Fall armyworm, Spodoptera frugiperda (J. E. Smith), response to cottons, Gossypium hirsutum L., expressing Bacillus thuringiensis (Bt) insecticidal proteins, Cry1Ac (Bollgard®), Cry1Ac + Cry2Ab (Bollgard II®), and Cry1Ac + Cry1F (WideStrike), was evaluated in field and laboratory experiments. In field trials, larvae that were infested on selected fruiting forms (squares, white flowers, and bolls) of WideStrike plants had lower survivorship and caused less injury than larvae on non-Bt plants, regardless of fruiting structures. Bollgard® and Bollgard II® plants produced no consistent negative effects on fall armyworm survivorship and injury. In no-choice laboratory assays, Bollgard II® and WideStrike cotton tissue reduced fall armyworm larval development and survivorship compared to those larvae offered non-Bt tissue. Fall armyworm preference for oviposition sites on non-Bt and Bt-expressing cotton plants was evaluated by releasing adults into isolation cages containing plants of a single cotton line. The distribution of egg masses on non-Bt, Bollgard®, Bollgard II®, and WideStrike cotton plants was similar with the majority of egg clusters observed on the abaxial (underside) leaf surfaces. The field performance of selected novel and standard insecticides was evaluated against fall armyworm in conventional non-Bt cotton, sprayed with recommended (full) rates of products, and in Bollgard II® cotton, sprayed with reduced (one-half) rates of the same products. Insecticide-treated terminal leaves and bolls were removed from plants in a field environment, placed in plastic dishes and infested with a single third instar. Reducing insecticide rates on Bollgard II® cotton did not negatively affect efficacy of any insecticide compared to efficacy of full rates applied to conventional non-Bt cotton. These results show differences between the currently available Bt cotton technologies in their performance against fall armyworm larvae. This information should be used by the cotton industry in the selection of the most appropriate Bt traits if fall armyworm is considered a prevalent pest. Furthermore, opportunities to reduce insecticide rates without sacrificing satisfactory efficacy against fall armyworm on Bollgard II® plants could reduce chemical control costs. To better characterize fall armyworm identification and injury symptomology, descriptions and photographs were compiled in a manner that should be useful to cotton pest managers and producers.

Over 1000 dissections were performed on field, greenhouse and lab specimens in order to describe the reproductive system of Cyrtobagous salviniae, a biocontrol agent of Salvinia molesta (giant salvinia). The reproductive morphology of C. salviniae was described, the classes of reproductive development were characterized, and oviposition assessed. The reproductive system of C. salviniae consists of two ovaries, each of which is comprised of two membraneous ovarioles. These are each divided into a distal germarium and a proximal vitellarium that is connected to a lateral oviduct. The lateral oviducts unite to form a common oviduct through which eggs must pass for oviposition to take place. A schlerotized spermatheca and accessory glands are also present. There are 5 classes of reproductive development, 2 nonparous (no oviposition) and three parous. These are differentiated primarily by the number and maturity of follicles in the vitellarium, the presence of eggs in the oviducts, and the presence or absence of follicular relics. The number of eggs oviposited was quantified by holding one hundred C. salviniae weevils individually on sprigs of salvinia at 29.5 ° C, with 12:12 daylength, and counting the number of ovipositions per weevil each week. During the course of the five month study, over 12,000 eggs were enumerated. At the end of the study, all of the weevils were dissected, basic statistics calculated, and the data analyzed by ANOVA, Tukey-Kramer, and Chi-square procedures (p=.0001). The mean number of eggs oviposited for each of the parous classes (i.e., P1, P2, and P3) were 22.6, 84.3, and 208.3, respectively. ANOVA indicated that mean egg numbers for each class were significantly different (F=176.51, P<.0001), and Tukey-Kramer analysis (P<.0001) showed that each of the three classes were significantly different from each other (P<.0001). Values obtained from the oviposition study were related to the reproductive classes to create a physiological age-grading system, which can be used as a reference to gain a deeper understanding of the population dynamics of this important biocontrol agent.

