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 on gasteromycetes fungi by Pocadius species was shown not to be obligate but rather facultative. Some sympatric species were shown to have temporally disjunct occurrences that may provide reproductive isolation.

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 refuges and Bollgard® fields. The lowest occurrence of injury was detected at those sites in the Bollgard® fields farther away from the non-Bt refuge. The spatial variation in seedcotton yields across the Bollgard® and non-Bt refuge areas indicated no consistent trends with the exception that seedcotton yield was consistently lower at sample sites in the Bollgard® fields adjacent to the non-Bt refuge compared to the mean yield for the entire Bollgard® sample sites. Pheromone-baited wire cone traps also were used to quantify heliothine adult dispersal in Bollgard® and non-Bt refuge areas. Traps were placed on the field margins of these areas at pre-determined sites starting in the center of the non-Bt refuge and continuing at intervals across the Bollgard® field for 2.4 to 3.5 km. Both species were captured in all traps, but mean numbers of bollworms were higher than that for tobacco budworm. Tobacco budworm captures were consistently higher in traps located closer to the non-Bt refuge, but bollworm captures were not influenced as much by the location of the non-Bt refuge as were tobacco budworm. In addition, the frequency of tobacco budworm adult captures declined as trap distance increased from the refuge. These data serve to explain the distributions of the heliothine species and injury in non-Bt refuges and Bollgard® cotton fields and provide additional information for the future development of Bt-resistance management strategies in transgenic crops.

Host plant preference and chemical ecology of the sugarcane beetle, Euetheola humilis were evaluated in greenhouse and laboratory studies. Sweet potato, Ipomoea batatas, was significantly preferred over all other plant species evaluated in a host plant preference test. Corn, Zea mays, and sugarcane, Saccharum spp., were the next most chosen plant species in the study. In olfactometer experiments, sugarcane beetles responded significantly more to beetle injured and mechanically injured roots vs. uninjured roots. Male and female beetles were also significantly more attracted to female conspecifics. Differences were not detected between sweet potato cultivars in olfactometer trials. Cultivar preference studies suggested that some cultivars may be more attractive than others. Susceptibility of sugarcane beetle and sweetpotato weevil, Cylas formicarius, to selected insecticides was evaluated in laboratory bioassays. Sugarcane beetles were significantly more susceptible to z-cypermethrin than to chlorpyrifos and bifenthrin. Sweetpotato weevils from two cohorts were most susceptible to methyl parathion and the cohorts were differentially susceptible to selected insecticides. Reduced susceptibility of a reference cohort of sweetpotato weevil was noted for all insecticides evaluated. A planting date study was conducted over two years in two locations in Louisiana. Damage from soil insects in sweet potato can be affected by many factors, such as insect abundance and life stage, and stage of the crop. A representative early, middle, and late planting date were used to assess soil insect abundance and damage throughout the sweet potato production season. Planting date affected damage from soil insects in sweet potato. Significantly more total insect damaged roots were sampled from late planting dates compared to early and middle planting dates. Cucumber beetle, Diabrotica spp., damage was greater in late planting dates, relative to early and middle planting dates. Late planting dates also had an increased probability of sugarcane beetle damage compared to early and middle planting dates. The majority of adult insects sampled were Diabrotica beetles and Diabrotica abundance was variable throughout the season and was positively correlated with percent larvae damaged roots at various seasonal intervals. Sweet potato soil insect abundance and damage was also investigated at various herbicide regimes in a two year study. Differences in soil insect damage or adult insect abundance were not detected between various herbicide regimes. U.S. No. 1 and 2 yield was significantly higher in herbicide treated plots vs. untreated control plots and weed densities were significantly reduced in some treated plots compared to untreated control plots. Sugarcane beetle studies have provided information on the biology, chemical ecology and possible management options for this insect in sweet potato. In addition, these studies have examined the importance of an integrated pest management system in sweet potato. Integrated pest management involves manipulating the crop as well as careful management of insect species.

