Invasive species increasingly threaten ecosystems, food production, and human welfare worldwide. Hundreds of eradication programs have targeted a wide range of nonnative insect species to mitigate the economic and ecological impacts of biological invasions. Many such programs used multiple tactics to achieve this goal, but interactions between tactics have received little formal consideration, specifically as they interact with Allee dynamics. If a population can be driven below an Allee threshold, extinction becomes more probable because of factors such as the failure to find mates, satiate natural enemies, or successfully exploit food resources, as well as demographic and environmental stochasticity. A key implication of an Allee threshold is that the population can be eradicated without the need and expense of killing the last individuals. Some combinations of control tactics could interact with Allee dynamics to increase the probability of successful eradication. Combinations of tactics can be considered to have synergistic (greater efficiency in achieving extinction from the combination), additive (no improvement over single tactics alone), or antagonistic (reduced efficiency from the combination) effects on Allee dynamics. We highlight examples of combinations of tactics likely to act synergistically, additively, or antagonistically on pest populations. By exploiting the interacting effects of multiple tactics on Allee dynamics, the success and cost-effectiveness of eradication programs can be enhanced.

Synchronizing Megachile rotundata (F.) nesting activity with alfalfa bloom is essential for ensuring optimal pollination for alfalfa seed production. This is achieved by timing the initiation of spring bee incubation so that adults will emerge ∼2 wk before peak bloom. If weather conditions change so as to delay the bloom, bee managers will commonly expose the developing bees to a period of low-temperature incubation to slow their development. We have previously demonstrated survival during low-temperature incubation can be significantly increased by using a fluctuating thermal regime (FTR) where the bees receive a daily pulse at 20°C. A FTR incubation protocol is composed of a number of different components, such as the base and pulse temperatures, and the duration and frequency of the pulse. In this investigation, the effect of the duration of the pulse (5–120 min) and the frequency of a pulse (twice daily to weekly) on the survival of developing M. rotundata was examined. A pulse as short as 5 min at 20°C increased survival of the developing bees as compared with the constant 6°C controls. Increasing the pulse duration induced a further increase in tolerance to 6°C. As with the pulse duration, increasing the pulse frequency from once weekly to twice daily had a significant effect on improving the bees tolerance to low-temperature incubation. This investigation further strengthens the argument that a FTR protocol is superior to using a constant low-temperature exposure for interrupting the spring incubation of M. rotundata.

Honey bee queens mate with multiple males, which increases the total genetic diversity within colonies and has been shown to confer numerous benefits for colony health and productivity. Recent surveys of beekeepers have suggested that ‘poor queens’ are a top management concern, thus investigating the reproductive quality and mating success of commercially produced honey bee queens is warranted. We purchased 80 commercially produced queens from large queen breeders in California and measured them for their physical size (fresh weigh and thorax width), insemination success (stored sperm counts and sperm viability), and mating number (determined by patriline genotyping of worker offspring). We found that queens had an average of 4.37 ± 1.446 million stored sperm in their spermathecae with an average viability of 83.7 ± 13.33%. We also found that the tested queens had mated with a high number of drones (average effective paternity frequency: 17.0 ± 8.98). Queen “quality” significantly varied among commercial sources for physical characters but not for mating characters. These findings suggest that it may be more effective to improve overall queen reproductive potential by culling lower-quality queens rather than systematically altering current queen production practices.

Two kinds of experiments were conducted with Aethina tumida Murray larvae over four temperatures: “consumption” experiments, in which larvae and diet were weighed to determine food consumption rates under conditions of unlimited food and few conspecifics; and “competition” experiments, in which varying numbers of larvae were presented with the same amount of honey and pollen diet, and larval weight at final instar was used to determine competition effects. In consumption experiments temperature, diet and their interaction all had significant effects on the ratio of larval weight to the weight of food consumed, which was higher at 24°C than at any other temperature. In competition experiments, three relationships were examined and modeled: that between the number of larvae per experimental unit and the average weight of those larvae; that between average larval and adult weights; and that between average adult weight and survivorship to adult (emergence rate). An exponential decay function was fit to the relationship between number of larvae per experimental unit and their average weight. Average adult weight was linearly correlated with larval weight. Likewise, emergence rates for adults <11.6 mg in weight were linearly correlated with adult weights, but no significant relationship was observed for heavier adults. Using these relationships, the reproductive potential for A. tumida were estimated for a frame of honey and pollen. Information on resource acquisition by A. tumida will be useful in evaluating the impact of different factors on beetle population dynamics, such as bee hygienic behavior or control strategies used by the beekeeper.

The foraging behavior of bumble bees (Bombus impatiens Cresson) was examined as a function of feeder location containing sugar solution in a commercial tomato greenhouse in Manotick, Ontario, Canada. The feeders were located within the nest-box (fed-close) or placed 1.5 m away (fed-far) and the placement of the two types of colonies was counterbalanced over time. No effect of feeder location was found in colony activity levels or in pollen load size. A foraging trade-off between sugar solution and pollen collection, however, was found: the proportion of foraging trips in which pollen was brought back was significantly reduced for fed-far colonies, which contrasts with our laboratory study in which the opposite effect was found. We interpret our findings as possibly reflecting a limitation in pollen supply in the greenhouse: an already possibly strained ability to find and bring back pollen to the colony was accentuated by increasing the task demands of collecting sugar solution.

