insects associated with three wildlife species; and to identify new methods of evaluating succession patterns using statistical measures. Twenty-one large vertebrate carcasses were monitored throughout decomposition in a mixed flatwood forest in East Baton Rouge Parish, LA …

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Bees Associated With Louisiana Longleaf Pine Savannas, Chanda Sara Bartholomew Jan 2004

Bees Associated With Louisiana Longleaf Pine Savannas, Chanda Sara Bartholomew

LSU Master's Theses

Longleaf pine savannas are perhaps the most threatened ecosystems in North America. Despite a well documented and highly diverse flora, little has been published on insects in general and, in particular, on bees that provide the valuable service of plant pollination. Thus, the aims of this study were to: 1) survey bees found in two savanna types in southeastern Louisiana; and 2) contrast the diversity and species composition of these two savanna types. An ancillary goal was to contrast two collecting protocols for bees in the savanna habitat. Overall, a total of 3,407 bees were collected representing 125 species. Of …

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Volatiles Associated With Formosan Subterranean Termites And Related Methods Development, Paul Mclaughlin Jan 2004

Volatiles Associated With Formosan Subterranean Termites And Related Methods Development, Paul Mclaughlin

LSU Master's Theses

An investigation was conducted to identify volatiles associated with active Formosan termites. Using a combined technique of short path thermal desorption-gas chromatography/mass spectrometry (SPTD-GC/MS), qualitative comparisons were made between compounds detected in treatments containing active Formosan termites versus those detected in controls without Formosan termites. Except for dimethyl disulfide, none of the compounds were consistently detected in the treatments but not the controls for the four termite groups tested. However, in each of the three groups that dimethyl disulfide was detected, dead termites that were decomposing along with active termites were present. Therefore, none of the compounds could be classified …

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Bollworm (Lepidoptera: Noctuidae) Production From Alternate Host Crops And Their Contribution To A Non-Bollgard Cotton Refuge, Edward Ashley Peters Jan 2004

Bollworm (Lepidoptera: Noctuidae) Production From Alternate Host Crops And Their Contribution To A Non-Bollgard Cotton Refuge, Edward Ashley Peters

LSU Master's Theses

The bollworm’s, Helicoverpa zea (Boddie), inherent tolerance to the Bacillus thuringiensis toxin expressed in Bollgard® cotton and its ability to exploit numerous hosts has caused the Environmental Protection Agency to re-evalute the refuge component of the resistance management strategy. The goal of this project was to evaluate selected alternate host crops as supplemental non-cotton refuges for bollworm. The relative density, temporal occurrence, and life stage synchrony for bollworm larvae and adults was studied in Bollgard® cotton, Bollgard® cotton non-Bollgard® cotton, field corn, grain sorghum, and soybean. Native populations of bollworm larvae were monitored June to September during 2002 and 2003 …

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Insect Pest Management Approaches Among Currently Recommended Sugarcane Varieties In Louisiana, Frederick R. Posey Jan 2004

Insect Pest Management Approaches Among Currently Recommended Sugarcane Varieties In Louisiana, Frederick R. Posey

LSU Master's Theses

The sugarcane borer, Diatraea saccharalis (F.), (Lepidoptera: Crambidae), is responsible for more than 90% of the total insect damage to sugarcane in Louisiana. The decision to apply insecticides is complex and influenced by numerous variables. Included among these variables are insect infestation levels, varieties, weather conditions, production input levels, and environmental concerns. Predicting damage that may result from infestations occurring at a particular time of the crop production season is also important. The objective of this research was to evaluate the impact of these variables on sugarcane borer populations and subsequent yield loss. Results from a two-year survey indicated a …

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The Performance Of The Baldcypress Leafroller (Archips Goyerana Kruse, Lepidoptera: Torticidae) In Response To Fertilization, Thinning, And Genetic Variation In Host Baldcypress (Taxodium Distichum L. Richard), Crawford Wood Johnson Jan 2004

The Performance Of The Baldcypress Leafroller (Archips Goyerana Kruse, Lepidoptera: Torticidae) In Response To Fertilization, Thinning, And Genetic Variation In Host Baldcypress (Taxodium Distichum L. Richard), Crawford Wood Johnson

