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 sequence. Visual orientation appeared to affect host tree location by histerids and may facilitate niche partitioning among species. Platysoma parallelum was attracted to horizontally positioned logs, representing trees more likely to be infested by Ips spp., while Pla. attenuata preferred vertical logs, representing standing pines, which tend to be colonized by the southern pine beetle, Dendroctonus frontalis Zimmermann. Histerid predators also utilized bark beetle pheromones as kairomonal odor cues to locate their prey. Histerid species had differential electrophysiological (antennal) and behavioral responses to three prey aggregation pheromones: ipsenol (produced by Ips grandicollis (Eichhoff)), ipsdienol (Ips avulsus (Eichhoff) and Ips calligraphus (Germar)), and frontalin (D. frontalis). Histerids may use various strategies of long-range host habitat finding and short-range host finding, which could reduce interspecific competition. Measurement of antennal threshold responses indicated that Pla. parallelum could perceive frontalin at lower quantities than Ple. transversus and, thus, may have the ability to locate D. frontalis attacks earlier. In a controlled study, Pla. parallelum was found to have a greater impact on I. grandicollis mortality than Ple. transversus when only one histerid and one prey species were present. More I. grandicollis brood was killed per introduced Pla. parallelum adult likely as a result of Pla. parallelums larger size and biomass requirements. In a separate experiment, Pla. parallelum adults consumed I. calligraphus larvae until satiation (up to four per day). Collectively, these experiments provide evidence that augmentative releases of histerids have potential use for biological control of bark beetles.

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 losses were due to a combination of decreases in panicle densities, numbers of grains per panicle, and grain weights. Experiments on density-yield relationships documented that larval densities during earlier stages of rice growth were more strongly correlated with yield losses than were larval densities later in the growing season. Slopes of yield loss were greater negative for early-flood than for delayed-flood plots, and greater negative for susceptible varieties. A phenology model predicted that emergence of weevils occurred after the accumulation of 139.2 degree-days (°C * Day). Using a temperature threshold of 10°C, the total degree-days required for development of one generation is about 623.4 degree-days (from egg to pupation was 359.1 ± 19.4; pupal development was 264.3). Larval development did not differ between varieties with different resistant levels. In conclusion, this study showed that host-plant resistance, delayed-flooding and reduced insecticide can be integrated together. Although use of high rate of insecticide currently gives the best economic return, integrated control provides a combination of adequate control and environmental friendliness. The same economic return can be achieved using a more tolerant variety and delayed-flood without insecticide treatment.

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 invicta (RIFA), Linepithema humile (Argentine ants), and Brachymyrmex sp. (rover ants) were analyzed with stepwise regression, backward regression, and r-square selection method. The number of red imported fire ants foraging at Vienna sausage vials and honey vials were affected by cloud cover, vegetation type, relative humidity, and distance to nearest water source. Mounds of RIFA were most affected by percent of clay in the soil. Abundance of Brachymyrmex was affected by vegetation type, canopy cover, and bulk density, and presence of Argentine ants was affected by temperature, relative humidity, and bulk density. Bulk density may be associated with areas of high disturbance which would lead to soil compaction. Another study was conducted in the laboratory to determine the level of aggression demonstrated by RIFA and Argentine ants when they were allowed to interact. Intraspecific nestmate and non-nestmate interactions were observed for both RIFA and Argentine ants. Interactions between lab-reared RIFA and field-collected RIFA were also examined. The level of aggression, role of the ant (initiator or respondent), and mortalities were studied. Chi-square, logistic regression, and mixed model analyses were used to determine significant effects. When RIFA and Argentine ants interact, Argentine ants face a higher risk of mortality even though Argentines were the initiators. Lab-reared fire ants were less aggressive toward each other than toward field-collected RIFA and Argentine ants. These aggression bioassays will help determine what occurs in the field at the interface of the two competing species and how this may affect their distribution.