Thrips-transmitted Iris yellow spot virus (IYSV) (Family Bunyaviridae, Genus Tospovirus) affects onion production in the United States and worldwide. The presence of IYSV in Georgia was confirmed in 2003. Two important thrips species that transmit tospoviruses, the onion thrips (Thrips tabaci (Lindeman)) and the tobacco thrips (Frankliniella fusca (Hinds)) are known to infest onion in Georgia. However, T. tabaci is the only confirmed vector of IYSV. Experiments were conducted to test the vector status of F. fusca in comparison with T. tabaci. F. fusca and T. tabaci larvae and adults reared on IYSV-infected hosts were tested with antiserum specific to the nonstructural protein of IYSV through an antigen coated plate ELISA. The detection rates for F. fusca larvae and adults were 4.5 and 5.1%, respectively, and for T. tabaci larvae and adults they were 20.0 and 24.0%, respectively, indicating that both F. fusca and T. tabaci can transmit IYSV. Further, transmission efficiencies of F. fusca and T. tabaci were evaluated by using an indicator host, lisianthus (Eustoma russellianum (Salisbury)). Both F. fusca and T. tabaci transmitted IYSV at 18.3 and 76.6%, respectively. Results confirmed that F. fusca also can transmit IYSV but at a lower efficiency than T. tabaci. To attest if low vector competency of our laboratory-reared F. fusca population affected its IYSV transmission capability, a Tomato spotted wilt virus (Family Bunyaviridae, Genus Tospovirus) transmission experiment was conducted. F. fusca transmitted Tomato spotted wilt virus at a competent rate (90%) suggesting that the transmission efficiency of a competent thrips vector can widely vary between two closely related viruses.

The whitefly Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) is a cryptic species complex that contains some of the most damaging pests in tropical and subtropical regions. Recent studies suggested that this complex is composed of at least 24 distinct species. We use the approach from these studies to consider the identity of B. tabaci in Argentina. Previous studies have suggested the presence of a B. tabaci presumably indigenous to the Americas and referred to as the BR biotype in Argentina. We placed the entity referred to as the BR biotype within the B. tabaci cryptic species complex using whiteflies collected in soybean and bean crops in northern and central Argentina. The whiteflies were assigned using the mitochondrial cytochrome oxidase (mtCOI) gene. Four unknown haplotypes plus two Argentina sequences from GenBank formed a cluster that was basal to the rest of the New World sequences. These sequences diverged from the consensus sequence across the range of 3.6 to 4.3%. Applying the species assignment rules of recent studies suggests that the individuals from Argentina form a separate species. A fifth unknown haplotype fell within the New World putative species and formed a distinct cluster with haplotypes from Panama. These results suggest that Argentina has two indigenous species belonging to the B. tabaci cryptic species complex. Rather than using mtCOI sequencing for all B. tabaci collected, a simple random amplified polymorphic DNA-polymerase chain reaction diagnostic was used and tested along with previously published primers designed to work specifically with the BR biotype from Brazil. These primers were either unable to distinguish between the two indigenous members of the complex in Argentina or indicated a difference when none was evident on the basis of mtCOI sequence comparison.

Adult Epiphyas postvittana Walker were irradiated using a Cobalt 60 source to determine the dose needed to achieve complete egg sterility of mated female moths, and egg sterility of female moths mated to F1 generation males. Adult male and female E. postvittana were irradiated at 100, 200, 250, and 300 Gy and their fertility (when crossed with normal moths) was compared with nonirradiated moths. Viable progeny (determined by egg hatch) were found at doses of 100 and 200 Gy, but very little at 250 and 300 Gy. In particular, there was no survival of female progeny into the F1 generation. Males irradiated at 250 and 300 Gy had very low egg eclosion rates (2.25 and 1.86% at 250 and 300 Gy, respectively) when mated with normal females. The F2 generation from those male progeny had a mean percent hatched of <1.02%. Based on our results, a dose of 250–300 Gy is recommended for irradiation of E. postvittana adults used for sterile insect technique (SIT) if sterility of parental moths is the desired outcome. Our data also suggests that inclusion of F1 hybrid sterility rather than parental generation sterility into programs using the SIT may allow for doses lower than what we have reported, especially during initial phases of an eradication program where increase fitness of moths might be desirable. Further research is needed to verify the use of F1 hybrid sterility in light brown apple moth SIT programs.

A behavioral method applicable in biodegradation facilities for separation of house fly (Musca domestica L.) larvae from processed pig manure is presented. The method is based on placing a cover over the larval rearing tray, while escaping larvae are collected in collection trays. Separation units must be placed in a dark room to avoid negative phototactic responses of the larvae. After 24 h of separation, over 70% of the larvae escaped from processed manure and were collected in collection trays. Most of the larvae pupated within 48 h after separation. Mean weight of pupae recovered from manure residue was not significantly different from mean weight of pupae of separated individuals. Eclosion rate of pupae recovered from manure residue was significantly lower than eclosion of separated individuals, and was strongly related to separation success. Factors responsible for escape behavior of larvae are discussed.

ELISA techniques were used to detect imidacloprid in guttation fluid of young cantaloupe plants in Arizona. Imidacloprid was detected at up to 4.1 µg/ml (ppm) in a coincidental guttation collection 3 d after a top label rate soil application and at 37 µg/ml one d after a separate top label rate soil application study. These imidacloprid titers exceed reported median oral toxicities for several insect species by factors of 10 or more. Pesticides in guttation fluid are a relatively unexplored route of exposure for both pest and beneficial insects, and could represent an important risk for both of these groups in guttation-prone environments.

