The house fly is a ubiquitous pest commonly associated with animal facilities and urban waste. When present in large numbers, house flies can negatively impact humans and animals through nuisance and the transmission of pathogens. Since the development of fly traps and sticky papers to capture flies in the late 1800s, these and other methods have been used as a means to monitor change in house fly density or fly activity over time. Methods include substrate sampling to record density of immature flies, visual observations of adult fly activity, instantaneous counts of landing or resting flies, accumulation of adult flies on/in traps, or accumulation of fly fecal and regurgitation spots deposited by flies onto white cards. These methods do not estimate true house fly density, but rather provide an index of house fly activity that is related to both fly density and the frequency of individual fly behavior (e.g., frequency of flight, landing events) and which is likely more predictive of negative impacts such as nuisance and pathogen transmission. Routine monitoring of house fly activity is a critical component of a house fly management program. Fly activity should be held to a level below a predetermined activity threshold (‘action threshold') above which negative impacts are anticipated to occur. This article is a review of methods utilized for monitoring house fly (Diptera: Muscidae) activity.

Queens and workers are very distinct phenotypes that develop from the same genome. Larvae from worker cells up to 3.5 d old can be transferred to larger queen cells and will subsequently be reared as queens and develop into functional queens. This has become a very popular queen rearing practice in contemporary apiculture. Here we used RNA-Seq to study the consequences of rearing queens from transplanted worker larvae on the transcriptome of the adult queens. We found that queens reared from transferred older larvae developed slower, weighted less, and had fewer ovarioles than queens reared from transferred eggs, indicating queens were cryptically intercaste. RNA-Seq analysis revealed differentially expressed genes between queens reared from transferred larvae compared with queens reared from transferred eggs: the older the larvae transferred, the greater the number of differentially expressed genes. Many of the differentially expressed genes had functions related to reproduction, longevity, immunity, or metabolism, suggesting that the health and long-term viability of queens was compromised. Our finds verify the previous studies that adult queens reared from older transferred larvae were of lower quality than queens reared from transferred eggs or younger larvae.

Graphical Abstract

The efficacy and safety of dry and wet formulations of three nonsynthetic compounds, oxalic acid (OA), thymol (T), and oregano oil (OO), for the control of Varroa destructor Anderson and Trueman infestations in honey bee (Apis mellifera Linnaeus) colonies were determined. The treatments were OA in dust, OA diluted in glycerin solvent embedded in a towel, T in dust,T in glycerin solvent and towel, OO in dry microcapsules, OO in glycerin solvent and towel, and the control. The treatments were applied weekly for 4 wk during the fall season. The rates of acaricide efficacy, weekly mite fall, bee mortality, colony survivorship, and strength, were determined for each of the treatments. All formulations, with the exemption of OO microcapsules, were effective at controlling infestations of V. destructor. The most effective formulations were T dust (96.6%), T glycerin (92.4%), and OA glycerin (79%). More than 85% of the mites were killed during the first 2 wk of treatment withT formulations, compared to less than 30% for the OA glycerin formulation. The lowest efficacy rate was for OO microcapsules (21.3%), and the only treatment that significantly increased bee mortality was OA glycerin. The rates of winter colony survival and honey bee populations were related to the varroacidal efficacy of the formulations. The implications of these findings are discussed.

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.

Amblyseius swirskii (Athias-Henriot) is one of the most important biological control agents and has been used in many countries. In this study, the suitability of Carpoglyphus lactis L. (Acari: Carpoglyphidae), Tyrophagus putrescentiae (Schrank), and their mixture for rearing A. swirskii was evaluated by using the two-sex life table. When reared on C. lactis, the durations of egg, deutonymph, total preadult, total preoviposition period, and adult male longevity of A. swirskii (1.95, 1.17, 6.13, 6.30, and 10.09 d, respectively) were significantly shorter than those reared on the mixed prey (2.05, 1.45, 6.55, 6.64, and 15.56 d, respectively). When reared on the mixed prey, however, the fecundity (110.21 eggs/female) of A. swirskii was significantly higher in comparison with those solely reared on C. lactis (82.17 eggs/female) or on T. putrescentiae (98.23 eggs/female). When reared on the mixed diet, the intrinsic rate of increase (r = 0.3792 d^–1), finite rate of population increase (λ = 1.4611 d^–1), and net reproductive rate (R₀ = 79.69 offspring) of A. swirskii were significantly higher than those on single-species diets. For a daily production of 10,000 eggs of A. swirskii, a smaller population size (2,626 individuals) of A. swirskii is needed when reared on the mixed diet, in contrast to the 4,332 individuals on C. lactis and 3,778 individuals on T. putrescentiae. The population projection and mass-rearing analysis based on life table showed that the mixed diet was the most suitable and economical diet for the mass-rearing of A. swirskii.

