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Neonicotinoid insecticides are used to manage spotted lanternfly (Lycorma delicatula (White); hereafter SLF), a recently introduced pest in the United States. Neonicotinoids can harm nontargets, such as pollinators potentially exposed via floral resources of treated plants. We quantified neonicotinoid residues in whole flowers of two SLF host plant species, red maple (Acer rubrum L. [Sapindales: Sapindaceae]) and tree-of-heaven (Ailanthus altissima (Mill.) [Sapindales: Simaroubaceae]), treated with post-bloom imidacloprid or dinotefuran applications that differed in timing and method of application. In red maple flowers, dinotefuran residues from fall applications were significantly higher than summer applications, while imidacloprid residues from fall applications were significantly lower than summer applications. Residues did not differ between application methods or sites. In tree-of-heaven flowers, dinotefuran residues were only detected in one of 28 samples at a very low concentration. To assess acute mortality risk to bees from oral exposure to residues in these flowers, we calculated risk quotients (RQ) using mean and 95% prediction interval residue concentrations from treatments in this study and lethal concentrations obtained from acute oral bioassays for Apis mellifera (L. (Hymenoptera: Apidae)) and Osmia cornifrons (Radoszkowski (Hymenoptera: Megachilidae)), then compared these RQs to a level of concern. For A. mellifera, only one treatment group, applied at 2X maximum label rate, had an RQ that exceeded this level. However, several RQs for O. cornifrons exceeded the level of concern, suggesting potential acute risk to solitary bees. Further studies are recommended for more comprehensive risk assessments to nontargets from neonicotinoid use for SLF management.

Since 2000, wild black cherry (Prunus serotina Ehrh.) has produced erratic seed crops, especially in the Allegheny National Forest where poor seed production has been implicated in difficulties with black cherry regeneration in forest stands. Given that black cherry is insect pollinated and unable to produce viable seed from self-pollination, a reduction in seed crops could be due to a pollination deficit; however, its key pollinators are unknown. Identifying the pollinators and factors that influence pollinator abundance and fidelity is critical for supporting and enhancing seed production for this valuable timber species. Over a two-year period in developed, semideveloped, and forested areas in Pennsylvania, we identified the potential pollinators of black cherry and examined how their abundance, along with several other abiotic and biotic factors, influenced viable seed production. We found that andrenid (Andrenidae: Hymenoptera) bees are likely the most important pollinators. The proportion of viable seeds increased as the number of andrenids increased, and these ground nesting bees were most abundant on forest edges, highlighting this habitat’s potential to support pollination services. Andrenids carried an average of 347-fold more black cherry pollen than flies and 18-fold more than halictid (Halictidae: Hymenoptera) bees. We did not find a significant relationship between the abundance of any other taxa besides andrenids and viable seed production. Black cherry flowers also provide resources for natural enemies such as the economically important parasitoid of Popillia japonica Newman (Scarabaeidae: Coleoptera), Tiphia vernalis Rohwer (Tiphiidae: Hymenoptera), which was observed feeding on black cherry nectar in this study.

The spotted lanternfly, Lycorma delicatula (Hemiptera: Fulgoridae) (White, 1845), is an invasive pest in the Mid-Atlantic region of the United States. Understanding this pest’s dispersion patterns is fundamental for development of management and surveillance programs. To address this knowledge gap, we quantified spotted lanternfly nymph dispersion patterns by instar for rural and urban/suburban habitats, and we compared the number of sample units required for sticky traps and in situ visual counts to estimate population densities at several precisions. In addition, we assessed the ability of two experimental designs (completely random and randomized complete block) to detect management practices’ impacts in the field. All instars typically followed an aggregated dispersion pattern. Sample size and time requirements for checking and replacing sticky traps and for conducting in situ counts were similar, but in situ counts do not require purchasing traps, installation time, or delays before treatment, and do not remove insects. Although the cost for using in situ counts is likely less than for sticky traps, early instar spotted lanternfly nymph populations are harder to visually detect than later instars because of their small size, which may negate any cost advantage when treatments are applied early. In general, using a randomized complete block design resulted in higher statistical power than a completely random design, allowing detection of proportional population reductions of 10–20% less with equal replication. Studies aiming to evaluate treatments that reduce spotted lanternfly numbers by less than 60% will require researchers to evaluate the feasibility of using the required large sample sizes.

Plant chemistry plays an important role in mediating resistance against insect herbivores. Depending on insect species and feeding strategies, plant defenses can prevent insect attacks, impact digestive physiology and influence reproductive output. The Asian longhorned beetle (Anoplophora glabripennis) is an invasive, tree-killing insect that exploits multiple host plant species. Anoplophora glabripennis is documented to attack Populus spp., but the ability for adults to consume Populus varies between beetle populations. In this study, we explored the influence of salicinoid phenolic glycosides, known to be potent chemical defenses in Populus against generalist insects, on A. glabripennis adult behavior and fecundity. We performed a series of choice- and no-choice experiments using extracts of salicinoids applied to plants that do not produce these compounds. Salicinoids affected A. glabripennis performance in a dose-dependent manner, with higher concentrations significantly reducing feeding. Egg development was reduced by > 90% in females fed salicinoids at ~ 1.3% dry weight. We then compared salicinoids present in feeding material vs. frass and found both a decrease in concentration and a shift in composition of these compounds. However, some of the more complex salicinoids were unchanged in the excrement, suggesting minimal detoxification had occurred. Our results show that salicinoids disrupt egg development in A. glabripennis, thereby reducing fitness. These results have implications for how A. glabripennis metabolizes plant defense chemicals and how tolerance may vary among populations.

Insects possess specific immune responses to protect themselves from different types of pathogens. Activation of immune cascades can inflict significant developmental costs on the surviving host. To characterize infection kinetics in a surviving host that experiences baculovirus inoculation, it is crucial to determine the timing of immune responses. Here, we investigated time-dependent immune responses and developmental costs elicited by inoculations from each of two wild-type baculoviruses, Autographa californica multiple nucleopolyhedrovirus (AcMNPV) and Helicoverpa zea single nucleopolyhedrovirus (HzSNPV), in their common host H. zea. As H. zea is a semi-permissive host of AcMNPV and fully permissive to HzSNPV, we hypothesized there are differential immune responses and fitness costs associated with resisting infection by each virus species. Newly molted 4th-instar larvae that were inoculated with a low dose (LD15 ) of either virus showed significantly higher hemolymph FAD-glucose dehydrogenase (GLD) activities compared to the corresponding control larvae. Hemolymph phenoloxidase (PO) activity, protein concentration and total hemocyte numbers were not increased, but instead were lower than in control larvae at some time points post-inoculation. Larvae that survived either virus inoculation exhibited reduced pupal weight; survivors inoculated with AcMNPV grew slower than the control larvae, while survivors of HzSNPV pupated earlier than control larvae. Our results highlight the complexity of immune responses and fitness costs associated with combating different baculoviruses.

