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Insects harbor bacterial endosymbionts that provide their hosts with nutritional benefit or with protection against natural enemies, plant defenses, insecticides, or abiotic stresses. We used directed sequencing of 16S rDNA to identify and compare endosymbionts of Bactericera maculipennis (Crawford) and the western, central, and northwestern haplotypes of B. cockerelli (Šulc) (Hemiptera: Psylloidea: Triozidae). Both species are native to North America, are known to harbor the plant pathogen ‘Candidatus Liberibacter solanacearum’ and develop on shared host plants within the Convolvulaceae. The Old-World species Heterotrioza chenopodii (Reuter) (Psylloidea: Triozidae), now found in North America, was included as an outgroup. 16S sequencing confirmed that both Bactericera species harbor ‘Candidatus Liberibacter solanacearum’ and revealed that both species harbor unique strains of Wolbachia and Sodalis. However, the presence of Wolbachia and Sodalis varied among haplotypes of B. cockerelli. The central and western haplotypes harbored the same strains of Wolbachia, which was confirmed by Sanger sequencing of the wsp and ftsZ genes. Wolbachia was also detected in very low abundance from the northwestern haplotype by high-throughput sequencing of 16S but was not detected from this haplotype by PCR screening. The northwestern and central haplotypes also harbored Sodalis, which was not detected in the western haplotype. Heterotrioza chenopodii harbored an entirely different community of potential endosymbionts compared with the Bactericera spp. that included Rickettsia and an unidentified bacterium in the Enterobacteriaceae. Results of this study provide a foundation for further research on the interactions between psyllids and their bacterial endosymbionts.

Bactericera cockerelli (Šulc) (Hemiptera: Triozidae) is a vector of ‘Candidatus Liberibacter solanacearum’ (Lso), the pathogen that causes potato zebra chip. Zebra chip incidence varies regionally, perhaps because of geographic differences in species of noncrop hosts available to the vector and in susceptibility of those hosts to Lso. Native and introduced species of Lycium (Solanales: Solanaceae) are important noncrop hosts of B. cockerelli in some regions of North America. Susceptibility of native Lycium species to Lso is uncertain. We investigated the use of two native species of Lycium by B. cockerelli in South Texas and tested whether they are susceptible to Lso. Bactericera cockerelli adults and nymphs were collected frequently from L. berlandieri Dunal and L. carolinianum Walter. Greenhouse assays confirmed that B. cockerelli develops on both species and showed that Lso infects L. carolinianum. Molecular gut content analysis provided evidence that B. cockerelli adults disperse between potato and Lycium. These results demonstrate that L. berlandieri and L. carolinianum are likely noncrop sources of potato-colonizing B. cockerelli in South Texas and that L. carolinianum is a potential source of Lso-infected psyllids. We also routinely collected the congeneric psyllid, Bactericera dorsalis (Crawford), from both Lycium species. These records are the first for this psyllid in Texas. Bactericera dorsalis completed development on both native Lycium species, albeit with high rates of mortality on L. berlandieri. B. dorsalis acquired and transmitted Lso on L. carolinianum under greenhouse conditions but did not transmit Lso to potato. These results document a previously unknown vector of Lso.

The Psylloidea (Hemiptera) comprise ~4,000 species of small sap-feeding insects known as psyllids or jumping plant-lice. We summarize species composition of the nonnative psyllid fauna in North America and review detection records, current distributions, host use, life histories, and geographical sources. Forty-six species are considered to be nonnative accounting for ~10% of the known North American psyllid fauna. The family Psyllidae is overrepresented in the pool of exotics (52% of exotic species) relative to global psyllid diversity, whereas Triozidae (at 11% of exotic species) is underrepresented. Records of initial detection range from the 1832 detection of a European pear psyllid to the 2016 detection of a Ficus specialist from Asia. Many species exhibit discontinuous distributions in North America presumably caused by multiple introductions or by secondary spread of established populations. Host plants of nonnative species are almost exclusively trees and shrubs. The factor most correlated with introduction is presence of hosts from the psyllid’s native region. Virtually all host plants in North America have been imported intentionally for human-related use, with initial importation beginning in the 1500s and 1600s. Arrival of host plants in North America often preceded psyllid detection or arrival by decades or centuries. There has been almost no spillover by psyllids onto native plant species reflecting the narrow host range of Psylloidea. A glaring exception is the recent damaging colonization of a native Fraxinus closely related to the psyllid’s European Fraxinus host. Biological and geographical traits correlated with arrival and establishment of nonnative psyllids have shifted through time. Temperate Europe was the source of the earliest arriving species, with initial detection records primarily in New England and eastern Canada. In contrast, recent arrivals are mostly Myrtaceae- and Fabaceae-feeding species from the Neotropics or Australia, with detection records limited mostly to Florida or California. Early-arriving, temperate zone species exhibit a formal winter diapause while recent arrivals from the Neotropics and Australia appear to reproduce more-or-less continuously.

Understanding host use by psyllids (Hemiptera: Psylloidea) benefits from comparative studies of behavior on host and nonhost plant species. While most psyllid species develop on one or a few closely related plant species, some species are generalized enough to develop on species across plant families. We used electropenetography (EPG) technology to compare probing activities of an oligophagous psyllid (Bactericera cockerelli (Šulc)) and a host-specialized psyllid (Bactericera maculipennis) on two species of Solanaceae (potato, Solanum tuberosum L. and matrimony vine, Lycium barbarum L.) and two species of Convolvulaceae (field bindweed, Convolvulus arvensis L. and sweet potato, Ipomoea batatas). Bactericera cockerelli develops on all four species, albeit with longer development times on Convolvulaceae. Bactericera maculipennis develops only on Convolvulaceae. Bactericera cockerelli fed readily from phloem of all four species, but the likelihood of entering phloem and duration of time in phloem was reduced on suboptimal hosts (Convolvulaceae) relative to behavior on Solanaceae. We observed instances of cycling between bouts of phloem salivation and ingestion in assays of optimal (Solanaceae) hosts not observed on Convolvulaceae. The Convolvulaceae-specialized B. maculipennis (Crawford) failed to feed from phloem of nonhosts (Solanaceae). Both psyllid species readily ingested from xylem of all plant species, irrespective of host status. Our finding that phloem feeding by B. maculipennis did not occur on potato has implications for understanding epidemiology of phloem-limited psyllid-vectored plant pathogens. Our results also showed that EPG assays detect subtle variation in probing activities that assist in understanding host use by psyllids.

The potato psyllid, Bactericera cockerelli (Šulc), is a major pest of potato (Solanum tuberosum L.; Solanales: Solanaceae) as a vector of ‘Candidatus Liberibacter solanacearum’, the pathogen that causes zebra chip. Management of zebra chip is challenging in part because the noncrop sources of Liberibacter-infected psyllids arriving in potato remain unknown. Adding to this challenge is the occurrence of distinct genetic haplotypes of both potato psyllid and Liberibacter that differ in host range. Longleaf groundcherry (Physalis longifolia Nutt.) has been substantially overlooked in prior research as a potential noncrop source of Liberibacter-infected B. cockerelli colonizing fields of potato. The objective of this study was to assess the suitability of P. longifolia to the three common haplotypes of B. cockerelli (central, western, and northwestern haplotypes), and to two haplotypes of ‘Ca. L. solanacearum’ (Liberibacter A and B haplotypes). Greenhouse bioassays indicated that B. cockerelli of all three haplotypes produced more offspring on P. longifolia than on potato and preferred P. longifolia over potato during settling and egg-laying activities. Greenhouse and field trials showed that P. longifolia was also highly susceptible to Liberibacter. Additionally, we discovered that infected rhizomes survived winter and produced infected plants in late spring that could then be available for psyllid colonization and pathogen acquisition. Results show that P. longifolia is susceptible to both B. cockerelli and ‘Ca. L. solanacearum’ and must be considered as a potentially important source of infective B. cockerelli colonizing potato fields in the western United States.

