Traps for monitoring of flying insect pests constitute a critical part of integrated pest management strategies. However, interpretation of trap captures is hampered by 1) factors associated with the performance of traps (i.e., lure, trap design, placement); 2) an often poorly defined relationship between trap captures and population density; and 3) interpretation approaches being highly specific to a certain insect species, trapping method, or trapping environment. The main purpose of this study was to identify a trap capture interpretation approach with little sensitivity to characteristics specific to a given data set, which would allow easier comparison of trapping data sets and make it easier to standardize sampling plans across insect pests and trapping environments. Based on fits of trapping data sets to standard distributions (normal, Poisson, and negative binomial), evaluations of the index of aggregation, k, and linear regression coefficients from Taylor’s power law, we concluded that these characteristics varied considerably among data sets, which means that enumerative sampling plans may not be appropriate. Across 13 trapping data sets of six insect species, we showed a consistent nonlinear relationship between average trap captures and number of traps with zero captures and that the k can be stabilized by converting trapping data into binomial data. A trap interpretation approach based on number of zero captures is both easy to use, was found to be species-independent, and means that it may be possible to establish meaningful and reliable action thresholds based on trap captures of flying insects. Although developed using trapping data from food facilities, this approach may have application to trapping data from other environments as well.

Thirty-seven boll weevils, Anthonomus grandis grandis Boheman (Coleoptera: Curculionidae), were captured in pheromone traps near Lubbock, TX, in the Southern High Plains/Caprock eradication zone during August–October 2006. No boll weevils had been captured in this zone or neighboring zones to the north earlier in the year, and only very low numbers had been captured in neighboring zones to the south and east. Therefore, the captures near Lubbock were unexpected. Five of the weevils captured the last week of August were preserved and genotyped at 10 microsatellite loci for comparison with a database of genotypes for 22 boll weevil populations sampled from eight U.S. states and four locations in Mexico. The Lubbock population itself is an unlikely source, suggesting that the captured weevils probably did not originate from a low-level endemic population. Populations from eastern states, Mexico, and Big Spring, TX, can be confidently excluded as potential source regions. Although the Weslaco and Kingsville, TX, areas cannot be statistically excluded, they are unlikely sources. The most likely sources are nearby areas in New Mexico, TX, or southwest Oklahoma, or from areas of eastern Texas represented by Waxahachie and El Campo populations. Together, genetic and circumstantial evidence suggest either that the trapped boll weevils are the offspring of a lone mated female that immigrated from eastern Texas earlier in the summer or that weevils originally captured near Waxahachie but now long-dead were planted in the traps by a disgruntled employee of the eradication program.

The nutritive value of pollen blends purchased by bumble bee producers from beekeepers is a key factor of successful mass rearing. We have already devised a method for quality ranking of pollen diets. It was a 1-mo bioassay using queenless micro-colonies of three callow workers (Bombus terrestris L.; Apidae: Bombinae). In the current study, we tested three pollen diets through the micro-colony method and compared the results to the development of queenright colonies supplied with the same diets. The three diets were “A,” a spring blend with a protein rate of 15.7% and a dominance of Corylus avellana L.(46%) and Buxus sempervivens L. (35%); “B,” a summer assemblage with a lower crude protein content (14.4%), with a dominance of Helianthus annuus L.(37%), Zea mays L. (35%), and Poaceae (21%); and “C,” a 50/50 mixture by weight of A and B, with a crude protein content of 15.8%. In micro-colonies, the more sensitive parameter for diet ranking was the mean weight of a larva, whereas in queenright colonies, the discrimination between treatments was enabled by considering the body size of new queens (weight and length of the radial cell) and the slope of the sigmoidal curve of the pollen consumption at the inflection point reflecting brood growth. Both testing methods assigned the lower rank to diet B compared with diet A. Despite the closeness of the three diets in terms of nitrogen content, we concluded that micro-colonies were a good estimate of colony development when nutritive value of pollen was tested.

Although sublethal dosages of insecticide to nontarget insects have never been an important issue, they are attracting more and more attention lately. It has been demonstrated that low dosages of the neonicotinoid insecticide imidacloprid may affect honey bee, Apis mellifera L., behavior. In this article, the foraging behavior of the honey bee workers was investigated to show the effects of imidacloprid. By measuring the time interval between two visits at the same feeding site, we found that the normal foraging interval of honey bee workers was within 300 s. However, these honey bee workers delayed their return visit for >300 s when they were treated orally with sugar water containing imidacloprid. This time delay in their return visit is concentration-dependent, and the lowest effective concentration was found to be 50 μg/liter. When bees were treated with an imidacloprid concentration higher than 1,200 μg/liter, they showed abnormalities in revisiting the feeding site. Some of them went missing, and some were present again at the feeding site the next day. Returning bees also showed delay in their return trips. Our results demonstrated that sublethal dosages of imidacloprid were able to affect foraging behavior of honey bees.

Fatty acid esters extractable from the surface of honey bee, Apis mellifera L. (Hymenoptera: Apidae), larvae, called brood pheromone, significantly increase rate of colony growth in the spring and summer when flowering plant pollen is available in the foraging environment. Increased colony growth rate occurs as a consequence of increased pollen intake through mechanisms such as increasing number of pollen foragers and pollen load weights returned. Here, we tested the hypothesis that addition of brood pheromone during the winter pollen dearth period of a humid subtropical climate increases rate of colony growth in colonies provisioned with a protein supplement. Experiments were conducted in late winter (9 February–9 March 2004) and mid-winter (19 January–8 February 2005). In both years, increased brood area, number of bees, and amount of protein supplement consumption were significantly greater in colonies receiving daily treatments of brood pheromone versus control colonies. Amount of extractable protein from hypopharyngeal glands measured in 2005 was significantly greater in bees from pheromone-treated colonies. These results suggest that brood pheromone may be used as a tool to stimulate colony growth in the southern subtropical areas of the United States where the package bee industry is centered and a large proportion of migratory colonies are overwintered.