Thirty-six FRP composite welds were wetted with UV curing vinyl ester resin and used to join fiberglass tubes. The effects of UV light intensity and weld thickness on performance (as measured by bursting pressure and stiffness) were evaluated to determine optimal conditions for joint construction. The joined composite pipes were cured vertically with UV lamps at three different light intensities, 80 mW/cm2, 35 mW/cm2 and 15 mW/cm2 to isolate the effect of UV light intensity. Eight-layer, five-layer and three-layer joints were prepared and cured at constant light intensity to evaluate the effect of reducing the thickness of the composite joint. Finite element analysis (FEA) models were developed to simulate the physical conditions of testing, known mechanical properties of the materials used, and the negative effects of under curing and gravity leaching of resin due to vertical curing. The mechanism for variation in performance is under curing; joint performance is increased by reducing the incidence of under curing by increasing light intensity and decreasing joint thickness.

Although the brown rot fungus, Gloeophyllum trabeum (Pers.:Fr.) Murrill, has been shown to be attractive and beneficial to subterranean termites, including Coptotermes formosanus Shiraki, to date no research has been conducted to determine if the association is mutualistic. We first set out to determine if the fungus could be spread by termites. This would represent an obvious benefit to the fungus. We found that C. formosanus does not spread G. trabeum. Unexpectedly, Formosan subterranean termites were found to suppress the growth of G. trabeum. To further investigate this finding, Formosan subterranean termite workers were released into Petri dishes with wood chips inoculated with G. trabeum. To serve as controls, an equal number of Petri dishes received all components as above but without termites. Growth of G. trabeum was measured on the 6th day of incubation and a significant suppression of fungus growth was observed in treatments with termites. In follow up studies G. trabeum inoculated wood chips were placed on to potato dextrose yeast agar medium and measured for G. trabeum growth after 7 days. G. trabeum did not grow but, many green-spored fungi were predominant in all the cultures. We hypothesized that these green-spored fungi may be carried on or in the body of C. formosanus and were the cause of the observed G. trabeum suppression. Dual culture tests of fungi isolated from the external surface of Formosan subterranean termites showed that several isolates were parasites and/or antagonists and effectively controlled the growth of G. trabeum. These fungi included Aspergillus flavus Link, Trichoderma harzianum Rifai, Trichoderma virens (Miller et al.), Trichoderma asperellum Samuels, Lieckfeldt & Nirenberg and Trichoderma ghanense Y. Doi, Y. Abe & J. Sugiyama. In the intestinal tracts of C. formosanus a different complex of fungi were present, some of which were antagonistic to G. trabeum. Aspergillus flavus, Hypocrea virens Chavarri, Samuels and Steward, T. asperellum, along with Penicillium janthinellum Biourge and Cladosporium cladosporioides (Fres.) de Vries were the fungi isolated from the guts. A. flavus was commonly isolated from external surface and gut of laboratory maintained termite colonies when compared to freshly collected field termite colonies. When these fungi were tested against C. formosanus, only A. flavus was found to be toxic to termites. Our study is the first to show that fungi present on the termite exoskeleton control the growth of a competing cellulose consumer, G. trabeum.

The Northern Bobwhite (Colinus virginianus L.) has experienced average yearly decline of 3% in the United States from 1966-2005. Factors implicated in decline include habitat destruction, alteration of farm practices, and red imported fire ant (RIFA) (Solenopsis invicta Buren). Effect of RIFA on bobwhites has been a hot topic leading to formation of polarized camps those who believe RIFA have little effect and those who believe the effect will further threaten the species survival. The main objective of this study was to determine if RIFA affect nesting of bobwhites and at what stage in nesting birds are most vulnerable. Effect of broadcast-spread fire ant bait on RIFA and non-target ant species also was studied. In 2005, eight 4.45 ha plots, each with one aviary housing breeding bobwhites from Louisiana captive stock, were paired by habitat feature. Four plots were broadcast-treated aerially with Amdro® (0.73% hydramethylnon). Sticky traps indicated successful dispersal of bait, although percent composition of particle size on traps differed from that expected. Food traps were used to measure success of RIFA suppression and to determine effect of bait on non-RIFA ants. In 2006, number of plots was reduced to six (three pairs), but number of aviaries per plot increased to four. Two aviaries per plot contained captive-bred bobwhites from Arkansas, whereas the other two contained Louisiana captives. In addition to RIFA, which was successfully suppressed on treated plots, Aphaenogaster fulva-rudis-texana was negatively affected by treatment. Data from other myrmecines suggested similar patterns of decrease by treatment. Only Prenolepis imparis showed a possible competitive release from RIFA. In 2005, lack of nesting reduced number of replicates. One nest hatched successfully; another failed overrun by RIFA. In 2006, mean number of nests, eggs, and chicks did not differ significantly between treated and untreated plots nor between the two populations of bobwhites. A significantly greater proportion of AR and LA nests were attacked by RIFA on untreated plots. Three nests hatched successfully on treated plots versus one on untreated. RIFA appear to breach intact bobwhite eggshells. In areas of sympatry, RIFA may exacerbate bobwhite decline by attacking eggs prior to hatch.