Artificial diets have been employed for the mass-rearing of numerous insects because of their ease of use and standardized quality. An ability to store artificial diets under nonrefrigerated conditions over the long term could improve the efficacy of mass-rearing systems considerably. However, it remains largely unknown how long artificial diets can be stored at such temperatures without any adverse effects on the insects reared. In this study, we investigated yield, body size, and reproductive potential of West Indian sweet potato weevil, Euscepes postfasciatus (Fairmaire), which is a major sweet potato pest, under management using the sterile-insect technique in Japan and reared using artificial diets with different storage periods (14, 28, and 42 d) at nonrefrigerated temperatures (25 ± 1°C), and compared them with those of the control (0 d). Notably, E. postfasciatus yield and reproductive potential increased significantly with an increase in storage period (28 and 42 d). Conversely, male body size decreased significantly following feeding with artificial diet stored for 42 d, when compared with the control, while there were no significant differences in female body size between the control and all the treatments. We discuss the potential causes of such varying effects between yield and body size and conclude that E. postfasciatus artificial diet can be stored for at least 28 d without any adverse effects on weevil yield and weevil quality. To the best of our knowledge, this is the first report revealing the positive effects of long-term storage of the artificial diet on mass-reared insects.

Plants play a pivotal role in interactions involving herbivores and their natural enemies. Variation in plant primary and secondary metabolites not only affects herbivores but, directly and indirectly, also their natural enemies. Here, we used a commercial NPK fertilizer to test the impact of three fertilizer, namely 50, 100, and 200 ppm nitrogen, and one control (i.e., water) treatments, on the weight of the nymphs of the whitefly Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae). Subsequently, the whitefly parasitoid Eretmocerus mundus Mercet (Hymenoptera: Aphelinidae) was reared on the different groups of whitefly nymphs and upon parasitoid emergence, the number of oocytes was determined as a measure of reproductive capacity.Trials were done on tomato and tobacco plants.The level of nitrogen concentration in tobacco leaves was directly correlated with the fertilizer applications, thus confirming the effect of our fertilizer treatments. Both in tomato and tobacco plants, healthy as well as parasitized whitefly nymphs, were heaviest in the 200 ppm nitrogen treatment.The highest number of oocytes per female parasitoid was recorded in the 200 ppm nitrogen treatment in tomato (31% more oocytes as compared with the control) and in the 100 and 200 ppm nitrogen treatments in tobacco (200% more oocytes). We suggest that the increase in oocytes was the result of the enhanced size (food quantity) and/or nutritional quality of the whitefly host.The practical implications of these results for the mass rearing of whitefly parasitoids and for biological pest control are discussed.

The objectives of this study were to quantify the virulence of four entomopathogenic fungal species to pupae of Rhagoletis pomonella (Walsh) (Diptera: Tephritidae) and to determine the potential to combine entomopathogenic fungi (EPFs) and entomopathogenic nematodes (EPNs) for biological control of this pest. The four species of EPFs included Beauveria bassiana (strain GHA), Metarhizium brunneum (strain F52), Isaria javanica (wf GA17), and Isaria fumosorosea (Apopka 97 strain). In laboratory assays, all fungi reduced adult emergence but there were no differences between fungal species. Isaria javanica and M. brunneum were examined further in a EPFs and EPNs bioassay that also included the EPNs Steinernema carpocapsae (ALL strain) and S. riobrave (355 strain). All nematodes and fungi were applied either alone or in combination (fungus + nematode). There were no differences between species within the same entomopathogen group (fungi and nematodes). However, the treatment with S. riobrave resulted in lower R. pomonella emergence than either fungal species. The combination of S. riobrave and I. javanica resulted in the lowest R. pomonella emergence (3%) at fourth-week interval, which was significantly lower than any of the single-agent applications, yet virulence of the other three combination treatments was not different from their respective nematode treatments applied alone. Additive interactions were detected for all fungus–nematode combinations. This study suggests that application of entomopathogenic nematodes and fungi could be an effective option to suppress R. pomonella populations.

The coleopteran parasitoid Dastarcus helophoroides (Fairmaire) (Coleoptera: Bothrideridae) is considered an efficient preventative method against the damage caused by a large number of cerambycid pests in China and other East Asian countries. Mass rearing of this parasitoid depends on screening appropriate factitious hosts. In this paper, the fitness-related traits of this parasitic beetle were explored using pupae of the two tenebrionid beetles, Tenebrio molitor Linnaeus and Zophobas morio Fabricius (Coleoptera: Tenebrionidae) as factitious hosts. The results showed that in dual-choice trials, D. helophoroides larvae preferred to attack Z. morio pupae. In no-choice trials, D. helophoroides reared on Z. morio pupae displayed significantly higher pupation and emergence rate, longer developmental duration of larval and larval–pupal stages, larger adult body size, shorter preoviposition period, more egg masses and egg production, and higher relative expected reproduction than those reared on T. molitor pupae. These results demonstrate that Z. morio is a more suitable factitious host for mass rearing of D. helophoroides.

Emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), is one of the most serious forest pests in the United States. Ongoing research indicates that establishment of larval parasitoids depends upon the season-long availability of host stages susceptible to parasitism. We monitored emerald ash borer overwintering stages at 90 sites across 22 states to: 1) produce a model of the percentage of emerald ash borer overwintering as non-J larvae; 2) link that model to establishment of Tetrastichus planipennisi; and 3) explore changes to our model under climate change scenarios. Accumulated growing degree days (GDD) is an important predictor of the proportion of emerald ash borer overwintering as non-J larvae (1–4 instar larvae under the bark; available to parasitoids emerging in spring) versus J-larvae (fourth-instar larvae in pupal chambers in the outer wood; unavailable to parasitoids). From north to south, the availability of non-J emerald ash borer larvae in the spring decreases as accumulated GDD increases. In areas where the model predicted >46–75%, >30–46%, >13–30%, or ≤13% of emerald ash borer overwintering as non-J larvae, the probability of establishment of T. planipennisi was 92%, 67%, 57%, and 21%, respectively. We determined that 13% of emerald ash borer overwintering as non-J larvae was the lowest threshold for expected T. planipennisi establishment. Additional modeling predicts that under climate change, establishment of T. planipennisi will be most affected in the Central United States, with areas that are currently suitable becoming unsuitable. Our results provide a useful tool for the emerald ash borer biological control program on how to economically and successfully deploy emerald ash borer biological control agents.

The Asian longhorned beetle (Anoplophora glabripennis [Motschulsky]) is an invasive wood-boring beetle that threatens urban trees and forests in North America and Europe. The entomopathogenic fungus Metarhizium brunneum Petch strain F52 can infect and kill A. glabripennis adults. Products containing this fungus were available for commercial use in the United States but not registered for Asian longhorned beetle. This study tested different formulations and application rates of M. brunneum F52 microsclerotial granules for their potential development for management of A. glabripennis adults. Three application rates of M. brunneum microsclerotial granules relative to a 1× formulation from previous experiments (0.03 g/cm²; 2× = 0.06 g/cm² and 3× = 0.09 g/ cm²) were exposed on tree trunks for 4-wk periods during May–September. Increased application rates had better retention (% of initial g applied) than the 1× rate, rather than greater weathering loss. Microsclerotia at the 2× application produced 5.05 × 10⁶ conidia/cm², which was 18 times more conidia than the 1× application. Since A. glabripennis is under active eradication, bioassays with adult beetles were carried out in a quarantine laboratory, using the formulation samples from field exposures. The 2× application resulted in faster beetle mortality. The 3× and 2× rates were not significantly different in retention of the formulation, conidial production, or mortality, but 2× produced the most conidia per gram applied (3.92 × 10⁹ conidia/g). An augmented formulation containing 70% M. brunneum by weight, rather than 50%, produced significantly more conidia and faster beetle mortality than the 50% formulation.

The FraxiProtec, an autodissemination device loaded with the fungus Beauveria bassiana isolate CFL-A, was tested in the field to evaluate its potential to infect emerald ash borer adults and reduce their populations. During the 2-yr experimental period, the dispersion of B. bassiana-infected adults was also documented to assess the dissemination capacity of the biocontrol agent beyond the treated areas. The mean percentage of infected emerald ash borer in 2017 and 2018 in 15 treated sites was 43.3 ± 2.9% and 39.7 ± 3.9%, respectively, and no significant variation was observed over the tested years. Furthermore, a 40% significant reduction of the mean emerald ash borer population growth per tree in treated sites was recorded when compared to the control sites. Emerald ash borer infected with B. bassiana isolate CFL-A were collected from baited sticky traps in the sentinel stations in the area surrounding the FraxiProtec-treated sites. Even at a distance of 125 m, an average of 9.4 ± 2.6% infected emerald ash borer were collected. Finally, exploratory analyzes were carried out on parameters such as the area to be treated, ash tree density, and FraxiProtec density to document potential relationships, which could be used in the determination of a prescription.

The German cockroach, Blattella germanica (L.) (Blattaria: Blattidae) harbored diverse microorganisms in the digestive tract, including bacteria, fungi, viruses, archaea, and protozoa. This diverse community maintains a relatively stable balance. Some bacteria have been confirmed to play crucial roles in the insect's physiology, biochemistry, and behavior. Antibiotics can effectively eliminate bacteria and disrupt the balance of gut microbiota, but the time-course of this process, the structure of the new microbial community, and the dynamics of re-assemblage of a bacterial community after antibiotic treatment have not been investigated. In the present study, antibiotic (levofloxacin and gentamicin) ingestion reduced bacterial diversity and abundance in the cockroach gut. Within 14 d of discontinuing antibiotic treatment, the number of culturable gut bacteria returned to its original level. However, the composition of the new bacterial community with greater abundance of antibiotic-resistant Enterococcus and Dysgonomonas was significantly different from the original community. Network analysis showed that antibiotic treatment made the interaction between bacteria and fungi closer and stronger in the cockroach gut during the recovery of gut microorganisms. The study on the composition change, recovery rules, and interaction dynamics between gut bacteria and fungi after antibiotic treatment are helpful to explore gut microbes' colonization and interaction with insects, which contributes to the selection of stable core gut bacteria as biological carriers of paratransgenesis for controlling Blattella germanica.