The pattern of inheritance of tracheal mite resistance in selected Russian bees was determined in bioassays and in samples from field colonies. Resistant colonies of Russian origin and colonies selected for high susceptibility in the United States were used to generate divergent parental populations. Seven groups of F₁ colonies were produced by crossing queens and drones from these selected resistant Russian and selected susceptible populations. In a series of bioassays with young workers exposed in infested colonies, average mite abundance (female mites per worker) in F₁ colonies was intermediate (1.04 ± 0.13 [mean ± SE]) and significantly different from that of both resistant Russian (0.74 ± 0.13) and selected susceptible (1.57 ± 0.13) colonies. Colonies representing the three populations were established in two apiaries in July 2005. Colonies surviving with original queens after 10 mo had mite prevalences supporting the findings of the bioassay. All three resistant colonies had undetectable mite levels, whereas prevalences in four F₁ colonies ranged from 0 to 53%, and in 10 susceptible colonies ranged from 0 to 90%. Tracheal mite resistance in Russian bees is likely polygenic, but there may be a number of genes with major dominance interacting with minor genes. Use of selected Russian queens mated with Russian drones or with drones from unknown sources is beneficial for beekeeping in areas with persistent problems with tracheal mite infestation.

Storage of Gonatocerus ashmeadi Girault (Hymenoptera: Mymaridae) adults at 2, 5, and 10°C showed that these parasitoids do not survive at 2°C for 5 d, and exposure to 5 and 10°C shortens their life span. The lethal time (LT)₅₀ (i.e., length of storage time for 50% wasp survival) at 5°C was 14 d for males and ≈29 d for females, whereas at 10°C was 32 and 39 d, respectively. Effects of adult storage at 10°C on other factors indicating fitness, such as fecundity, developmental time, parasitism, emergence, and sex ratio, were examined on female wasps and their progeny at 10-d intervals for up to 60 d. Glassy-winged sharpshooter, Homalodisca vitripennis (Germar), eggs were used as hosts for propagation of this wasp and for assessing its oviposition and fecundity. Increasing adult storage time decreased the length of the ovipositional period for the maternal generation, and oviposition was decreased by 90% after 60-d storage. A significant reduction in maternal lifetime fecundity occurred after 20-d storage and in the incidence of parasitism after 40 d. We also found a carryover effect caused by storage of the maternal generation that was expressed in the F₁ generation. When cold storage of the adult parents was ≥20 d, we observed delayed development, decreased fecundity, reduced longevity, and increased male production occurring in the F₁ generation. Reduced fitness of the F₁ generation was also expressed as a decrease in net reproductive rate (R₀) and an increase in mean generation time (T_c). However, none of these deleterious effects were evident in the F₂ progeny that descended from grandparents that had experienced cold storage. Damage caused by indirect chilling injury and/or induced maternal aging occurring during storage can account for the decreased fitness of maternal and F₁ generations. Providing that the limits of cold tolerance of G. ashmeadi as defined in this study are not exceeded, our results show that short-term cold storage of adults could be used in a mass-rearing program.

Selectively collecting a single natural enemy species that parasitizes one member of a guild of herbivores that attack the same host plants can be a challenging problem during development of biological control programs. We present here a successful strategy for the collection of a strain of the egg parasitoid Avetianella longoi Siscaro (Hymenoptera: Encyrtidae), that parasitizes eggs of the longhorned borer Phoracantha recurva Newman (Coleoptera: Cerambycidae). This cerambycid is one member of a large guild of woodborers that simultaneously infest dying and fallen Eucalyptus in Australia, and it has become a major pest of Eucalyptus in many areas of the world where Eucalyptus has been introduced. Adult P. recurva of both sexes were caged on freshly cut Eucalyptus logs, and the resulting egg masses were marked and then left exposed to natural parasitization in the field. Parasitized egg masses were then harvested and held in the laboratory until adult parasitoids emerged. Parasitoids were identified as A. longoi by morphological comparisons with reference specimens, and with molecular markers. This strain of A. longoi readily accepted and had high survival rates in eggs of P. recurva. In contrast, the strain of A. longoi that has been used for biological control of P. semipunctata in California since the 1990s strongly prefers eggs of eucalyptus longhorned borer, Phoracantha semipunctata (F.) (Coleoptera: Cerambycidae), and has relatively low rates of survival to adulthood in eggs of P. recurva. The causes of these behavioral and physiological differences between the two strains are not yet known.

To mitigate risks of invasive pests, international nursery exporters may soon be expected to participate in clean stock programs that reduce the probability of shipping crops that contain pests of quarantine significance. We worked with Costa Rican producers of Dracaena marginata Lam. (Ruscaceae) to identify critical pests, as well as the field conditions and production practices that could be explored for lowering pest abundance in a clean stock program. We sampled the abundance of leafhopper and katydid eggs, armored scales, and snails on leaves using a 10- by 10-m grid in a total of 34 production plots located in two distinct growing regions during the rainy and dry seasons of 2006. Growers were surveyed to determine the production practices in each field. Populations of leafhoppers and snails increased during the rainy season, whereas armored scale populations reached higher densities in the dry season. Fertilizer applications were associated with a greater abundance of leafhoppers, the keystone pests in the system. In contrast, abundances of armored scales and katydids were somewhat lower in fertilized fields. Insecticide applications targeting leafhoppers succeeded in reducing their populations, but secondary outbreaks of armored scales and katydids were observed. Increased frequency of herbicide application was associated with lower populations of leafhoppers with no significant effects on the other herbivores. Although effects of specific production practices in a given plot are confounded, the effects of fertilizer, insecticide, and herbicide use on leafhoppers are consistent with those predicted by literature on this pest. For this reason, the 10- by 10-m sampling grid is sensitive enough for use in controlled studies that evaluate effects of specific practices on pest abundance. As such, it is likely to be a useful tool for developing a clean stock program for D. marginata in Costa Rica.