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 and ThermaCell® cordless mosquito repellent treatment sites was significantly less than the number collected at the ABC Mosquito Magnet® or the Dragonfly®/Mosquito Cognito® trap system sites. When the two repellent devices were placed with ABC traps they reduced mosquito numbers in the ABC traps when compared to sites with ABC traps alone. These data indicate that the SC Johnson OFF!® Mosquito Lantern and ThermaCell® cordless mosquito system may reduce attack from biting mosquitoes.

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 thiamethoxam significantly reduced cotton aphid densities (P < 0.05), the aphicides did not provide 100 percent control. In both years, the entomopathogenic fungus, Neozygites fresenii, established epizootics in late June or early July and rapidly reduced cotton aphid densities to near zero. Cotton aphids did not influence plant height, vegetative branch number, sympodial fruiting node number, vegetative boll number, sympodial bolls, sympodial fruiting positions, and plant maturity measured at the time of harvest. Also, cotton aphid feeding did not influence seedcotton yields from whole plots, micro-plots, and individual paired plants. No significant differences were observed between aphicide treated and non-treated plots for percent retention of first, second, and third fruiting position bolls, and seedcotton weights from first, second, and third fruiting position bolls. Cotton aphids caused transient injury symptoms during the period of infestation, but did not influence final crop maturity, total seedcotton weights, or yield distribution on plants.

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 flowering. Boll density increased from 5.1 to 6.6-fold from week one to week five. There was a corresponding 4.6 to 6.2-fold increase in total bolls injured. Boll injury ranged from 10.7% (week 4) to 27.4% (week 2) and 9.2% (week 3) to 16.0% (week 2) in 2002 and 2003, respectively. The frequency of injured bolls was highest for bolls accumulating 165.2 through 672 heat units beyond anthesis (1.161 to 3.586 cm diameter). However, brown stink bug significantly reduced seedcotton yields during weeks four and five due to the inability of cotton plants to compensate for injured bolls. Infestations of southern green stink bug during boll maturation, in combination with persistent rainfall and humidity, increased the proportion of rotted (2.0-fold) and ¡§hard locked¡¨ (1.4-fold) bolls compared to a non-infested treatment. Although stink bug injury was observed in hard locked (35.8%) and harvestable (20.3%) bolls, other abiotic and/or biotic factors are contributing to late-season harvest losses. In laboratory and field studies, the order of susceptibility (least to most) of stink bug species and life stages to insecticides commonly used for management was adult Euschistus spp. < late-instar nymphs < southern green stink bug adults. These studies defined brown stink bug and southern green stink bug to be significant pests of cotton during boll development stages. Stink bug management strategies should consider species, life stages, and the characteristics of specific insecticides.

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 these, there were two possible new species, 67 state records, and 23 range extensions. Upland savannas consistently showed higher richness and abundance than the wet savanna by about ten species and by many hundreds of individuals. Despite this, diversity statistics yielded no significant differences. Similarity indices between upland savanna sites were consistently more similar than to the wet savanna sites, suggesting greater compositional similarities within upland sites. Of the two collecting protocols compared, both were effective at collecting bees though pan traps showed a tendency to capture more species and individuals than malaise traps. There were several management implications of this research. First, a savanna in the early stages of restoration had a relatively high level of bee diversity suggesting pollinators are capable of rapid colonization or recovery in this ecosystem. Second, there was a trend toward increased bee abundance and richness after prescribed fires consistent with increased flowering after fires. Third, size of preserve appeared to have no effect on bee diversity. An important outcome of this study was creation of a checklist of bees with distributional and biological information for each species.