Management of the European gypsy moth [Lymantria dispar dispar (Linnaeus)] in North America has benefited from more than a century of research. The East Asian strains of the gypsy moth, however, bring new challenges including multiple subspecies (Lymantria dispar asiatica Vnukovskij and Lymantria dispar japonica Motschulsky), broad distributions across heterogeneous habitats, and a lack of data on the variation in the phenology of source populations, which may affect risk. To address these issues, published phenology parameters for eight populations of Asian gypsy moth were used to develop eight strain-specific agent-based phenological models. These models were applied to 47 ports in East Asia where the Asian gypsy moth is native, and output was compared with available trap data to assess the role of interpopulation variation in phenological parameters in predicting moth flight among varied locations, assess variation in the performance of models among years, and assess the importance of modeling phenology using parameters from a ‘local’ moth population. Variation in phenological parameters among the eight populations yielded variation in predicted flight times among the 47 ports analyzed, and the use of ‘local’ populations did not generally improve model fit. Model accuracy varied substantially among ports and among years within some ports. The larva-to-adult agent-based models described here have utility in estimating flight periods for some ports in their current form, but variation in model quality across the landscape suggests that there is potential for unsampled and unparameterized moth populations and factors that remain to be quantified.

The spotted lanternfly, Lycorma delicatula (White), is a new invasive pest in the United States. To quantify spotted lanternfly population abundance, one must understand this pest’s dispersion pattern, that is, the spatial arrangement of individuals within a population. Spotted lanternflies overwinter in egg masses from late fall to May, making this life stage suitable for population assessments. We measured the dispersion pattern of egg masses at two types of sites: a suburban housing development, where we used individual trees as the sampling unit, and rural woodlots, where we used individual trees and also plots with 5.64 m radius as sampling units. Plots were the same size as those recommended for monitoring the gypsy moth, a well-studied pest with similar egg laying habit to the spotted lanternfly. Egg masses in both sampling units were counted up to a height of 3 m. With trees as the sampling unit, egg masses were aggregated in 12 of 20 rural sampling universes, randomly dispersed at 6, and completely absent at 2. Similar patterns were seen when using the 5.64-m radius rural sampling units and for suburban sampling universes. We calculated sample size requirements for a range of mean densities at a precision of 25 and 30%. Additionally, the vertical distribution of egg masses was characterized on the invasive tree of heaven [Ailanthus altissima (Mill.) Swingle], a preferred host for spotted lanternflies. For small trees, there was a positive relationship between number of egg masses in the bottom 3 m of the tree and the total count.

Spotted lanternfly (Lycorma delicatula) is a recently introduced pest in the United States, where it threatens the wine, timber, and ornamentals industries. Knowledge of the dispersal ability of L. delicatula is key to developing effective management strategies for this invasive pest. We conducted a mark, release, re-sight study, marking nymphs with fluorescent powders and observing dispersal distances from a central release point at three time points over 7 d following release. To examine how dispersal patterns changed over the course of nymphal development, we repeated this process for each of L. delicatula’s four instars. All releases were conducted in contiguous, deciduous forest, which is a widespread habitat type within L. delicatula’s invaded range and a habitat where this pest may have negative ecological and economic impacts. We found that nymphs displayed clear directionality in their movement following release, apparently preferring to move uphill on the modest 6° grade at our release site. Most nymphs remained near the release location, while some moved tens of meters. The maximum displacement we observed was 65 m from the release point, 10 d after release. Nymphs were re-sighted singly and in small groups on a variety of trees, shrubs, and understory vegetation. All four instars had similar dispersal distances over time, though third instar nymphs moved farthest on average, with estimated median displacement of 16.9 m 7 d after release. Further studies are needed to provide additional information on what factors influence spotted lanternfly dispersal.

Despite its broad host range, the spotted lanternfly Lycorma delicatula (White), is known to have a marked preference for Ailanthus altissima. However, whether this polyphagous phloem feeder can complete its life cycle in the absence of A. altissima is unknown. We examined the performance of L. delicatula with and without access to A. altissima by tracking development, survival, host tree species association, and oviposition in large enclosures planted with Salix babylonica and Acer saccharinum along with either A. altissima or Betula nigra. We monitored enclosures from late May 2019 through June 2020. Lycorma delicatula survival was slightly higher in enclosures with A. altissima and 50% of individuals in A. altissima enclosures reached the adult stage ~6.5 d earlier than in enclosures without A. altissima. In the presence of A. altissima, nymphs were most frequently observed on this host while adults were found at similar frequencies on A. altissima and A. saccharinum. In the absence of A. altissima, nymphs were most frequently associated with S. babylonica and A. saccharinum, while adults were most often found on A. saccharinum. Females laid a total of 46 and 6 egg masses in enclosures with and without A. altissima, respectively, before freezing temperatures killed the remaining adults. The proportion of eggs that hatched per egg mass did not differ between treatments. Although L. delicatula can complete development and reproduce on other host species without access to A. altissima, fitness was reduced. These findings have implications for management that relies exclusively on treatment of A. altissima.

Insect herbivores possess a diverse and abundant gut microbiota that may influence plant growth in nature. The application of plant beneficial bacteria to improve agricultural production and soil quality has long been of interest. Thus, these insect-associated microbiota have the potential to be developed into effective bio-fertilizers. The bacterium, Enterobacter ludwigii, was isolated from the regurgitant of field-collected tomato fruitworm, Helicoverpa zea. The bacterium can be secreted by the insect onto tomato seeds during fruit feeding and is also commonly found in the soil. We applied E. ludwigii to germinated tomato seeds and measured tomato plant growth and productivity under controlled greenhouse conditions. Since there are often trade-offs between plant growth and plant defenses, we examined whether the E. ludwigii-mediated faster growth corresponds with weaker anti-herbivore defenses. When E. ludwigii was applied to germinated tomato seeds, the plants exhibited faster root, shoot and hypocotyl growth, and produced more fruits and seeds than untreated control plants. The plants treated with bacteria exhibited the same activity levels of two key enzymes involved in anti-herbivore defenses, polyphenol oxidase and peroxidase, and induced the same levels of mortality and growth inhibition in H. zea larvae as untreated plants. Thus, our results demonstrate that the application of E. ludwigii to seeds can promote tomato plant growth and yield without compromising anti-herbivore defenses.

Insect guts harbor diverse microbial assemblages that can be influenced by multiple factors, including gut physiology and interactions by the host with its environment. The Asian longhorned beetle (A. glabripennis; Cerambycidae: Lamiinae) is an invasive tree-killing insect that harbors a diverse consortium of fungal and bacterial gut associates that provision nutrients and facilitate lignocellulose digestion. The physicochemical conditions of the A. glabripennis gut and how these conditions may influence the microbial composition across gut regions are unknown. In this study, we used microsensors to measure in situ oxygen concentrations, pH, and redox potential along the length of the A. glabripennis larval gut from two North American populations. We then analyzed and compared bacterial and fungal gut communities of A. glabripennis within individual hosts along the length of the gut using 16S and ITS1 amplicon sequencing. The A. glabripennis midgut lumen was relatively anoxic (0.01kPa) with a pH gradient from 5.5 to 9, moving anterior to posterior. Redox potential was higher in the anterior midgut relative to posterior regions. No differences in physicochemistry were measured between the two populations of the beetle, but the two populations harbored different communities of bacteria and fungi. However, microbial composition of the A. glabripennis gut microbiota did not differ among gut regions despite physicochemical differences. Unlike other insect systems that have distinct gut compartmentalization and corresponding microbial assemblages, the A. glabripennis gut lacks dramatic morphological modifications, which may explain why discrete microbial community structures were not found along the digestive system.