LSU Master's Theses

Mississippi River diversions into coastal Louisiana wetlands aim to provide nutrient inputs and slow the impacts resulting from saltwater intrusion. Baldcypress (Taxodium distichum L. Richard) exhibits significant intraspecific tolerance to salinity and is being developed for restoration projects. Two studies were conducted using five half-sibling families of baldcypress planted at two locations in southeast Louisiana to investigate the effects of nutrient additions, thinning, and phenology on the growth of the baldcypress leafroller (Archips goyerana Kruse, BCLR). In the Jeanfreau study, families were subjected to a control, low, and high level of fertilization simulating two-four years’ effects, respectively, from a Mississippi …

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Species Diversity And Biogeography Of Ants (Hymenoptera: Formicidae) In Louisiana With Notes On Their Ecology, Shawn T. Dash Jan 2004

Species Diversity And Biogeography Of Ants (Hymenoptera: Formicidae) In Louisiana With Notes On Their Ecology, Shawn T. Dash

LSU Master's Theses

Over three decades have passed since the completion of Moser and Blum's (1960) treatment of the ants of Louisiana. This research represents a significant contribution to and update of their work. I report the first-ever comprehensive assessment of the Louisiana Formicid fauna. More than 100 species from 38 genera and eight subfamilies are covered. This faunistic survey gives valuable data of biodiversity and macro/microhabitat selection of ant species. Included are keys to all subfamilies, genera, and species with illustrations photographs, and a regional map for each species.

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Field Evaluation Of Mosquito Control And Repellent Devices In Southern Louisiana, Brett Warren Collier Jan 2004

Field Evaluation Of Mosquito Control And Repellent Devices In Southern Louisiana, Brett Warren Collier

LSU Master's Theses

The effect of 2 mosquito traps and 2 repellent systems upon the catch of an American Biophysics Corporation (ABC) light trap were evaluated over a 14-month period at 3 locations in Louisiana. Devices evaluated included: 1) ABC Mosquito Magnet® with dry ice and octenol, 2) the BioSensory 500 cc Dragonfly® Biting Insect Trap with CO2, octenol, and Mosquito Cognito® which uses Conceal™ inhibitor, 3) the SC Johnson OFF!® Mosquito Lantern, and 4) the ThermaCell® cordless mosquito repellent system for residential use. The number of mosquitoes caught in the ABC light traps at the SC Johnson OFF!® Mosquito Lantern …

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Effect Of Cotton Aphids, Aphis Gossypii (Glover), On Cotton Plant Development And Yield Components, Robert Hankins Jones Jan 2004

Effect Of Cotton Aphids, Aphis Gossypii (Glover), On Cotton Plant Development And Yield Components, Robert Hankins Jones

LSU Master's Theses

The effect of cotton aphids, Aphis gossypii (Glover), on cotton plant development and yield was studied during 2000 and 2001. Tests were conducted at the Macon Ridge Station (Winnsboro, Louisiana) in 2000 and 2001, and at the Northeast Research Station (St. Joseph, Louisiana) in 2001. Tests were performed in irrigated and non-irrigated regimes using individual plant comparisons, micro-plots, and whole plots. In both years and at both locations, cotton aphid densities induced chlorosis, and a downward cupping of leaves during the infestation period. The insecticides, pymetrozine and thiamethoxam, were applied to control natural infestations of cotton aphids. Although pymetrozine and …

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Abiotic And Biotic Factors Affecting The Distribution Of Solenopsis Invicta Buren, Brachymyrmex Sp., And Linepithema Humile (Mayr) In East Baton Rouge Parish, Louisiana, Jessica Lynn Rosson Jan 2004

Abiotic And Biotic Factors Affecting The Distribution Of Solenopsis Invicta Buren, Brachymyrmex Sp., And Linepithema Humile (Mayr) In East Baton Rouge Parish, Louisiana, Jessica Lynn Rosson

LSU Master's Theses

Ant populations and their distribution are affected by many circumstances. Abiotic factors such as weather, water availability, and soil characteristics may determine if a habitat is suitable for ants. Other factors such as level of disturbance, available food resources, reproductive biology, and natural enemies also contribute to defining ant distribution. Three ant species in East Baton Rouge parish, Louisiana were studied to determine what factors affected their distribution by measuring abiotic and biotic factors at sampling sites throughout the parish. These factors included weather, water availability, vegetation types, level of disturbance, and soil characteristics. Factors which predict abundance of Solenopsis …

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Investigation Of Insect-Weed Interactions In The Rice Agroecosystem, Kelly V. Tindall Jan 2004

Investigation Of Insect-Weed Interactions In The Rice Agroecosystem, Kelly V. Tindall