Our previous study provided correlative evidence that morning glory species harboring endophytic fungi (Periglandula) are resistant to potato psyllid [Bactericera cockerelli (Šulc)], whereas species free of fungi often allowed psyllid development. In this study, we manipulated levels of ergot alkaloids in host tissues by inoculating clippings from potato plants with extracts from morning glories that harbor Periglandula [Ipomoea leptophylla Torrey, Ipomoea imperati (Vahl) Grisebach, Ipomoea tricolor Cavanilles, Ipomoea pandurata (L.) G. F. Meyer, and Turbina corymbosa (L.)] and one species (Ipomoea alba L.) that does not harbor the endophyte. Ergot alkaloids (clavines, lysergic acid amides, and ergopeptines) were detected in potato clippings, thus confirming that leaves had taken up compounds from solutions of crude extracts. Psyllid mortality rates on inoculated clippings ranged between 53 and 93% in treatments producing biochemically detectable levels of alkaloids, when compared with 15% mortality in water controls or the alkaloid-free I. alba. We then tested synthetic analogs from each of the three alkaloid classes that had been detected in the crude extracts. Each compound was assayed by inoculating clippings of two host species (potato and tomato) at increasing concentrations (0, 1, 10, and 100 µg/ml in solution). Psyllids exhibited a large and significant increase in mortality rate beginning at the lowest two concentrations, indicating that even very small quantities of these chemicals led to mortality. Feeding by nymphs on artificial diets containing synthetic compounds resulted in 100% mortality within 48 h, irrespective of compound. Further testing of ergot alkaloids to characterize the mode of action that leads to psyllid mortality is warranted.

Asian citrus psyllid Diaphorina citri Kuwayama (Hemiptera: Psyllidae) is an important economic pest of citrus crops because it vectors the causal pathogen of huanglongbing (HLB, aka citrus greening). Population suppression of D. citri with insecticides has been disproportionally relied on for HLB management and a greater diversity of more sustainable tools is needed. Periglandula spp. is a fungal endosymbiont (family Clavicipitaceae) that forms a mutualistic relationship with members of plants in family Convolvulaceae. This association results in the production of ergot alkaloids that were previously documented as having psyllicidal properties. We investigated the mortality and behavior of D. citri exposed to crude extracts from morning glories in the plant family Convolvulaceae, as well as synthetic ergot alkaloids. Nymphs and adults were exposed to the crude plant extracts from Periglandula positive species of Convolvulaceae, as well as five synthetic ergot alkaloids. Treatments were prepared by exposing clippings of citrus to 100 ng/µL of crude extract from Periglandula-positive species of Ipomoea (I. imperati, I. leptophylla, I. pandurata and I. tricolor), and Turbina corymbosa, and from one Periglandula-negative species (I. alba) (100 ng/µL). Mortality of adult and nymphal D. citri was significantly higher than the control after exposure to extracts from I. tricolor and I. imperati. The synthetic ergot alkaloids, lysergol (10–100 ng/µL), ergonovine maleate (100 ng/µL), agroclavine (10–100 ng/µL), and ergosine (10–100 ng/µL) increased mortality of D. citri nymphs, while ergosine (100 ng/µL) and agroclavine (100 ng/µL) increased mortality of adults compared to water controls. Fewer D. citri adults settled on plants treated with crude extracts or synthetic ergot alkaloids than on water controls at 48 h after release. D. citri that fed on citrus leaves treated with 10 ng/μL solution of crude extract from the Periglandula-positive species Ipomoea (I. imperati, I. leptophylla, I. pandurata, I. tricolor), and Turbina corymbosa excreted significantly less honeydew compared with a negative water control and extract from Periglandula-negative species (I. alba). Our results indicate that crude extracts and ergot alkaloids exhibit toxic and sub-lethal effects on D. citri that could be useful for management of this pest.

Psyllids (Hemiptera: Psylloidea) are phloem-feeding insects that tend to be highly specific in their host plants. Some species are well-known agricultural pests, often as vectors of plant pathogens. Many pest psyllids colonize agricultural fields from non-crop reproductive hosts or from non-host transitory and winter shelter plants. Uncertainty about which non-crop species serve as sources of psyllids hinders efforts to predict which fields or orchards are at greater risk of being colonized by psyllids. High-throughput sequencing of trnL, trnF, and ITS was used to examine the dietary histories of three pest and two non-pest psyllid species encompassing a diversity of lifecycles: Cacopsylla pyricola (Förster) (Psyllidae), Bactericera cockerelli (Šulc) (Triozidae), Diaphorina citri Kuwayama (Liviidae), Aphalara loca Caldwell (Aphalaridae), and a Cacopsylla species complex associated with Salix (Malphighiales: Salicaceae). Results revealed an unexpectedly high level of feeding on non-host species by all five psyllid species. The identification of the dietary history of the psyllids allowed us to infer their landscape-scale movements prior to capture. Our study demonstrates a novel use for gut content analysis-to provide insight into landscape-scale movements of psyllids-thus providing a means to pinpoint the non-crop sources of pest psyllids colonizing agricultural crops. We observed previously unknown psyllid behaviors during our efforts to develop this method and discuss new research directions for the study of psyllid ecology.

Arrival and spread of nonnative plant species can lead to changes in structure and function of the native insect fauna that include shifts in host use by native insect herbivores. Well-documented examples showing that these host shifts also lead to range expansion of native herbivores are, however, surprisingly rare. Evidence for range expansion requires an understanding of the insect’s distribution preceding arrival of exotic species. These data often are lacking. The North American psyllid Bactericera maculipennis (Crawford) (Hemiptera: Triozidae), a specialist herbivore on plants in the Convolvulaceae, has been hypothesized to have expanded its geographic range after colonizing the exotic field bindweed (Convolvulus arvensis L.; Convolvulaceae). Efforts to test this idea run into the same retrospective problems typical of these analyses, in that the psyllid’s host plant and its geographic distribution preceding arrival of C. arvensis are uncertain. We used the psyllid’s current association with C. arvensis to help identify its natal (pre-bindweed) host, reasoning that a host shift by this specialist herbivore would be more likely if natal and exotic species are closely related. Phylogenetic analyses of plants, rearing trials, and field records led us to target species of Calystegia R. Brown (hedge and false bindweeds; Convolvulaceae) as natal hosts of B. maculipennis. The current presence of B. maculipennis in regions lacking Calystegia but where C. arvensis is common supported the hypothesis that arrival of the exotic weed C. arvensis has indeed led to range expansion by this host-specialized psyllid.

Potato psyllid (Bactericera cockerelli) is a vector of “Candidatus Liberibacter solanacearum”, the pathogen associated with potato zebra chip disease. While the psyllid apparently colonizes potato from non-crop Solanaceae or Convolvulaceae, the identity of these weed sources is uncertain. We examined susceptibility of ten non-crop species (one Convolvulaceae and nine Solanaceae) to potato psyllid and Liberibacter, with an emphasis on psyllid populations (northwestern and western haplotypes) and plant species that are present in the Pacific Northwest. Psyllids of the western haplotype survived and developed on all plant species, while psyllids of the northwestern haplotype survived on all species except Solanum physalipholium. All species except Lycium barbarum and Convolvulus arvensis were susceptible to Liberibacter. Results of our study provide the most extensive examination of plant suitability to potato psyllid and Liberibacter and will lead to improved capabilities of predicting which potato fields are at risk to arrival of infective psyllids.