Periodic introductions of the Asian subspecies of gypsy moth, Lymantria dispar asiatica Vnukovskij and Lymantria dispar japonica Motschulsky, in North America are threatening forests and interrupting foreign trade. Although Asian gypsy moth has similar morphology to that of European and North American gypsy moth, it has several traits that make it a greater threat, the most important being the flight capability of females. Asian gypsy moth is not yet established in North America; however, infestations have been detected multiple times in Canada and the United States. To facilitate detection and eradication efforts, we evaluated the effect of a range of temperatures on development time, survivorship, and fertility of eight populations of Asian gypsy moth. There were significant impacts of temperature and population on these life history characteristics. The larval developmental rate increased with temperature until it reached an optimum at 29 °C. Larvae experienced significant molting problems at the highest and lowest temperatures tested (10 °C and 30 °C). At 30 °C, female fitness was markedly compromised, as evidenced by reduced fecundity and fertility. This suggests that development and survival of Asian gypsy moth may be limited by summer temperature extremes in the Southern United States. We also determined the degree-day requirements for two critical life stages and two populations of Asian gypsy moth, which represent the extremes in latitude, to predict the timing for biopesticide application and adult trap deployment. Our data will benefit pest managers in developing management strategies, pest risk assessments, and timing for implementation of management tactics.

Electrophysiological recordings from the labial and maxillary palps of the Asian longhorned beetle, Anoplophora glabripennis, revealed their ability to detect several volatile chemicals, including water vapor and acetic acid. The results indicate that these appendages may play a large role in this beetle's assessment of its immediate environment. A. glabripennis is a highly destructive, invasive pest that feeds preferentially on maple - but accepts many other tree species - in North America, warranting USDA quarantine zones and an eradication program. While control and sampling techniques are being developed for this insect, a better understanding of its sensory capabilities is helpful. Electropalpograms (EPGs) revealed that both the maxillary and labial palps are highly sensitive to changes in humidity, indicating the presence of hygroreceptors and the likely important role of humidity in such things as feeding and finding water or oviposition sites. Strong EPG responses to a narrow set of volatile chemicals indicate that olfactory sensory neurons (OSNs) on the palps may be tuned to a small number of volatile compounds. The types of odorant molecules eliciting responses indicate that there are likely both odorant receptors (ORs) as well as ionotropic receptors (IRs) expressed on the OSNs, enabling palp OSNs to be able to respond to acids and aldehydes such as acetic acid and butyraldehyde. There were no significant EPG responses to this species' trail-sex pheromone components, which may indicate that the trail pheromone is primarily perceived via gustatory receptors contacting the substrate. These results indicate that the palps have a role in the beetle's assessment of its immediate environment underfoot, and that the sampling of surface odors and humidity via mouth parts may be important to this species' success.

Anoplophora glabripennis has a complex suite of mate-finding behaviors, the functions of which are not entirely understood. These behaviors are elicited by a number of factors, including visual and chemical cues. Chemical cues include a male-produced volatile semiochemical acting as a long-range sex pheromone, a female-produced cuticular hydrocarbon blend serving as a sex-identification contact pheromone, and a recently identified female-produced trail sex pheromone that is followed by mate-seeking males. However, the sensory appendages and sensilla on these appendages used to detect the trail sex pheromone are unknown. We evaluated the ability of virgin male A. glabripennis to follow a sex pheromone trail after removal of the terminal four antennal segments and/or the maxillary and labial palps using a two-choice behavioral bioassay. We also tested the ability of males to follow the trail sex pheromone using volatile pheromone cues only, without physical contact with the pheromone. Results indicate that the palps are primarily responsible for sensing the pheromone, with males lacking palps unable to respond behaviorally to the trail sex pheromone. Under the conditions of this study, males could not follow the sex pheromone trail without direct contact, suggesting that olfaction may not be involved in detection of this pheromone. However, we did not determine to what degree the trail pheromone chemicals can volatilize under our experimental conditions. This work is important in elucidating the behaviors and sensory structures involved in mate-finding by this species on host trees, and these studies may help determine whether the trail sex pheromone has applications for monitoring and management.

Culture-independent analysis of the gut of a wood-boring insect, Anoplophora glabripennis (Coleoptera: Cerambycidae), revealed a consistent association between members of the fungal Fusarium solani species complex and the larval stage of both colony-derived and wild A. glabripennis populations. Using the translation elongation factor 1-alpha region for culture-independent phylogenetic and operational taxonomic unit (OTU)-based analyses, only two OTUs were detected, suggesting that genetic variance at this locus was low among A. glabripennis-associated isolates. To better survey the genetic variation of F. solani associated with A. glabripennis, and establish its phylogenetic relationship with other members of the F. solani species complex, single spore isolates were created from different populations and multi-locus phylogenetic analysis was performed using a combination of the translation elongation factor alpha-1, internal transcribed spacer, and large subunit rDNA regions. These analyses revealed that colony-derived larvae reared in three different tree species or on artificial diet, as well as larvae from wild populations collected from three additional tree species in New York City and from a single tree species in Worcester, MA, consistently harbored F. solani within their guts. While there is some genetic variation in the F. solani carried between populations, within-population variation is low. We speculate that F. solani is able to fill a broad niche in the A. glabripennis gut, providing it with fungal lignocellulases to allow the larvae to grow and develop on woody tissue. However, it is likely that many F. solani genotypes could potentially fill this niche, so the relationship may not be limited to a single member of the F. solani species complex. While little is known about the role of filamentous fungi and their symbiotic associations with insects, this report suggests that larval A. glabripennis has developed an intimate relationship with F. solani that is not limited by geographic location or host tree.

Following the increasing international phasing out of methyl bromide for quarantine purposes, the development of alternative treatments for timber pests becomes imperative. The international accreditation of new quarantine treatments requires verification standards that give confidence in the effectiveness of a treatment. Probit-9 mortality is a standard for treatment effectiveness that has its origin in fruit fly research, and has been adopted by the United States Department of Agriculture for fruit flies and several other pests. Following this, the probit-9 standard has been adopted as a benchmark for many quarantine treatments worldwide. This article discusses aspects of the application of this concept for a range of timber pests. Problematic issues include the often small pest populations available for testing, the limits of modeling pest responses to a treatment in the absence of sufficient numbers for treatment verification, the species diversity of pests and host materials and the physical and chemical conditions of host material or treatment conditions. Where treatment verification by killing large numbers of individuals is impossible, data collected from small populations or under specific conditions must be interpreted with caution. We discuss possible alternative approaches to probit-9 as a treatment efficacy standard.

Naturally occurring insect viruses can modify the behaviour of infected insects and thereby modulate virus transmission. Modifications of the virus genome could alter these behavioural effects. We studied the distance moved and the position of virus-killed cadavers of fourth instars of Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) infected with a wild-type genotype of H. armigera nucleopolyhedrovirus (HaSNPV) or with one of two recombinant genotypes of this virus on cotton plants. The behavioural effects of virus infection were examined both in larvae infected with a single virus genotype, and in larvae challenged with mixtures of the wild-type and one of the recombinant viruses. An egt-negative virus variant caused more rapid death and lower virus yield in fourth instars, but egt-deletion did not produce consistent behavioural effects over three experiments, two under controlled glasshouse conditions and one in field cages. A recombinant virus containing the AaIT-(Androctonus australis Hector) insect-selective toxin gene, which expresses a neurotoxin derived from a scorpion, caused faster death and cadavers were found lower down the plant than insects infected with unmodified virus. Larvae that died from mixed infections of the AaIT-expressing recombinant and the wild-type virus died at positions significantly lower, compared to infection with the pure wild-type viral strain. The results indicate that transmission of egt-negative variants of HaSNPV are likely to be affected by lower virus yield, but not by behavioural effects of egt gene deletion. By contrast, the AaIT recombinant will produce lower virus yields as well as modified behaviour, which together can contribute to reduced virus transmission under field conditions. In addition, larvae infected with both the wild-type virus and the toxin recombinant behaved as larvae infected with the toxin recombinant only, which might be a positive factor for the risk assessment of such toxin recombinants in the environment.