We evaluated the acute toxicities and the physiological effects of plant monoterpenoids (eugenol, pulegone, citronellal and α-terpineol) and neuroactive insecticides (malathion, dieldrin and RH3421) on flight muscle impulses (FMI) and wing beat signals (WBS) of the blow fly (Phaenicia sericata). Topically-applied eugenol, pulegone, citronellal, and α-terpineol produced neurotoxic symptoms, but were less toxic than malathion, dieldrin, or RH3421. Topical application of eugenol, pulegone, and citronellal reduced spike amplitude in one of the two banks of blow fly dorsolongitudinal flight muscles within 6–8 min, but with citronellal, the amplitude of FMIs reverted to a normal pattern within 1 hr. In contrast to pulegone and citronellal, where impulse frequency remained relatively constant, eugenol caused a gradual increase, then a decline in the frequency of spikes in each muscle bank. Wing beating was blocked permanently within 6–7 min of administering pulegone or citronellal and within 16 mins with eugenol. α-Terpineol-treated blow flies could not beat their wings despite normal FMI patterns. The actions of these monoterpenoids on blow fly flight motor patterns are discussed and compared with those of dieldrin, malathion, RH3421, and a variety of other neuroactive substances we have previously investigated in this system. Eugenol, pulegone and citronellal readily penetrate blow fly cuticle and interfere with flight muscle and/or central nervous function. Although there were differences in the effects of these compounds, they mainly depressed flight-associated responses, and acted similarly to compounds that block sodium channels and facilitate GABA action.

Evidence suggests that there are separate binding domains for type I and II pyrethroid insecticides on the voltage gated sodium channel of the nerve cell axon, but there are no studies that have examined the mixture toxicity of nonester pyrethroids and type I and II pyrethroids. Therefore, we examined the effect of nonester pyrethroid (etofenprox), type I (permethrin), and type II (cypermethrin) pyrethroid insecticides alone and in all combinations to Drosophila melanogaster Meigen. The combination of permethrin etofenprox and permethrin cypermethrin demonstrated antagonistic toxicity, while the combination of cypermethrin etofenprox demonstrated synergistic toxicity. The mixture of permethrin cypermethrin etofenprox demonstrated additive toxicity. The toxicity of permethrin cypermethrin was significantly lower than the toxicity of cypermethrin alone, but the combination was not significantly different from permethrin alone. The toxicity of permethrin cypermethrin etofenprox was significantly greater than the toxicity of both permethrin and etofenprox alone, but it was significantly lower than cypermethrin alone. The mixture of permethrin and etofenprox was significantly less toxic than permethrin. The explanation for the decreased toxicity observed is most likely because of the competitive binding at the voltage-gated sodium channel, which is supported by physiological and biochemical studies of pyrethroids. Our results demonstrate that the assumption that the mixture toxicity of pyrethroids would be additive is not adequate for modeling the mixture toxicity of pyrethroids to insects.

Both chemical and biological methods are essential for control of insects, for example, lepidopterans, on rice. Thus, it is important to know the effect of chemicals on the biological control agents. In this study, we assessed the toxicity of commonly used insecticides on a biological control agent, Trichogramma japonicum Ahmead (an egg parasitoid of rice lepidopterans) by using a dry film residue method. Results showed that thirty insecticides from seven chemical classes exhibited various degree of toxicity to this parasitoid. Among the seven classes of chemicals tested, organophosphates (chlorpyrifos, fenitrothion, phoxim, profenofos, and triazophos) and carbamates (carbaryl, carbsulfan, isoprocarb, metolcarb, and promecarb) exhibited the highest intrinsic toxicity to T. japponicum, with an LC₅₀ of 0.035 (0.029–0.044) to 0.49 (0.34–0.87) mg active ingredient (a.i.) L^-1, followed by antibiotics (abamectin, emamectin benzoate, and ivermectin), phenylpyrazoles (butane-fipronil, ethiprole, and fipronil), pyrethroids (cyhalthrin, Cypermethrin, fenpropathrin, and lambda-cyhaothrin), and neonicotinoids (acetamiprid, imidacloprid, imidaclothiz, nitenpyram, thiacloprid, and thiamethoxam). Moreover, the insect growth regulator insecticides (chlorfluazuron, fufenozide, hexaflumuron and tebufenozide) exhibited the lowest toxicity to the wasps with an LC₅₀ of 3,383 (2406–5499) to 30206 (23107–41008) mg a.i. L^-1. Risk quotient analysis showed that phenylpyrazoles, pyrethroids, insect growth regulators, neonicotinoids (with the exception of thiamethoxam), and antibiotics (with the exception of abamectin) are classified as safe agents to the parasitoid, while organophosphates and carbamates are classified as slightly, moderately, or highly toxic agents to the parasitoid. The data presented in this paper provided useful information on the selection of compatible insecticides with T. japonicum.

Domestic sheep (Ovis spp.) grazing is emerging as an integrated pest management tactic for alfalfa weevil, Hypera postica (Gyllenhal), management and a degree-day model is needed as a decision and support tool. In response to this need, grazing exclosures with unique degree-days and stocking rates were established at weekly intervals in a central Montana alfalfa field during 2008 and 2009. Analyses indicate that increased stocking rates and grazing degree-days were associated with decreased crop levels of weevil larvae. Larval data collected from grazing treatments were regressed against on-site and near-site temperatures that produced the same accuracy. The near-site model was chosen to encourage producer acceptance. The regression slope differed from zero, had an r2of 0.83, and a root mean square error of 0.2. Crop data were collected to achieve optimal weevil management with forage quality and yield. Differences were recorded in crude protein, acid and neutral detergent fibers, total digestible nutrients, and mean stage by weight. Stem heights differed with higher stocking rates and degree-days recording the shortest alfalfa canopy height at harvest. The degree-day model was validated at four sites during 2010 with a mean square prediction error of 0.74. The recommendation from this research is to stock alfalfa fields in the spring before 63 DD with rates between 251 and 583 sheep days per hectare (d/ha). Sheep should be allowed to graze to a minimum of 106 and maximum of 150 DD before removal. This model gives field entomologists a new method for implementing grazing in an integrated pest management program.