Erythritol is a dietary sweetener that is used for low-calorie or diabetic diets. Although safe for human consumption, erythritol is lethal to certain Dipteran pests, but insecticidal effects of erythritol on phloem-feeding insects have yet to be examined. Our goal was to determine whether erythritol has insecticidal activity against pear psylla, Cacopsylla pyricola (Foerster) (Hemiptera: Psyllidae). We first demonstrated that ingestion of erythritol solutions compared with water by pear psylla caused reduced feeding, impaired motor functions, and reduced survival time of adults. We then tested whether foliar treatment of pear leaves with erythritol was also lethal to pear psylla. Foliar treatment of erythritol led to reduced 3-d survival of pear psylla nymphs and adults, and reduced rates of oviposition by pear psylla adults. Psylla adults also preferred to settle on untreated leaves than on erythritol-treated leaves in preference assays. Finally, we conducted field experiments to test whether applications of erythritol provided pear trees with protection against pear psylla under natural field conditions. Those experiments showed a reduction in pear psylla nymphs on erythritol-treated trees compared with untreated trees, but only if the erythritol was completely dissolved into solution by heating. Laboratory trials confirmed the importance of heating. Results of our experiments demonstrate that erythritol is insecticidal to pear psylla nymphs and adults and provide the first report that erythritol is lethal to a phloem-feeding insect. These findings suggest that erythritol may provide a new safe and effective tool for the management of pear psylla.

An insect trap constructed using three-dimensional (3D) printing technology was tested in potato (Solanum tuberosum Linnaeus; Solanaceae) fields to determine whether it could substitute for the standard yellow sticky card used to monitor Bactericera cockerelli (Šulc) (Hemiptera: Psylloidea: Triozidae). Sticky cards have shortcomings that prompted search for a replacement: cards are messy, require weekly replacement, are expensive to purchase, and accumulate large numbers of nontarget insects. Bactericera cockerelli on sticky cards also deteriorate enough that specimens cannot be tested reliably for the presence of vectored plant pathogens. A prototype trap constructed using 3D printing technology for monitoring Diaphorina citri Kuwayama (Hemiptera: Psylloidea: Liviidae) was tested for monitoring B. cockerelli. The trap was designed to attract B. cockerelli visually to the trap and then funnel specimens into preservative-filled vials at the trap bottom. Prototype traps were paired against yellow sticky cards at multiple fields to compare the captures of B. cockerelli between cards and traps. The prototype trap was competitive with sticky cards early in the growing season when B. cockerelli numbers were low. We estimated that two or three prototype traps would collect as many B. cockerelli as one sticky card under these conditions. Efficacy of the prototype declined as B. cockerelli numbers increased seasonally. The prototype trap accumulated nontarget taxa that are common on sticky cards (especially Thysanoptera and Diptera), and was also found to capture taxa of possible interest in integrated pest management research, including predatory insects, parasitic Hymenoptera, and winged Aphididae (Hemiptera), suggesting that the traps could be useful outside of the purpose targeted here. We believe that 3D printing technology has substantial promise for developing monitoring tools that exploit behavioural traits of the targeted insect. Ongoing work includes the use of this technology to modify the prototype, with a focus on making it more effective at capturing psyllids and less susceptible to capture of nontarget species.

Pear psylla, Cacopsylla pyricola (Forster) (Hemiptera: Psyllidae), is a key pest of pear and is a vector of “Candidatus Phytoplasma pyri”, the pathogen associated with pear decline disease. Although commercial pear trees are grafted to Phytoplasma-resistant rootstock, a recent report indicated that many C. pyricola in Washington and Oregon harbor this bacterium. Using fluorescence in situ hybridization, we confirmed that Phytoplasma invades internal tissues of C. pyricola, suggesting the pathogen is persistently transmitted. Because many persistently transmitted plant pathogens alter the flight behavior of their insect vectors, we examined the effects of Phytoplasma infection on dispersal of C. pyricola. Flight behavior was investigated using greenhouse bioassays, which demonstrated that Phytoplasma-infected psylla were less likely than uninfected psylla to emigrate from trees and become captured on yellow traps. Pear psylla occurs as two seasonal morphotypes—summerform and winterform—and the ef...

The Palearctic psyllid Heterotrioza chenopodii (Reuter) (Hemiptera: Psylloidea: Triozidae) belongs to a complex of psyllids having plants in the Amaranthaceae (including the former Chenopodiaceae) as hosts. Geographic records for this introduced species in North America date from 1988, and include a number of coastal regions in eastern Canada, the Northeastern U.S., inland Virginia, coastal British Columbia, California, and wetland habitats near Lincoln, Nebraska. We updated North American records for H. chenopodii to include inland Washington and Oregon, southwestern Idaho, northcentral California, western Colorado, and southern and central Alberta. Psyllids were collected from Atriplex micrantha (Amaranthaceae) and unidentified Atriplex species, and from yellow sticky cards that had been placed in potato fields to monitor arthropod pests of potatoes. Traits of the adult psyllid, fifth-instar nymph, and egg used in identifying specimens are summarized.We provide the first photographs of the egg, fifthinstar nymph, and terminalia of the adult male psyllid. Rearing trials showed that H. chenopodii developed on A. micrantha, A. hortensis, Chenopodium album, C. berlandieri, and garden beet, Beta vulgaris, but failed to develop on Amaranthus tricolor. Development was most rapid on the two Atriplex species. Heterotrioza chenopodii has been shown in Europe to exhibit photoperiod-controlled dimorphism in wing size, producing a long-winged form in spring and summer, and a short-winged form in autumn. We confirmed in rearing trials and by field collections that populations of H. chenopodii from central Washington State also exhibit this dimorphism. Short-winged forms began replacing long-winged forms in field populations between late August and early October.

Potato psyllid, Bactericera cockerelli (Sulc), causes economic damage to potato crops throughout the major potato growing regions of western North America. When cultivated crops are not available, potato psyllid often occurs on non-crop hosts. In the southern U.S. and northern Mexico, native species of Lycium (Solanaceae) are important non-crop hosts for the psyllid. We determined whether Old World species of Lycium now widespread in the Pacific Northwest are reservoirs of potato psyllid in this growing region. We examined Lycium spp. across a wide geographic region in Washington, Oregon, and Idaho at irregular intervals during three growing seasons. Potato psyllids were present at all locations. To determine whether Lycium is also a host during intervals of the year in which the potato crop is not available, we monitored a subset of these sites over the entire year. Six sites were monitored at 1- to 3-week intervals from June 2014 to June 2016. Psyllids were present on Lycium throughout the year at all sites, including during winter, indicating that Lycium is also a host when the potato crop is seasonally not available. Psyllid populations included a mixture of Northwestern and Western haplotypes. We observed well-defined spring and fall peaks in adult numbers, with peaks separated by long intervals in which psyllid numbers were very low. Seasonal patterns in psyllid numbers on these non-native Lycium hosts were very similar to what has been observed on native Lycium in the desert southwest region of the U.S. Our findings demonstrate that potato psyllid associates with Lycium across a broad geographic region within the Pacific Northwest. These results will assist in predicting sources of potato psyllid colonizing potatoes in this important growing region.

