In short-term laboratory experiments, we studied the influence of light intensity, photoperiod, and temperature on the feeding and oviposition activity of two aphelinid parasitoids, Encarsia formosa Gahan and Eretmocerus eremicus Rose and Zolnerowich, on the greenhouse whitefly, Trialeurodes vaporariorum (Westwood). E. eremicus parasitized significantly more whitefly hosts than E. formosa in all treatment combinations of light intensity and photoperiod at 24 and 20°C. At 24°C, both E. formosa and E. eremicus parasitized approximately twice as many whitefly hosts at the high light intensity (112–114 W/m²)–long daylength (L 16:D 8 h) treatment than at the low light intensity (12–14 W/m²)–short daylength (L 8:D 16 h) treatment. In most instances at 20 and 24°C, significantly more dead whitefly hosts were recorded in leaf cages introduced with parasitoids than leaf cages with no parasitoids, indicating that host feeding occurred. Both E. formosa and E. eremicus parasitized significantly more whitefly hosts under the simulated summer (i.e., high light intensity [82.0–83.6 W/m²]; long daylength [L 16:D 8 h], 24°C) treatment than the winter (i.e., low light intensity [10.8–11.1 W/m²]; short daylength [L 8:D 16 h], 20°C) treatment. In addition, significantly more dead whitefly hosts were observed in leaf cages introduced with E. eremicus than E. formosa under the winter treatment, suggesting that E. eremicus killed more whitefly hosts through host feeding than E. formosa. This was not the case for the other treatment combinations. E. eremicus contributes more to greenhouse whitefly mortality than E. formosa by a combination of greater parasitism and host feeding and therefore is recommended for use in winter months with day temperatures ≥ 20°C, in addition to later in the season, where it is currently being used.

Feeding on mature potato foliage and low temperatures can influence diapause preparation and winter survival in insects adapted to northern regions such as the Colorado potato beetle (Leptinotarsa decemlineata Say). The effects of potato leaf maturity and temperature regimen, in a full factorial combination, on prediapause feeding, digging depth in the soil, and survival after a brief exposure to −2°C were studied in beetles induced to diapause under short day conditions in the laboratory. Newly emerged adults were fed either younger or older potato leaves (cultivar Norland) at temperatures cycling daily according to a sine wave averaging 17 or 11.5°C. As expected, time spent feeding before satiation was significantly longer at 11.5°C (25 ± 1.12 [SE] d) than at 17°C (17 ± 0.37 d); leaf age or its interaction with temperature had no significant effect. Beetles consumed older foliage at a faster rate, especially at the 17°C regime. Cumulative fresh weight of older leaves consumed before satiation was 45% higher (3.50 ± 0.07 g/beetle) than young leaves (2.25 ± 0.05 g/beetle); temperature regime and the interaction were nonsignificant. Despite variation in feeding rate and feeding time before satiation, weight gain during prediapause (25–30 mg/individual) remained nearly constant over all factor combinations. Thus, metabolic reserves for overwintering in terms of weight gain are more or less fixed, and any variations in food quality and temperature are compensated for by varying feeding behavior. Satiated prediapause beetles showed no significant variation of postfeeding delay before initiating digging; this delay averaged 8 d under all conditions. Mean depth reached in soil columns before final resting was 30 ± 2.1 cm at 11.5°C compared with 45 ± 2.4 cm at 17°C, with no significant effect of leaf age or interaction. Thus, feeding on older foliage did not affect overwintering depth. Survival after a 4-h cold shock at −2°C, after 6 mo at 4°C, was 59% for beetles under the 17°C regime during prediapause compared with 84% for those under the 11.5°C regime during prediapause. Our results show that a higher temperature regime during prediapause preparation reduces beetle resistance to frost in late dormancy, but beetles dig deeper at high temperatures, which could compensate for the higher risk of freezing.

Light and temperature are ecological factors that are known to influence leaf quality and herbivory. Because temperature is likely to vary with light environment, the effects that each factor has on herbivore performance and seasonal herbivory rates are likely to be confounded. We studied how light and thermal environment influenced consumption and conversion of Lindera benzoin L. (Lauraceae) leaf material by Epimecis hortaria F. (Lepidoptera: Geometridae) in field and laboratory settings. Ambient and leaf surface temperatures were higher in the sun than in the shade. Experimental enclosures increased feeding temperatures by <1°C. Larvae of E. hortaria feeding at warmer temperatures consumed more leaf material than their counterparts in cooler conditions in the laboratory. However, in the field, herbivores tended to remove less leaf material from plants in warm, sunlit habitats where seasonal herbivory is lower. Conversion of leaf area eaten into biomass was higher in larvae feeding on L. benzoin leaves from sun habitats for all field and laboratory treatments and was independent of temperature, suggesting that sun leaves are more nutritious for E. hortaria than shade leaves. While elevations in ambient temperature play a significant role in laboratory-based settings, the effects of ambient temperature on herbivory rates in the natural environment seem to be muted by differences in leaf quality and antiherbivore defenses in sun and shade populations of L. benzoin.