LSU Doctoral Dissertations

Interactions between graminaceous weed and insect pests of rice and between management practices for these pests were investigated. Studies were conducted to examine preference and performance of rice water weevil, Lissorhoptrus oryzophilus Kuschel, on several weeds commonly found in rice fields. Several weeds were more preferred than rice, and larvae were present on several dicotyledonous weeds, suggesting the host range of L. oryzophilus is broader than previously thought. Effects of the presence of barnyardgrass, (Echinochloa crus-galli Beauv.), on rice stink bugs, Oebalus pugnax F., and L. oryzophilus populations in rice fields were investigated. Presence of barnyardgrass and the synchrony …

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Integration Of Management Tactics For The Rice Water Weevil Lissorhoptrus Oryzophilus Kuschel With Particular Emphasis On Use Of Plant Resistance (Tolerance), Li Zou Jan 2004

Integration Of Management Tactics For The Rice Water Weevil Lissorhoptrus Oryzophilus Kuschel With Particular Emphasis On Use Of Plant Resistance (Tolerance), Li Zou

LSU Doctoral Dissertations

Studies were conducted to test the hypothesis, significant benefits can be achieved for the management of rice water weevil, Lissorhoptrus oryzophilus Kuschel, by the use of rice varieties with low levels of host plant resistance coupled with the judicious use of cultural practices and insecticides. Tolerant traits of a current commercial variety of rice, "Bengal", was manifested consistently over multiple years. Study on rice growth as effected by weevil injury showed that pruning of root systems by larvae of weevil resulted in a decrease in tiller number and shoot biomass of rice plants in the vegetative stage of growth. Yield …

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Interactions Of Insect Herbivory And Multiple Abiotic Stress Agents On Two Wetland Tree Species In Southeast Louisiana Swamps, Rebecca Faye Souther-Effler Jan 2004

Interactions Of Insect Herbivory And Multiple Abiotic Stress Agents On Two Wetland Tree Species In Southeast Louisiana Swamps, Rebecca Faye Souther-Effler

LSU Doctoral Dissertations

Forested wetlands in Louisiana are hydrologically isolated from the Mississippi River, impounded by manmade structures, impacted by saltwater intrusion, and are sinking, resulting in more frequent flooding for longer periods. Additionally, defoliation of the two dominant trees, baldcypress (Taxodium distichum L. Rich) and water tupelo (Nyssa aquatica L.), occur frequently during spring. In Louisiana, the baldcypress leafroller, BCLR, (Archips goyerana Kruse) and the forest tent caterpillar, FTC, (Malacosoma disstria Hubner) defoliate up to 120,000ha of baldcypress-tupelo swamps. Restoration plans call for reintroducing Mississippi River water (diversions) to increase sediment elevation, promote natural regeneration, and enhance primary and secondary productivity. In …

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Biology And Host Finding Of Predaceous Hister Beetles (Coleoptera: Histeridae) Associated With Ips Spp. (Coleoptera: Scolytidae) In Loblolly Pine (Pinus Taeda L.), William Pinson Shepherd Jan 2004

Biology And Host Finding Of Predaceous Hister Beetles (Coleoptera: Histeridae) Associated With Ips Spp. (Coleoptera: Scolytidae) In Loblolly Pine (Pinus Taeda L.), William Pinson Shepherd

LSU Doctoral Dissertations

The most common predaceous Histeridae (Coleoptera) found associated with Ips engraver beetles (Coleoptera: Scolytidae) in Louisiana were Platysoma attenuata LeConte, Pla. cylindrica (Paykull), Pla. parallelum (Say), and Plegaderus transversus (Say). Seasonal abundance of histerids in flight traps coincided with Ips spp. activity in the area. Histerid adults arrived at loblolly pine (Pinus taeda L.) logs one wk after Ips attacks had begun. As a group, histerids exhibited a bimodal emergence pattern with the first peak occurring during Ips emergence and a second four wks later, indicating that they fed on bark beetles and associated organisms arriving later in the colonization …

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Evaluation Of Injury And Management Strategies For Stink Bugs (Heteroptera: Pentatomidae) On Cotton, Gossypium Hirsutum L., Melissa Marie Willrich Jan 2004

Evaluation Of Injury And Management Strategies For Stink Bugs (Heteroptera: Pentatomidae) On Cotton, Gossypium Hirsutum L., Melissa Marie Willrich