The Formosan subterranean termite is an important structural pest in the southern United States, especially Louisiana. Baiting systems and spot treatment with non-repellent delayed action termiticides are among the most eco-friendly control approaches. However, to achieve a desired success from these approaches requires a sophisticated knowledge of foraging behavior and food transfer system of these social insects. Moisture and temperature play a vital role in influencing the foraging behavior of these desiccation prone insects. A series of laboratory experiments were conducted to understand the subtleties of foraging behavior of Coptotermes formosanus Shiraki in relation to moisture, relative humidity and temperature. Foraging behavior, food consumption and distribution pattern were studied in a suitably designed sand moisture gradient arena. Results showed that C. formosanus can adapt to a wide range of sand moisture levels but not in dry and saturated sand. Next, termites were studied to determine how combinations of various food moisture and temperature levels impact their foraging behavior. C. formosanus was unable to maintain sustained feeding when the wood moisture was lower than the fiber saturation point (~ 25% wt/wt). In the absence of moist soil, C. formosanus always preferred the highest moisture wood with the optimum feeding and survival obtained at 28°C. Relative humidity and temperature mainly determine the water loss from an organism. Soldiers and workers of C. formosanus, which are extremely prone to desiccation, were exposed to various temperature and relative humidity conditions to determine their survival. Even the near saturated relative humidity (~99%) level was not sufficient to keep them from desiccating, indicating that a continuous supply of moisture either from moist substrate or food is required for their normal survival. Likewise, impact of food source disturbance on termites escape behavior was studied with wet versus dry sand conditions in the periphery of the food source, and its implications for termite baiting is discussed. Finally, exploratory tunneling behavior was examined in different substrates in different moisture and temperature situations. With the same moisture level, sand was found to be the preferred substrate for aggregation and tunnel construction to sandy loam and loam.

Induced resistance to the rice water weevil, Lissorhoptrus oryzophilus, was assessed in greenhouse and field experiments. The fall armyworm,Spodoptera frugiperda, and an elicitor, jasmonic acid, were used to induce resistance. The effect of these treatments on rice resistance to oviposition varied between cultivar used, but significantly fewer larvae were found on plants exposed to S. frugiperda and jasmonic acid on both cultivars tested. Application of jasmonic acid significantly reduced the number of L. oryzophilus larvae per plant, and represents the first example of elicitor-induced resistance in rice in field experiments. Oviposition by the sugarcane borer, Diatraea saccharalis, induced resistance to further oviposition by D. saccharalis in several cultivars. Plants with egg masses present received 33- 50% fewer egg masses when exposed to gravid D. saccharalis. However, D. saccharalis oviposition on cultivar M202 rendered plants more susceptible to subsequent oviposition. M202 plants with egg masses present received 2-3 fold more egg masses when subsequently exposed to D. saccharalis. The rice stink bug, Oebalus pugnax, was reared on rice (Oryza sativa), barnyardgrass (Echinochloa crus-galli) and amazon sprangletop (Leptochloa panicoides) and the metathoracic gland (MTG) contents were analyzed using GC/MS. Quantities of three compounds ((E)-2- decenal, (E)-2-hexenyl acetate and n-dodecane) are significantly influenced by host-plant. Crude metathoracic gland extracts attracted O. pugnax at low concentrations, and attraction decreased as the concentration increased, suggesting a bifunctional role of metathoracic gland compounds. Field experiments using a synthetic mixture of the four most abundant MTG chemicals significantly reduced O. pugnax in plots sprayed with this mixture. In addition, the host-plant on which O. pugnax was reared was found to significantly alter the ratio of four MTG chemicals, as well as influence development time and adult weights. The biological activity of four common phenolic compounds in rice (ferulic, p-coumaric, cinnamic and caffeic acids) were evaluated for their effects on the growth rate of D. saccharalis and S. frugiperda larvae. Levels of these compounds were quantified and then incorporated into diet bioassays. Despite minor structural differences, these compounds were found to have widely divergent effects on the larval weights of D. saccharalis and S. frugiperda.