The fennel aphid, Hyadaphis foeniculi (Passerini) (Hemiptera: Aphididae) is a major pest of fennel, Foeniculum vulgare Miller in northeast region of Brazil. We hypothesize that intercropping can be used as an alternative pest management strategy to reduce aphid yield loss in fennel. Thus, we investigated the severity of fennel plant damage in relation to infestation by the fennel aphid and predation by Cycloneda sanguinea (L.) (Coleoptera: Coccinellidae) (spotless lady beetle), green lacewing, Chrysoperla cornea (Stephens) (Neuroptera: Chrysopidae), and Scymnus spp. (Coleoptera: Coccinellidae) in sole fennel plots and plots of fennel intercropped with cotton with colored fibers. The fennel aphid populations in nontreated plots were significantly larger in sole fennel plots than in intercropped plots. The highest densities of C. sanguinea, green lacewings and Scymnus spp., associated with the suppression of fennel aphid populations was found in fennel in the intercropping systems. Fennel aphids reduced the fennel seed yield by 80% in the sole fennel plots compared with ≈30% for all intercropping systems. The results obtained in this research are of practical significance for designing appropriate strategies for fennel aphid control in fennel-cotton intercropping systems. In summary, intercropping fennel with cotton with colored fibers apparently promoted biocontrol of fennel aphid in fennel.

Various pests, such as those in the order Lepidoptera, frequently feed on young maize (Zea mays) plants and pose a significant threat to plant development and survival. To manage this problem, maize generates a wide variety of responses to attack by pests, from activation of wound-response pathways to the release of volatile compounds. Mp708, an inbred line resistant to feeding by the larvae of the fall armyworm (Spodoptera frugiperda J.E. Smith Lepidoptera: Noctuidae), has been developed through traditional breeding methods, but its underlying mechanisms of resistance are still not completely understood. Mp708 has been shown to have a moderately high constitutive expression of jasmonic acid (JA) before infestation by fall armyworm. However, Tx601, a genotype susceptible to feeding by fall armyworm, activates JA pathway only in response to feeding, suggesting that Mp708 is “primed” to respond swiftly to an attack. Current research indicates that fall armyworm show a lack of preference to feeding on Mp708, leading to the hypothesis that volatiles constitutively released by the plant may also play an important role in its resistance. Analysis of volatiles released by Mp708 and Tx601 in the presence and absence of fall armyworm larvae identified (E)-β-caryophyllene, a terpenoid associated with resistance, released constitutively in Mp708. Fall armyworm fed samples of both Mp708 and Tx601 showed high transcript number of tps23, the gene responsible for the synthesis of (E)-β-caryophyllene. In addition, fall armyworm larvae show a preference for Tx601 whorl tissue over Mp708 tissue, and the dosage of Tx601 whorl with (E)-β-caryophyllene repels the fall armyworm.

Particular alkaloids produced by Neotyphodium endophytes show toxicity to invertebrates. Italian ryegrass (Lolium multiflorum Lamarck) cultivars and strains that are symbiotic with Neotyphodium endophytes have been recently established in Japan. N. uncinatum-infected Italian ryegrass lines accumulate N-formylloline, a type of loline alkaloid (1-aminopyrrolizidine) showing neurotoxicity to herbivorous insects. This study investigated the toxicity of N-formylloline and resistance of N. uncinatum-infected Italian ryegrass to vascular-sap feeding Clypeorrhynchan pests. When four vascular-sap feeding insects: Laodelphax striatellus (Fallén) (Homoptera: Delphacidae), Sogatella furcifera (Horváth) (Homoptera: Delphacidae), Cicadulina bipunctata (Melichar) (Homoptera: Cicadellidae), and Nephotettix cincticeps (Uhler) (Homoptera: Cicadellidae) fed on N. uncinatum-infected Italian ryegrass, significant decreases in survival rate were observed for three phloem-sap feeders but not for a xylem-sap feeder, N. cincticeps. This result suggests an uneven distribution of N-formylloline among plant tissues. A potency assay for N-formylloline using a Parafilm feeding sachet and a quantitative analysis of N-formylloline in plant showed a concentration-dependent lethal effect of N-formylloline on all four tested vascular-sap feeders. Our results strongly suggest that N. uncinatum-infected plants can control some Clypeorrhynchan pests in crop fields.

Aluminum phosphide, a well-known stored grain fumigant, available in solid formulation, has shown promise as wood fumigant. This chemical decomposes to phosphine when exposed to moisture. The feasibility of fumigant treatment to extend the service life of wood was evaluated in a small block test of two wood species. Hard wood (Mangifera indica L.) and conifer blocks (Pinus roxburghii Sargent) were fumigated with different concentrations (0.05, 0.1, 0.2, 0.4, 0.8, and 1.6%) of aluminum phosphide. Fumigated blocks were exposed to Lyctus africanus Lesne (Coleoptera; Lyctidae) larvae. Results revealed that aluminum phosphide showed complete mortality of Lyctus larvae at 0.2% concentration, that is, 0.93 g/m³ retention level. Mean mortality of 74% of Lyctus larvae was observed in soft wood blocks fumigated with lowest concentration, that is, 0.05% of aluminum phosphide, whereas in hard wood blocks >85% mortality was observed at this concentration.