LSU Doctoral Dissertations

The effects of brown stink bug, Euschistus servus (Say), and southern green stink bug, Nezara viridula (L.), feeding on pre-flowering, flowering, and senescing cotton, Gossypium hirsutum L., plants were evaluated in field studies. Vegetative stage seedlings and flower buds (squares) were not significantly injured by adults or nymphs of either species in no-choice studies. Brown stink bug adults induced boll abscission, and reduced seedcotton yield and seed germination in bolls accumulating „T 350, „T 550, and 101 to „T 600 heat units beyond anthesis, respectively. In free-choice tests, boll preference was evaluated during each of the initial five weeks of …

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Seasonal Occurrence Of Phyllophaga Species And Biological Studies Of Phyllophage Ephilida (Say) On Sweet Potato, Ipomoea Batatas (L) Lam, In Louisiana, Aboubacar Diagne Jan 2004

Seasonal Occurrence Of Phyllophaga Species And Biological Studies Of Phyllophage Ephilida (Say) On Sweet Potato, Ipomoea Batatas (L) Lam, In Louisiana, Aboubacar Diagne

LSU Doctoral Dissertations

The biology of Phyllophaga ephilida (Say) was studied in Louisiana with both laboratory and field experiments from 1998 through 2003. The seasonal occurrence of common adult Phyllophaga species in sweet potato growing areas was surveyed with blacklight traps. P. ephilida and P. crinita (Burmeister) were the most common species at all locations. The attractiveness of seven methyl esters of L-isoleucine and L-valine blends to P. ephilida males was evaluated in sweet potato fields in 1999 and 2000. The 100% methyl ester of L-isoleucine was significantly more attractive than all other blend ratios that were tested. The life cycle of P. …

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Effects Of Mid-Season Avermectin Treatments Of Cattle On Pyrethroid Resistance In Three Populations Of Horn Flies, Haematobia Irritans Irritans (L.) (Diptera: Muscidae), Glenn R. Oremus Jan 2003

Effects Of Mid-Season Avermectin Treatments Of Cattle On Pyrethroid Resistance In Three Populations Of Horn Flies, Haematobia Irritans Irritans (L.) (Diptera: Muscidae), Glenn R. Oremus

LSU Master's Theses

The effects of mid-season avermectin treatments on pyrethroid-resistant horn fly populations were examined between 1999-2002 at three separate Louisiana State University Agricultural Center research stations; Red River Research Station (Bossier City, LA), Macon Ridge Research Station (Winnsboro, LA) and St. Joseph (St. Joseph, LA). The cattle were treated with pyrethroid ear tags in all years at all farms, and each farm received a mid-season avermectin treatment in one year. With consecutive yearly use of pyrethroids the number of weeks of control decreased for all farms. The number of weeks of control rebounded at Red River from 2 to 13 weeks …

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Thrips Species Composition In Louisiana Cotton And Associated Management Strategies, Donald Ray Cook Jan 2003

Thrips Species Composition In Louisiana Cotton And Associated Management Strategies, Donald Ray Cook

LSU Doctoral Dissertations

The common species of thrips infesting cotton seedlings include flower thrips, Frankliniella tritici (Fitch); tobacco thrips, Frankliniella fusca (Hinds); western flower thrips, Frankliniella occidentalis (Pergande); onion thrips, Thrips tabaci (Lindeman); and soybean thrips, Neohydatothrips variabilis (Beach). In surveys of cotton seedlings at several locations in Louisiana, tobacco thrips was the most common species. The occurrence of flower thrips and soybean thrips was variable. Western flower thrips accounted for < 15% of adults collected at all locations, except two. The performance of acephate and imidacloprid applied as seed treatments and in-furrow, and aldicarb applied in-furrow was evaluated for thrips management across different production environments. Insecticide treatments reduced thrips densities and delayed development of thrips larval populations. The at-planting insecticides influenced thrips species composition in some instances. In studies to evaluate the effects of winter-spring vegetation type (native vegetation and wheat) on aldicarb efficacy, vegetation type did not influence thrips densities on cotton, with one exception. Aldicarb reduced thrips densities regardless of vegetation type. Vegetation type or insecticide treatments did not influence lint yield. Increasing aldicarb rates generally did not improve thrips control. Aldicarb rates currently recommended in conventional tillage systems should be adequate for systems that incorporate winter-spring vegetation as cover crops. Additional studies were conducted to further investigate the influence of thrips on crop maturity and yield. The addition of an at-planting insecticide improved lint yield in one of six tests. Thrips infestations did not affect crop maturity, and with few exceptions boll distribution and boll retention. The majority of these exceptions were associated with the test where the addition of an at-planting insecticide improved lint yield. Several soil applied at-planting insecticides were evaluated against tarnished plant bug, Lygus lineolaris (Palisot de Beauvois), in a field caged infestation study. Acephate and imidacloprid provided little control of tarnished plant bugs. Thiamethoxam and aldicarb resulted in ≥ 50% tarnished plant bug mortality until 10 and 18 DAE, respectively. These are the first reports of western flower thrips infesting cotton seedlings in Louisiana. The addition of an at-planting insecticide provided control of thrips, but affects on crop maturity and yield were variable.