The Nearctic psyllid Bactericera maculipennis (Crawford) (Hemiptera: Psylloidea: Triozidae) is one of only five known species of Psylloidea worldwide whose host plants include species of Convolvulaceae (Solanales). Current checklists of North American Psylloidea report B. maculipennis only from California and Utah. Our surveys of field bindweed, Convolvulus arvensis L. (Convolvulaceae), an Old World plant introduced into North America, show that B. maculipennis is considerably more widespread than indicated by historical accounts. We update the psyllid's geographic range to include four states (Washington, Idaho, Oregon, Montana) not previously included in contemporary checklists. The egg and fifth instar nymph are described. We provide characters of the egg and nymph that distinguish this species from a congeneric species, Bactericera cockerelli (Sulc), occasionally found on field bindweed. Photographs of the male and female terminalia are provided. Bactericera maculipennis developed successfully on field bindweed and on several species of Ipomoea (Convolvulaceae) in laboratory assays. Overwintering females collected from leaf litter and dead or dormant stems of C. arvensis at locations in Central Washington mated and began to oviposit within 7 days of removal from the field, suggesting that B. maculipennis overwinters in a temperature-controlled quiescence rather than in a true reproductive diapause. Eggs and nymphs of B. maculipennis were found on stems of C. arvensis well into November in Central Washington, suggesting that this psyllid also may overwinter in pre-adult stages, as indicated by literature accounts from the 1940s and 1950s. Lastly, we propose that successful colonization of the invasive and exotic weed C. arvensis by B. maculipennis has allowed the psyllid to expand its geographic range well beyond historical boundaries. This conclusion is based upon the scarcity of native Convolvulaceae within regions in which the psyllid is newly recorded, combined with the now extensive distribution of the invasive C. arvensis in North America.

Changing climate and land‐use practices have the potential to bring previously isolated populations of pest insects into new sympatry. This heightens the need to better understand how differing patterns of host–plant association, and unique endosymbionts, serve to promote genetic isolation or integration. We addressed these factors in populations of potato psyllid, Bactericera cockerelli (Šulc), a generalist herbivore that vectors a bacterial pathogen (Candidatus Liberibacter solanacearum, causal pathogen of zebra chip disease) of potato (Solanum tuberosum L.). Genome‐wide SNP data revealed two major genetic clusters—psyllids collected from potato crops were genetically similar to psyllids found on a common weed, Lycium spp., but dissimilar from those found on another common non‐crop host, Solanum dulcamara L. Most psyllids found on Lycium spp. and potato represented a single mitochondrial cytochrome oxidase I (COI) haplotype that has been suggested to not be native to the region, and whose arrival may have been concurrent with zebra chip disease first emerging. The putatively introduced COI haplotype usually co‐occurred with endosymbiotic Wolbachia, while the putatively resident COI haplotype generally did not. Genetic intermediates between the two genetic populations of insects were rare, consistent with recent sympatry or reproductive isolation, although admixture patterns of apparent hybrids were consistent with introgression of genes from introduced into resident populations. Our results suggest that both host–plant associations and endosymbionts are shaping the population genetic structure of sympatric psyllid populations associated with different non‐crop hosts. It is of future interest to explicitly examine vectorial capacity of the two populations and their potential hybrids, as population structure and hybridization might alter regional vector capacity and disease outbreaks.

We embarked on a large project designed to help enhance biological control in apple, pear and walnut orchards in the western U.S., where management programs were in the midst of a transition from older organo-phosphate insecticides to mating disruption and newer reduced-risk insecticides. A “pesticide replacement therapy” approach resulted in unstable management programs with unpredictable outbreaks of spider mites and aphids. Our project was designed to provide growers and pest managers with information on the effects of newer pesticide chemistries on a suite of representative natural enemies in both the laboratory and field, potential of new monitoring tools using herbivore-induced plant volatiles and floral volatiles, phenology of the key natural enemy species, economic consequences of using an enhanced biological control program, and value of an outreach program to get project outcomes into the hands of decision-makers. We present an overview of both the successes and failures of the project and of new projects that have spun off from this project to further enhance biological control in our systems in the near future.

In this study we used sticky traps baited with plant volatile lures to monitor the biodiversity of natural enemies in orchard ecosystems in the western U.S. We compared the diversity of predator genera from season total trap catches in 37 different orchards (apple, cherry, pear and walnut) over a two-year period (2010−2011) using standardized Hill number biodiversity indices and community similarity profiles. For a subset of 23 of these orchards we were also able to monitor the change in biodiversity of predator genera over the full growing season in the different orchard crops. A total of 37,854 individuals from 31 different genera of foliage-active generalist predators were collected from all orchards combined. Mean sample coverage was high (0.98) and richness, diversity and evenness differed between crops in 2010, but not in 2011. There was more than 90% similarity in the richness of predator genera among crops and among orchards within crops, but a greater level of differentiation was observed among orchards when variation in their relative abundance and dominance in the communities was taken into account. There was a consistent rise in predator generic richness and diversity through the season in both years for apple, cherry and pear orchards, but in walnut orchards, a steep rise from March to May was followed by a decline through the rest of the season. In an additional component of the study, the species level similarity of predator and parasitoid communities was analyzed for total season trap catch data from six walnut orchards. The rarefied species richness of parasitoids was much greater than that for predators, although the diversity, evenness and dominance of the parasitoid species varied considerably among orchards. The results from this study highlight the fact that natural enemy communities in orchard ecosystems can be effectively monitored using plant volatile traps, and that these communities are surprisingly diverse despite frequent disturbance from pest management intervention.

The ability to estimate natural enemy abundance is crucial to the integration of biological control into IPM programs. Traditional sampling approaches for natural enemies are few and most are inefficient, but recent studies suggest attraction of natural enemies to plant volatiles may be a useful proxy for direct sampling. We evaluated various combinations of herbivore-induced plant volatiles and floral volatiles as monitoring tools for natural enemies found in apple, pear, and walnut orchards in California, Oregon, and Washington. In 2010 we used a full factorial experimental designs to evaluate lures for all combinations of acetic acid (AA), acetophenone (AP), phenylacetaldehyde (PAA) and 2-phenylethanol (PE). Of nine natural enemy taxa analyzed, we found syrphid flies responded strongly to PE, but combining AA with PE attenuated trap catch and combining PAA to PE eliminated the activity of PE. Chrysoperla spp. (Chrysopidae) responded strongly to most of the individual compounds and the various interactions between the components allowed multiple ways to achieve roughly the same trap catch. All of the hymenopteran taxa collected responded strongly to PAA, and PAA containing lures were nearly always a component of the top eight lures. A smaller factorial experiment testing all possible combinations of AA, PAA and methyl salicylate (MS) showed that single component AA or MS lures were generally not significantly different than the controls for all taxa tested, but for the hymenopteran taxa, traps baited with MS+PAA performed the best or were not significantly different than the best performing lure. A 2011 trial was conducted to test the influence of the addition of AA and/or MS on previously tested lures. Combining AA or MS with other lures, improved the capture of Chrysoperla spp.; Scaeva pyrastri (L.) (Syrphidae) capture was enhanced when MS was used with PE; and PE was attractive to the three syrphid flies, Chrysoperla spp., and the parasitoid Aphelinus mali (Haldeman) (Aphelinidae). The differential responses to various blends exhibited among taxa show that combinations of plant volatiles can be chosen to increase specificity of attraction to a few taxa or increase the number of species attracted. This flexibility should add to the general value and breadth of use of plant volatile monitoring lures.

Codling moth, Cydia pomonella (L.), is the key pest of pome fruits in many temperate areas of North America, Eurasia, South Africa, South America and Australia. Many predatory arthropods species are found in organic apple orchards of central Washington; here we use PCR-based gut content analysis of arthropod predators to identify predators that attack codling moth. Predators were sampled from tree canopies, tree trunks and from the understory and were homogenized in a lysis buffer to provide a template for Direct PCR. PCR showed 8.9% of 2591 predators had preyed on C. pomonella. Spiders, including 25 genera from 15 families, two carabid beetle species (Pterostichus melanarius (Illiger) and Harpalus pennsylvanicus DeGeer) and the European earwig (Forficula auricularia [L.]) represented 87% of predator specimens analyzed and were 8.2%, 8.3% and 14.7% positive for C. pomonella. PCR products from 38% of predators that appeared positive for C. pomonella COI were sequenced; all showed 99% or more similarity to C. pomonella COI sequences in GenBank. Digestion rates of adult earwigs fed on mature codling moth larvae showed a detection half-life of 3.7 days; half-life from the fecal pellets from the same earwigs was 3.6 days. When fed mature codling moth larvae, the carabid P. melanarius showed a digestion half-life of 3.14 days. Identification of the key predators of C. pomonella can guide the use of selective insecticides and the conservation of these natural enemies, enhancing biological control and supporting stable IPM programs in pome fruit orchards in the western USA.