U.S. exported lettuce, broccoli, asparagus, and strawberries often harbor western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), a quarantined pest in Taiwan, and therefore require quarantine treatment. Fumigation with diluted pure phosphine at a low temperature of 2°C was studied to control western flower thrips and to determine effects on the quality of the treated products. Total thrips control was achieved in ≥18-h fumigation treatments with ≥250 ppm phosphine. One day fumigation treatment with 1,000 ppm phosphine was tested on lettuce and broccoli. One-day fumigation treatments with 500 ppm and 1,000 ppm phosphine were tested on asparagus and strawberry. Visual quality of lettuce, broccoli, and asparagus was evaluated after 2-wk posttreatment storage. Strawberry quality was evaluated immediately after fumigation and after 1-wk posttreatment storage. For all the products, there were no significant differences between the treatments and the controls in postharvest quality, and there were no injuries caused by the fumigation treatments. Therefore, phosphine fumigation at low temperature was promising for postharvest control of western flower thrips on lettuce, broccoli, asparagus, and strawberry.

Marginal vegetation in crops is very important for natural enemies and their pest control capacity. The effects of Brassica nigra L. (Brassicaceae), Daucus carota L. (Apiaceae), and Sonchus oleraceous L. (Asteraceae) flowers as supplemental food on the number of eggs laid during 7 d and on the preoviposition time in Hippodamia variegata (Goeze, 1777) were studied in the laboratory under conditions of several densities of Acyrthosiphon pisum (Harris, 1776). The results show the presence of flowers of Brassica and Sonchus increased egg production 1.44× and doubled the preoviposition period (2.13×). This suggests that the availability of flowers of Brassica and Sonchus as supplemental foods (pollen and nectar) in the marginal vegetation of crops can serve to improve reproductive performance of H. variegata, specifically under conditions of prey limitation. Thus, the increase in fitness of this predator allows a better response to changes in pest density.

Effect of temperature on the life history of the mealybug Paracoccus marginatus Williams & Granara de Willink (Hemiptera: Pseudococcidae) was investigated in the laboratory. P. marginatus was able to develop and complete its life cycle at 18, 20, 25, and 30 ± 1°C. At 15, 34, and 35°C, the eggs hatched after 27.5, 5.9, and 5.5 d of incubation, respectively, but further development of the first-instar nymphs was arrested. No eggs hatched at 37°C. The developmental time for egg to adult was the longest at 18°C for both males and females. Approximately 80–90% of the eggs survived between 20 and 30°C. The highest fecundity was at 25°C with each female producing an average of 300 eggs. Adult longevity, and preoviposition and oviposition periods increased with decreasing temperature up to 25°C. The proportion of females was ≈42% at 25°C and was between 70 and 80% at 18, 20, and 30°C. Adult males and females required 303.0 and 294.1 degree-days (DD), respectively, to complete their development. The estimated minimum temperature thresholds for the adult males and females were 14.5 and 13.9°C, respectively. For adult males, the estimated optimum and maximum temperature thresholds were 28.7 and 31.9°C; and for adult females, they were 28.4 and 32.1°C, respectively. The ability of P. marginatus to develop, survive, and reproduce successfully between 18 and 30°C suggests that it has the capability to develop and establish in areas within this temperature range.

Various pesticides directly impact insect pest populations through acute toxicity (lethal) effects, but they also cause a range of indirect (sublethal) effects on pest physiology or behavior. In this study, we describe both lethal and sublethal effects of endosulfan on the survival, development, and fecundity of Apolygus lucorum Meyer-Dür (Hemiptera: Miridae), an important pest of Bacillus thuringiensis (Bt) cotton, Gossypium hirsutum L., in China. We quantify pesticide effects on adult mirids as well as on subsequent (F1, F2) generations. Toxicity bioassays determined the median lethal concentration (LC₅₀) for adult A. lucorum as 0.58 ppm. To evaluate the sublethal effect of endosulfan, we used LC₂₀ and LC₄₀ concentrations at 0.30 ppm and 0.48 ppm, respectively. Sublethal concentrations of endosulfan significantly reduced longevity and fecundity of female adults, but slightly affected male longevity. We also found sublethal effects on the F1 generation, through a reduction of egg hatching rate, nymphal mortality, adult molting rate, and adult fecundity, and on the F2 generation, through a decrease of egg hatching rate. These results show that endosulfan has far greater effects on A. lucorum than estimated by acute toxicity tests, and the effects of this pesticide on surviving mirids can be comparatively long-lived. This pesticide likely causes severe disruptions of A. lucorum population dynamics, with single endosulfan application, invoking a great reduction of population growth of resident mirid populations. We discuss implications of this work for control programs for A. lucorum on Bt cotton.

Field studies were conducted at two locations on the Canadian prairies to investigate use of reduced ratios of insecticide-treated seed in controlling flea beetle (Coleoptera: Chrysomelidae, Phyllotreta spp.) damage to canola (Brassica napus L. and Brassica rapa L.). Five treatments were evaluated: bare seed control, fungicide-only (0X), and three ratios of insecticide plus fungicide in proportions of all (1X), two thirds (0.67X), or one third (0.33X) of the seeds coated with insecticide. Decreasing treated seed ratios by one third had no consistent deleterious effects on flea beetle damage, seedling growth, plant density, seed yield, or net cash return. Flea beetle injury to seedlings in the 1X treatment was similar to that of seedlings in the 0.67X treatment, with only two exceptions, and it was almost always lower than that of seedlings without insecticide. The 0.33X treatment generally had flea beetle feeding levels between those of the two high and the two noninsecticide treatments. Plant stand and seedling growth rates with 1X and 0.67X treatments were similar and higher than with bare seed or fungicide-alone treatments. Seed yields were inversely proportional to flea beetle feeding levels. Under very heavy flea beetle feeding, seed yields and net cash returns were highest in 1X plots, but when flea beetle feeding pressure was less extreme and canola growing conditions were favorable, 0.67X seed yields and profits from them were comparable to those in 1X treatments. On an economic basis, currently there is no advantage to decreasing the level of insecticide treated canola seed, but other considerations may affect this assessment.