The redbanded stink bug, Piezodorus guildinii (Westwood), was identified as a pest of Louisiana soybean during 2000. Currently, this species has become established throughout Louisiana and into the soybean production regions of bordering states. Seasonal abundance, patterns of oviposition, and population dynamics of this species were surveyed in soybean during 2008-10. The redbanded stink bug comprised the largest percentage (54%) of the total stink bug complex collected at five survey sites followed by the southern green (27%), Nezara viridula L. and brown (7%) stink bugs, Euschistus servus L. Peak oviposition occurred during the (R5) soybean growth stage. Most (80%) egg clusters were observed on leaves and pods in the lower two-thirds of the soybean plant canopy. Additional field experiments evaluated redbanded stink bug effects on soybean seed yield, as well as susceptibility to selected insecticides. Both native and artificial infestations of redbanded stink bug significantly reduced yield and seed quality, and increased incidence of delayed crop maturity at population levels below the Louisiana recommended action threshold of nine insects per 25 sweeps. Native populations reduced yields up to 55% in the non-insecticide treated control plots. Yield losses (4.7 to 14.1%), stink bug damaged seed (4.1 to 8.1%), and incidence of green stems (4.7 to 32.3%) from artificial infestations occurred during the R4, R5, and R6 growth stages at infestations of 0.5-1 insect/0.3 row m. No significant effects were detected for yield, stink bug damaged seed, or incidence of green stem with infestations at the R7 growth stage. Populations of redbanded stink bug collected from Louisiana soybean fields were less susceptible to neonicotinoid, organophsphate, and pyrethroid insecticides compared to the southern green stink bug in field and laboratory tests. The occurrence of redbanded stink bug in Louisiana soybean has altered pest management strategies and increased production costs that are now necessary to reduce yield and quality losses.

Numerous arthropods are pests of soybean in the subtropical environment of Louisiana. The most important pod-feeding guild includes a complex of stink bugs (Hemiptera: Pentatomidae). One of these species, redbanded stink bug (Piezodorus guildinii [Westwood]), has emerged as a significant pest in Louisiana soybean. Currently, limited information is available describing soybean plant injury from this pest in the United States or compares injury relative to native stink bugs. Therefore, a field protocol was modified to assess injury to soybean seeds. Studies conducted in Louisiana during 2009-2011 used procedures to isolate the effects of infestation duration (24-96 h after infestation [HAI]) on seed injury at selected pod stages (R5-R6.5). In addition to redbanded stink bug; seed injury from brown stink bug, Euschistus servus (Say); and E. quadrator (Rolston) also was evaluated. For the infestation duration experiments, all injury to immature seed was significant between treatments (non-infested and infested pods). Injury to immature seed in R5.5 stage pods peaked (P=0.0102) by 72 HAI for redbanded stink bug. Injury to immature seed in R5 stage soybean pods peaked (P=0.0084) by 96 HAI for brown stink bug. For mature seed injury and weights significant differences (P<0.0001) between non-infested and infested pods were detected for all species. A second experiment evaluated seed injury among pod stages (R5-R6.5). Immature and mature seed injury was not significantly different (P>0.05) among pod stages for any species. Weights of mature seed were significantly lowest for redbanded stink bug (P=0.0177) and E. quadrator (P=0.0261) infestations during the R5 and R5.5 stages. Based upon mature seed weights similar levels of injury were produced by native infestations and caged stink bugs. Non-injured seed did not compensate for injured seed within the same pod. These results add to our understanding of stink bug-induced seed injury during selected pod stages and will allow further improvement to Louisiana soybean IPM recommendations.