Enzyme activities toward lignocellulose substrates were analyzed in the gut of larval Asian longhorned beetle (Anoplophora glabripennis). Total protein was extracted from gut contents of wild collected larvae from an invasive population in Worchester, MA, USA. From these protein extracts, lignocellulolytic activities were measured (β-1,4- endoglucanase, β-1,4-glucosidase and birch wood xylanase). β-1,4-glucosidase activity was 0.075 μmol glucose/mg protein per min, endoglucanase activity was measured at 0.41 μmol glucose/mg protein per min and xylanase activity was 0.058 μmol xylose/mg protein per min. To identify specific enzymes that may provide these activities, zymo- gram analysis was performed to detect enzymes active toward carboxymethyl cellulose (CMC), 4-methylumbelliferyl-β-D-glucopyranoside and birch wood xylan. Three protein bands were found to be active toward CMC, three displayed β-1,4-glucosidase, and one displayed xylanase activity. Proteins from active bands from these zymograms were then identifiedbyin-geltrypsindigestionsfollowedbypeptideidentificationbymatrix-assisted laser desorption ionization - time of flight - time of flight mass spectrometry (MS). A custom A. glabripennis transcriptome database was used for peptide identification, giv- ing highly significant matches in all MS analyses. These matches were then searched against the National Center for Biotechnology Information database to provide annotation to the transcripts and provide possible classification. From these analyses, we were able to detect enzymes active toward cellulose and xylan, and proteins putatively involved in lignocellulose degradation in the gut of this wood-feeding insect. Future research will be focused on characterizing these enzymes through cloning and expression experiments and understandinghowthelignocellulosedegradationsystemfunctionsinthegutofthisinsect.

The male-produced pheromone of Anoplophora glabripennis (Motschulsky) (Coleoptera: Cerambycidae), which is an equal blend of 4-(n-heptyloxy)butan-1-ol and 4-(n-heptyloxy)butanal, was used in laboratory bioassays and in the greenhouse to determine its potential for attracting A. glabripennis adults. In modified "walking wind tunnels," virgin females were most attracted to the alcohol component, and virgin males were repelled by the pheromone blend at the lowest and highest amounts offered. Y-tube olfactometer bioassays also showed that females were significantly more attracted to the pheromone and its components than males were. However, males were more attracted to plant volatiles than females. Of 12 plant volatiles tested, delta-3-carene and (E)-caryophyllene were highly attractive to males, whereas (Z)-3-hexenyl acetate was repellent to males. Combining the male pheromone blend with (-)-linalool alone or with (Z)-3-hexen-1-ol attracted significantly more males than did the pheromone alone. We tested four trap designs in our quarantine greenhouse with eight different lures. The Intercept Panel traps and the hand-made screen sleeve traps caught more beetles than the Plum Curculio traps and Lindgren funnel traps. Intercept traps worked best when baited with male blend and (Z)-3-hexen-1-ol, whereas screen sleeve traps were most attractive when baited with (-)-linalool. Our findings provide evidence of the attractiveness of the A. glabripennis male-produced pheromone and suggest that it has a role in mate-finding. It is also a first step toward the development of an efficient trap design and lure combination to monitor A. glabripennis infestations in the field.

The peritrophic matrix (PM) lines the midgut of most insects, providing protection to the midgut epithelial cells while permitting passage of nutrients and water. Herein, we provide evidence that plant-mediated alteration of the PM contributes to the well-documented inhibition of fatal infection by Autographa californica multiple nucleopolyhedrovirus (AcMNPV) of Heliothis virescens F. larvae fed cotton foliage. We examined the impact of the PM on pathogenesis using a viral construct expressing a reporter gene (AcMNPV-hsp70/lacZ) orally inoculated into larvae with either intact PMs or PMs disrupted by Trichoplusia ni granulovirus occlusion bodies containing enhancin, known to degrade insect intestinal mucin. Larvae possessing disrupted PMs displayed infection foci (lacZ signaling) earlier than those with intact PMs. We then examined PMs from larvae fed artificial diet or plant foliage using electron microscopy; foliage-fed larvae had significantly thicker PMs than diet-fed larvae. Moreover, mean PM width was inversely related to both the proportion of larvae with lacZ signaling at 18h post-inoculation and the final percentage mortality from virus. Thus, feeding on foliage altered PM structure, and these foliage-mediated changes reduced baculoviral efficacy. These data indicate that the PM is an important factor determining the success of an ingested pathogen in foliage-fed lepidopteran larvae.

Gypsy moth larvae become increasingly resistant to lethal infection by the Lymantria dispar M nucleopolyhedrovirus (LdMNPV) as they age within the fourth instar. Newly molted larvae are most sensitive to infection, mid-instars are least sensitive, and late-instars display intermediate sensitivity. This resistance occurs whether the virus is delivered orally or intrahemocoelically. The present study reveals a nearly identical pattern of resistance in third instar larvae. An LD48 dose of polyhedra for newly molted third instars produced 18%, 10%, 8%, 25%, and 24% mortalities in larvae to which virus was orally administered at 12, 24, 48, 72, and 96 hours post-molt (hpm), respectively, which is a 6-fold reduction in mortality between newly molted larvae and mid-instars. An LD44 dose of budded virus for newly molted third instars produced 33%, 23%, 17%, 31%, and 31% mortalities when injected into larvae that were 12, 24, 48, 72, and 96 hpm, respectively, which is a 2.6-fold reduction in mortality between newly molted larvae and mid-instars, indicating that approximately half of this resistance is midgut-based and half is systemically based. Doubling the viral dose did not overcome developmental resistance whether the virus was delivered orally or intrahemocoelically. In addition, time to death was significantly affected by the time post-molt at which the insect was inoculated with the virus. We suggest that intrastadial developmental resistance may affect both the ecology and management of the gypsy moth.

Scymnus (Neopullus) camptodromus Yu and Liu (Coleoptera: Coccinellidae) was brought to the United States from China as a potential biological control agent for hemlock woolly adelgid (Adelges tsugae Annand) (Hemiptera: Adelgidae). Scymnus camptodromus phenology is closely synchronized with that of A. tsugae and has several characteristics of a promising biological control agent. As a prerequisite to field release, S. camptodromus was evaluated for potential nontarget impacts. In host range studies, the predator was given the choice of sympatric adelgid and nonadelgid prey items. Nontarget testing showed that S. camptodromus will feed to some degree on other adelgid species, but highly prefers A. tsugae. We also evaluated larval development of S. camptodromus on pine bark adelgid (Pineus strobi (Hartig)) (Hemiptera: Adelgidae) and larch adelgid (Adelges laricis Vallot) (Hemiptera: Adelgidae); a small proportion of predator larvae was able to develop to adulthood on P. strobi or A. laricis alone. Scymnus camptodromus showed no interest in feeding on woolly alder aphid (Paraprociphilus tessellatus Fitch) (Hemiptera: Aphididae) or woolly apple aphid (Eriosoma lanigerum (Hausmann)) (Hemiptera: Aphididae), and minimal interest in cotton aphid (Aphis gossypii Glover) (Hemiptera: Aphididae) in choice and no-choice experiments. Scymnus camptodromus females did not oviposit on any host material other than A. tsugae-infested hemlock. Under the circumstances of the study, S. camptodromus appears to be a specific predator of A. tsugae, with minimal risk to nontarget species. Although the predator can develop on P. strobi, the likelihood that S. camptodromus would oviposit on pine hosts of this adelgid is small.