We collected, identified, and quantified volatiles arising from individual gallery entrances of the monogamous bark beetle Dendroctonus frontalis Zimmermann. Samples were collected while the insects were mass attacking mature loblolly pines (Pinus taeda L.) in an established infestation in western Mississippi, 1 August through 3 October 2005. Following volatile sample collection, the entrances were dissected and categorized according to those that 1) contained a solitary female (the gallery initiating sex), 2) contained a pair that had not yet produced an egg gallery, 3) led to an egg gallery with niches and/or eggs, or 4) represented failed attacks (either abandoned or containing dead beetles). The greatest mean release rate of the female-produced aggregation pheromone components frontalin (74 µg/h) and trans-verbenol (0.35 µg/h) was detected from entrances of solitary females, whereas the highest mean quantities of the male-produced multifunctional pheromone components endo-brevicomin (18 ng/h) and verbenone (0.15 µg/h) were detected from entrances of preoviposition beetle pairs. Alpha-pinene, a host-produced monoterpene that functions as a synergist for the aggregation attractant for D. frontalis, was detected from entrances of solitary females and preoviposition pairs at a rate of 0.6 mg/h, or 3–4 orders of magnitude greater than the insect-produced components of the attractant. Our results indicate that the release rates of pheromone components used in published field studies of the chemical ecology of D. frontalis (generally >0.1 mg/h) represent thousands of ‘attack equivalents’ or production rates on the scale of a beetle mass attack on a single host. Additionally, our data suggest that the loss in attractiveness of host tissue fully colonized by D. frontalis is because of the disappearance of attractants rather than an increase in inhibitors.

Currently, techniques for managing western pine beetle, Dendroctonus brevicomis LeConte (Coleoptera: Curculionidae, Scolytinae), infestations are limited to tree removals (thinning) that reduce stand density and presumably host susceptibility, and/or the use of insecticides to protect individual trees. There continues to be significant interest in developing an effective semiochemicalbased tool for protecting trees from D. brevicomis attack, largely as an alternative to conventional insecticides. The responses of D. brevicomis to tree volatiles and verbenone were documented in eight experiments (trapping assays) conducted over a 4-yr period in which 88,942 individuals were collected. Geraniol, a tree volatile unique to Pinus ponderosa that elicits female-specific antennal responses in D. brevicomis, did not affect D. brevicomis behavior. Blends of two green leaf alcohols [hexanol (Z)-3-hexen-1-ol] tested at two release rates (5.0 and 100.0 mg/d) had no effect on the response of D. brevicomis to attractant-baited traps. A nine-component blend [benzaldehyde, benzyl alcohol, guaiacol, nonanal, salicylaldehyde, (E)-2-hexenal, (E)-2-hexen-1-ol, (Z)-2-hexen-1-ol, and (-) -verbenone; NAVV] and subsequent revisions of this blend disrupted the response of D. brevicomis to attractant-baited traps in all experiments. The inhibitory effect of a revised five-component blend [nonanal, (E)-2-hexenal, (E)-2-hexen-1-ol, (Z)-2-hexen-1-ol, and (-)-verbenone; NAVV5] on the response of mountain pine beetle, D. ponderosae Hopkins, to attractant-baited traps was also documented. Acetophenone significantly reduced D. brevicomis attraction, but was not as effective as verbenone alone. Acetophenone increased the effectiveness of NAVV5 in one of two experiments. Furthermore, by adding acetophenone to NAVV5 we were able to remove the aldehydes from NAVV5 without compromising effectiveness, resulting in a novel four-component blend [acetophenone, (E)-2-hexen-1-ol (Z)-2-hexen-1-ol, and (-)-verbenone; Verbenone Plus]. We discuss the implications of these and other results to development of Verbenone Plus as a semiochemical-based tool for management of D. brevicomis and D. ponderosae infestations.

Host plant species can affect the behavior and attributes of parasitoids, such as host searching, oviposition, and offspring fitness. In this study, parasitism, host feeding, and sex ratios of Diglyphus isaea (Walker) (Hymenoptera: Eulophidae) on Liriomyza huidobrensis (Blanchard), Liriomyza sativae Blanchard, and Liriomyza trifolii (Burgess) (Diptera: Agromyzidae) larvae reared on Phaseolus vulgaris L., Pisum sativum L., Solanum lycopersicum L., and Vicia faba L. were determined. In no-choice tests, L. huidobrensis had the highest rate of parasitism when reared on P. vulgaris (46%), L. sativae when reared on V. faba (59%) and P. vulgaris (59%), and L. trifolii when reared on S. lycopersicum (68%). Host feeding in no-choice tests ranged between 2% and 36% and was highest on L. trifolii reared on V. faba. Results of choice tests showed a significant interaction effect for host plant and Liriomyza species on parasitism and host feeding. Within plant mixtures, L. sativae reared on P. vulgaris had the highest rate of parasitism (31%), followed by L. trifolii on S. lycopersicum (29%) and L. huidobrensis on V. faba (28%). Host feeding was highest on L. trifolii reared on S. lycopersicum (14%) and lowest on L. huidobrensis reared on P. sativum and S. lycopersicum (1%). In some instances, plant mixtures resulted in a higher proportion of females of D. isaea than single plant species. The highest proportion of females was obtained in plant mixtures on L. huidobrensis and L. trifolii on V. faba (71 and 72%, respectively). This study suggests that planting crop mixtures can potentially lead to higher proportions of females, thus improving parasitism and host feeding, depending on Liriomyza and host plant species.

Root weevils in the genus Otiorhynchus are cited as one of the most important pests in the major nursery and small fruit production areas throughout the United States, western Canada, and northern Europe. A major problem in combating weevil attack is monitoring and timing of control measures. Because of the night-activity of the adult weevils growers do not observe the emerging weevils in a timely manner and oviposition often starts before effective control measures are taken. Several vine weevil electroantennogram-active plant volatiles were identified from a preferred host plant, Euonymus fortunei. Main compounds evoking antennal responses on the weevils' antennae were (Z)-2-pentenol, (E)-2-hexenol, (Z)-3-hexenol, methyl benzoate, linalool, (E)-4,8-dimethyl-1,3,7-nonatriene, methyl eugenol, and (E, E)-α-farnesene. Several of these compounds were tested alone and in mixtures on attractiveness for the vine weevil Otiorhynchus sulcatus (F.) in field-grown strawberry in Oregon. O. sulcatus were attracted to (Z)-2-pentenol (≈3× more than control) and a 1:1 ratio mixture of (Z)-2-pentenol and methyl eugenol (4.5× more than control). This is the first report of field-active attractants for O. sulcatus which holds promise for the development of new monitoring strategies for growers in the near future.