The soybean looper, Chrysodeixis includens (Walker), is a defoliating insect pest of soybean in the Mid-South and Texas. In 2008, Louisiana producers reported unsatisfactory control of soybean loopers in soybean with methoxyfenozide. In 2009 and 2010, field collections from Louisiana, Missouri, Mississippi and Texas were exposed to discriminating concentrations (0.020 to 5.000 ai ìg/ml) of methoxyfenozide in diet incorporation bioassays. All field colonies were compared to a reference strain LC50 of 0.007 ìg/ml for 2009 and 0.008 ìg/ml for 2010. Louisiana populations exhibited LC50s of 0.079 ìg/ml and 0.122 ìg/ml for 2009 and 2010, respectively, which were the highest values among all field collections during three years. The Missouri collections demonstrated the lowest LC50s with 0.025 ìg/ml in 2009 and 0.011 ìg/ml in 2010. In general, results of these discriminating concentration tests indicated that all field collections showed elevated LC50s compared to the reference colony. Additional field experiments were conducted to evaluate the efficacy of foliar insecticides against Louisiana soybean loopers. Significant differences among treatments for defoliation area were determined between lepidopteran specific and broad spectrum insecticides. For the 2009-10 experiment chlorantraniliprole had the lowest defoliation 3,7,14,21 and 28 days after treatment (DAT) (0.20, 0.20, 0.50, 0.57, 0.97 cm2) while lambda-cyhalothrin had the highest (1.12, 2.38, 2.06, 2.79, 2.25 cm2). In 2011, defoliation and days to 100% mortality were evaluated at two locations for R3 and R5 development stages. Chlorantraniliprole provided the lowest days to mortality (2.3) at R3 and (1.0) at R5 while oxadiazine resulted in the highest (5.7 and 6.0).

The sugarcane borer, Diatraea saccharalis (F.), is a major target of Bacillus thuringiensis (Bt) corn in the U.S. mid southern region. Corn expressing pyramided Bt proteins has recently become commercially available in the U.S. The objectives of this study were 1) to determine survival and plant injury of Cry1Ab-susceptible (Cry1Ab-SS), -resistant (Cry1Ab-RR), and heterozygous (Cry1Ab-RS) genotypes of D. saccharalis on Bt corn containing single and pyramided Bt genes and 2) to assess larval movement of D. saccharalis in different planting patterns of non-Bt and Bt corn. One laboratory leaf tissue bioassay and two independent greenhouse trials were conducted to evaluate larval survival and plant injury on five corn hybrids. On intact plants of non-Bt corn, 43-62% larvae survived after 21 days. Larval survivorship on Cry1Ab corn was 4.7- 5.6% for Cry1Ab-SS, 29.4-32.5 % for Cry1Ab-RS, and 36.6- 45.6% for Cry1Ab-RR. In contrast, the 21-day survivorship on the two pyramided Bt corn hybrids was <5% for the three insect genotypes. Results of the leaf tissue bioassays were consistent with the greenhouse tests. Larval movement of D. saccharalis was evaluated in four planting patterns of non-Bt and Bt plants containing Genuity® SmartStaxTM traits. The four planting patterns were: 1) pure stand of Bt corn, 2) a non-Bt corn plant surrounded by 26 Bt corn plants, 3) pure stand of non-Bt corn, and 4) a Bt corn plant surrounded by 26 non-Bt corn plants. Studies were conducted in three conditions: 1) greenhouse; 2) open field with artificial infestations of 50 eggs on the center plants; and 3) open field study with artificial infestations of 10 neonates on every plant. Larvae of D. saccharalis showed the ability to move from infested plants to at least four plants away and from the infested rows to adjacent rows. The results showed that the pyramided Bt corn can overcome the Cry1Ab resistance and thus should offer a means for Cry1Ab resistance management in D. saccharalis. Together with previous data, the results indicate that the seed mixture strategy might be able to provide a similar refuge population of D. saccharalis as the structured refuge planting.