Insects are unable to synthesize essential amino acids (EAAs) de novo, thus rely on dietary or symbiotic sources for them. Wood is a poor resource of nitrogen in general, and EAAs in particular. In this study, we investigated whether gut microbiota of the Asian longhorned beetle, Anoplophora glabripennis (Motschulsky), a cerambycid that feeds in the heartwood of healthy host trees, serve as sources of EAAs to their host under different dietary conditions. δ 13 C-stable isotope analyses revealed significant δ 13 C-enrichment (3.4 ± 0.1‰; mean ± SEM) across five EAAs in wood-fed larvae relative to their woody diet. δ 13 C values for the consumers greater than 1‰ indicate significant contributions from non-dietary EAA sources (symbionts in this case). In contrast, δ 13 C-enrichment of artificial diet-fed larvae (controls) relative to their food source was markedly less (1.7 ± 0.1‰) than was observed in wood-fed larvae, yet still exceeded the threshold of 1‰. A predictive model based on δ 13 C EAA signatures of five EAAs from representative bacterial, fungal, and plant samples identified symbiotic bacteria and fungi as the likely supplementary sources of EAA in wood-fed larvae. Using the same model, but with an artificial diet as the dietary source, we identified minor supplementary bacterial sources of EAA in artificial diet-fed larvae. This study highlights how microbes associated with A. glabripennis can serve as a source of EAAs when fed on nutrient-limited diets, potentially circumventing the dietary limitations of feeding on woody substrates.

The Asian longhorned beetle, Anoplophora glabripennis (Motschulsky), threatens urban and forest hardwood trees both where introduced and in parts of its native range. Native to Asia, this beetle has hitchhiked several times in infested wood packaging used in international trade, and has established breeding populations in five U.S. states, Canada, and at least 11 countries in Europe. It has a broad host range for a cerambycid that attacks living trees, but in the introduced ranges it prefers maples. Identification, classification, and life history of this insect are reviewed here. Eradication is the goal where it has been introduced, which requires detection of infested trees using several approaches, including ground and tree-climbing surveys. Several agencies and researchers in the United States and Europe are evaluating the use of pheromone- and kairomone-baited traps. Control options beyond cutting down infested trees are limited. To date, the parasitoids and predators of this beetle have broad host ranges and are unlikely to be approved in the United States or Europe. An effective delivery system under development for entomopathogenic fungi appears promising. Systemic insecticides have been widely used in the United States, but the ability of these chemicals to reach lethal doses in the crown of large trees is disputed by some scientists, and the potential nontarget effects, especially on pollinators, raise concerns. The most practical approach for eradicating Asian longhorned beetle is to optimize trapping methods using semiochemicals for early detection to eliminate the insect before it spreads over large areas.

Recent advances in the understanding of plant signaling pathways have opened the way for using elicitor-induced plant resistance as a tactic for protecting plants against arthropod pests. Four common elicitors of induced responses in tomato, Lycopersicon esculentum Mill. (Solanaceae), were evaluated with regard to phytotoxicity, induction of plant defensive proteins, and effects on population growth and fecundity of a common pest, the green peach aphid, Myzus persicae (Sulzer) (Homoptera: Aphididae). Ethephon and methyl jasmonate (MJ) treatments caused varying degrees of phytotoxicity. Ethephon caused pronounced changes in plant growth form and severe, dose-dependent negative impacts on plant growth and flowering. Effects with MJ were milder, but still caused temporary inhibition of development, leading to smaller plants and delayed flowering. The commercial elicitors benzothiadiazole (BTH) and harpin did not cause detectable phytotoxicity. The highest doses of ethephon and MJ significantly increased leaf peroxidase (POD) levels but only MJ treatments significantly increased polyphenol oxidase (PPO) levels. BTH and harpin had no detectable effects on POD and PPO. Populations of green peach aphids grew significantly more slowly on plants treated with BTH or MJ than on control plants or plants treated with harpin or ethephon. Slowed aphid population growth on BTH-treated plants was due to significant reductions in aphid fecundity, although this was independent of changes in time to onset of reproduction or time to death. Aphid fecundity was also reduced on MJ-treated plants relative to controls, but this difference was not statistically significant, suggesting that other mechanisms are involved in slowing aphid population growth on MJ-treated plants. Growth of aphid populations on plants treated with a MJ-BTH mixture was reduced almost as much as with treatments of MJ alone, suggesting that antagonism between JA-dependant and SA-dependent plant signaling pathways is only mild with regard to induced defenses against aphids.

The invasive wood-boring beetleAnoplophora glabripennis(Motschulsky) (Coleoptera: Cerambycidae) poses a serious threat to deciduous trees in North America and Europe, where it has been introduced in solid wood packing material from China (Haacket al.1997; Krehan 2003). This beetle attacks and ultimately kills a wide variety of hardwood tree species (Nowaket al.2001; Lingafelter and Hoebeke 2002); it has infested urban shade trees in Canada (Canadian Food Inspection Agency 2004), the United States (Haack 2003), and Austria (Tomiczek 2003) and has damaged poplar (PopulusL.; Salicaceae) plantations in its native China (Luoet al.2003).

Anoplophora gbbriperznis (Motschulsky) (Coleoptera: Cerambycidae: Lamiini) is an invasive woodboring beetle with an unusually broad host range and a proven ability to increase its host range as it colonizes new areas and encounters new tree species. The beetle is native to eastern Asia and has become an invasive pest in North America and Europe, stimulating interest in delineating host and non-host tree species more clearly. When offered a choice among four species of living trees in a greenhouse, adult A. glabripennis fed more on golden-rain tree (Koelreuteria paniculata Laxmann) and river birch (Betub nigra L.) than on London planetree (Platanus x acerifolia (Aiton) Willdenow) or callery pear (Pyrus calleryana Decaisne). Oviposition rate was highest in golden-rain tree, but larval mortality was also high and larval growth was slowest in this tree species. Oviposition rate was lowest in callery pear, and larvae failed to survive in this tree species, whether they eclosed from eggs laid in the treg or were manually inserted into the trees. Adult beetles feeding on c&ery pear had a reduced longevity and females feeding only on callery pear failed to develop any eggs. The resistance of golden-rain tree against the larvae appears to operate primarily through the physical mechanism of abundant sap flow. The resistance of callery pear against both larvae and adults appears to operate through the chemical composition of the tree, which may include compounds that are toxic or which otherwise interfere with normal growth and development of the beetle. Unlike river birch or London planetree, both golden-rain tree and callery pear are present in the native range of A. glabripennis and may therefore have developed resistance to the beetle by virtue of exposure to attack during their evolutionary history.