The sterile insect technique (SIT), used to control different species of tephritid fruit flies (Diptera: Tephritidae), is an important element in sustainable agriculture because of its low negative impact on the environment. In SIT, flies are mass produced and sterilized in the laboratory and then released in a target area. However, once released, laboratory flies may confront harass environments that would reduce their performance and consequently SIT efficiency. Selecting flies that resist stressful conditions may help to improve the efficiency of the SIT by releasing males that resist desiccation, for example, ensuring, thus, their survival in environments with low relative humidity. However, the selection process may affect the resistance of flies to the stress of sterilization, since some life history traits are affected. Here, we studied the effect of irradiation on Anastrepha ludens (Loew) (Diptera: Tephritidae) desiccation resistant flies (DR) compared with nonselected flies (NS). We measured the effect of gamma irradiation dose (0, 20, 40, 60, and 80 Gy) on sterility (males and females) and quality parameters (emergence, flight ability, survival, and male sexual performance) in A. ludens adults of the DR and NS (control) strains. Our results indicate that irradiation affected equally the sterility of adults of both strains. None of the quality parameters differed between strains. The only difference was that DR flies survived longer than control flies. Thus, flies that are resistant to desiccation can be used in the SIT without altering the current process of irradiation and packing.

The genetic sexing strain (GSS) of the Mediterranean fruit fly (Ceratitis capitata (Wiedemann)) Vienna 8^D53– is based on a male-linked translocation system and uses two selectable markers for male-only production, the white pupae (wp) and the temperature sensitivity lethal (tsl) genes. In this GSS, males emerge from brown pupae and are resistant to high temperatures while females emerge from white pupae, are sensitive to high temperatures. However, double homozygous females (wp tsl/wp tsl) exhibit a slower development rate compared to heterozygous males (wp⁺ tsl+/wp tsl) during the larval stage, which was attributed to the pleiotropic effects of the tsl gene. We present the first evidence that this slower development is due to a different gene, here namely slow development (sd), which is closely linked to the tsl gene. Taking advantage of recombination phenomena between the two loci, we report the isolation of a novel temperature sensitivity lethal strain using the wp mutation as a morphological marker, which showed faster development (wp tsl FD) during the larval stage and increased in its temperature sensitivity compared with the normal tsl strain. Moreover, the introgression of this novel wp tsl FD combined trait into the Vienna 8^D53– GSS, resulted in a novel Vienna 8^D53– FD GSS, where females showed differences in the thermal sensibility, larval development speed, and productivity profiles. The modification of these traits and their impact on the mass rearing of the GSS for sterile insect technique applications are discussed.

Some plant pathogens are capable of manipulating their insect vectors and plant hosts in a way that disease transmission is enhanced. Aster leafhopper (Macrosteles quadrilineatus Forbes) (Hemiptera: Cicadellidae) is the main vector of AsterYellows Phytoplasma (Candidatus Phytoplasma asteris) in the Canadian Prairies, which causes Aster Yellows (AY) disease in over 300 plant species including cereals and oilseeds. However, little is known about the host range of Aster leafhoppers or their host-choice selection behavior in this geographical region. Several crop and noncrop species commonly found in the Canadian Prairies were evaluated as food and reproductive hosts for Aster leafhoppers through no-choice bioassays. To study possible effects of pathogen infection, AY-uninfected and AY-infected insects were used. Cereals and some noncrops like fleabane were suitable reproductive hosts for Aster leafhoppers, with numbers of offspring observed in treatments using both AY-uninfected and AY-infected insects, suggesting an egg-laying preference on these plant species. Development was similar across the different plant species, except for canola and sowthistle, where growth indexes were lower. Sex-ratios of Aster leafhopper adults did not differ among the plant species or with respect to AY infection. Potential fecundity differed across plant species and was affected by the infection status of the insect. These findings have implications for AY epidemiology and suggest that while cereals can be suitable host plants for Aster leafhopper oviposition and development, some noncrop species could act as alternate hosts for leafhoppers that migrate into the Canadian Prairies before emergence of cereal and canola crops.

Bees are economically critical pollinators, but are declining broadly due to several stressors, including nontarget exposure to insecticides and deficiencies in nutrition. Understanding the simultaneous impact of stressors, particularly interactions between them, is critical to effectively conserving bees. Although behavioral effects of pesticides like neonicotinoids have received some attention in solitary bees, our understanding of how they are modulated by diet quality is limited. Furthermore, scarce data exist on what concentrations of orally ingested neonicotinoids elicit mortality in solitary bees. In a controlled exposure laboratory experiment, we investigated how diet quality, as sugar concentration, and chronic oral exposure to imidacloprid affect adult alfalfa leafcutting bees, Megachile rotundata (Fabricius). We provided individuals ad libitum with either 20 or 50% (m/m) sucrose syrups containing either 0, 30, or 300 ppb imidacloprid (measuring 0, 27, and 209 ppb via an ELISA assay). Over 5 wk, we tracked behavior and survivorship of individuals. Imidacloprid decreased survivorship in a dose-dependent fashion, but sucrose content did not affect survivorship, even in bees not fed imidacloprid. In the high imidacloprid treatment, 45% of bees were observed in a motionless supine position while still alive, with this effect appearing to be buffered against by the higher sucrose diet. Our results suggest that diets higher in sugar concentration may prevent an intermediate stage of poisoning, but do not ultimately extend longevity. In devising risk assessments for bees, it is important to consider that interactions between stressors may occur in the stages leading up to death even if survivorship is unaffected.