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 during the spring and fall of 1999, and winter of 2000. Each seasonal experiment included one Louisiana black bear (a threatened species), two white-tailed deer, two American alligators, and two swine (experimental standard). Fresh carcasses were sampled simultaneously for necrophilous arthropods manually and by pitfall traps. Manual sampling contributed qualitative observational data regarding decomposition patterns and species interactions not easily revealed using pitfall traps alone and represented typical entomological collections recovered during criminal investigations. Principle component analysis reduced the complete pitfall trap dataset (451,036 specimens representing 438 taxa) to a statistically manageable size, and regression analysis (Proc Mixed, SAS Institute) determined that season, animal type, and stage of decomposition were significant for species composition. Three discriminant analyses determined which taxa were most discriminating for animal type: Proc StepDisc identified 50 taxa, Proc Discrim determined that these taxa were more discriminating for alligator, and Proc CanDisc identified species assemblages per animal type and illustrated that alligator and bear were more unique than deer and swine carrion. Canonical correlation analysis (Proc CanCorr) tested daily time trends in arthropod activity in relation to days of decomposition. Two diversity tests were conducted for these data, Shannons diversity index and Pielous J test of species evenness. Season was significant for both species diversity and evenness, while stage of decomposition was significant for only Pielous J, and animal type was never significant. Results from this project further our understanding of the carrion habitat and provide baseline data to wildlife law enforcement agencies for prosecuting poachers.

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 this study, insect-tree-health relationships were evaluated in field and in multifactor, greenhouse and larval rearing experiments incorporating these environmental stressors and nutrient enhancements under simulated diversion conditions. It was ascertained from three field sites of varying tree density/health in Lake Maurepas swamps that nutrient augmentation (similar to N and P loading rates expected from 8000cfs diversion) increased stem growth of both tree species (more for cypress than tupelo) at moderately degraded sites. Nutrient augmentation also increased nitrogen in foliage, insect frass (insect feces), spring-clipped leaves, and abscised litterfall at all sites for both tree species. Nitrogen content of canopy foliage and litterfall was positively correlated with site health. These findings support the hypotheses that the swamps in Lake Maurepas are nutrient limited, and the existing trees can utilize, benefit, and act as nutrient sinks for nutrient-laden river water accompanying diversions. Positive insect responses to nitrogen found in lab rearing assays and field studies that defoliators are receiving nitrogen augmentation, and insect field populations might increase, particularly the FTC. The greenhouse study demonstrated that the combination of nutrient deprivation and flooding lead to the poor sapling growth, which was similar to the growth in the salt-stressed (3ppt) saplings. Encouragingly, when fresh water and nutrients were supplied to saplings after prolonged stresses of defoliation, flooding, and salt stress, growth was restored. Taken collectively, these studies demonstrated that river diversions are viable management tools for improving health and productivity of declining forested wetlands.

The bollworms, 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 in 0.1011-hectare plots in Northeast Louisiana and in commercial fields in Rapides, Concordia, Richland, and Tensas parishes. Bollworm larval occurrence varied considerably among all sites and crops based upon crop phenology, local environment, cultural production practices, and pest management strategies. Records of larval collection ranged from entirely absent in a sample to collections over a period of seven weeks. Peak densities in Bollgard® cotton were recorded from the 5 nodes above white flower (NAWF) to 1 node above cracked boll (NACB) growth stages, in non-Bollgard® cotton during the 7 NAWF to 1 NACB stages, in field corn during the R2-R5 growth stages, in grain sorghum during growth stages 4 to 9, and in maturity group (MG) 6 soybean during the R1-R6 growth stages. No larvae were observed in MG 4 soybean or in Bollgard® 2 cotton. Larval productivity was generally lowest in Bollgard® cotton fields and highest in grain sorghum and field corn, but larval development in the latter host crops was not consistently in temporal synchrony with that in Bollgard® cotton. The only host crops that exhibited temporal synchrony of larvae to that in Bollgard® cotton was non-Bollgard® cotton and MG 6 soybean. Bollworm adults were monitored with pheromone-baited wire cone traps at the interfaces of Bollgard® cotton and alternate crop hosts at the commercial field sites. During 2002 and 2003, totals of 39,356 and 42,552 adults were collected across all sample sites. Bollworm adult occurrence and total densities were generally similar among traps at all crop interfaces.