Anoplophora glabripennis (Motschulsky) is an invasive wood-boring cerambycid beetle that kills hardwood trees. The host range of this species is unusually broad but is not well defined in the available literature and may include tree species that have not been reported as hosts because they have not previously been exposed to the beetle. We evaluated oviposition by A. glabripennis offered a choice of four common eastern North American forest and landscape hardwood tree species, and performance of the resulting larvae, under greenhouse conditions. Significantly greater numbers of oviposition sites were found on sugar maple, Acer saccharum Marshall, than on red maple, Acer rubrum L., green ash, Fraxinus pennsylvanica Marshall, or red oak, Quercus rubra L., with no significant differences among the other three tree species. Similarly, significantly greater numbers of living larvae were found in sugar maple than in the other tree species; however, more were found in red oak and fewer in green ash than expected, considering relative numbers of oviposition sites. After 90 d, mean mass of living larvae did not differ significantly among tree species. These results suggest that all four tree species may be suitable hosts for A. glabripennis. Most importantly, although larval establishment was poor in green ash and larval growth may have been retarded in red oak, larvae did survive and grow in both species. We recommend that these tree species be considered potential hosts when surveys are conducted to detect infested trees or when replanting infested areas.

We investigated intrastadial developmental resistance of the gypsy moth, Lymantria dispar , to its host-specific baculovirus, L. dispar multinucleocapsid nucleopolyhedrovirus (LdMNPV). Susceptibility of the gypsy moth to LdMNPV decreased markedly as the insect aged within the fourth instar and this resistance was systemic because it could not be overcome by bypassing the midgut and injecting the virus directly into the hemocoel. An LD 88 dose of polyhedra delivered orally to newly molted fourth instars produced 74, 37, 29, 27, 38, and 60% mortalities in larvae that were orally inoculated at 12, 24, 48, 72, 96, or 120 h post-molt to the fourth instar, respectively. An LD 77 dose of budded virus delivered intrahemocoelically to newly molted fourth instars produced 84, 54, 29, 48, 59, and 46% mortalities in larvae that were injected at 12, 24, 48, 72, 96, or 120 h post-molt, respectively. Developmental resistance was also observed in fourth instars fed on oak foliage, no matter whether they were inoculated orally or intrahemocoelically, suggesting that intrastadial developmental resistance in gypsy moth larvae has a systemic component. Also, the host plant did not appear to affect systemic resistance, although it did increase midgut-based resistance. The degree of developmental resistance by intrahemocoelic inoculation was equivalent in oak- and diet-fed insects. In contrast, the degree of resistance by oral inoculation was much greater in oak- than in diet-fed insects, probably because of the combined effects of host-plant inhibition and increasing resistance to viral disease as the larvae aged within the instar.

Native to China and Korea, the Asian longhorned beetle, Anoplophora glabripennis (Motschulsky) (Coleoptera: Cerambycidae), is a polyphagous wood-boring pest for which a trapping system would greatly benefit eradication and management programs in both the introduced and native ranges. Over two field seasons, a total of 160 flight intercept panel traps were deployed in Harbin, China, which trapped a total of 65 beetles. In 2012, traps using lures with a 1:1 ratio of the male-produced pheromone components (4-(n-heptyloxy)butanal and 4-(n-heptyloxy)butan-1-ol) designed to release at a rate of 1 or 4 milligram per day per component in conjunction with the plant volatiles (-)-linalool, trans-caryophyllene, and (Z)-3-hexen-1-ol caught significantly more A. glabripennis females than other pheromone release rates, other pheromone ratios, plant volatiles only, and no lure controls. Males were caught primarily in traps baited with plant volatiles only. In 2013, 10× higher release rates of these plant volatiles were tested, and linalool oxide was evaluated as a fourth plant volatile in combination with a 1:1 ratio of the male-produced pheromone components emitted at a rate of 2 milligram per day per component. Significantly more females were trapped using the pheromone with the 10-fold higher three or four plant volatile release rates compared with the plant volatiles only, low four plant volatile + pheromone, and control. Our findings show that the male-produced pheromone in combination with plant volatiles can be used to detect A. glabripennis. Results also indicate that emitters should be monitored during the field season, as release rates fluctuate with environmental conditions and can be strongly influenced by formulation additives.

Environmental Entomology, 43 (4), ISSN:0046-225X, ISSN:1938-2936

Development time and prey consumption of Scymnus (Neopullus) camptodromus Yu and Liu (Coleoptera: Coccinellidae) larvae by instar, strain, and temperature were evaluated. S. camptodromus, a specialist predator of hemlock woolly adelgid Adelges tsugae (Annand) (Hemiptera: Adelgidae), was brought to the United States from China as a potential biological control agent for A. tsugae. This beetle has been approved for removal from quarantine but has not yet been field released. We observed that temperature had significant effects on the predator's life history. The larvae tended to develop faster and consume more eggs of A. tsugae per day as rearing temperature increased. Mean egg consumption per day of A. tsugae was less at 15°C than at 20°C. However, as larvae took longer to develop at the lower temperature, the total number of eggs consumed per instar during larval development did not differ significantly between the two temperatures. The lower temperature threshold for predator larval development was estimated to be 5°C, which closely matches the developmental threshold of A. tsugae progrediens. Accumulated degree-days for 50% of the predator neonates to reach adulthood was estimated to be 424. Although temperature had a significant effect on larval development and predation, it did not impact survival, size, or sex ratio of the predator at 15 and 20°C. Furthermore, no remarkable distinctions were observed among different geographical populations of the predator.

Xylophagous insects often thrive on nutritionally suboptimal diets through symbiotic associations with microbes that supplement their nutritional requirements, particularly nitrogen. The wood-feeding cerambycid Anoplophora glabripennis (Motschulsky) feeds on living, healthy host trees and harbors a diverse gut microbial community. We investigated gut microbial contributions to larval nitrogen requirements through nitrogen fixing and recycling (urea hydrolysis) processes, using a combination of molecular, biochemical, and stable isotope approaches. Genes and transcripts of conserved regions of the urease operon (ureC) and nitrogen fixing (nif) regulon (nifH) were detected in A. glabripennis eggs and larvae from naturally infested logs and from larvae reared on artificial diet. Significant nitrogen fixation and recycling were documented in larvae using (15)N2 gas and (15)N-urea, respectively. Subsequent (15)N-routing of incorporated recycled nitrogen into larval essential and nonessential amino acids was shown for (15)N-urea diet-fed larvae. Results from this study show significant gut microbial contributions to this insect's metabolic nitrogen utilization through nitrogenous waste product recycling and nitrogen fixation.

Analysis of bioassays data from experiments with mixtures require use of special statistical techniques, especially when responses are recorded over time. Often, response curves from bioassays with mixtures do not fit a probit or logit curve. In addition, observations recorded over time are not independent. As a result, standard statistical packages for probit or logit analysis are not applicable. In these bioassay s. the shape of the response curve depends on the type of interactions between mixture components. Here we present models that describe response (e.g., mortality) curves over time when mixtures are applied to insects. The shapes of the response curves depend on the modes of both action and interaction between the mixture compounds. We describe a procedure to assess whether the assumed modes of interaction (e.g., independent action or similar action additive models) are appropriate. We demonstrate use of the statistical methods with data obtained when a baculovirus and a synthetic organic insecticide were mixed.