Graphical Abstract

The cabbage aphid, Brevicoryne brassicae (L.), is one of the major insect pests of cole crops in Iran. In most instances outbreaks are normally kept under control by application of insecticides. In this study, the sublethal effects (LC₃₀) of three insecticides, acetamiprid, buprofezin, and thiamethoxam-lambda cyhalothrin, (TLC) were evaluated on the population growth rate of the progeny of insecticide-treated cabbage aphid adults. The age-stage, two-sex life table method was used to analyze the collected data. The results indicated that the insecticide applications affected the duration of the preadult period, their survival, reproduction, life span/longevity, and consequently, the population growth rate of the F₁ generation. The indicators of the greatest sublethal effects were noted in the progeny of the TLC-treated adults. These included the lowest net reproductive rate (R₀), intrinsic rate of increase (r), finite rate of increase (λ), and the longest mean generation time (T). The highest values of r, λ, R, and the lowest value of T occurred in the control group followed by, in order, the acetamiprid and buprofezin groups. These research findings will be useful in the development and implementation of future aphid management programs.

A combination of pesticides and biological control agents is frequently necessary to achieve successful pest management requiring the assessment of their compatibility for the intended purpose. Aphidius flaviventris Kurdjumov is one of the parasitoids of the cotton aphid Aphis gossypii Glover, whose susceptibility to pesticides was not yet investigated. Accordingly, we investigated the lethal and sublethal effects of the commonly utilized insecticide mixture thiacloprid + deltamethrin on the cotton aphid and its parasitoid wasp Aphidius flaviventris.The estimated LC₅₀ for the aphid was 14.1 mg ai/l; the effects of sublethal exposure at LC₁₀ (2.80 mg ai/l) and LC₃₀ (7.28 mg ai/l) on the aphid life-table parameters led to significantly increase on the development time of third- and fourth-instar nymphs and preadult. Sublethal exposure to the insecticide mixture compromised aphid longevity, fecundity, and life-table parameters (r, R₀, and T). Moreover, population growth and parasitism rate of the parasitoid were significantly compromised at both concentrations of the insecticide mixture under sublethal exposure.These results not only indicate the efficacy of thiacloprid + deltamethrin against the cotton aphid, but also raise concerns regarding its negative impacts on the parasitoid Aphidius flaviventris and caution against its use in pest management programs.

Southern green stink bug, Nezara viridula (L.) and redbanded stink bug, Piezodorus guildinii (Westwood) are two of the most important seed sucking pests affecting Louisiana soybean production and rice stink bug, Oebalus pugnax (F.) is an important late season pest in Louisiana rice. Exploration of chemicals that exhibit attraction or repellent activities toward major stink bug species would be beneficial in developing push–pull strategies. Spinosad is a commercially available natural insecticide that may have arrestant, attractant, or phagostimulant properties against stink bugs. To test this, a series of laboratory experiments were conducted to investigate the tactile, olfactory, and feeding responses of these stink bugs toward two commercial spinosad products (Entrust and Tracer) and technical grade spinosad. In tactile assays, female and male redbanded stink bug were arrested by Entrust, Tracer, and technical grade spinosad, whereas only rice stink bug and southern green stink bug males were arrested by Entrust.Y-tube assays revealed no attraction to any of the products by either male or female rice stink bug, redbanded stink bug, or southern green stink bug. In paired (treated or untreated soybean seed) feeding preference experiments, southern green stink bug showed no preference for any treatment, whereas redbanded stink bug fed more on Entrust- and Tracer-treated seed. From these results, spinosad appears to have an arrestant and phagostimulant effect on redbanded stink bug in the laboratory.

A meridic diet overlay bioassay using empty, positively charged zein nanoparticles ((+)ZNP) was performed on soybean looper (Chrysodeixis includens (Walker)), tobacco budworm (Heliothis virescens (F.)), and velvetbean caterpillar (Anticarsia gemmatalis Hübner) (Lepidoptera: Noctuidae). Assessment of effects on mortality and development weights 7 d after ingestion of (+)ZNP were evaluated on larvae of each species. Treatments involved different concentrations, with H. virescens and A. gemmatalis offered 0 and 3,800 ppm (+)ZNP, whereas C. includens colonies were offered 0, 630, 1,260, and 2,520 ppm (+)ZNP. Mortality of A. gemmatalis and C. includens increased after ingestion of the highest (+)ZNP concentrations, while H. virescens neonate mortality was unaffected. Neonate and third-instar weights of A. gemmatalis and C. includens, and neonate H. virescens, decreased with high (+)ZNP concentrations. Following mortality results from A. gemmatalis neonates, a concentration response test was performed using a range of (+)ZNP concentrations.The LC₅₀ for A. gemmatalis was 1,478 ppm.The potential of (+)ZNP as a pest management tactic is discussed.