Conium maculatum L. (Apiaceae), or poison hemlock, is an invasive plant native to Europe that has become extensively naturalized throughout North America. This species contains piperidine alkaloids, including coniine and γ-coniceine, that are highly toxic to vertebrates. C. maculatum was relatively free from herbivores in North America until the accidental introduction 30 yr ago of its monophagous European associate Agonopterix alstroemeriana (Clerck) (Lepidoptera: Oecophoridae). At present, A. alstroemeriana is widespread across the United States, and in some areas, such as the Northwest, can inflict substantial damage on its host plant, leading to desiccation and death. A. alstroemeriana has been used in recent years for the biological control of C. maculatum, although its use has been limited by the availability of larvae, which are field-collected from early to mid-spring, and by the lack of available information about its life history and feeding habits. Here we describe a laboratory-rearing protocol incorporating a simulated winter to induce diapause and a semidefined artificial diet that allows the production of multiple generations per year and enabled us to determine the number and duration of A. alstroemeriana developmental stages. The development of the artificial diet also permitted studies of preference and performance of A. alstroemeriana in relation to hostplant chemistry. Rearing A. alstroemeriana on artificial diet supplemented with 1.5% DW coniine had no adverse impact on ultimate instar growth or performance. In a feeding behavior assay, the presence of coniine in the diet increased A. alstroemeriana consumption three-fold relative to control diet. This behavioral response contrasts dramatically with that of Agonopterix clemensella, a native Apiaceae specialist that does not use C. maculatum as a host; of 30 larvae tested, 29 fed exclusively on diets lacking supplemental coniine. The rearing protocol and artificial diet presented here can facilitate further studies of ecological and evolutionary responses of C. maculatum after its reassociation with a coevolved herbivore in North America.

Seasonal flight activity of Rhyzopertha dominica near grain elevators and in forest habitats was monitored weekly in central Oklahoma from 2002 to 2005 using Lindgren four-unit multiple funnel traps baited with the synthetic pheromones Dominicalure-1 and Dominicalure-2. Response surface regression was used to model flight activity (R. dominica trap data) relative to weather variables (temperature, humidity, amount of rainfall, wind speed) and daylength. Overall, the results show more beetle flight activity near grain elevators than in forest sites. Among years, the earliest R. dominica flight activity was recorded from 20 to 27 March, and the yearly flight activity ended between 6 and 13 November. Seasonal flight activity patterns were similar among habitats; however, across years, the flight activity generally initiated at least 1–2 wk earlier in forest than at grain elevator sites in 2 of the 3 yr. R. dominica was most active during the warmer part of the year. No R. dominica were trapped from December through February. Approximately 80 and 86% of the variability in R. dominica trap catches were explained by weekly means of weather variables for grain storage elevators and forest sites, respectively. The weather-based flight activity models for both habitats were validated with independent data.

Commensal microorganisms have significant impacts on the health of many insect hosts. Little is known, however, about the structure of commensal bacterial communities associated with the Cerambycidae, despite the important roles this large family of herbivorous endophytic insects plays in ecosystem processes, economic losses to ornamental and forest trees, and biological invasions. We analyzed the bacterial commensal communities of the exotic Asian longhorned beetle, Anoplophora glabripennis, and the native linden borer, Saperda vestita, by randomly sequencing 16S rRNA gene fragments from bacterial DNA extracted directly from the gut of larvae. The 16S rRNA gene sequences sampled from S. vestita were derived entirely from the γ-Proteobacteria phylum of Bacteria. In contrast, the gut of A. glabripennis larvae contained members of the α-Proteobacteria, β-Proteobacteria, γ-Proteobacteria, Firmicutes, Actinobacteria, and Bacteroidetes. A better understanding of insect-microbe interactions may lead to new strategies to reduce the effects of these pest species.

A new species of wasp, Stethynium sp. (Hymenoptera: Mymaridae), was found parasitizing eggs of an introduced weed biological control agent, Zygina sp. (Hemiptera: Cicadellidae), a leafhopper released against bridal creeper (Asparagus asparagoides L. Druce). A series of laboratory experiments was conducted to determine the development time and longevity of the wasp under different temperatures and the oviposition preference of the wasp for leafhopper eggs of different ages. Parasitized leafhopper eggs were placed in controlled temperature rooms set at either 15, 20, or 25°C and monitored for adult emergence. It was determined that development time of Stethynium sp. from egg to adult eclosion decreased as temperature increased and female wasps took longer to develop than males. Adult male and female wasps were placed in controlled temperature rooms set at these same temperatures and provided either water, a 10% sugar solution, or no food at all. Female wasps lived longer than males and sugar solution increased longevity significantly over no food or water alone, but this effect decreased with increasing temperature. Adult female wasps, given a choice between 1-, 2-, 3-, 5-, and 7-d-old eggs, showed no preference, and all progeny were able to develop and emerge at the same rate from any aged egg. Adult females also laid eggs in 8- and 9-d-old host eggs. There was a slight decrease in emergence rate from 9-d-old host eggs compared with 8-d-old eggs.