Dendroctonus frontalis Zimmermann (Coleoptera: Scolytinae) is the most serious pest of pines (Pinus spp.) in Mexico. Conspecifics are attracted to trees undergoing colonization by the aggregation pheromone frontalin, which is synergized by odors of pine oleoresin released from beetle-damaged host tissue. Synthetic racemic frontalin combined with turpentine has been the operational bait used in traps for monitoring populations of D. frontalis in Mexico as well as the United States. Recently, racemic endo-brevicomin has been reported to be a synergist of the frontalin/turpentine bait and as an important component of the aggregation pheromone for D. frontalis populations in the United States. To determine whether racemic endo-brevicomin also might function as an aggregation synergist for the geographically isolated D. frontalis populations of Central America and Mexico, we performed a field trapping trial in Lagunas de Montebello National Park, Chiapas, Mexico, during July and August 2007. The combination of endo-brevicomin (placed either directly on the trap or 4 m away) plus racemic frontalin and turpentine caught at least 5 times more D. frontalis of both sexes than did turpentine either alone or in combination with either frontalin or endo-brevicomin. The addition of endo-brevicomin to the frontalin/turpentine bait also increased the proportion of females trapped. We conclude that the addition of endo-brevicomin might substantially improve the efficiency of the frontalin/turpentine bait for monitoring of D. frontalis in Central America and Mexico. We discuss factors that reconcile our results with previous studies that reported endo-brevicomin to be an attractant antagonist for populations of D. frontalis in Mexico and Honduras.

The Douglas-fir beetle, Dendroctonus pseudotsugae Hopkins (Coleoptera: Curculionidae), antiaggregation pheromone, 3-methylcyclohex-2-en-1-one (MCH), has been used by natural resource managers and landowners to protect high-value, high-risk trees from Douglas-fir beetle infestation throughout the western United States since 2000. Labor is a major portion of the cost of MCH treatments. MCH is applied by walking through treatment areas and stapling the formulated pheromone in bubble capsules to trees and other objects on a regular grid pattern. Reducing the number of MCH release points and increasing the distance between them could significantly reduce labor costs, particularly in areas with steep terrain or large volumes of woody debris that could impede the movement of applicators. This study compared the standard MCH application method with a method releasing MCH at a 3 times higher rate and placed at three times fewer release points per unit area. Treatments were applied to 2-ha plots simulating an operational application. Aggregation pheromone-baited traps were placed at plot centers to ensure that dispersing adult beetles would be present on all plots. Both MCH treatments were equally effective at preventing the infestation of live Douglas-fir, Pseudotsugae menziesii (Mirbel) Franco, trees (≥30 cm diameter at breast height). These results confirm that MCH formulated to release at three times the current standard rate and placed at 3 times fewer points per unit area can effectively prevent the infestation of live Douglas-fir. The new treatment will significantly reduce the labor cost of MCH applications making them feasible for areas that may have previously been marginal economically.

The key to an effective pest management program for the emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera Buprestidae), is a survey program equipped with tools for detecting and delimiting populations. We studied the effects of trap design, color, and placement on the efficacy of sticky traps for capturing the emerald ash borer. There were significant differences in trap catch along a transect gradient from wooded to open field conditions, with most beetles being caught along the edge, or in open fields, 15–25 m outside an ash (Fraxinus spp. L.) (Oleaceae) woodlot. Greater emerald ash borer catch occurred on purple traps than on red or white traps. Traps placed in the mid-canopy of ash trees (13 m) caught significantly more beetles than those placed at ground level. We also describe a new trap design, a three-sided prism trap, which is relatively easy to assemble and deploy.

All published studies on effects of abiotic factors on plum curculio, Conotrachelus nenuphar (Hersbt), adults have taken a retrospective approach. Here, we present the results of experiments where factors and their levels were determined and controlled a priori. We compared the effectiveness of miniature pyramidal traps (45 by 20 by 20 cm) constructed of four kind of materials—wood, geotextile, nylon screening, and corrugated plastic—to monitor overwintered and summer adults of univoltine plum curculio. We also studied the effects of photoperiod, temperature, wind, and rain on pyramidal trap effectiveness. The experiments, which were replicated over time, were done in two controlled chambers that were divided into four sections, corresponding to simulated combinations (wind or no wind/rain or no rain). The temperatures tested (15, 20, and 25°C) were randomly assigned in the chambers. During scotophase, geotextile traps captured significantly more overwintered and summer adults than traps made of other materials. The maximum proportion of captures (for overwintered and summer adults) during photophase was obtained at 25°C, and it was significantly different than captures at 15 and 20°C. During scotophase, significantly more overwintered and summer plum curculios were caught at 20 and 25°C than at 15°C. Our experiments demonstrated that geotextile is a good alternative to wooden pyramidal trap. Our results suggest that captures were higher 1) at night, 2) during warmer periods (20 and 25°C), 3) when wind velocity was low and 4) during or shortly after rainfall, and 5) that photoperiod is a factor having an important predictive value for plum curculio captures.

The grub Tomarus subtropicus Blatchley (Coleoptera: Scarabaeidae) is one of the most destructive pests of turfgrass and sugarcane (Saccharum spp.) in southern Florida, but its life cycle has only been described in sugarcane production. Preventive insecticides applied against T. subtropicus in turfgrass when adult activity and oviposition were expected in sugarcane have necessitated subsequent curative treatments. Thus, the seasonal activity of T. subtropicus was monitored using UV blacklight traps and by sampling soil in infested St. Augustinegrass lawns in Cape Coral and Punta Gorda, FL, during 2005–2006. Several preventive and curative insecticides and entomopathogenic nematode species were evaluated in laboratory, greenhouse and field tests. T. subtropicus is univoltine in both sugarcane and St. Augustinegrass, but adult flight peaked ≈1 mo later in St. Augustinegrass than in sugarcane. Halofenozide, clothianidin, and imidacloprid were effective preventive control products, and carbaryl and trichlorfon were satisfactory curative insecticides. The nematodes Steinernema scarabei (Stock & Koppenhöfer), S. glaseri (Steiner), and Heterorhabditis bacteriophora (Poinar) were most effective against T. subtropicus grubs, and second instars were more susceptible compared with third instars. Improved knowledge of the biology and effectiveness of different management options for T. subtropicus will help minimize excessive pesticide use, especially in coastal areas of Florida.