A variable rate pesticide application system was developed and tested during 2001 for an agricultural aircraft in Louisiana. Using technology available to the agricultural aviation industry, a variable rate prescription of insecticide was successfully applied to a cotton field in 2002. These studies compared the efficacy and value of spatially variable insecticide (SVI) applications based on yield maps to the producer standard, whole-field broadcast treatments. Insecticide prescriptions were created from historical yield and production data. Treatments included whole-field broadcast sprays, yield-based SVI sprays, and profit-based SVI sprays. Twenty-two SVI applications were made to test fields from 2002-2005 using two aircraft equipped with on-board computer systems. SVI technologies reduced crop input costs for insect pest management, but did not significantly impact yield or crop profit within the conditions of these tests. Insecticide costs were reduced by $12 to $35 per hectare depending on the application frequency and SVI strategy. There was a 13% to 32% reduction in hectares treated in the SVI treatment strategies compared to the whole-field broadcast (producer standard). These studies showed that variable rate application of pesticides can be accomplished using an agricultural aircraft. Intra-field management zones for reducing crop inputs (insecticides) were developed from yield and profit maps. SVI prescriptions can allow producers to manage crop production costs by restricting inputs in Louisiana cotton fields.

A field study was conducted in 2005 and 2006 to evaluate the impact and interaction of the herbivores <i>Cyrtobagous salviniae</i> Calder and Sands and <i>Samea multiplicalis</i> Guenee on common salvinia, <i>Salvinia minima</i> Baker in south Louisiana. It was a completely randomized experimental design in which treatments consisted of <i>C. salviniae</i> and <i>S. multiplicalis</i> feeding on common salvinia both independently and together along with a control. Our study revealed that treatments consisting of <i>C. salviniae</i> and <i>S .multiplicalis</i> feeding both independently and together had a significant impact on the biomass of common salvinia. Sampling done in October of both 2005 and 2006 showed that the lowest biomass was recorded for the treatment with both <i>C. salviniae</i> and <i>S. multiplicalis</i>. There was also a significant treatment by month interaction with a linear decrease in biomass for the treatment consisting of feeding by both <i>C. salviniae</i> and <i>S. multiplicalis</i> in 2005. Also, biomass showed a quadratic trend for the treatment with only <i>S. multiplicalis</i> in 2005. Percentage terminal damage (PTD) and percentage mat green (PMG) showed a significant treatment effect and a significant treatment by month interaction in 2005. Also, PTD showed a significant treatment effect and a significant treatment by month interaction in 2006. A field study was conducted in May of 2007 to document the foraging behavior of red imported fire ants (RIFA), <i>Solenopsis invicta</i> Buren, on common salvinia mats in flooded woodlands and dredged canals. RIFA mounds were found in flooded woodlands at the base of live trees and on dead tree stumps. The recruitment of RIFA to the bait stations was not uniform up to 100 m into the flooded woodlands and in most instances there was no linear relationship between distance from the levee and number of ants. Also, the recruitment at different times of the day was not the same. Results of this study provide evidence that RIFA forage extensively on common salvinia in both flooded woodlands and dredged canals, and could possibly have an adverse impact on the populations of native <i>S. multiplicalis</i> and also on the survival and establishment of <i>C. salviniae</i>.