A molecular phylogenetic investigation was undertaken to identify species within the morphologically homogeneous Simulium jenningsi species group, a pestiferous group of 22 species of black flies restricted to the Nearctic region. Several species in this group have well documented medical and veterinary importance, most notably S. luggeri and S. jenningsi. Unfortunately, females are monomorphic, a conundrum given their pest status. The objective of this study was to examine the utility of molecular data in species identification, with obvious application to identification of pest females. Towards this end, we sequenced approximately 2 kilobases of sequence data from the mitochondrial (Cox I + proximal one-half of Cox II) and nuclear (big zinc finger 2) genomes from positively identified exemplars (pupae, some larvae) and analyzed them phylogenetically using parsimony and Bayesian criteria. Combined analyses were not conducted due to extreme incongruence between the data sets. Mitochondrial and nuclear data sets sufficient for ready identification of approximately one-third and one-half, respectively, of the known species. Both genes recovered S. aranti, S. luggeri, S. ozarkense, S. penobscotense, and portions of the S. fibrinflatum complex (S. fibrinflatum, S. underhilli, S. notiale, and S. snowi). Species positively identified by analyses of independent data sets include S. taxodium and S. chlorum with the mitochondrial data and S. haysi, S. krebsorum, S. dixiense, S. definitum, S. remissum, S. infenestrum, S. podostemi, and S. jenningsi with big zinc finger 2. Future studies to better resolve species identities in this group should focus on additional nuclearly encoded markers or perhaps amplified fragment length polymorphism (AFLP) approaches. However, we suspect that introgression, lineage sorting, and differential sorting of ancestral polymorphisms occurred in various lineages within this group and may make complete phylogenetic reconstruction of all species lineages impossible.

The Mexican rice borer, Eoreuma loftini (Dyar) (Lepidoptera: Crambidae) is an invasive stem borer pest of sugarcane, rice, corn, and sorghum, and poses a threat to the production of dedicated bioenergy feedstocks in the U. S. Gulf Coast region. Studies were conducted to assess insect-plant interactions between E. loftini and bioenergy and conventional cultivars of sugarcane and sorghum, including yield response, oviposition preference, and host suitability. In addition, the efficacy of select cultural and biological control tactics to manage E. loftini in these crops was assessed. Bioenergy sugarcane (energycane) and sweet sorghum exhibited reduced E. loftini injury; however, these crops sustained greater losses in fresh stalk weight. Negative impacts to sucrose concentration from E. loftini injury were greatest in energycane, high-biomass sorghum, and sweet sorghum cultivars. Eoreuma loftini eggs per plant and eggs per oviposition event were greater on mature plants than immature plants. On a crop type basis, sweet sorghum was preferred over sugarcane and high-biomass sorghum when measuring eggs per plant. The mortality-survival ratio during the neonatal stage was greater in immature sugarcane cultivar HoCP 85-845 and high-biomass cultivar ES 5200. The percentage of bored internodes increased with higher nitrogen (N) rates. Yields indicated that N rate was positively associated with increases in stalk weight and ethanol productivity, but not sucrose concentration. Because higher N rates were associated with increased yields, our data suggest that increases in yield from additional N outweigh decreases from additional E. loftini injury. Populations of S. invicta reduced percent relative survival of E. loftini by 0.1% per increase unit increase of S. invicta; however, reductions in the percentage of bored internodes and adult emergence holes were not detected. Reductions in E. loftini injury from S. invicta were not detected in transects of johnsongrass. This research showed that select cultivars of bioenergy sugarcane and sorghum can be more resistant than conventional sugarcane and sorghum, demonstrating their compatibility in the Gulf Coast region. Because bioenergy crops are less tolerant to E. loftini in some instances, proper management practices should be continued, including judicial fertilization and conservation of natural enemies.