Bark and ambrosia beetles are commonly moved among continents within timber and fresh wood-packaging materials. Routine visual inspections of imported commodities are often complemented with baited traps set up in natural areas surrounding entry points. Given that these activities can be expensive, trapping protocols that attract multiple species simultaneously are needed. Here we investigated whether trapping protocols commonly used to detect longhorn beetles (Coleoptera: Cerambycidae) and jewel beetles (Coleoptera: Buprestidae) can be exploited also for detecting bark and ambrosia beetles. In factorial experiments conducted in 2016 both in Italy (seminatural and reforested forests) and Canada (mixed forest) we tested the effect of trap color (green vs purple), trap height (understory vs canopy), and attractive blend (hardwood-blend developed for broadleaf-associated wood-boring beetles vs ethanol in Italy; hardwood-blend vs softwood-blend developed for conifer-associated wood-boring beetles, in Canada) separately on bark beetles and ambrosia beetles, as well as on individual bark and ambrosia beetle species. Trap color affected catch of ambrosia beetles more so than bark beetles, with purple traps generally more attractive than green traps. Trap height affected both beetle groups, with understory traps generally performing better than canopy traps. Hardwood-blend and ethanol performed almost equally in attracting ambrosia beetles in Italy, whereas hardwood-blend and softwood-blend were more attractive to broadleaf-associated species and conifer-associated species, respectively, in Canada. In general, we showed that trapping variables suitable for generic surveillance of longhorn and jewel beetles may also be exploited for survey of bark and ambrosia beetles, but trapping protocols must be adjusted depending on the forest type.

Oak wilt is slowly expanding in the northeastern United States. Several nitidulid beetle species are known vectors of the fungus [Bretziella fagacearum (Bretz) Z. W. De Beer, Marinc., T. A. Duong, and M. J. Wingf (Microascales: Ceratocystidaceae)] that causes this disease, acquiring spores from fungal mats on infected trees and transmitting them to uninfected trees. Survey and fungal isolation from captured nitidulid beetles could be an important tool for detecting the presence of this disease in a geographic area not previously known to have oak wilt. In preparation for monitoring activities in such areas, two trapping studies were conducted in the northeastern United States: 1) trap test comparing the efficacy of wind-oriented pipe, multiple-funnel, and modified pitfall traps for nitidulids and 2) wet and dry collection cup comparison. Lures were a combination of nitidulid pheromones and fermenting liquid. Results support the use of multiple-funnel traps over the other two trap types, for both targeted species-specific surveys and community sampling. More total nitidulids, Colopterus truncatus (Randall), and Glischrochilus fasciatus (Olivier) were captured in wet collection cups compared with dry cups. Twenty-seven fungal species were isolated, none of which were B. fagacearum. Many fungi isolated from beetles were plant pathogens, indicating that in addition to the oak wilt fungus, sap beetles may contribute to the spread of other plant diseases.

The walnut twig beetle, Pityophthorus juglandis Blackman, and its associated fungal pathogen that causes thousand cankers disease, currently threaten the viability of walnut trees across much of North America. During a 2011 assessment of seasonal flight patterns of P. juglandis with yellow sticky traps baited with the male-produced aggregation pheromone component, 3-methyl-2-buten-1-ol, dramatically reduced catches were recorded when Tree Tanglefoot adhesive was used to coat the traps. In summer 2011, two trap adhesives were tested for potential repellency against P. juglandis in a field trapping bioassay. SuperQ extracts of volatiles from the most repellent adhesive were analyzed by gas chromatography–mass spectrometry, and limonene and α-pinene were identified as predominant components. In field-based, trapping experiments both enantiomers of limonene at a release rate of ∼700 mg/d conferred 91–99% reduction in trap catches of P. juglandis to pheromone-baited traps. (+)- and (–)-α-Pinene reduced trap catch by 40 and 53%, respectively, at the highest release rate tested. While a combination of R-(+)-limonene and (+)-α-pinene resulted in a 97% reduction in the number of P. juglandis caught, the combination did not consistently result in greater flight trap catch reduction than individual limonene enantiomers.The repellent effect of limonene may be valuable in the development of a semiochemical-based tool for management of P. juglandis and thousand cankers disease.