The effects of codling moth (Cydia pomonella (Linnaeus)) (Lepidoptera: Tortricidae) management programs on secondary pests of apple were examined from 2008 to 2011 in five replicated large-plot trials. The orchards were chosen for a history of Eriosoma lanigerum (Hausmann) (Hemiptera: Aphididae) and tetranychid mite outbreaks. Programs covered the first, second, or both generations of C. pomonella, and employed some of the newer insecticides for comparison to older materials. Increased levels of E. lanigerum were consistently associated with the use of spinetoram and novaluron throughout the tests. The mechanism of disruption was not completely clear, but suppression of Forficula auricularia Linnaeus (Dermaptera: Forficulidae) and Aphelinus mali (Haldeman) (Hymenoptera: Aphelinidae) were associated with the use of these materials. Methoxyfenozide, chlorantraniliprole, and azinphos-methyl did not disrupt biological control of tetranychid mites or aphids, and negative effects on natural enemies were infrequent. Lambda-cyhalothrin provided direct control of aphid species, thus reduced levels of natural enemies could also be ascribed to lack of prey. The effect of some of the insecticide applications made during the first generation were evident for many months after the application in terms of pest and natural enemy populations; however, attempts to mitigate disruptive effects by shifting the use of materials to the second generation of C. pomonella were not successful. The effect on biological control of tetranychid mites was less consistent, although some detrimental effects (increased pest or decreased predatory mite levels) were associated with spinetoram, novaluron, and lambda-cyhalothrin. The difficulties in sampling natural enemies and determining their impact made pest outbreaks the most reliable indicator of pesticide-induced disruption.

A model predicting phenology of adult Chrysopa nigricornis (Burmeister) (Neuroptera: Chrysopidae) in orchards was developed from field (trapping) data supplemented with development data collected under laboratory conditions. Lower and upper thresholds of 10.1 °C and 29.9 °C, respectively, were estimated from published and unpublished laboratory observations, and were used to develop a phenology model. Season-long field data were collected using white delta traps that had been baited with squalene, a volatile shown previously to be highly attractive to C. nigricornis . The model was developed from data collected in three Washington apple orchards, and was validated using independent data sets collected from apple, sweet cherry, pear, and walnut orchards over a 2–4 year period across a much wider geographic region. We found that the mean absolute deviation across all crops and years was 39.7 ± 1.2 day-degrees (DD), or 4.4 ± 0.14 days. Populations of C. nigricornis from walnut orchards in California emerged 105 DD later than those in Oregon and Washington, thus requiring correction of average time of first trap catch in California to synchronize models. The ability to use a single model across multiple crops, different prey species and abundances, and different pesticide regimes demonstrates that phenology models for generalist predators may have broader application to IPM programs in other cropping systems.

The nontarget effects of insecticide programs used to control codling moth, Cydia pomonella L. (Lepidoptera: Tortricidae), were studied in large-plot field trials in apples, pears, and walnuts in the western United States. We assessed the health of the natural enemy community by sampling the abundance of natural enemies and by monitoring for outbreaks of secondary pests. The insecticides used in the field tests overlapped those tested in laboratory bioassays. Using these parallel lab and field studies, we examined two hypotheses: 1) pesticides found to have negative effects on natural enemy fitness in laboratory bioassays will predict reductions in natural enemy densities in the field, and 2) reductions in natural enemy densities in the field will result in outbreaks of secondary pests. We found only one clear instance, Forficula auricularia (L.) (Dermaptera: Forficulidae), where laboratory results documenting negative effects corresponded to a significant reduction in field studies (apple). This same instance was the only case where a reduction in a natural enemy population was associated with a significantly increased density of a secondary pest, Eriosoma lanigerum (Hausmann) (Hemiptera: Aphididae). There were several instances where secondary pest outbreaks were associated with unchanged or even increased natural enemy densities. The limited number of field trials, variability in field trial conditions among years and sites, duration of the negative effect relative to sampling interval, sampling efficiency, plot size/inter-plot movement, and compensation by other natural enemies attracted to a large host/prey resource may all have contributed to the poor predictive success. Overall, the laboratory bioassays predicted a far greater negative impact than was found in the field trials.

Clubiona pacifica Banks, 1896 is a common secondary occupant of lepidopteran leafrolls on alders (Alnus spp.). We collected rolled alder leaves at riparian sites in Washington State to determine seasonal phenology of C. pacifica and to examine egg laying and predatory activity. All stages of the spider occurred in rolled leaves, and spiders were found in rolled leaves throughout the season. Rolled alder leaves were used by C. pacifica as protected sites in which to molt and spend inactive periods and possibly to seek prey. Field observations and greenhouse experiments indicated that C. pacifica is capable of preying upon leafroller larvae. Occasionally, lepidopteran leafrolls were used by C. pacifica as ready-made chambers in which to oviposit, but more commonly the female spider herself folded an alder leaf to form a protective retreat for oviposition. These egg sac retreats and the associated egg sac are described and illustrated. After eclosion C. pacifica passes through a prelarval stage, a larval stage, and six nymphal stages before reaching adulthood. The principal period of reproduction and egg deposition is June and July, and most post-larval stages of C. pacifica appear to overwinter. We postulate that some individuals require two years to complete their life cycle although others may do so in a shorter time. Three ichneumonid wasps parasitized C. pacifica: Gelis sp. attacked the eggs; Schizopyga frigida and Zaglyptus varipes parasitized immature and adult spiders.

Potato psyllid, Bactericera cockerelli (Sulc) (Hemiptera: Triozidae), is a key pest of potato (Solanum tuberosum L.) and other solanaceous crops (Solanales: Solanaceae) as a vector of “Candidatus Liberibacter solanacearum” (Lso), the pathogen associated with zebra chip disease of potato. Potato psyllid populations typically are monitored using sticky card traps, and psyllids collected from sticky traps often are subjected to polymerase chain reaction (PCR) to monitor the incidence of Lso within psyllid populations. Psyllids collected from sticky traps are often mangled, desiccated, and coated with sticky residue, which may interfere with detection of Lso by PCR. A recently developed prototype 3-dimensional-printed trap that captures insects directly into a preservative (70% ethanol) was previously tested for monitoring psyllid populations. The capture of psyllids directly into a preservative may reduce degradation of DNA or protect specimens from PCR-inhibiting contaminants, thus improving the detection of Lso by PCR. Our goal was to compare the detectability of Lso in psyllids captured into preservative (prototype trap) to that in psyllids removed from sticky card traps. Overall, detection rates were higher in psyllids from the prototype trap than from sticky card traps. This improvement in Lso detection appeared to be partly due to the specimens yielding more DNA of higher quality. Results of this study demonstrate that compared with sticky card traps, a trap that captures psyllids directly into a preservative provides higher quality specimens for collection of molecular data, including pathogen diagnosis, population genetics, and molecular gut content analysis.