Increasing evidence of non-indigenous ambrosia beetles aggressively attacking hosts in their new environment in the United States has led to concern over the potential for damage to urban trees, nurseries, orchards, and forests. A novel technique of flooding host trees was devised to stimulate ambrosia beetle attacks, with ambrosia beetle attraction peaking four days following flooding. In-situ sampling identified significant differences in the composition, quantity and point of release (leaf or bole) of volatiles emitted by the flooded and non-flooded trees. Coupled gas chromatography electroantennographic detection revealed olfactory sensitivity by the ambrosia beetle Xylosandrus crassiusculus (Motschulsky) to 29 of these compounds and 12 other compounds apparently not associated with hosts. Traps baited with the combination of ethanol and eugenol showed a mean increase in catches over ethanol baits alone. During a trapping survey of Camp Beauregard, Louisiana, flight periods and biodiversity indices were collected for up to 37 species of ambrosia beetles.. Multiple regression analyses identified significant correlations between forest stand characteristics and ambrosia beetle abundances. In fungal competition and vectoring experiments, Rafaella sp., a highly pathogenic, recently discovered fungus associated with the newly-established, exotic ambrosia beetle Xyleborus glabratus (Eichhoff), did not provide significant nutritional benefits to X. crassiusculus. When Rafaella sp. was introduced into a laboratory rearing medium in advance of X. crassiusculus, fewer beetle offspring ultimately emerged. Additionally, the ambrosial associate of X. crassiusculus, Ambrosiella xylebori, demonstrated superior ability to secure and hold resources against Rafaella sp. in differential and spatial separation competition experiments. Relatively earlier addition of Rafaella sp. into beetle media decreased the likelihood of gallery construction, suggesting that X. crassiusculus could detect the presence of Rafaella sp. These three experiments support the hypothesis that these two fungi might compete for spatial and/or nutritional resources, ultimately lowering the fitness of X. crassiusculus. There was no evidence that X. crassiusculus could transport Rafaella sp. in its mycangium, hence X. crassiusculus likely cannot serve as a significant vector of Rafaella sp. in the field.

Red imported fire ants (RIFA), Solenopsis invicta Buren, are medical, urban, and agricultural pests from South America. Fourth-instar larvae are used by the colony to digest solid food and then regurgitate it for consumption by workers and queens. Larvae are an ideal source of investigations of obligate endosymbiotic bacteria possibly involved in nutrient distributions. I attempted to first identify what bacteria species are in the guts of larvae followed by antibiotic and microscopy work to further study their roles in the ants. The composition of the bacterial community in fire ant larvae was described with culture-independent methods utilizing 16S rDNA sequencing. The 16S rRNA gene was directly amplified from mixed-population DNA of whole fire ant larval guts and cloned into Escherichia coli. Bacterial communities from three geographically separated RIFA colonies were examined. Sequenced bacterial clones from guts were determined to be predominantly from the phylum Proteobacteria and the family Enterobacteriaceae. The colony from Baton Rouge had 34 identified species, 25 identified species from the Rosepine colony, and nine from the Bogalusa colony. None of the identified bacteria were closely related to known coadapted endosymbionts from other insect species. Bacterial inventories from each location provided little evidence of common bacteria among them. Even though Klebsiella pneumoniae appeared in all three colonies, its biology suggested that it came from the environment. Obligate symbiotic bacteria, if present should be present in all larvae regardless of physical location. Antibiotic treatments indicated that ants were not affected by clearing the guts of microorganisms. Clearing of obligate symbiotic bacteria should have detrimental effects on ant mortality. Since no significant change was found, obligate symbiosis is not likely to be present between fire ants and their gut bacteria. I was unable to detect bacteriocytes in the guts of larvae using light and electron microscopy, providing further data against an obligate symbiotic relationship. In this study I did not detect the presence of common symbiotic bacteria in the guts of RIFA larvae among the colonies. Bacteria communities appeared to be unique to each colony and were determined by the food and environment.