Systena frontalis (F.) is a major insect pest of nursery production systems in the Midwest and Northeastern regions of the United States with the adults feeding on plant leaves, which reduces salability. However, there is conflicting information on overwintering, and no information on host-plant selection or insecticide susceptibility of S. frontalis adults. Therefore, we conducted a series of experiments under greenhouse, laboratory, and field conditions from 2015 to 2019. The overwintering experiment was isolated in a greenhouse to assess adult emergence from growing medium of containerized plants collected from a wholesale nursery. We found that S. frontalis overwinters in growing medium based on adults captured on yellow sticky cards and the presence of adults on new plant growth. Host-plant selection experiments were conducted at the wholesale nursery and under laboratory conditions to determine feeding selection based on S. frontalis adult feeding damage on whole plants using a foliar damage ranking scale for different cultivars of Itea virginica L., Hydrangea paniculata Siebold, Weigela florida (Bunge), and Cornus sericea L., plants. We found that S. frontalis adults exhibited no preference for the leaves of the plant species or cultivars tested in the field or laboratory. Insecticide efficacy experiments were conducted under field and laboratory conditions. In the field experiments, the insecticides acetamiprid, dinotefuran, and Isaria fumosorosea (Wize) (Hypocreales: Clavicipitaceae) provided better protection of plants from S. frontalis adult feeding than the untreated check. In the laboratory experiments, the acetamiprid and pyrethrins with canola oil treatments provided the highest percent S. frontalis adult mortality.

The Asian citrus psyllid, Diaphorina citri Kuwayama, is the most serious pest of citrus because it is a vector for the highly destructive citrus greening disease (huanglongbing, HLB). Currently, insecticide applications are being used widely to control psyllid populations, thereby suppressing the spread of HLB. In the present study, topical application bioassays were performed to detect the joint actions of beta-cyfluthrin and thiamethoxam or tolfenpyrad against D. citri adults in the laboratory. In 2019, a field plot experiment was conducted to evaluate the control efficacies of beta-cyfluthrin+thiamethoxam 22% capsule suspension and beta-cyfluthrin+tolfenpyrad 30% microemulsion against D. citri using foliar sprays. For the former, a 9:13 mass ratio had the highest synergistic effect, with a cotoxicity coefficient of 188.64. For the latter, a 5:25 mass ratio had the highest synergistic effect, with a cotoxicity coefficient of 153.94. A one-time foliar spray of the former at 30–40 mg/kg or of the latter at 40–60 mg/kg effectively controlled D. citri, with control efficacies varying from 80.1 to 99.4% or 80.4 to 100.0%, during the 3–30 d after treatment, respectively. Moreover, field observations indicated that these foliar sprays at the tested rates had no negative effects on citrus trees. Thus, foliar sprays of beta-cyfluthrin+thiamethoxam or beta-cyfluthrin+tolfenpyrad under the given conditions may control D. citri.

Tephritid flies released in sterile insect technique pest management programs are usually marked with fluorescent dyes so that they can be distinguished from wild flies in monitoring traps. Dyes can have adverse effects on emergence, quality, and survival, which can impact sterile insect technique (SIT) success, and so it is important to identify dyes and doses that maximize marking efficacy while minimizing deleterious effects on fly quality. This study examines the effects of five fluorescent dye products, Fluoro Pink, Fluoro Orange, Stella Green, Arc Chrome, and Astral Pink applied at four dose levels (1, 2, 3, and 4 g/liter) on Queensland fruit fly. All dye products caused a similar dose-dependent reduction in percentage of adult emergence. Incidence of morphological deformity of emerged adults increased with dose, and this trend was similar for all dye products. No effects of dye product or dose were found on survival rates over the first 35 d of adulthood, although females tended to have higher survival than males. Visibility varied with dose and dye product; 1 g/liter dye was less visible than 2, 3, or 4 g/liter, and Stella green had lower visibility than other dyes. All of the tested dyes except for Stella green were similar in all assessed metrics of fly performance and are recommended for use in SIT programs.

The flatheaded appletree borer, Chrysobothris femorata (Olivier) (Coleoptera: Buprestidae), and related species are deciduous tree pests. Female beetles prefer to oviposit at tree bases, and larvae tunnel beneath the bark, which weakens or kills young or newly transplanted trees. In the first objective of this study, Discus N/G (2.94% imidacloprid + 0.7% cyfluthrin) applied at six lower-than-labeled rates (0.0, 0.98, 1.97, 3.94, 5.91, and 7.87 ml/cm of average trunk dia.) was evaluated for protection of field-grown maples. A second objective evaluated imidacloprid with and without herbicides to assess the impact of weed competition at the tree base on insecticide effectiveness. A third objective determined relative imidacloprid concentrations in leaf tissue samples with ELISA and related to insecticide rates, herbicide treatments, and the level of flatheaded borer protection. In two trials, higher rates of insecticide were more effective at protecting trees, with rates ≥3.94 ml product/cm trunk diameter performing equivalently. Weed-free trees had more borer attacks and grew faster than trees in weedy plots. Imidacloprid content in leaf tissues had a trend for higher concentrations in smaller, weedy trees in the first season, but that pattern disappeared in subsequent years. Based on fewer attacks in weedy versus weed-free trees (60–90% reduction), it was concluded that weed presence can reduce borer attack success in nurseries independent of insecticide treatment, but tree growth was reduced by weed presence. In addition, Discus applied at rates >3.94 ml/cm did not confer added borer damage protection in weedy plots.