Plant species in the family Solanaceae are the usual hosts of potato psyllid, Bactericera cockerelli (Šulc) (Hemiptera: Psylloidea: Triozidae). However, the psyllid has also been shown to develop on some species of Convolvulaceae (bindweeds and morning glories). Developmental success on Convolvulaceae is surprising given the rarity of psyllid species worldwide associated with this plant family. We assayed 14 species of Convolvulaceae across four genera (Convolvulus, Calystegia, Ipomoea, Turbina) to identify species that allow development of potato psyllid. Two populations of psyllids were assayed (Texas, Washington). The Texas population overlaps extensively with native Convolvulaceae, whereas Washington State is noticeably lacking in Convolvulaceae. Results of assays were overlain on a phylogenetic analysis of plant species to examine whether Convolvulaceae distantly related to the typical host (potato) were less likely to allow development than species of Convolvulaceae more closely related. Survival was independent of psyllid population and location of the plant species on our phylogenetic tree. We then examined whether presence of a fungal symbiont of Convolvulaceae (Periglandula spp.) affected psyllid survival. These fungi associate with Convolvulaceae and produce a class of mycotoxins (ergot alkaloids) that may confer protection against plant-feeding arthropods. Periglandula was found in 11 of our 14 species, including in two genera (Convolvulus, Calystegia) not previously known to host the symbiont. Of these 11 species, leaf tissues from five contained large quantities of two classes of ergot alkaloids (clavines, amides of lysergic acid) when evaluated by LC-MS/MS. All five species also harbored Periglandula. No ergot alkaloids were detected in species free of the fungal symbiont. Potato psyllid rapidly died on species found to harbor Periglandula and fungus-produced alkaloids, but survived on species in which the mutualism was absent. These results support the hypothesis that a plant-fungus symbiotic relationship affects the suitability of certain Convolvulaceae to potato psyllid.

Examination of minute pirate bugs, Orius spp. (Hemiptera: Heteroptera: Anthocoridae), from a broad geographic range in the western United States prompted a reappraisal of the taxonomic composition of the fauna native to the western United States and Canada. Current syntheses and catalogs list three species of Orius native to this region. In a previous study, we showed how geographic variation in external traits of one of these species, Orius diespeter Herring, 1966, had led to mistakes in identification of species within this complex. More extensive collecting efforts have now led to the discovery of specimens having traits not fully consistent with descriptions of any described species. We provisionally categorized these unresolved specimens into one of eight phenotypic groups based upon combinations of body size, visual appearance of genitalia, association with specific plant taxa, and geographic source. Genitalia from 382 specimens were then measured to determine whether phenotypic groupings were confirmed by statistical analysis of genitalic morphology. Principal components analysis showed that size and shape of the male’s paramere differed among phenotypes. The paramere of unresolved specimens often diverged from the paramere of described species. Length of the female’s copulatory tube differed between several of the unresolved phenotypes and described species. Analysis of DNA sequences showed that five of the eight phenotypes diverged genetically from other phenotypes and from described species. DNA sequence data did not separate two described species ( Orius tristicolor (White, 1879) and Orius harpocrates Herring, 1966), suggesting that these two species are a single species. The combined morphological and genetic evidence indicates that the Orius fauna of the western United States is composed of a mix of two described species and possibly five undescribed cryptic species. We summarize the known distributions of described and cryptic undescribed species, and discuss the implications of our work for the biological control community.

Carnivores indirectly protect plants by reducing herbivory. This important ecosystem service can be undermined, however, as carnivores feed upon fellow carnivores. Such intraguild predation is exceedingly common, yet measurement of the degree to which this occurs has remained elusive due to difficulties in measuring the trophic tendencies of free-roaming animals. Conventional molecular methods, such as bulk-isotopic analyses, do not produce reliably accurate trophic position estimates, and often the inaccuracy is substantial. With the advent of compound-specific isotopic analysis (CSIA), it is now possible to accurately quantify the lifetime trophic tendencies of wild carnivore populations. Unfortunately, CSIA is extraordinarily expensive and time-consuming, limiting the number of samples that can be analyzed. The need for high-quality trophic information has to be balanced with the inaccessibility of CSIA. Here, we propose coupling CSIA-derived trophic position estimates with conventional bulk-15N analysis, effectively calibrating site-specific bulk-15N data and thereby allowing for trophic position estimation using bulk data alone. We also create a framework that uses trophic position as a basis to characterize carnivores as beneficial for crop protection. Within an agricultural field, we demonstrated the utility of this new approach by measuring the trophic positions of six common arthropod species. We then compare these trophic position estimates to those deriving from conventional bulk-15N analysis. Our hybrid approach produced more accurate trophic position estimates than the stand-alone bulk-15N method. Ultimately, we were able to examine enough specimens to determine which carnivore populations were likely beneficial for plant protection, and which were not.

The potato psyllid, Bactericera cockerelli (Sulc) (Hemiptera: Triozidae) is a small phloem-feeding insect that develops almost exclusively on plants within the Solanaceae (Fig. 1A). The psyllid was described in 1909 by Karel Sulc from specimens collected in Boulder, Colorado, and is found in Mexico, Central America, the western U.S., and southern Canada, and as an introduction in New Zealand (Wallis 1955, Teulon et al. 2009, Munyaneza 2012). Outbreaks of potato psyllid in North America occurred at regular intervals in potatoes, tomatoes, and peppers beginning in the late 1800s and extending into the mid-1900s, largely along a corridor on both sides of the Rocky Mountains. The outbreaks failed to extend into the Pacific Northwest. That pattern changed dramatically in 2011, when an outbreak of potato psyllid caused massive economic losses to potato growers in Washington, Oregon, and Idaho. Losses were due to a new tuber disorder (“zebra chip”; Fig. 1 B-C), now known to be associated with a bacterium that is vectored by potato psyllid. Fig. 1. (A) Adult potato psyllid. (B, C) Discoloration of infected fresh tubers and of tuber slices after frying. The historical absence of psyllid problems in the Pacific Northwest means that our understanding of psyllid biology under Pacific Northwest conditions is woefully lacking. The outbreak in 2011, coupled with our limited …

Orius sibiricus Wagner, a dark-colored minute pirate bug widespread in the Eurasian Steppe, is recorded from sites near the Yukon River in Yukon, Canada. This species is distinguished from the melanic phenotype of Orius diespeter Herring by the more deeply and uniformly punctured dorsum, the subangular anterolateral angles of the pronotum of the female, the lack of denticles on the forefemora of the male, the entirely dark embolium, and the shape of the paramere. Collection sites for O. sibiricus in Yukon are in ecoregions that contain sun-warmed steppe in or near East Beringia. The species has also been collected in eastern Siberia from steppe sites within the boundaries of West Beringia. Specimens of O. sibiricus from East Beringia and West Beringia have very similar genitalic structures. Orius sibiricus has been collected from the plant genera Artemisia, Caragana and Spiraea, as well as from unidentified herbaceous vegetation. The geographical distribution of O. sibiricus suggests a relativel...

Four mitochondrial (cytrochrome oxidase I) haplotypes of the potato psyllid, Bactericera cockerelli (Sulc) (Hemiptera: Triozidae), have been identified in North America: western, central, northwestern, and southwestern. A recent study found that females of the northwestern haplotype mated by males of the western or central haplotypes failed to produce viable eggs. Our goal was to determine whether these patterns in reproductive incompatibility are associated with differences among haplotypes in the presence of cytoplasmic incompatibility-inducing bacteria, Wolbachia or Cardinium. Polymerase chain reaction (PCR) revealed that psyllids of the western and central haplotypes were both simultaneously infected with two strains of Wolbachia, but Wolbachia was not detected in psyllids of the northwestern haplotype. PCR using archived DNA from field-collected psyllids confirmed patterns in Wolbachia infection among the western, central, and northwestern haplotypes, and also indicated that Wolbachia was no...