Oriental beetle, Anomala orientalis Waterhouse (Coleoptera: Scarabaeidae), is a pest of turfgrass that may be controlled by applications of synthetic pheromone (Z)-/(E)-7-tetradecen-2-one to disrupt mating. Laboratory experiments were conducted to determine release profiles of pheromone from experimental wax-based granules, a proprietary wax granule, and rubber septa commonly used in pheromone traps. Rubber septa loaded with 10, 100, and 300 μg per septum provided steady rates of pheromone release (zero-order) over 4 wk of laboratory evaluation (total = 1.1, 9.0, and 26.9 μg/4 wk, respectively). Septa with 1,000 μg per septum had a significant decline in the rate of pheromone release for this 4-wk exposure time (total = 119 μg/4 wk). A large proprietary wax granule (44 mg per granule, 25% wt:wt pheromone) provided a steady rate of pheromone release (total = 2,347 μg/4 wk per granule). Experimental granules (16 mg per granule) made of soywax with higher pheromone loads (10% wt:wt) approached zero-order release (steady state) (total = 69 μg/4 wk per granule), whereas smaller granules (4 mg per granule) with less pheromone (0.1% wt:wt) provided first-order release profiles (decreasing rate with longer exposure time) (total = 0.35 μg/4 wk per granule). A field trial in turfgrass demonstrated the potential of selected granular formulations to provide effective mating disruption for up to 4 wk, as measured by pheromone trap shutdown. Documenting pheromone release profiles for these experimental granules and rubber septa provides valuable information that will support future field evaluations of mating disruption as a control strategy.

Nesidiocoris tenuis Reuter (Heteroptera: Miridae) is one of the most controversial dicyphines because of the injuries it causes to tomato (Solanum esculentum) crops. The aim of this study was to quantify the impact of N. tenuis on fruit yield. Tomato plants were exposed to an average of 0.53 ± 0.26, 3.4 ± 1.1, 12.0 ± 1.4, and 35.2 ± 7.7 N. tenuis per plant for 3 wk. When fruit were exposed to N. tenuis as flowers, the percentage of aborted fruit was higher in compartments infested with N. tenuis, and this was related directly to the cumulative number of N. tenuis (CNN). However, compartments with the highest abortion rates had heavier and bigger fruit and were not significantly different from the controls. The variation in fruit weight was satisfactorily explained with a logistic equation in relation to the proportion of aborted fruit. To estimate the density thresholds, the variation in truss weight was predicted as a function of fruit weight and aborted fruit. The two latter variables were expressed as a function of the CNN. A maximum of 15% truss weight overcompensation was predicted at 15.8% of fruit abortion. Yield reduction was predicted at fruit abortion rates ≥27.7%, which corresponded to 566 CNN per plant or 32.11 CNN per leaf. N. tenuis may be considered a useful predator of small pests in tomato crops if kept under these thresholds. Mathematical models predict a yield increase and fruit upgrade that overcompensates for the reduction in the number of fruit below the density threshold.

Sweetpotatoes, Ipomoea batatas (L.) Lam. (Convolvulaceae), are typically grown on bare soil where weeds and erosion can be serious problems. Conservation tillage systems using cover crop residues as mulch can help reduce these problems, but little is known about how conservation tillage affects yield and quality of sweetpotato or how these systems impact populations of beneficial and pest insects. Therefore, field experiments were conducted at the U.S. Vegetable Laboratory, Charleston, SC, in 2002–2004 to evaluate production of sweetpotatoes in conventional tillage versus a conservation tillage system by using an oat (Avena sativa L. (Poaceae)–crimson clover (Trifolium incarnatum L.) (Fabaceae) killed-cover crop (KCC) mulch. The four main treatments were 1) conventional tillage, hand-weeded; 2) KCC, hand-weeded; 3) conventional tillage, weedy; and 4) KCC, weedy. Each main plot was divided into three subplots, whose treatments were sweetpotato genotypes: ‘Ruddy’, which is resistant to soil insect pests; and ‘SC1149-19′ and ‘Beauregard’, which are susceptible to soil insect pests. For both the KCC and conventional tillage systems, sweetpotato yields were higher in plots that received hand weeding than in weedy plots. Orthogonal contrasts revealed a significant effect of tillage treatment (conventional tillage versus KCC) on yield in two of the 3 yr. Ruddy remained resistant to injury by soil insect pests in both cropping systems; and it consistently had significantly higher percentages of clean roots and less damage by wireworm-Diabrotica-Systena complex, sweetpotato flea beetles, grubs, and sweetpotato weevils than the two susceptible genotypes. In general, injury to sweetpotato roots by soil insect pests was not significantly higher in the KCC plots than in the conventionally tilled plots. Also, more fire ants, rove beetles, and carabid beetle were captured by pitfall traps in the KCC plots than in the conventional tillage plots during at least 1 yr of the study. This study suggests that a sweetpotatoes can be successfully grown under a killed-cover crop production system.