Global atmospheric carbon dioxide concentration [CO₂] increased 20% in the last century and is expected to increase another 48% by 2050. Surface concentrations of ozone [O₃] also are increasing rapidly in agricultural areas of the northern hemisphere and are expected to increase another 20% by 2050. To better understand the combined impact of increased [CO₂] and [O₃] on crop production in the Midwest, we used a 32-ha experimental field planted with soybean (Glycines max L. Merr.). The field included sixteen 21.3-m-diameter plots using free air gas concentration enrichment (FACE) to simulate the changes in atmospheric composition forecast for 2050. We evaluated the impact of elevated [CO₂] and [O₃] singly and in combination on adult and egg densities of the variant western corn rootworm, Diabrotica virgifera virgifera LeConte. During 2003–2004, each of the four blocks included four plots, representing the four treatments (ambient atmospheric control, elevated [O₃], elevated [CO₂], and an elevated [CO₂] and [O₃] combination). Although elevated [CO₂] and [O₃] did not have an effect on adult female densities of the variant western corn rootworm, they did significantly affect egg densities. Approximately twice as many eggs were found in the soil of soybean plots exposed to elevated [CO₂] compared with ambient control plots or those with elevated [O₃]. Egg densities were even greater (approximately three times) in plots with the elevated [CO₂] and [O₃] combination treatment than in ambient plots. This suggests that rising [CO₂] and [O₃] are stimulating egg-laying by the variant western corn rootworm, potentially increasing population densities and risk of damage to the subsequent corn crop.

Release rates of a blend of monoterpenes (spruce blend) and ethanol significantly affected mean trap catch of Tetropium fuscum (F.), Tetropium castaneum L., and Tetropium cinnamopterum Kirby. Addition of an ethanol lure to traps baited with the spruce blend lure was necessary to attract T. castaneum and T. cinnamopterum and significantly increased attraction of T. fuscum. The combination of spruce blend and ethanol at high release rates had the highest mean catch of Tetropium spp. and was the only lure treatment that resulted in capture of T. fuscum and T. castaneum (in Poland) in every test block, suggesting it would be the best for detection surveys among the lures tested. The effect of trap design on mean catch of T. fuscum was inconsistent. In one experiment, the larger collapsible cross-vane Colossus trap caught about twice as many beetles as the IPM-Intercept trap, but in two other experiments, mean catch did not differ significantly. Type of killing agent in the collecting bucket significantly affected mean catch of T. fuscum. Traps with liquid killing agent (50/50 mixture of propylene glycol and deionized water plus 0.5 ml/liter of Kodak Photo-Flo 200 and 12.5 mg/liter of Bitrex) in the collecting bucket caught more beetles than traps with an insecticidal (dichlorvos) strip. Although any of cross-vane traps tested seem suitable for trapping several cerambycid species, the Colossus trap with liquid killing agent is recommended for use as a detection tool for T. fuscum because it caught similar or greater numbers than the other trap types.

The effects of different doses and enantiomers of verbenone on the interruption of response of red turpentine beetle, Dendroctonus valens LeConte (Coleoptera: Scolytidae), a very aggressive and destructive exotic pest, were conducted using electoantennogram (EAG) assays and behavioral tests in the laboratory and field. No significant differences were found between antennal responses of D. valens by sex, and only one significant difference occurred between their responses to equivalent doses of the (S)-(−) and (R)-( ) enantiomers.Antennal responses to increased doses of (S)-(−)-verbenone reached a plateau at 0.1 μg, whereas the amplitude of response to increased dosages of (R)-( )-verbenone continued to rise. In a laboratory bioassay, (S)-(−)-verbenone at a stimulus load of 0.1 μg synergized D. valens response to a kairomone blend; but at higher stimulus loads (10 and 100 μg), it functioned as a repellent. In field trials using funnel traps, both (S)-(−)- and (R)-( )-verbenone bubblecaps inhibited the response of D. valens to the host kairomone blend. These results indicate that verbenone functions as a multipurpose pheromone for D. valens