Defense elicitors are products that activate acquired defense responses in plants, thus rendering the plants less susceptible to attack by a broad range of pests. We demonstrated previously under laboratory conditions that foliar applications of the defense elicitors Actigard (acibenzolar-S-methyl), Employ (harpin protein), or ODC (chitosan) to potted pear trees (Pyrus communis L.) each caused an increase in mortality of Cacopsylla pyricola (Förster) (Hemiptera: Psyllidae) nymphs and altered the settling and oviposition behavior of the adults. In this study, we monitored C. pyricola populations over a 3-yr period on orchard-grown trees treated with water (untreated control), Actigard, Employ, or ODC. Fewer nymphs were observed on trees treated with elicitors compared with untreated trees in both 2014 and 2016. A similar but statistically nonsignificant pattern was observed in 2015 when nearly 30% fewer nymphs were observed on trees treated with elicitors versus untreated controls. Observed reductions in psyllid numbers by defense elicitors were modest and do not warrant the use of these products alone for managing C. pyricola. However, these products are often used for management of fire blight, and our observations that elicitors also reduce C. pyricola populations may be useful for system-wide integrated pest management approaches.

Psyllids (Hemiptera: Pyslloidea) harbor bacterial symbionts in specialized organs called bacteriomes. Bacteriomes may be subject to manipulation to control psyllid pests including Bactericera cockerelli (Sulc) (Hemiptera: Triozidae) and Cacopsylla pyricola (Forster) (Hemiptera: Psyllidae) if the biological and ecological functions of bacteriomes and symbionts were better understood. To support research on psyllid bacteriomes and symbionts, this report provides descriptions of bacteriomes from B. cockerelli, C. pyricola, and Aphalara calthae L. (Hemiptera: Aphalaridae). In each species, bacteriomes were situated between the reproductive organs and the posterior midgut appendages. Tracheae attached to, and deeply penetrated the lateral margins of the bacteriome lobes. The shape of the bacteriome of A. calthae differed from those of B. cockerelli and C. pyricola, which were similar in appearance. Bacteriomes of females were larger and more darkly pigmented compared with those of males, regardless of psyllid species. Bacteriocytes of females also stained more intensely with hemotoxylin-eosin compared with those of males. These descriptions will be useful in future studies on the roles of bacteriomes and symbionts in interactions between psyllids, host-plants, and psyllid-vectored plant pathogens.

The eastern foothills of the Cascade Range in Washington State, United States of America are west of the State's major fruit-producing region. Alders (Alnus Hill (Betulaceae)), an important floristic component of riparian communities in the Cascade Range foothills, were surveyed for leafrolling caterpillars (Lepidoptera: Tortricidae) that might serve as alternate hosts for parasitoids of orchard pest leafrollers, particularly the nonnative wasp Colpoclypeus florus (Walker) (Hymenoptera: Eulophidae). Tortricid leafrollers were abundant on alder, but reared parasitoids did not include C. florus. Survey results also revealed that rolled leaves were secondarily colonised by a wide variety of predatory and phytophagous arthropods. Rolled leaves were almost 10-fold more likely to be occupied by predatory arthropods than adjacent, roll-free leaves. Phytophagous thrips and mites showed a similar preference for rolled leaves. The most abundant predaceous arthropods in the leafrolls were Anthocoris antevolens White (Hemiptera: Anthocoridae), found in 4.4% of leafrolls, and the spider Clubiona pacifica Banks (Araneae: Clubionidae), found in 8.3% of leafrolls. Both species, and several other predatory insect and spider species found in the rolled leaves, also occur in eastern Washington orchards where they contribute to biological control. Because of its frequent colonisation by beneficial arthropods, alder may prove useful in conservation biological control programs.

Galendromus occidentalis (Nesbitt) is one of several phytoseiid species that are available for purchase to supplement endemic predator populations that are not providing sufficient control of spider mites. We performed a series of releases of commercially reared G. occidentalis in commercial apple (Malus domestica Borkhausen) orchards in Washington from 2010 to 2012. Releases of up to 50,000 mites per acre did not lead to an increase in populations of predatory mites or to a decrease in populations of pest mites. Assessments of mite numbers in shipments and quality (survival and fecundity) of those mites indicated that the commercial insectary was correctly estimating the number of predatory mites in their shipments, and that predator quality was not different than a laboratory colony. Finally, a predator-prey model that used the intrinsic rates of increase of tetranychid prey and the prey consumption rate of the predator indicated that the density of G. occidentalis required to control the prey at the action threshold was not economically feasible. We conclude that G. occidentalis cannot be used to bring about short-term control via inundative releases in crops such as apple with large canopy volumes.

We investigated the effect of mating on female attractiveness and male responsiveness in the potato psyllid, Bactericera (= Paratrioza) cockerelli (Sulc) (Hemiptera: Triozidae), a major pest of potato. Assays were designed to examine response by mated or virgin males to volatile odors produced by virgin or mated females. Mating induced a behavioral refractory period during which males were not attracted to females. The refractory period was shown to include a mating-induced lowering of male response to females, as well as a mating-induced lowering of female attractiveness. The refractory period was longer in females (at least 48 h) than in males (less than 24 h). Following a post-copulatory refractory period of 96 h, females were as attractive to males as virgin females. We also explored how rapidly spermatophores became depleted in females as a function of the amount of time following mating. The percent of females carrying spermatophores and the number of spermatophores per female decreased with the length of the female post-mating period, possibly due to the absorption by females of the spermatophores and their content. By 96 h following mating, spermatophores were not visible in the majority of females, thus the absence of spermatophores in females of this species should not be used as evidence of mating status.

Specimens of Anthocoridae, Lyctocoridae, and Lasiochilidae (Hemiptera: Heteroptera) intercepted at various ports-of-entry and housed at the Animal and Plant Health Inspection Services (APHIS) Miami Plant Inspection Station (Miami, FL) were examined and identified to species or genus. The collection comprised 127 specimens intercepted primarily at the Miami Inspection Station. Specimens were distributed among 14 genera and 26 identified species in 3 families: Anthocoridae (99 specimens), Lyctocoridae (9 specimens), and Lasiochilidae (19 specimens). Seventy-eight of the 127 specimens could be identified to species. The remaining 49 specimens were identified to genus, except for 2 specimens that could not be identified below tribal level. For each identified species, we provide brief descriptions of habitat and prey preferences (where known), and a summary of currently known geographic range. Fifty-six of the 127 specimens were of a single genus: Orius Wolff, 1811 (Anthocoridae: Oriini). The specimens of Orius comprised at least 9 different species; 17 specimens could not be identified to species. The 127 specimens were intercepted on a variety of commodities, including ornamental plants, cut flowers, bouquets, agricultural produce, ceramic tiles, and wood products. Fourteen of the identified species do not currently occur in the continental U.S.; moreover, the 49 specimens that we could identify only to genus very likely also are of species not currently established in the continental U.S. The majority of intercepted specimens (93 of 127) arrived on shipments from the Neotropics and Europe. Specimens of Lasiochilidae and Scolopini (Anthocoridae) were entirely from shipments arriving from the Neotropical region. Specimens of Orius were intercepted on shipments from the Neotropics, Mexico, Europe, and Sub-Saharan Africa. Finally, 10 species were intercepted on shipments arriving from countries not previously listed as being part of their known geographic ranges. One Old World species, Cardiastethus affinis Poppius, 1909, known previously only from East Africa and India, was intercepted in 2 separate shipments arriving from Central America and the West Indies.