The effect of irrigation on the abundance of Empoasca vitis (Göthe) populations was investigated in four vineyards located in northeastern Italy. In two experiments, we compared leafhopper population densities in plots irrigated (micro-spray irrigation system) or nonirrigated. In another experiment, we studied the effect of various irrigation systems on E. vitis populations over two successive seasons. In particular, five treatments were compared: control (not irrigated), traditional drip system, three types of subirrigation varying in distance from the row (40, 135, and 95 cm). In this vineyard, stem water potential was monitored with a pressure chamber. E. vitis population densities were affected by irrigation, with higher densities of this pest recorded on irrigated vines. Highest E. vitis densities were detected in drip irrigation plots compared with nonirrigated plots where water stress was highest. Moderate water stress (subirrigation plots) was associated with intermediate leafhopper densities. Implications for integrated pest management are discussed.

The biology of olive fruit fly, Bactrocera oleae (Rossi), was studied in the laboratory, greenhouse, and in canning olives, Olea europaea L., in relation to California regional climates. Adults survived in laboratory tests at constant temperatures and relative humidities of 5°C and 83%; 15°C and 59%; 25°C and 30%; and 35°C and 29% for 15, 6, 3, and 2 d without provisions of food and water and for 37, 63, 25, and 4 d with provisions, respectively. In a divided greenhouse, adults survived for 8–11 d in the warm side (36°C and 31% RH daytime) ; and in the cool side (26°C and 63% RH daytime) 10 d without provisions and 203 d with provisions. A significantly greater number of adults survived in the cool side than the warm side, and with provisions than without. First and last eggs were oviposited in olive fruit when females were 6 and 90 d old, respectively. The highest number of eggs was 55 per day in 10 olive fruit oviposited by 10 28 d-old females, with maximum egg production by 13–37 d-old females. A significantly greater number of ovipositional sites occurred in all sizes of immature green fruit when exposed to adults in cages for 5 d than 2 d. Adults emerged from fruit with a height of a 1.0 cm or a volume of ≥0.2 cm³. More than seven adults per 15 fruit emerged from field infested fruit with a height of 1.1 cm and volume of 0.1 cm³. Larval length was significantly different among the first, second, and third instars and ranged from 0.7 to 1.6, 2.4–4.3, and 4.8–5.6 mm at 14°C; 0.8–1.1, 1.9–2.9, and 3.9–4.4 mm at 21°C, and 0.7–1.3, 2.4–2.9, and 4.4–4.8 mm at 26°C, respectively. Survival of pupae to the adult stage was significantly lower at 26°C than 14°C or 21°C. The period of adult emergence began at 38, 14, and 11 d over a period of 8, 5, and 1 d at 14, 21, and 26°C, respectively. Findings were related to the occurrence and control of California olive fruit fly infestations.

Emerald ash borer, Agrilus planipennis (Fairmaire) (Coleoptera: Buprestidae), plays a significant role in the health and extent of management of native North American ash species in urban forests. An economic analysis of management options was performed to aid decision makers in preparing for likely future infestations. Separate ash tree population valuations were derived from the i-Tree Streets program and the Council of Tree and Landscape Appraisers (CTLA) methodology. A relative economic analysis was used to compare a control option (do-nothing approach, only removing ash trees as they die) to three distinct management options: 1) preemptive removal of all ash trees over a 5 yr period, 2) preemptive removal of all ash trees and replacement with comparable nonash trees, or 3) treating the entire population of ash trees with insecticides to minimize mortality. For each valuation and management option, an annual analysis was performed for both the remaining ash tree population and those lost to emerald ash borer. Retention of ash trees using insecticide treatments typically retained greater urban forest value, followed by doing nothing (control), which was better than preemptive removal and replacement. Preemptive removal without tree replacement, which was the least expensive management option, also provided the lowest net urban forest value over the 20-yr simulation. A “no emerald ash borer” scenario was modeled to further serve as a benchmark for each management option and provide a level of economic justification for regulatory programs aimed at slowing the movement of emerald ash borer.

Baseline toxicity levels to a novel semicarbazone insecticide, metaflumizone were established for 25 field populations of Colorado potato beetle, Leptinotarsa decemlineata Say (Coleoptera: Chrysomelidae), from North America. Excluding the susceptible laboratory strain, 50% lethal concentrations of metaflumizone ranged from 0.57 to 1.31 ppm, while response slopes ranged from 1.92 to 4.24 (average = 2.93), and were unrelated to the 50% lethal concentration (r = 0.06; P = 0.76). Beetle populations with known resistance to the neonicotinoid imidacloprid also exhibited the highest LC₅₀ levels to metaflumizone suggesting at least the possibility of cross-resistance. Additional experiments using a potato leaf-dip bioassay as well as field efficacy evaluations confirmed the high level of toxicity of metaflumizone to L. decemlineata and demonstrated a potential benefit of tank mixing a low rate of the pyrethroid esfenvalerate with metaflumizone at one-tenth the recommended field rate. These research findings confirm that metaflumizone is highly active against L. decemlineata larvae and adults and could provide an effective alternative insecticide for potato pest management.