Differences in dispersal abilities between parasitoid species sharing a host may result in asynchronous colonization of host patches and periods of time (delays) when hosts are exploited in the absence of potential competitors. Previous field cage studies showed Eretmocerus mundus Mercet and Encarsia pergandiella Howard were able to coexist for the duration of a field season when released simultaneously and at the same rate on whitefly-infested cotton plants, and interspecific competition did not influence their ability to suppress their host. The objectives of this study were to investigate the effects of time delay and initial population density on the population dynamics of En. pergandiella and Er. mundus and their abilities to suppress Bemisia argentifolii Bellows and Perring. Field cages enclosing cotton plants were inoculated with whitefly adults and treated by releasing Er. mundus and En. pergandiella either in sequence (one before the other), at two release rates (1× or 3×), and both in sequence and at two release rates. The sequence of release alone did not affect parasitoid population dynamics. However, when released at two rates, or in sequence and at two rates, the density of En. pergandiella was higher at the high rate and when released first. Results suggest that early colonization of host patches is favorable to En. pergandiella without a negative impact on host suppression. Results provide insight to explain the observed patterns of establishment and population dynamics of Aphelinid parasitoids assemblages in agroecosystems.

We evaluated mortality of Sparganothis sulfureana (Clemens) caused by exposing submerged insects to hypoxic (low oxygen) conditions. Taking advantage of the harvest flood in New Jersey, we measured changes in dissolved oxygen (DO) in a cranberry bog and the mortality of first-instar larvae submerged for 1 d. The DO in floodwater rose to 9.2 ppm during the day, dropped during the night to 7.1 ppm at sunrise, and increased again during the morning. Larval mortality was 3.5 ± 2.1%. In the laboratory, we evaluated the effect of submerging first-instar larvae in water at different DO for 1 d. Larval mortality was similar in all treatments but tended to increase with submergence in water with low DO. When first- through third-instar larvae were submerged in water at 15°C and 6.1 ppm DO for different periods of time, their mortality increased with longer submergence. Although long submergence (9 d) caused substantial mortality of S. sulfureana larvae, especially second and third instars, we conclude that a flood of similar duration will likely not be used because if applied to nondormant vines it could potentially impact the cranberry plant. Two important cautions for future studies were identified: (1) mortality can be substantially overestimated if hypoxia-induced lethargy is mistaken for death and (2) the impact of hypoxia may be underestimated if delayed mortality after removal from the water is not considered.

Three different on-farm sites in east central Illinois (Iroquois County), each containing a commercial production maize and soybean field, were sampled for variant western corn rootworm, Diabrotica virgifera virgifera LeConte, eggs from June 1999 through September 2001. Egg densities of D. v. virgifera eggs were determined at the 0.0- to 10- and 10- to 20-cm depths in these fields. Total mean egg densities of D. v. virgifera were significantly greater in soybean (0.42 and 0.57 eggs/0.47 liter) than in maize (0.27 and 0.29 eggs/0.47 liter) in 1999 and 2001, respectively. However, in 2000, there was no significant difference in the numbers of eggs in maize (0.43 eggs/0.47 liter) and soybean (0.52 eggs/0.47 liter). Most D. v. virgifera eggs were found in the 0.0- to 10.0-cm depth in both maize and soybean in 1999, 2000, and 2001. Oviposition was ≈50% complete by 28 and 28 July and 1 August in maize and by 31 and 30 July and and 10 August in soybean fields from 1999 through 2001, respectively. Oviposition was ≈90% complete by 9, 17, and 14 August in maize and by 15, 12, and 26 August in soybean fields from 1999 through 2001, respectively. Although densities of female D. v. virgifera adults increased significantly in soybean and decreased in maize after maize reached the R2 stage of development, oviposition by variant D. v. virgifera is indiscriminate and occurs in soybean before maize reaches the R2 stage.

Arthropod trophic relationships in temperate rice fields during the growing season were explored in 2000 and 2001 by measuring signatures of naturally occurring carbon and nitrogen stable isotopes. δ¹³C and δ¹⁵N values for rice plants, soil, and arthropods varied slightly between both years, and the values were rather distinctive according to functional groups. Isotopic changes in rice plants affected values for herbivorous insects. Seasonal changes in δ¹³C and δ¹⁵N values for predators indicated that prey composition of their diets changed seasonally. Early in the season, there were two distinct clusters: (1) rice plants-herbivorous insects-parasitoids cluster and (2) filter-feeders/detrivores and predators cluster. The correlations in each case suggest interactions. During mid-season, the rice plants-herbivorous insects-parasitoids interaction was maintained, and herbivorous insects such as planthoppers were linked to predators. Also, detritivores such as Entomobryidae spp. seemed to be linked. During the late season, close interactions occurred at all trophic levels. Our study provided isotopic evidence that filter feeders/detrivores such as Chironomidae and Entomobryidae play a valuable role in maintaining the predator complex in the rice ecosystems during the rice-growing season. Also, fundamental data of stable carbon and nitrogen isotopes acquired in this study would be of value for use in advanced community studies for rice fields.