Field-collected Reticulitermes flavipes (Kollar) termites were placed in bioassay tubes containing soil treated with one of three termiticides: thiamethoxam, acetamiprid, or a combination of acetamiprid bifenthrin. In the bioassay tubes, treated soil was placed in a layer centered within untreated sand between two 1.5-cm agar plugs. All termiticides were tested at concentrations of 0.1, 1, 10, and 100 ppm with narrow (1 mm), medium (5 mm), and broad (50 mm) thicknesses of treated soil. Soil penetration and termite mortality were measured after 7 d, and repellency was assessed. Thiamethoxam treatments allowed the greatest soil penetration, whereas acetamiprid bifenthrin treatments were the most inhibitory to soil penetration. Thiamethoxam treatments also caused consistently greater termite mortality than acetamiprid treatments. These data indicated that acetamiprid prevented soil penetration by termites more than thiamethoxam, although both were less repellent compared with bifenthrin alone, which causes little termite mortality at the tested doses. When there was direct contact of treated soil with the agar plugs in broad treatments, the combination of acetamiprid bifenthrin was more toxic to R. flavipes termites than either acetamiprid or thiamethoxam alone. The combination acetamiprid bifenthrin termiticide may be effective in keeping termites away from the treated soil, because of the combined effects of acetamiprid and bifenthrin.

A full-length cDNA, with an open reading frame (ORF) of 1,449 bp, encoding a subunit of the γ-aminobutyric acid (GABA)-activated chloride channel was isolated from Plutella xylostella (L.) (Lepidoptera: Plutellidae) (GenBank accession no. EF156251). The subunit gene encoded a 483-amino acid polypeptide that showed 84% sequence identity with DmRdl subunit (U02042) (Drosophila melanogaster resistant to dieldrin). When expressed in Xenopus laevis oocytes, the subunit assembled as a functional homomeric complex activated by GABA and abamectin in a dose-dependent manner. The EC₅₀ value of GABA was 0.49 mM (0.41–0.58) (n = 5). However, the responses to abamectin were very robust, with an EC₅₀ of 4.85 μM (4.02–5.89) (n = 6), indicating that abamectin was >100-fold more potent in activating chloride currents than GABA. The results suggest that this subunit is vital to the formation of a functional channel and contains the binding site of abamectin.

To investigate insecticide resistance levels and dynamic changes of carboxylesterase polymorphism with time in resistant populations of mosquitoes in the Culex pipiens complex, four field populations were collected in September 2006. The resistance levels of fourth-instar larvae to organophosphate (dichlorvos, parathion, and chlorpyrifos), carbamate (fenobucarb and propoxur), and pyrethroid (permethrin and tetramethrin) insecticides were determined by bioassay. Larvae had a low but significant resistance to organophosphate and carbamate insecticides but no significant resistance to pyrethroid insecticides. Starch gel electrophoresis revealed the presence of the overproduced esterases B1, A2-B2, A8-B8, A9-B9, and A11-B11. The frequency of each overproduced esterases varied depending on its regional localities. Compared with previous surveys, the polymorphism of amplified esterase alleles in Beijing populations increased, although the resistance level to organophosphate insecticides declined.

Varying susceptibility to tebufenozide was recorded in the sugarcane borer, Diatraea saccharalis (F.) (Lepidoptera: Crambidae), collected from Louisiana sugarcane locations with different selection pressures. Results from diet incorporation bioassays with tebufenozide indicated significant increases in LC₅₀ (3.78-fold) and LC₉₀ (7-fold) values for a colony from Duson (DU), an area with higher selection pressure, compared with a colony from Alexandria (ALEX), an area with no selection pressure. Differences were not detected in LC₅₀ values among colonies from areas where use of tebufenozide was discontinued or rotated with other chemistries. Selections with tebufenozide of DU larvae over 12 generations resulted in a highly resistant colony (DU-R) with 27.1- and 83.3-fold increases in LC₅₀ and LC₉₀ values, respectively. Comparison of pupal weight, days to pupation, and emergence after exposure to an equitoxic (LC₂₀) concentration of tebufenozide revealed a decrease in pupal weight (34 and 33% for males and females, respectively), and an increase in days to pupation (47 and 40% for males and females, respectively), and emergence (43 and 33% for males and females, respectively) for the DU-R colony compared with the parent DU colony. Fecundity of DU-R females decreased to 72 eggs per female compared with 180 (DU) and 261 (ALEX). Egg viability of the ALEX and DU colonies was 61 and 56%, respectively, whereas only 27% of eggs laid by females from the DU-R colony hatched. These results are discussed in terms of their practical implications for control of D. saccharalis in Louisiana sugarcane.

The diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), is considered as one of the most difficult pests to control. It has developed resistance not only to synthetic insecticides but also to Bacillus thuringiensis-based pesticides. We tested the hypothesis that selection in a P. xylostella population, from Hosur, India, with deltamethrin would give a broad spectrum of resistance to several insecticides. We also were interested in genetically classifying resistance to deltamethrin in the selected population and in evaluating whether resistance can be suppressed using synergists. Bioassays (at generation 1, G₁) using deltamethrin indicated a resistance ratio of 161-fold compared with a laboratory-susceptible population of P. xylostella (Lab-UK). At G₂, the field-derived population was divided into two subpopulations; one population was selected (G₁ to G₈) with deltamethrin (Delta-SEL), and the second population was left unselected (UNSEL). Bioassays at G₉ indicated that selection with deltamethrin gave a resistance ratio of 15-fold compared with UNSEL and 1,647-fold compared with Lab-UK. The resistance to deltamethrin in the UNSEL population was stable. The Delta-SEL population maintained resistance to lambda-cyhalothrin, but there was no cross-resistance to indoxacarb, DDT, or Cry1Ac. Crossing experiments indicated that resistance to deltamethrin in Delta-SEL was multigenic and inherited in an incompletely dominant fashion. Piperonyl butoxide (PBO) and S.S.S-tri-n-butyl phosphorotrithioate with potent inhibitory activity against esterases and/or monooxygenases significantly increased the toxicity of deltamethrin against both UNSEL and Delta-SEL, but they showed no such synergism with Lab-UK. Thus, it can be predicted that development of resistance to deltamethrin would be delayed under appropriate control strategies that favor the dilution of resistance alleles by enhanced flow of susceptible alleles. Further analysis suggested that mixing PBO and deltamethrin could eliminate the substantial resistance to deltamethrin in this population.