Insects often have facultative associations with bacterial endosymbionts, which can alter the insects' susceptibility to parasitism, pathogens, plant defenses, and certain classes of insecticides. We collected pear psylla, Cacopsylla pyricola (Forster) (Hemiptera: Psyllidae), from pear orchards in Washington and Oregon, and surveyed them for the presence of bacterial endosymbionts. Adult psyllids were collected on multiple dates to allow us to assay specimens of both the summer ("summerform") and the overwintering ("winterform") morphotypes. Two endosymbionts, Arsenophonus and Phytoplasma pyri, were detected in psyllids of both morphotypes in both states. A separate survey revealed similar associations present in psyllids collected in 1987. Arsenophonus was present in 80-100% of psyllids in all growing regions. A slightly lower proportion of summerform than winterform psyllids harbored the bacterium. Arsenophonus was present in the bacteriomes and developing oocytes of most psyllids, indicating that this endosymbiont is transovarially transmitted. This bacterium was also observed in the salivary glands and midguts of some psyllids. Phytoplasma pyri was present in a greater proportion of pear psylla from orchards near Yakima, WA, than from other regions, and was present in a higher proportion of winterforms than summerforms. We did not detect Wolbachia, Profftella, or Liberibacter europaeus, which are associated with other psyllid pests, including other species of Cacopsylla. Our study is the first to survey North American populations of C. pyricola for endosymbionts, and provides a foundation for further research on how bacterial associations may influence the ecology and management of this pest.

Potato psyllid, Bactericera cockerelli (Sulc) (Hemiptera: Triozidae), is a key pest of potato (Solanum tuberosum L., Solanales: Solanaceae) and a vector of "Candidatus Liberibacter solanacearum," the pathogen associated with zebra chip disease. In addition to its presence on cultivated crops, the psyllid regularly occurs on numerous uncultivated annual and perennial species within the Solanaceae. A better understanding of landscape-level ecology of B. cockerelli would substantially improve our ability to predict which potato fields are most likely to be colonized by infected psyllids. We developed three PCR-based methods of gut content analysis to identify what plant species B. cockerelli had previously fed upon. These methods included-1) sequencing PCR amplicons of regions of plant-derived internal transcribed spacer (ITS) or the chloroplast trnL gene from psyllids, 2) high-resolution melting analysis of ITS or trnL real-time PCR products, and 3) restriction enzyme digestion of trnL PCR product. Each method was used to test whether we could identify psyllids that had been reared continuously on potato versus psyllids reared continuously on the perennial nightshade, Solanum dulcamara. All three methods of gut content analysis correctly identified psyllids from potato and psyllids from S. dulcamara Our study is the first to demonstrate that plant DNA can be detected in a phloem-feeding insect. Gut content analysis, in combination with other landscape ecology approaches, could help elucidate patterns in landscape-level movements and host plant associations of B. cockerelli.

Predatory insects and spiders were collected from apple orchards in two geographic regions of Central Washington State, United States of America to assess seasonal phenology and diversity of the generalist predator community. Arthropods were collected from orchard canopy every 3–7 days over two growing seasons (March–October) at seven organically managed and two insecticide-free orchards. Over 35 000 specimens and 80 species of spiders (Araneae), ladybeetles (Coleoptera: Coccinellidae), lacewings (Neuroptera), and predatory true bugs (Hemiptera) were collected. Composition of insect and spider communities differed between the two geographic regions. Indicator species analysis identified several species that had a significant association with one of the two regions. Counts of the most common taxa were examined in detail on a calendar date basis to determine seasonal phenology of adult and immature stages. We observed substantial differences among taxa in number of generations, seasonal timing of first appearance in orchards, overwintering stages, and seasonal occurrence of the adult and immature life stages in orchards. Understanding seasonal phenology of natural enemies in orchards is a core requirement in integrated pest management programs for apple pests, and results of this study provide this information for the generalist predator community of orchards in the Pacific Northwest.

The potato psyllid, Bactericera (= Paratrioza) cockerelli (ˇ Sulc) (Hemiptera: Triozidae), is a major pest of potato. Studies were conducted to determine the age at which bothmalesandfemalesreachreproductivematurityandtheeffectofageandtimeofdayon sex attraction. Adult B. cockerelli reach reproductive maturity within 48 h post-eclosion, with females being mature on the day of eclosion and males at 1 day post-eclosion. Oviposition generally began 2 days after mating but was delayed when females mated within 2 days post-eclosion. In laboratory olfactometer assays, the age of females used as odor sources and the age of males assayed to these odors did not affect sex attraction, with both younger (1-4-day-old) and older (8-10-day-old) males being attracted to females, regardless of female age (1-4-day-old or 8-10-day-old). Males assayed to live females at different times during the photophase (between 8:00 and 20:00 hours) were attracted to females between 11:00 and 17:00 hours, showing a temporal periodicity in sex attraction with B. cockerelli at least during the photophase.

We compared morphology of internal reproductive anatomy and genitalia among 10 species of North American Anthocoris (Hemiptera: Heteroptera: Anthocoridae). Reproductive structures of males, including internal reproductive organs (testes, seminal vesicles, ejaculatory bulb, phallus), the paramere, and the endosoma, were found to vary in size, shape, and appearance among the 10 species, although with similarities among species within some groupings. All species except Anthocoris bakeri Poppius have two testicular follicles per testis; A. bakeri has five to seven follicles per testis. In seven of the 10 species, a longitudinal groove was found to be present on the paramere; we believe this groove functions to guide the male's intromittent organ as it enters the female during copulation. Variation among species in morphology of the male's inflated endosoma included differences in length, presence or absence of looping, and in presence of spinulate, dentate, or tuberculate projections. The summary presented here is the first description of the endosoma for any species of Anthocoris. We observed substantial variation among species in length of the female's copulatory tube (i.e., the organ which receives the male's intromittent organ), although again with some similarities among certain groupings of species. Variation in length of the female's copulatory tube parallels variation in length of the male's endosoma, which suggests that morphology of genitalia within this genus has coevolved between sexes.

We examined the role of chemical signals in sex attraction of pear psylla, Cacopsylla pyricola (Förster), assessing the response of summerform male and female psyllids to male- and female-produced volatile chemicals. Male psyllids were attracted to odors from live females and pentane extracts of females. Extracts of females were as attractive to males as live females, suggesting that the female-produced volatile chemicals responsible for male attraction might be isolated by extracting females with pentane. Females were not attracted to odorants from live females and tended to avoid odorants from extracts of females. Furthermore, summerform males and females were not attracted or repelled by male-produced odorants from live males or extracts of males. Results of olfactometer assays using male summerform C. pyricola are consistent with results from earlier studies with the winterform morphotype of this species.

Potato psyllid, Bactericera cockerelli , is a serious pest of potato and other solanaceous vegetables in the United States, Mexico, Central America, and New Zealand and is responsible for transmission of Candidatus Liberibacter solanacearum which causes a disease known as “zebra chip” (ZC). Entomopathogenic fungi could provide a viable component for an integrated pest management strategy for control of B. cockerelli and other potato pest insects. Three field trials of commercial formulations of Metarhizium anisopliae (F 52®, Novozymes Biologicals) and Isaria fumosorosea (Pfr 97®, Certis USA) and abamectin (Agri-Mek®, Syngenta, USA) were conducted in Weslaco, Texas. Rates are expressed in quantity of product delivered in 375–470 l of water/ha. F 52 applied at 0.51, 1.1, and 2.2 l/ha and Agri-Mek applied at 584 ml/ha produced reductions of B. cockerelli eggs and nymphs of 45%, 59%, 67%, and 63%, respectively. Only Agri-Mek significantly reduced plant damage. Pfr 97 at 1.1 kg/ha with and without 1% Trilogy® (neem oil, Certis, USA), and Agri-Mek at 584 ml/ha resulted in psyllid reductions of 78%, 76%, and 84%, respectively. Significantly decreased plant damage and ZC symptoms were observed for all treatments. Tuber yields for Pfr plus Trilogy and Agri-Mek were significantly higher than the control. F 52 applied at 1.1 and 2.2 l/ha and Pfr 97 at 1.1 and 2.2 kg/ha produced 62%, 62%, 66%, and 65% reduction, respectively. Tuber yield for both rates of Pfr and the high rate of F 52 were significantly higher than the control. All fungal treatments significantly reduced plant damage and ZC symptoms.