Field experiments and surveys were conducted in 2003 and 2004 to evaluate the efficacy of using the parasitoid Microplitis mediator (Haliday) to control populations of Helicoverpa armigera (Hübner) in cotton fields in Northwestern China’s Xinjiang Province. The population levels of the second generation of H. armigera in southern Xinjiang in 2003 and 2004 were ≈20–60% above the economic threshold of this pest. The longevity of field-released female and male parasitoids was 7.6 ± 0.4 and 3.9 ± 0.4 d, respectively. Field tests showed that the number of parasitized H. armigera increased with an increasing number of M. mediator cocoons released in the field. The release of 2,250 or 15,000 laboratory-reared M. mediator cocoons per hectare in cotton fields resulted in 38–61% parasitism of H. armigera in 2003 and 35–66% parasitism in 2004. The efficiency of the parasitoids varied considerably with different numbers of parasitoid cocoons and with the frequency and sites of release. However, the highest damage reduction in these studies was obtained with a single release of cocoons and the highest number of release sites. Large-area releases of M. mediator in cotton fields of Shufu, Shule, and Shache counties resulted in >60% parasitism and an 80% decrease in cotton boll and bud damage compared with the control fields. The above results indicated that field release of M. mediator could be used effectively in managing H. armigera in cotton in Xinjiang.

The role of the chemical cues during the host-finding behavior of neonate Estigmene acrea (Drury) larvae was studied in the laboratory using olfactometer bioassays. Three host plant species of E. acrea were used in the experiments: soybean, Glycine max L. Merr.; tomato, Lycopersicum esculentum Miller; and maize, Zea mays L. The number of larvae showing an attraction toward the leaf volatiles of individual test plants was significantly higher than toward the control air in single-choice olfactometer bioassays. In dual-choice tests, larvae showed a clear preference for the volatiles from soybean over the volatiles from maize and tomato leaves. In contrast, larvae did not show any preference for the maize and tomato volatiles. The locomotory behavior of larvae was clearly affected by hexanic and methanolic soybean extracts. Larvae spent more time walking and walked more distance on the zones containing soybean extracts than on the zones treated with maize and tomato extracts and control solvents. The feeding preference tests revealed that larvae prefer feeding on soybean over maize and tomato foliages.

Honey bee (Apis mellifera L.) colonies in temperate climates often deplete winter pollen stores because of intense brood rearing activity in the spring. Nutritional stress can be exacerbated by a simultaneous spring peak in the incidence of the mid-gut parasite Nosema apis Zander in workers. We examined the effect of pollen supply in colonies during the spring on longevity, in-hive behavior, and foraging patterns of Nosema-infected and uninfected workers. In field colonies, pollen supplements did not offset the reduction in worker lifespan caused by inoculation with N. apis, a result that contradicts previous research that showed that increased access to pollen can improve the longevity of N. apis–inoculated workers in cage trials. This discrepancy is likely related to differences in the activity of workers in colonies versus cages; surplus nutrients in colonies were allocated to increased brood rearing activity, which presumably diverted resources away from improving the performance of infected workers in colonies. Trends were reversed when workers were transferred to a common observation hive as adults after being reared in field colonies with pollen supplements or limited pollen; pollen availability in the parental colony affected worker lifespan and the effects of N. apis status were negligible. Workers from colonies that had pollen-diet supplements lived longer, were more likely to be found in the brood area, and were more active on the comb than workers reared in colonies with less access to pollen. Pollen availability and inoculation status did not affect brood care behavior or foraging patterns.

The solitary larval parasitoid Dinarmus basalis Rondani is a promising biological control of Callosobruchus maculatus F, a major insect pest of stored cowpeas in West Africa. Farmers traditionally introduce Hyptis suaveolens L. Poit. leaves in their granaries for protection of cowpea seeds against bruchid damage. However, effects of botanical treatment using this plant on host location behavior and reproduction of D. basalis remain unknown. Olfactometer studies showed that sublethal doses of volatiles emitted by the crushed leaves and the essential oils were repellent for naive females D. basalis, which had previously developed in the absence of H. suaveolens volatiles. These females were able to move in a three-dimensional device and to avoid the host patches associated with H. suaveolens volatiles. Their reproductive activity was consequently reduced in such patches. Females, which had been exposed to sublethal doses of H. suaveolens volatiles during their postembryonic development, were no longer repelled or only partially repelled by the plant volatiles. A habituation process may be involved in the behavior of these D. basalis females. The importance of this habituation process is discussed within the scope of the integrated protection of cowpea seeds during storage.