The insecticides esfenvalerate, endosulfan, imidacloprid, and methamidophos were screened against 74 clonal populations of the green peach aphid, Myzus persicae (Sulzer), collected as fundatrices from peach (Prunus spp.) and as apterous virginoparae from various weeds near potato (Solanum spp.) fields in the Yakima Valley and Columbia Basin regions of Washington state. Response to diagnostic concentration of four insecticide products demonstrated a bimodal pattern of survival to endosulfan (Phaser), suggesting two phenotype classes responding to this insecticide. This pattern was not observed with the other products. Moderately significant correlations in mortality of aphid clones treated with diagnostic concentrations of endosulfan versus clones treated with methamidophos and similarly with the correlation of mortalities for imidacloprid-treated versus methamidophos-treated clones suggested modest levels of cross tolerance. No significant correlations were observed with the remaining four possible comparisons. Concentration–response bioassays were conducted on 16 clones with the four insecticides. The greatest difference between resistant and susceptible clones (expressed as the ratio of lethal concentrations producing 50% mortality; RR) was only seven-fold observed in the endosulfan-treated clones. The greatest RR was five-fold for imidacloprid, four-fold for esfenvalerate, and three-fold for methamidophos-treated clones. Only the endosulfan response is likely to be of biological significance and reflects the same cyclodiene resistance discovered in this region over a decade ago.

Insecticide resistance in Heliothis virescens (F.) (Lepidoptera: Noctuidae) has been documented from all over the world and is often associated with reduced fitness. Fitness costs could delay the development of resistance depending upon the prevailing conditions. We were interested in establishing whether a field-collected population from Washington County, MS, was resistant to spinosad, indoxacarb, and deltamethrin and whether any such resistance was associated with fitness costs. Bioassays results showed that the insecticides were equally toxic to the field population. Upon laboratory selection (generations [G]₃ to G₈), the resistance ratio increased only 2-, 3-, and 1-fold for spinosad, deltamethrin, and indoxacarb, respectively, compared with the field population. In contrast, the resistance ratios increased 213-, 65-, and 55-fold compared with an unselected population at G₉. The estimated realized heritability (h²) after six generations of selection was 0.17, 0.03, and 0.12, respectively, and the number of generations required for 10-fold increase in LC₅₀ of Spino-SEL, Indoxa-SEL, and Delta-SEL was estimated to be 14.3, 50, and 14.3. Comparison of life traits between the selected and unselected populations revealed that the selected populations laid a significantly lower number of eggs and that a lower percentage of eggs hatched. This also was reflected in both the net replacement rate and the intrinsic rate of population increase, which were both lower for the selected populations. It also was observed that the mean relative growth rate of the larvae was lower for the selected populations; not only did the larvae take longer to pupate but the mean weight of the prepupae from the selected populations was lower. Our data suggest that due to fitness costs the development of resistance to the insecticides was limited such that after six generations of selection the larvae were no less susceptible to the insecticides than the field population although were considerable more resistant than the unselected population.

Grape phylloxera, Daktulosphaira vitifoliae (Fitch) (Hemiptera Phylloxeridae) is a damaging pest of grapevines (Vitis spp.) around the world, and the management of this pest requires early detection of infestations. Here, we describe the development and validation of a sensitive DNA test for grape phylloxera that can be applied to soil. Species-specific primers were developed for grape phylloxera in the internal transcribed space region 2, and their specificity was confirmed after thorough screening by using a wide range of vineyard organisms and aphid genera. Preliminary testing of the detection limits of the grape phylloxera-specific primers was conducted using field-sourced soil types spiked with a known number of grape phylloxera. The assay was converted to a real-time polymerase chain reaction format (TaqMan MGB). This assay, in combination with DNA extraction from soil, can detect phylloxera crawlers added to soil. The assay was evaluated in the field at a recently detected grape phylloxera infestation site from the Yarra Valley in Victoria, Australia. The DNA assay proved to be substantially more sensitive than a standard ground survey for detecting grape phylloxera presence on vine roots in the infested vineyard. Moreover, unlike the ground survey, the assay provided quantitative information on grape phylloxera infestations, because grape phylloxera DNA concentrations in samples from vines closely matched the numbers of grape phylloxera crawlers collected with emergence traps placed at the base of vines. Unlike other detection techniques, the method can be applied at any time of the year, and it can be potentially modified to provide specific information on the virulence levels of the particular grape phylloxera genotypes responsible for any new infestations.

Three species of armored scale (Hemiptera: Diaspididae) are found on kiwifruit (Actinidia spp.) in New Zealand orchards: latania scale, Hemiberlesia lataniae (Signoret); greedy scale, Hemiberlesia rapax (Comstock); and oleander scale, Aspidiotus nerii (Bouché). Each of them is a quarantine pest in some of the markets to which New Zealand kiwifruit are exported. Adult females of the three species can be distinguished morphologically; however, the task is laborious when large numbers must be identified. Furthermore, it is not possible to distinguish among the immature stages. A DNA-based diagnostic using a multiplex polymerase chain reaction (PCR) method based on differences in the cytochrome oxidase I and II genes was developed to distinguish the three species. The test relies on the rapid isolation of amplifiable DNA by using a protease (prepGEM), followed by multiplex PCR using primers that distinguish the species at three or more nucleotide positions within cytochrome oxidase I and II, resulting in PCR products of characteristic size for each species. The test was validated in a double-blind experiment and then used to determine the relative distribution and abundance of the three species on leaves and fruit of ‘Hayward’ and ‘Hort16A’ kiwifruit across the dominant growing regions throughout New Zealand during the 2007 season. In total, 3,418 scale insects were identified to species level: 1,904 (56%) were latania scale; 1,473 (43%) were greedy scale; and 41 (1%) were oleander scale. Since the last survey in 1988, latania scale has displaced greedy scale as the dominant species of armored scale on Hayward kiwifruit in the North Island and was found for the first time in the South Island. Only a single latania scale was found on Hort16A fruit, consistent with previous reports of reduced rates of settlement on the fruit of this cultivar by latania scale compared with greedy scale.