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Effects Of Fire Frequency And The Red Imported Fire Ant On Native Insects In A Louisiana Longleaf Pine Savanna, Deanna M. Colby Jan 2002

Effects Of Fire Frequency And The Red Imported Fire Ant On Native Insects In A Louisiana Longleaf Pine Savanna, Deanna M. Colby

LSU Doctoral Dissertations

Ants and ground beetles were collected in pitfall traps from a longleaf pine savanna in the early stages of restoration. Insect abundance and species richness were compared among four treatment combinations of two fire frequencies and presence and absence of an exotic ant, Solenopsis invicta, the red imported fire ant. Amdro® was used to suppress S. invicta. Fire treatments consisted of a single fire in a two year period or two fires in a two year period, one applied each year. Fires were applied late in the growing season both years. Ten of the 28 ground beetle species …

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Screening And Characterization Of Pathogenic Fungi For Possible Control Of Coptotermes Formosanus, Jianzhong Sun Jan 2002

Screening And Characterization Of Pathogenic Fungi For Possible Control Of Coptotermes Formosanus, Jianzhong Sun

LSU Doctoral Dissertations

Coptotermes formosanus was used as “bait” to isolate pathogenic fungi from soil. Fifteen pathogenic fungal isolates were obtained, all either Metarhizium anisopliae (six isolates) or Beauveria bassiana (nine isolates). There were no differences in numbers of fungal isolates from the three sampling locations. However, significantly more isolates were found in woodlands (eleven) than in pastures (four). Median lethal doses (LD50s) of these fungal species to C. formosanus were interspersed, indicating that fungal isolates rather than species had the greatest effect on virulence. In vitro growth characteristics were significantly correlated with virulence against termites, suggesting that fungal virulence might be predicted …

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Development Of Diagnostic Tools For Detecting Expression Of Resistance-Associated Esterases In The Tobacco Budworm, Heliothis Virescens (F.), Huazhang Huang Jan 2002

Development Of Diagnostic Tools For Detecting Expression Of Resistance-Associated Esterases In The Tobacco Budworm, Heliothis Virescens (F.), Huazhang Huang

LSU Doctoral Dissertations

Esterase-based metabolic resistance was studied using biochemical and biological assays with organophosphate (OP)- and pyrethroid (PYR)- resistant tobacco budworms, Heliothis virescens. In biochemical assays, results suggest that: (1) esterase activities toward all substrates used were enhanced in both resistant strains compared with the susceptible strain, suggesting that esterases were involved in resistance; (2) esterase profiles differed depending on the strain and substrate used, and these differences were visualized by using native polyacrylamide gel electrophoresis; 3) esterase activities toward some pyrethroid substrates were significantly higher (P ≤ 0.01) in the PYR-R strain than those in the OP-R strain. These results suggest …

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Evaluation Of Bacillus Thuringiensis Transgenic Field Corn For Management Of Louisiana Corn Pests, Boris A. Castro Jan 2002

Evaluation Of Bacillus Thuringiensis Transgenic Field Corn For Management Of Louisiana Corn Pests, Boris A. Castro

LSU Doctoral Dissertations

Efficacy of Bt corn hybrids expressing an insecticidal delta-endotoxin through different transformation events was evaluated in Louisiana. Efficacy levels were determined for southwestern corn borer (SWCB), Diatraea grandiosella Dyar; sugarcane borer (SCB), Diatraea saccharalis (F.); corn earworm (CEW), Helicoverpa zea (Boddie); and fall armyworm (FAW), Spodoptera frugiperda (J. E. Smith). Insect (neonates and third instars) susceptibility was evaluated on Bt and non-Bt corn plants (V6 and R1 stages) in field plots and plant tissue in laboratory studies. Bt corn hybrids with MON810 and CBH351 transformation events sustained significantly (P < 0.05) less injury caused by SWCB, SCB, and FAW during infestations at mid-whorl stage. SWCB, SCB, and CEW infestations during silking stage were significantly reduced in Bt hybrids with the MON810 event. However, CEW infestations …

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