Trichogrammatid wasps are used widely as biocontrol agents against a variety of lepidopteran pests. However, the broad physiological host range of most Trichogramma species raises concerns about the potential impact of released wasps on nontarget Lepidoptera. If wasps exhibit a preference for agricultural over nonagricultural habitats, this could lessen the risk for many nontarget species that occur primarily in natural habitats. In this study, we examined the habitat selection behavior of Trichogramma ostriniae Pang and Chen, an Asian species that has shown considerable promise in the United States as a biological control agent against the European corn borer, Ostrinia nubilalis Hübner (Lepidoptera: Crambidae). On two different farms, we released wasps in a border area between corn (Zea mays L.) and natural forest, at locations equidistant to the two habitats. We monitored wasp movement for 4 wk using sticky cards placed up to 30 m inside each habitat. The results showed that T. ostriniae wasps have no inherent avoidance of entering forest habitat. Overall, however, corn habitat was more attractive to the wasps than forest habitat. The relative attractiveness of corn versus forest habitat also increased over time. We discuss our results on T. ostriniae habitat selection behavior within the context of information on T. ostriniae physiological host range and searching efficiency within different habitats and address the implications for risk to nontarget forest Lepidoptera.

Potato aphid, Macrosiphum euphorbiae (Thomas), is a highly mobile aphid species that dominates aphid communities in Maine potato fields and may contribute to virus transmission between potato plants. We studied effects of simulated rain, wind, mechanical raking, fungicide application, reflective mulch, and predator [lady beetle, Harmonia axyridis (Pallast)] on the interplant movement of wingless adult potato aphids in greenhouse experimental arenas that imitated small segments of a potato field. The number of aphids dispersing from the central plant in the arena after a tested perturbation was recorded. Experiments were repeated with 3- to 4-wk-old plants with nonoverlapping canopies and with 4- to 5-wk old plants with canopies overlapping within rows. Aphids moved between potato plants even when canopies did not overlap and without any environmental perturbations. However, more aphids moved between larger plants with overlapping canopies. Rain significantly encouraged aphid movement between plants with nonoverlapping canopies. Wind, rain, and mechanical raking significantly encouraged aphid movement between plants with overlapping canopies. Regardless of canopy overlap, most aphids moved within the rows of potato plants. However, there was also considerable movement between the rows, even though the aphids had to walk over bare soil.

We studied the effects of Melia azedarach L. fruit extracts on survival of Bemisia argentifolii Bellows and Perring nymphs and the parasitoid Eretmocerus rui Zolnerowich and Rose and on whitefly oviposition under laboratory conditions. In an experiment to determine toxicity to second-instar nymphs of aqueous extracts of three different sources of M. azedarch, survival of treated nymphs was significantly lower than survival of untreated control nymphs. In a second experiment to determine the effect of combined treatments involving extract application and exposure to parasitoids, the number of emerged whiteflies was significantly higher from control plants than from any of the combined treatments. Successful parasitism was the lowest when adult parasitoids were introduced after dipping second instars in the extract and when whitefly nymphs were dipped in extract 2 d after parasitism. However, the level of parasitism in parasitized nymphs dipped in extracts 4 and 8 d after parasitism was comparable with that of the control. The number of dead whitefly nymphs in combined treatments declined as the age of whitefly nymphs at application increased, with a concomitant increase in successful parasitism. Combined application of plant extract and parasitoids had an additive effect on whitefly nymphal mortality. In a test of whitefly oviposition, there was no significant difference in number of eggs laid on plants treated with extracts and on control plants. However, significantly fewer whiteflies emerged from eggs laid on treated plants than on control plants, indicating that M. azedarach extracts had affected egg development. Thus, M. azedarach fruit extract and the parasitoid E. rui are compatible and may contribute to lower whitefly populations in an integrated pest management program.

We examined integration of soil application of azadirachtin with two predatory mite species to control Frankliniella occidentalis (Pergande) on Phaseolus vulgaris. The release of a single predatory mite species reduced thrips numbers only to the lowest degree under this set of experimental conditions. Predator combinations increased corrected thrips mortality ranging from 54 to 85%. NeemAzal-U (17% azadirachtin), a formulation developed for root uptake, caused mortalities from 70 to 98% after soil application. A combination of azadirachtin with predatory mites enhanced not only consistency in thrips control but also resulted in efficacies of up to 99%. The survival of both predatory mite species were not significantly affected by NeemAzal-U soil treatments. However, a significant reduction in population development of H. aculeifer assumed an influence of NeemAzal-U on reproduction of the soil dwelling mites.