Cotton, Gossypium hirsutum L, plants expressing Cry1Ac and Cry1F (Phytogen 440W) insecticidal crystal proteins of Bacillus thuringiensis (Bt) Berliner, were evaluated against natural populations of tobacco budworm, Heliothis virescens (F.), and bollworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), across 13 southern U.S. locations that sustained low, moderate, and high infestations. The intrinsic activity of Phytogen 440W was compared with nontreated non-Bt cotton (PSC355) and with management strategies in which supplemental insecticides targeting heliothines were applied to Phytogen 440W and to PSC355 cotton. Infestations were composed primarily of bollworm, which is the least sensitive of the heliothine complex to Cry toxins. Therefore, damage recorded in these studies was primarily due to bollworm. Greater than 75% of all test sites sustained heliothine infestations categorized as moderate to high (10.6–64.0% peak damaged bolls in nontreated PSC355). Phytogen 440W, alone or managed with supplemental insecticide applications, reduced heliothine-damaged plant terminals, squares (flower buds), flowers, and bolls equal to or better (1.0–79.0-fold) than managing a non-Bt cotton variety with foliar insecticides across all infestation environments. Rarely (frequency of ≤11% averaged across structures), sprayed Phytogen 440W reduced damaged structures compared with nontreated Phytogen 440W. Protection against heliothine-induced plant damage was similar across the three levels of infestation for each viable management strategy, with exception to damaged squares for nontreated Phytogen 440W. In situations of moderate to high heliothine infestations, cotton plants expressing Cry1Ac and Cry1F may sustain higher levels of damage compared with that same variety in low infestations. No significant difference in yield was observed among heliothine management strategies within each infestation level, indicating cotton plants may compensate for those levels of plant damage. These findings indicate Phytogen 440W containing Cry1Ac and Cry1F provided consistent control of heliothines across a range of environments and infestation levels.

The toxicity to adult Sitophilus oryzae (L.) (Coleoptera: Curculionidae) of two cassia oils (Especial and true), four cinnamon oils (technical, #500, bark, and green leaf), and (E)-cinnamaldehyde and its 41 structurally related compounds was examined by residual and vapor-phase toxicity bioassays. Results were compared with those of dichlorvos. In residual bioassays, cassia and cinnamon oils exhibited good insecticidal activity. Based on 48-h LD₅₀ values, the toxicity of allyl cinnmate (0.0003 mg/cm²) was comparable with that of dichlorvos (0.00025 mg/cm²). Potent insecticidal activity also was observed with benzaldehyde, β-caryophyllene, cinnamonitrile, hydrocinnamyl acetate, (E)-4-hydroxycinnamic acid, and α-terpineol (LD₅₀ = 0.003–0.009 mg/cm²). Structure–activity relationships indicate that types of functional groups rather than hydrophobicity or vapor pressure parameters seem to play a role in determining the toxicities to adult S. oryzae. In vapor-phase toxicity tests with weevils, these compounds were more effective in closed containers than in open ones. These results indicate that the effect of the compounds was largely a result of action in the vapor phase. Cassia and cinnamon oils and test compounds described merit further study as potential fumigants for the control of S. oryzae because of their greater activity as a fumigant.

Natural insect infestation in cassava (Manihot esculenta Crantz subspecies esculenta) and yam (Dioscorea spp.) chips was evaluated during two consecutive storage seasons (2003–2004 and 2004–2005) in two agroecological zones of Benin (Northern Guinea Savanna [NGS] and Sudan Savanna [SS]). The insects infesting chips were collected, identified, and counted, they included Prostephanus truncatus (Horn) (Coleoptera: Bostrychidae), Cathartus quadricollis (Guerin) (Coleoptera: Silvanidae), Carpophilus dimidiatus (F.) (Coleoptera: Nitidulidae), Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae), and Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae). P. truncatus and C. quadricollis were observed with a higher prevalence on cassava than on yam chips. During both seasons after 3 mo of storage, all (100%) cassava chip samples were infested with P. truncatus and C. quadricollis in both agroecological zones, whereas yam chips only showed lower infestation rates of 59.5 and 19.1% for P. truncatus and C. quadricollis, respectively, at the end of storage in 2003–2004. During the 2004–2005 season after 3 mo of storage infestation rate in yam chips was 66 and 24% in NGS and 100 and 0% in SS for P. truncatus and C. quadricollis, respectively, showing that insect infestation levels vary significantly with commodity, year, and fluctuate during the storage season.

The recent recognition of psocids as a major concern in stored products and also the reemergence of heat treatment as a control tactic of stored-product insects led to the present investigation. The objectives of this study were to determine whether there are differences in heat shock tolerance of two species of stored-product psocids—Lepinotus reticulatus Enderlein (Trogiidae) and Liposcelis entomophila (Enderlein) (Liposcelididae)—and to determine whether heat shock proteins (HSPs) underlay such tolerance. Time-response bioassays were therefore carried out at increasing temperatures for both psocids. The lethal time (LT)₅₀ and LT₉₅ estimates were correlated with the expression of heat shock proteins after exposure at the same range of temperatures for 30 min. The expression of HSP was determined through Western blot analyses using HSP 70 antibody. Liposcelis entomophila was more than two-fold more tolerant than L. reticulatus for nearly all of the range of temperatures (≥40.0°C). Expression of HSP 70 was not observed for either of the psocid species, but the expression of two low-molecular-mass heat-inducible proteins (HIPs; 23 and 27 kDa) was observed in L. entomophila. The expression of these small proteins was induced by exposure to higher temperatures, and the trend was particularly strong for HIP 27. In contrast, no expression of small heat-inducible proteins was detected in L. reticulatus, reflecting its higher susceptibility to heat treatments. The relatively high heat tolerance of L. entomophila might help explain its more common occurrence in grain stored in warmer regions of the world.