Author(s): Hoover, Kelli; Alaniz, Susan A.; Yee, Julie L.; Rocke, David; Hammock, Bruce D.; Duffey, Sean S. | Abstract: Insecticidal pathogens such as baculoviruses are currently under intensive development as biorational agents for the control of lepidopteran pests. However, because the efficacy of these orally infective viruses is influenced by host diet, our ability to use baculoviruses effectively in an integrated pest management program requires understanding the influence of dietary components on the disease process. Nutritional stress caused by differences in the quality (casein or soy) or quantity (0-8%) of dietary protein altered the postinfectional course of disease caused by Autogropha californica M nucelopolyhedrovirus in 2 species of noctuids, Heliothis virescens (F.) and Tnchoplusia ni (Hubner). Lethal times of larvae infected with either the wild-type virus or a recombinant expressing a scorpion toxin (AaIT) derived from this parent virus were similarly affected by dietary protein. In general, the higher the level of dietary protein the shorter the lethal times. However, the influence of protein quality on lethal times depended on the insect species tested. The effect of chlorogenic acid on disease depended on dietary protein levels. At high protein concentrations, chlorogenic acid decreased speed of kill; whereas, at low protein levels, the phenolic had the opposite effect. The common factor among all treatments was that the faster larvae grew, the faster they died from viral infection. We suggest that insects that grow faster may support faster rates of viral replication in infected hosts. From an ecological perspective, it is possible that plants of higher protein content may increase the potential for the development of baculoviral epizootics in insect populations.

In tests with neonate Heliothis virescens (F.), we characterized interactions of all combinations of a recombinant Autographa californica (Speyer) nuclear polyhedrosis virus (AcAaIT) that expresses an insect-selective neurotoxin (AaIT) and wild-type AcNPV when combined with low concentrations of several conventional insecticides. All combinations of the recombinant virus AcAaIT and insecticides showed a positive interaction (decrease in the median lethal time (LT50) compared with the LT50 for either component alone). A type II pyrethroid (cypermethrin, which modifies currents of sodium channels) and a carbamate (methomyl, an inhibitor of acetylcholinesterase) were synergistic in combination with AcAaIT. Other insecticides also showed a positive interaction when tested in combination with the recombinant virus, but joint activity was slightly antagonistic (i.e., less than predicted activity when combined) with wild-type AcNPV. We also characterized the effectiveness of AcAaIT against pyrethroid-resistant H. virescens larvae. Our results show that a resistant strain of H. virescens is more sensitive to the recombinant virus compared with a susceptible strain. Results of these studies should be useful in planning of future field trials to increase the effectiveness of nuclear polyhedrosis viruses and to manage resistance to pyrethroids and other insecticides.

Conophthorus radiatae Hopkins, Ernobius punctulatus Fall, and Pityophthorus spp. infest cones and twigs of Monterey pines (Pinus radiata D. Don) and thus may be important vectors of the pitch canker fungus Fusarium subglutinans f. sp. pini in the central coast of California. Fifteen percent of 1st-year Monterey pine conelets infested with C. radiatae prior to August 1990 developed pitch canker by May 1991. Conophthorus radiatae, E. punctulatus, and Pityophthorus spp. were dissected from some of these conelets and found carrying F. s. pini. Between June 1990 and May 1991, 16% of 695 randomly selected uninfested 1st-year conelets from a total of 329 separate cone whorls were infested by at least one of the above beetle species, and F. s. pini was isolated from 42% of the attacked conelets. Average percentage contamination of beetles per conelet was highest for adults of Pityophthorus spp. (38%), followed by adults of C. radiatae (33%), larvae of E. punctulatus (24%), and larvae of Pityophthorus spp. (5%). There were significant associations between conelets that contained contaminated C. radiatae, Pityophthorus spp., and/or E. punctulatus and conelets with F. s. pini.Under experimental conditions, C. radiatae and E. punctulatus transmitted the fungus to healthy cones. Ernobius punctulatus required an entrance tunnel by C. radiatae to enter and infect the cone. Artificially wounded cones did not develop pitch canker. Intra- and interspecific transmission of F. s. pini was demonstrated among these beetle species. In infested branch tips without cones, interspecific transmission of F. s. pini between E. punctulatus and Pityophthorus spp. was also demonstrated.The roles of C. radiatae and E. punctulatus as vectors of F. s. pini and of Pityophthorus spp. as potential vectors are discussed in relation to the epidemiology of pitch canker disease. The spread of pitch canker to California’s native pines as well as other conifers may be enhanced by interspecific transmission of F. s. pini between E. punctulatus and C. radiatae in cones and between E. punctulatus and Pityophthorus spp. in branch tips. Ernobius punctulatus provides a pathway for the fungus to potential insect vectors that attack several hosts and a variety of plant parts.

Recombinant baculoviruses that express insect-specific toxins under the control of viral late gene promoters can kill susceptible lepidopteran hosts faster than the wild-type virus. In an effort to improve the efficacy of genetically engineered baculovirus pesticides, we have produced a recombinant that contains an insect specific toxin gene (AaIT) under the control of the promoter from an immediate early gene (ie1) ofAutographa californicanuclear polyhedrosis virus (AcNPV). AaIT protein was detected as early as 4 h postinfection in cultured insect cells infected with this recombinant. The protein continued to accumulate as the infection progressed and, even as late as 24 h postinfection, the amount of AaIT was about equal to that provided by a recombinant that expressed AaIT under the control of the very latep10promoter. Similar results were obtained with a recombinant that expressed a modified insect juvenile hormone esterase (JHE–KK) underie1control, confirming the ability of this promoter to provide early and abundant expression of gene products with potential pesticidal activity. Bioassays showed that theie1–AaIT recombinant killedHeliothis virescenslarvae faster than wild-type virus, but not faster than thep10–AaIT recombinant. However, larvae infected with theie1–AaIT recombinant were smaller than those infected with thep10–AaIT recombinant, suggesting that expression of AaIT earlier in infection enhanced the ability of the virus to reduce the feeding activity ofH. virescenslarvae.

Genetically engineered viral insecticides have considerable potential as biological control agents. Through genetic manipulation, the wild-type baculovirus Autographa californica nuclear polyhedrosis virus (WT AcNPV) has been modified to encode for an insect-selective toxin derived from the venom of the scorpion Androctonus australis to produce the recombinant virus AcAaIT. Larvae of tobacco budworm (Heliothis virescens) infected with the baculovirus AcAaIT fell off the plant 5-11 h before death and were unable to climb back on the plant to continue feeding. These larvae were capable of feeding if placed oil diet or confined to a leaf with a clip cage. Larvae infected with WT AcNPV died on the plant. Larvae infected with AcAaIT consumed significantly less foliage than larvae infected with WT AcNPV or uninfected controls. Thus, because larvae infected with the recombinant AcAaIT fall off the plant prior to cessation of feeding, there is a greater reduction in feeding damage than expected from lethal times. In addition, because AcAaIT causes a knock-off effect, the absence of liquefied cadavers on plants following treatment with AcAaIT may be more desirable to growers and consumers relative to treatment with wild-type virus. The relevance of our results to field use of recombinant viruses in pest control is discussed.