Sampling with UV fluorescent light tubes is a commonly used technique both in applied and basic insect studies. Our study compares the performance of two such methods: manual sampling (light towers) and automatic sampling (funnel light traps). The abundance, diversity, and body size of moths representing two species-rich families (Lepidoptera: Arctiidae, Geometridae) were analyzed in a lowland rain forest in Costa Rica (La Selva Biological Station, 10.4° N, 84.0° W) during 2003 and 2004. Light towers were equipped with two 15-W UV fluorescent tubes and were operated for 3 h in 16 nights. Traps equipped with single 8-W fluorescent tubes were run throughout 20 nights in the understory of the forest. In addition, parallel trap sampling was carried out in the canopy. A total of 1,238 arctiid moths representing 162 species and 1,769 geometrid moths representing 196 species were collected. In Geometridae, tower samples were significantly larger than trap samples. Towers also attracted a higher overall number of species. Very small geometrids (particularly of the subfamily Sterrhinae) were under-represented in trap samples, suggesting that this method is biased toward larger species. In arctiid moths, there were no significant differences in either the sample sizes, the number of species or in the size of the individuals sampled. Diversity calculated as Fisher’s α was similar for towers and understory traps in both families. A major component of diversity was added with canopy trap samples for arctiid moths, but not for geometrid moths. In conclusion, ground-based tower sampling proved to be the most suitable method for geometrid moths, and trap sampling including both understory and canopy for arctiid moths. For full moth species inventories, a combination of both approaches is recommended.

Studies were conducted in large arenas and simulated kitchens to compare the effectiveness of eight traps (seven sticky traps and one jar trap) and five attractants for monitoring German cockroaches (Blattella germanica L.). The evaluated traps were Trapper (type 9110–1), Catchmaster 150, 1001, and 2881, Victor-M330, Victor-M327, Glue board in D-Sect station, and a baby food jar trap. In choice tests, Victor-M330 consistently caught the most and Catchmaster 150 caught the fewest cockroaches. Numbers in the Victor-M330 were 78- and 36-fold greater than in the Catchmaster 150 in the large arena and simulated kitchen experiments, respectively. Sticky traps caught proportionally more small nymphs than large nymphs. Baby food jar trap samples had significantly greater adult/total ratio and large nymph/nymph ratios than the sticky trap samples. In addition, baby food jar trap catches had significantly lower male/adult ratio than Catchmaster 1001 and Victor-M327 trap catches. Flat Trapper traps caught significantly more cockroaches than the assembled (triangular) Trapper traps. Bread with beer, peanut butter, Trapper roach attractant, NAF430 gel bait, and Invite lure were compared in choice tests for their effect on sticky trap catches in simulated kitchens. All attractants significantly increased the number of cockroaches trapped in sticky traps compared with an unbaited trap. Bread with beer was by far the most attractive bait, increasing trap catches by 34-fold over the unbaited control. Baited sticky traps may have much greater efficacy than nonbaited traps for monitoring and controlling German cockroach infestations.

The southern green stink bug, Nezara viridula L., may disperse from alternate host plants, especially corn, Zea mays L., and peanuts, Arachis hypogaea L., into cotton, Gossypium hirsutum L. Trap crops may be useful to intercept dispersing stink bugs. Therefore, the ability of sorghum, Sorghum bicolor L. Moench, to trap N. viridula adults in cotton was studied for 3 yr. The 2002 experiment was designed to compare the ability of small plots of sorghum and cotton to trap N. viridula along the interface, or common boundary, of a corn and cotton field. In the 2003 experiment, cotton fields with sorghum and cotton plots planted along the interface of a corn–cotton farmscape were compared with cotton fields without these interface plots. In both experiments, N. viridula adults strongly preferred sorghum to cotton, and marking studies revealed that most N. viridula adults that dispersed into sorghum remained in sorghum instead of moving into cotton. Overall, percent parasitism of N. viridula adults by T. pennipes was higher in sorghum trap crop plots than in interface cotton control plots. In 2003, density of N. viridula adults was lower in cotton fields adjoining sorghum trap crop plots than in control cotton fields. Furthermore, economic threshold for N. viridula was not reached along the interface of the corn–cotton farmscape in any cotton field with sorghum plots. In contrast, economic threshold was reached in 61.5% of the control cotton fields. In the third season, a full-scale field experiment was conducted to determine the effectiveness of sorghum, planted in a strip along the length of the interface of a peanut–cotton farmscape, as a trap crop in cotton. Before the test, each cotton field was partitioned into eight side-edge and three interior block locations. Each field had four sides with side A occurring along the interface of the field. Edge 1 was 0–3.66 m from the outside edge of the field, and edge 2 was 3.66–7.31 m from the outside edge of the field. In control cotton fields, density of N. viridula adults was much higher in the interface side in edge one than in any other side-edge location, strongly indicating that N. viridula adults dispersed from peanuts into these cotton fields. Control cotton fields had higher numbers of N. viridula adults in the interface side in edge one compared with cotton fields with sorghum trap crops. Overall, in 2004, control cotton fields were treated with insecticides for control of N. viridula 1.4 times, whereas cotton fields with sorghum trap crops were treated for control of this stink bug only 0.2 times. These results show that sorghum can serve as a trap crop for N. viridula adults in cotton fields.