Maize hybrids expressing the Cry1F toxin provide efficient control of lepidopteran pests. The Mediterranean corn borer, Sesamia nonagrioides (Lefèvre), is one of the most damaging pests of maize in the Mediterranean basin. In this work we firstly determined the efficacy of maize hybrids expressing the Cry1F toxin (event TC1507) to control neonates of S. nonagrioides. Leaf tissue feeding bioassays revealed that TC1507 maize is highly effective against this pest, and the percentage mortality obtained was comparable to that obtained with a Cry1Ab-expressing maize hybrid (Compa CB, event 176), which is known to be highly efficacious against S. nonagrioides. Secondly, interpopulation variation in the susceptibility to the Cry1F insecticidal protein was established for nine field-collected populations of S. nonagrioides (three Spanish, two French, two Italian, one Greek, and one Turkish). Estimates of the susceptibility of larvae to the Cry1F toxin showed low variability in lethal concentrations and growth inhibition concentrations among field populations. Moreover, no significant differences were found when they were grouped by geographical areas [Western Mediterranean (Spain and France) versus Eastern Mediterranean (Italy, Greece and Turkey)] or by history of exposure to Bt plants (Spanish vs. other populations). Therefore, the minor differences found in field populations can be attributed to natural variation in sensitivity to Cry1F. The importance of establishing baselines of susceptibility for resistance detection is discussed. Future changes in susceptibility of S. nonagrioides populations to Cry1F could be documented based on this baseline data.

An emulsifiable concentrate (EC) and granular (G) formulation of the entomopathogenic fungus, Metarhizium brunneum strain F52 (formerly Metarhizium anisopliae strain F52) were tested against unfed adults and nymphs of Ixodes scapularis Say in the laboratory. Three exposure methods; dip, surface contact, and direct spray application, and three exposure time intervals (3, 30, and 300 min) were used to evaluate the EC formulation. Application rates ranged from 2.6 × 10² to 2.6 × 10⁸ conidia/cm². The surface treatment was used for granular formulation with concentrations ranging from 2.3 × 10⁵ to 2.3 × 10⁷ conidia/cm² for same three exposure times. Both the EC and G formulations of this fungus were highly pathogenic against I. scapularis adults and nymphs. Logistic regression analysis found formulation, spore concentration, time of exposure, and observation period were significant or highly significant factors influencing tick mortality. For adult I. scapularis, the spray application with the EC formulation of M. brunneum F52 resulted in a lower LC₅₀ (5.9 × 10⁴ conidia/cm²) at 30 min than surface exposure to the EC (LC₅₀ = 1.3 × 10⁶ conidia/cm²) or G formulation (LC₅₀ = 8.1 × 10⁵ conidia/cm²). At higher concentrations, fungal activity was evident in adult I. scapularis held at 5°C suggesting the fungus may provide control in the cooler fall season. While the observed pathogenicity of a fungus against ticks can be dependent upon the bioassay assessment, we found nymphs and adults of I. scapularis to be highly susceptible to M. brunneum F52, regardless of the exposure method used.

DNA methylation is a general epigenetic mechanism for plants, animals, and fungi to adapt to environmental variation. Two biotypes of the Russian wheat aphid (Diuraphis noxia), Biotype 1 and Biotype 2, have different virulence to host plants. In this study, in addition to a high polymorphism, DNA methylation at cytosines were observed in genomic fragments of four genes in Biotype 1 and Biotype 2, after the genomic DNA was treated with sodium bisulfite. These genes presumably encode proteins and enzymes in salivary glands of aphids. The two Biotype 1 showed different methylation levels, that is, Biotype 1 showed a higher methylation on the four genes. Two thirds of methyl cytosines were in a sequence context of CHH (H = A, C, or T). Some polymorphism and methylation sites were located at important positions in terms of enzyme function, such as close to catalytic residues or inhibitor binding residues. These findings may provide clues to explore the evolutionary mode between Russian wheat aphid virulence and resistance genes of host plants.

The Mediterranean group (commonly known as Q biotype; hereafter MED) of the sweetpotato whitefly, Bemisia tabaci (Gennadius), originated in the Mediterranean region, but it now has been found in at least 10 countries outside the Mediterranean. Collections of B. tabaci from some of these countries exhibit different pest behaviors and pesticide resistance characteristics, yet all may be classified as MED. A phylogenetic analysis of 120 mitochondrial cytochrome oxidase I (mtCOI) sequences (JN966761–JN966880) of MED whiteflies collected in Arizona and of 417 retrieved from the GenBank database resolves the MED into five subclades, designated as Q1–Q5. Only subclades Q1 and Q2 have been detected in the United States. Q1 and the other four subclades (Q2–Q5) differ in the number or position of the AluI recognition sites. Based on the differences in the AluI recognition sites reported here and the previously reported differences in VspI recognition sites, we developed a simple diagnostic technique to identify subclades Q1–Q5 by using mtCOI polymerase chain reaction (PCR) -restriction fragment-length polymorphism (RFLP). A test of a worldwide collection of whiteflies demonstrates that this combination mtCOI PCR-RFLP technique can reliably distinguish not only the MED from the Middle East-Asia Minor 1 group but also the Q1 from any of the other four MED subclades.