The objective of this study was to determine the quantitative and seasonal association between the pitch canker fungus, Fusarium subglutinans f. sp. pini, and two potential beetle vectors, Conophthorus radiatae Hopkins and Ernobius punctulatus Fall. In samples of reared and dissected cones, 21.4 ± 2.5% of C. radiatae and 30.1 ± 8.0% of E. punctulatus adults carried propagules of F. s. pini. Seasonal variation in mean percentage of contaminated C. radiatae and E. punctulatus emerged from cones ranged from 0 to 67% and was highest for both species February through April. In sticky traps 12.5 ± 2.3% and 11.8 ± 3.6% of E. punctulatus and Pityophthorus spp., respectively, were contaminated with propagules of F. s. pini.Conophthorus radiatae and E. punctulatus co-occurred in 26% of the cones. The percentage of cones containing contaminated C. radiatae was greater when E. punctulatus progeny were also contaminated than when E. punctulatus was not. When contamination status of E. punctulatus was not considered, there was no significant difference in C. radiatae contamination between cones with and without E. punctulatus. Because C. radiatae appears to be a vector of the pitch canker fungus, interspecific transmission of inoculum may increase the incidence of this disease.The parasitoid, Cephalonomia utahensis Brues (Hymenoptera: Bethylidae), was frequently observed parasitizing late-instar larvae of E. punctulatus, but was not found on larvae of C. radiatae. Emergence of large numbers of C. utahensis represents another potential source of inoculum for transmission to prey species.

Baculovirus insecticides are receiving renewed attention as insect pest control agents following the development of fast-acting recombinant baculoviruses. Here we report on the construction and biological activity of a recombinant baculovirus derived from the nuclear polyhedrosis virus of Autographa californica which expresses a modified form of juvenile hormone esterase (JHE). The serine at the catalytic site of the JHE has been mutated to a glycine residue so that the protein does not degrade JH. The recombinant baculovirus expressing this modified form of JHE, named AcJHE-SG, has enhanced activity against lepidopteran larvae. Lethal times of the recombinant are 20 to 30% lower than for the wild type virus, and a 66% reduction in feeding damage caused by infected larvae is observed. This result is comparable to the best recombinant baculovirus developed to date, AcAaIT, which expresses an insect-selective scorpion toxin. The potential of these recombinant viruses for commercialization as insecticides is discussed. Bioassays of AcJHE-SG in conjunction with anti-JH agents indicate that the virus is not killing by an anti-JH mechanism. Larvae apparently die from contraction-paralysis, or disruption of the normal sequence of events at the molt. © 1995 Wiley-Liss, Inc.

Anoplophora glabripennis (Motschulsky) (Coleoptera: Cerambycidae), commonly known as the Asian longhorned beetle, is a wood-boring invasive species introduced from Asia to North America and Europe in solid wood packing material. Efficient monitoring traps are needed to assess population density and dispersal in the field and to detect new introductions at ports of entry. For this purpose, we conducted field trapping experiments in China in the summers of 2007 and 2008. In 2007, we tested Intercept panel traps hung on poplar trees. In 2008, we used Intercept panel traps hung on poplar trees, screen sleeve traps wrapped around poplar trunks, and Intercept panel traps hung on bamboo poles 20 m away from host trees. Traps were baited with A. glabripennis male-produced pheromone alone or in different combinations with plant volatiles. Traps baited with the male-produced pheromone alone caught significantly more females than control traps in both years. The addition of a mixture of (-)-linalool, (Z)-3-hexen-1-ol, linalool oxide, trans-caryophyllene, and trans-pinocarveol to the pheromone significantly increased trap catches of females, 85% of which were virgin. Screen sleeve traps baited with a combination of (-)-linalool and the pheromone caught the highest number of beetles overall in 2008, whereas traps placed on bamboo polls caught the lowest number. Although the logistics for the most effective implementation of a trapping program using a mixture of the pheromone and plant volatiles require additional studies, these results indicate that this pheromone has considerable promise as a monitoring tool for A. glabripennis in the field.

How the innate immune system functions to defend insects from viruses is an emerging field of study. We examined the impact of melanized encapsulation, a component of innate immunity that integrates both cellular and humoral immune responses, on the success of the baculovirus Lymantria dispar multiple nucleocapsid nucleopolyhedrovirus (LdMNPV) in its host L. dispar . L. dispar exhibits midgut-based and systemic, age-dependent resistance to LdMNPV within the fourth instar; the LD 50 in newly molted larvae is approximately 18-fold lower than in mid-instar larvae (48–72 h post-molt). We examined the role of the immune system in systemic resistance by measuring differences in hemocyte immunoresponsiveness to foreign targets, hemolymph phenoloxidase (PO) and FAD-glucose dehydrogenase (GLD) activities, and melanization of infected tissue culture cells. Mid-instar larvae showed a higher degree of hemocyte immunoresponsiveness, greater potential PO activity (pro-PO) at the time the virus is escaping the midgut to enter the hemocoel (72 h post-inoculation), greater GLD activity, and more targeted melanization of infected tissue, which correlate with reduced viral success in the host. These findings support the hypothesis that innate immune responses can play an important role in anti-viral defenses against baculoviruses and that the success of these defenses can be age-dependent.

Anoplophora glabripennis, the Asian longhorned beetle, is a wood-boring insect that can develop in a wide range of healthy deciduous hosts and requires gut microbes to aid in wood degradation and digestion. Here we show that larval A. glabripennis harbor a diverse gut bacterial community, and this community can be extremely variable when reared in different host trees. A. glabripennis reared in a preferred host (Acer saccharum) had the highest gut bacterial diversity compared with larvae reared either in a secondary host (Quercus palustris), a resistant host (Pyrus calleryana), or on artificial diet. The gut microbial community of larval A. glabripennis collected from field populations on Brooklyn, NY, showed the highest degree of complexity among all samples in this study. Overall, when larvae fed on a preferred host, they harbored a broad diversity of gut bacteria spanning the alpha-, beta-, gamma-Proteobacteria, Firmicutes, Actinobacteria, and Bacteroidetes. Cellulase activities (beta-1,4-endoglucanase, beta-1,4-exoglucanase, and beta-1,4-glucosidase) in the guts of larvae fed in a preferred host (A. saccharum) or a secondary host (Q. palustris) were significantly higher than that of artificial diet fed larvae. Larvae that fed on wood from a resistant host (P. calleryana) showed suppressed total gut cellulase activity. Results show that the host tree can impact both gut microbial community complexity and cellulase activity in A. glabripennis.

The decrease in susceptibility to polyhedrosis disease when Heliothis virescens larvae feed on cotton is profound, limiting the utility of baculoviruses for controlling noctuids on this important crop. We observed that the mortalities of H. virescens larvae challenged with a reporter-gene construct of Autographa californica M nucleopolyhedrovirus (AcMNPV-hsp70/lacZ) and fed either lettuce or artificial diet were approximately 2.5-fold higher than that of cotton-fed insects. This decrease in susceptibility on cotton was observed following oral but not intrahemocoelic inoculation of virus, and it was negatively correlated with levels of foliar peroxidase. The rates of development of both infected and uninfected larvae also were correlated negatively with levels of foliar peroxidase, and hence, were significantly lower for insects fed cotton. When Calcofluor White M2R, an optical brightener reported to enhance the retention of AcMNPV-infected midgut cells, was included in inoculum administered orally to larvae, mortality levels were equivalent regardless of diet. These results suggest that sloughing of infected midgut cells occurred at a higher rate in insects that fed on cotton compared to the other two diets, and that midgut cell sloughing is the mechanism whereby susceptibility to mortal infection by AcMNPV-hsp70/lacZ is decreased on cotton. This conclusion is consistent with previous reports that ingestion of cotton can generate reactive oxygen species within the midgut lumen that may damage midgut epithelial cells. As far as we know, this is the first study to link resistance intrinsic to the physiology of the insect (e.g., developmental resistance) and resistance conferred by host plant chemistry to a single mechanism, i.e., midgut cell sloughing.