Emergence and survival of adults for 24 h was compared for Trichogramma chilonis Ishii reared on eggs of Corcyra cephalonica (Stainton) adults whose larval growth and development had been monitored on broken grains of four different cereals: finger millet (Eleusine coracana L. Gaertn), soft white wheat (Triticum aestivum L), short-grained white rice (Oryza sativa L.), and durra sorghum (Sorghum bicolor L. Moench). For C. cephalonica, the percentage adult emergence and several fifth-instar food use indices (consumption index, relative growth rate, and efficiencies of conversion of ingested and digested food) were significantly higher for millet-reared than for sorghum-reared larvae. The nutritional indices for wheat- and rice-reared C. cephalonica larvae were intermediate between the indices for larvae reared on millet and sorghum. The percentage adult emergence and percentage 24-h survival of T. chilonis were significantly higher on eggs of C. cephalonica hosts reared on millet than on eggs of those reared on sorghum. These results suggest that the rearing of C. cephalonica larvae on a high-quality nutritional source resulted in high-quality eggs, which ultimately resulted in high-quality T. chilonis reared on those eggs. Such an effect has been modeled in ecological theory as a “bottom up cascade.” Improved knowledge of the nutritional ecology of parasitoids and hosts can lead to improved understanding of the ecological mechanisms affecting host plant, host, and parasitoid abundance, as well as to improved efficiency and quality of Trichogramma production in mass rearing programs.

Ground covers were tested for 3 consecutive yr for their effect on Japanese beetle, Popillia japonica Newman (Coleoptera: Scarabaeidae), abundance and behavior in a blueberry planting. Alsike clover (Trifolium hybridum L.), buckwheat (Fagopyrum esculentum Moench), perennial ryegrass (Lolium perenne L.), and bare ground were compared within row-middles for their effect on abundance of adult female beetles, female beetle behavior after landing, density of larvae in the soil, and survival of larvae. Adult beetles were consistently most abundant on buckwheat, followed by clover and ryegrass, while they were generally absent from bare ground plots. Larval density was three times greater in ryegrass and clover than in buckwheat, with the fewest found in bare ground. There was high variability in larval survival within treatments, but overall survival was highest in plots with ryegrass. Observations of adult beetles revealed that the proportion of time spent feeding and the frequency of feeding were higher on buckwheat and clover than on ryegrass, and the average duration of digging bouts lasted longer on ryegrass than on the other two plant treatments. These results reveal that adult P. japonica behavior is affected by cover crops and that this behavior translates into variation in larval density of this pest.

Insect herbivores often respond to leaf texture in making oviposition or feeding choices. This study examined the importance of leaf pubescence for an assemblage of generalist caterpillars (Lepidoptera: Limacodidae) feeding on oaks (Quercus spp.) and a variety of other tree species in eastern North America. Based on 10 yr of larval sampling on canopy and understory black and white oak (Quercus velutina and Q. alba, respectively) in the Ozark Mountains of Missouri, larval density of slug caterpillars (14 species as a group and 3 individual species) was higher on glabrous canopy leaves of Q. velutina than on highly pubescent understory leaves of that species. In contrast, there was no effect of stratum on overall density for Q. alba, which has glabrous leaves in both microenvironments. Individually, stratum effects for Q. alba were significant for five species, four of which were more abundant in the understory. Additional censusing of larvae on 20 tree species varying in leaf pubescence found that, as a group, slug caterpillar density was negatively correlated with leaf hair density. Finally, feeding trials confirmed that slug caterpillars prefer canopy over understory leaves of Q. velutina and vice versa for Q. alba leaves. When hairs were experimentally removed from one side of Q. velutina understory leaves, caterpillars preferred the side from which hairs were removed over the intact side. Together, these results indicate that leaf pubescence influences patterns of host plant use by these generalist herbivores, and in so doing, contributes to the structuring of local herbivore communities.

Lycoriella pleuroti is a pest of edible fungi, commonly cultured on a cottonseed shell–based medium. L. pleuroti larvae were reared on culture media containing variety CRI30 (transgenic Bacillus thuringiensis [Bt]) cottonseed, variety CRI16 (nontransgenic) cottonseed, Bt (CryIAc) protein, gossypol, tannin, and quercetin. The mortality of larvae reared on media with CRI30 cottonseed was significantly higher than that of larvae reared on media with CRI16 cottonseed, and mortality increased with increasing CRI30 and CRI16 cottonseed content. Media containing Bt protein, gossypol, tannin, and quercetin negatively influenced survival of L. pleuroti larvae. Of the four ingredients, the negative effects of gossypol and tannin were the largest. The suppression caused by the Bt protein was not as great and did not increase with increasing dose. The presence of quercetin also increased larval mortality over the control, but mortality decreased with increasing quercetin content.