Aphis glycines Matsumura (Hemiptera: Aphididae) can reduce the yield of aphidsusceptible soybean (Glycine max (L.) Merrill) cultivars. The Rag1 and Rag2 genes confer resistance to some biotypes of A. glycines. These genes individually can limit population growth of A. glycines and prevent yield loss. The impact of these genes when combined is not known. We compared the development of A. glycines on soybean with Rag1 alone (R1/S2), Rag2 alone (S1/R2), both genes combined (R1/R2), or neither gene (S1/S2). In addition, we determined the impact of different levels of aphid infestation on seed yield. The genotypes were grown in cages and artificially infested with A. glycines to achieve five treatment levels: aphid-free, 675 aphids per plant, 25,000 cumulative aphid days (CAD) (25K), 50,000 CAD (50K), and 75,000 CAD (75K). The S1/S2 line reached the 50K treatment, but did not reach the 75K treatment. Aphid development on R1/S2 and S1/R2 soybeans after two infestations reached a maximum of 25K. The maximum treatment reached on R1/R2 was only 675 aphids per plant after two infestations, at which there was no significant yield reduction when compared with the aphid-free treatment. The maximum yield reduction of S1/S2 was 27% at 50K treatment compared with 2% for R1/S2 and 12% for S1/R2 at the 25K treatment. Our results indicated that for A. glycines used in our study, cultivars with both Rag1 and Rag2 had less aphid exposure and less yield reduction than soybeans with only one resistant gene.

The soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), is an economically important pest of soybean, Glycine max (L.) Merrill, in the United States. Phenological information of A. glycines is limited; specifically, little is known about factors guiding migrating aphids and potential impacts of long distance flights on local population dynamics. Increasing our understanding of A. glycines population dynamics may improve predictions of A. glycines outbreaks and improve management efforts. In 2005 a suction trap network was established in seven Midwest states to monitor the occurrence of alates. By 2006, this network expanded to 10 states and consisted of 42 traps. The goal of the STN was to monitor movement of A. glycines from their overwintering host Rhamnus spp. to soybean in spring, movement among soybean fields during summer, and emigration from soybean to Rhamnus in fall. The objective of this study was to infer movement patterns of A. glycines on a regional scale based on trap captures, and determine the suitability of certain statistical methods for future analyses. Overall, alates were not commonly collected in suction traps until June. The most alates were collected during a 3-wk period in the summer (late July to mid-August), followed by the fall, with a peak capture period during the last 2 wk of September. Alate captures were positively correlated with latitude, a pattern consistent with the distribution of Rhamnus in the United States, suggesting that more southern regions are infested by immigrants from the north.

Emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), a phloemfeeding pest of ash (Fraxinus spp.) trees native to Asia, was first discovered in North America in 2002. Since then, A. planipennis has been found in 15 states and two Canadian provinces and has killed tens of millions of ash trees. Understanding the probability of detecting and accurately delineating low density populations of A. planipennis is a key component of effective management strategies. Here we approach this issue by 1) quantifying the efficiency of sampling nongirdled ash trees to detect new infestations of A. planipennis under varying population densities and 2) evaluating the likelihood of accurately determining the localized spread of discrete A. planipennis infestations. To estimate the probability a sampled tree would be detected as infested across a gradient of A. planipennis densities, we used A. planipennis larval density estimates collected during intensive surveys conducted in three recently infested sites with known origins. Results indicated the probability of detecting low density populations by sampling nongirdled trees was very low, even when detection tools were assumed to have three-fold higher detection probabilities than nongirdled trees. Using these results and an A. planipennis spread model, we explored the expected accuracy with which the spatial extent of an A. planipennis population could be determined. Model simulations indicated a poor ability to delineate the extent of the distribution of localized A. planipennis populations, particularly when a small proportion of the population was assumed to have a higher propensity for dispersal.

With the phase-out and impending ban of methyl bromide, sulfuryl fluoride is among the most promising alternative fumigant insecticides for control of stored-product insect pests. It has been evaluated for control of several stored-product insect pests, but there are few data available on its efficacy for control of stored-product psocids (Psocoptera). We evaluated sulfuryl fluoride for control of different life stages of the psocids Liposcelis paeta Pearman, L. entomophila (Enderlein), L. bostrychophila Badonnel, L. decolor Pearman, and Lepinotus reticulatus Enderlein (Trogiidae) in 48-hr trials at 27.5 °C Adults and nymphs were susceptible to sulfuryl fluoride. Complete (100%) adult and nymphal mortality was recorded at concentrations between 4 and 8 g/m³, except for L. decolor for which all adults were only killed at 24 g/m³. Eggs were tolerant to sulfuryl fluoride. Complete egg mortality was achieved at 24 and 72 g/m³ for L. reticulatus and L. decolor, respectively. Survival of L. paeta eggs was recorded even after exposure to 96 g/m³. Given that the highest United States label concentration for sulfuryl fluoride for a 48-h exposure interval is 31.25 g/m³, our study indicates that high doses and/or longer exposures are needed for complete mortality of eggs of L. decolor and L. paeta. Moreover, the present work suggests that there is considerable variation in efficacy of sulfuryl fluoride for control of different psocid species.

Spodoptera litura (F.) larvae were fed with artificial food containing four different concentrations of copper (25, 50, 100, and 200 mg/kg). Copper affected growth, development, and population dynamics of late instar larvae. Our results indicate that the fourth and fifth instar survival rates were significantly reduced at 50–200 mg/kg copper (Cu² ). Moreover, all the Cu² treatments significantly reduced pupation and moth emergence rates in a dose-dependent manner. Larvae fed 25 or 50 mg/kg Cu² showed significant reductions in development period compared with non-Cu controls, and the pupation duration of animals fed 200 mg/kg was significantly longer than in non-Cu controls. All Cu² concentrations significantly reduced individual pupal weights compared with controls. In addition, Cu² at some concentrations significantly affected fertility parameters, such as doubling population time (DT), the net reproduction rate (R₀), the mean generation time (T), the intrinsic rate of increase (r_m), and the finite increase rate (λ). Our study demonstrates that low concentrations of Cu² in the diet (25 and 50 mg/kg) shorten the generation time by 4–5 d, whereas higher Cu² concentrations (100 and 200 mg/kg) increase DT for 1–2 d.