Spray coverage may influence the efficacy of insecticides targeting the invasive vinegar fly Drosophila suzukii (Matsumura), a primary pest of raspberries and blackberries. In commercially managed caneberries, spray coverage is typically lowest in the inner and lower plant canopy, regions that overlap with higher levels of adult D. suzukii activity.To understand how spray coverage of fruit impacts efficacy against D. suzukii, laboratory bioassays were conducted using raspberries. In laboratory bioassays, higher spray coverage did not impact larval infestation rates but did increase adult mortality, indicating that flies can avoid a lethal dose of insecticide when applications do not achieve adequate coverage. We also evaluated how carrier water volume impacts spray coverage patterns throughout the canopy of raspberry and blackberry plants using both airblast and CO₂ backpack sprayers. Increasing carrier water volume generally improved spray coverage in the lower plant canopy. However, effects in the upper plant canopy were inconsistent and varied between sprayer types. In addition to carrier water volume, other approaches, including adjusting the pesticide sprayer equipment used and/or sprayer calibration, should also be explored to improve coverage. Growers should evaluate spray coverage in their caneberries to identify and troubleshoot coverage issues. Results from this study indicate that taking the time to optimize this aspect of pesticide application may improve chemical management of D. suzukii and will likely also improve control of other important caneberry pests.

The sterile insect technique (SIT) and male annihilation technique (MAT) are important tools for the control of Queensland fruit fly (Q-fly), Bactrocera tryoni (Froggatt) (Diptera: Tephritidae), a major insect pest of horticultural crops in Australia. In MAT, mature Q-fly males are attracted to a toxic bait using Cuelure, a synthetic analog of raspberry ketone (RK). Substantial improvements in control could be achieved by simultaneous use of SIT and MAT, but this requires suppression of the Cuelure response in released sterile flies. Recent studies report that prerelease feeding with RK during the first 48 h after emergence can reduce the response of mature Q-fly males to Cuelure, but the mechanism underpinning this is unknown. Here, to test whether reduced sensory sensitivity to Cuelure is involved, we evaluated the effects of RK supplements, adult diet (yeast-supplemented diet throughout adult stage vs yeast-supplemented diet only for 48 h), and age on electroantennogram (EAG) and electropalpogram (EPG) responses of Q-flies to Cuelure stimuli. EAG responses did not vary with RK supplements, sex, or age of Q-flies fed yeast-supplemented diet throughout the adult stage, but the responses of Q-flies fed other diet regime decreased with age. EPG responses of both sexes of Q-flies were affected by RK supplements, age, and their interaction, but without patterns that might indicate reduced maxillary palp response of RK supplemented flies to Cuelure. Our findings do not support the hypothesis that reduced Cuelure response of male Q-flies fed RK supplements is explained by reduced electrophysiological response in antennae or maxillary palps.

Pear psylla, Cacopsylla pyricola (Förster), has remained the most challenging pest of commercial pears in Washington and Oregon, the top producers of pears in the United States. The lack of effective integrated pest management tactics for this pest has been a major barrier to effective management. In this study, we examined the potential for reflective plastic mulch affixed beneath pear trees to suppress pear psylla. In 2017 and 2018, single pear tree (cv. Bartlett) plots of reflective plastic mulch, black plastic mulch, and no mulch (check) were established in a research orchard to compare their effects on pear psylla. Arthropods were sampled every 7–14 d from March through late summer. In both years, reflective mulch plots had significantly fewer pear psylla adults, eggs, and nymphs of the first generation compared with black plastic and check plots. However, later generations of psylla were not suppressed by reflective mulch. Semi-field tests were conducted in 2019 and 2020 using uniformly pruned potted pear trees on either reflective plastic mulch or grass to determine whether summerform adults were tolerant to reflected light from mulch, or if shading from vegetative growth negated the effect of the mulch. In both years, significantly fewer summerform adults and eggs were found in reflective mulch plots, suggesting that shading, rather than summerform tolerance, reduced effects from reflective mulch in the summer.This study demonstrates the potential for reflective mulch to suppress pear psylla and justifies future examination as part of a season-long management program.

Bed bugs spend most of their lives hiding in harborages, usually in the seams of mattresses and box springs and in crevices of bed frames. For insecticidal products that target these shelters, the repellency of the products for bed bugs may influence their duration of contact. Bed bugs are known to avoid contacting surfaces treated with certain insecticides. The fungal biopesticide Aprehend contains spores of the entomopathogen, Beauveria bassiana. It is sprayed around bed frames, box springs, and furniture where bed bugs are likely to walk, which includes potential shelters. Here, I investigated the influence of a permethrin-impregnated cover, ActiveGuard, on bed bug sheltering behavior and the effectiveness of combining ActiveGuard with Aprehend. Bed bugs avoided harboring in a shelter constructed with ActiveGuard compared to a nontoxic encasement-type cover. This avoidance behavior reduced mortality induced by ActiveGuard shelters compared to forced continuous contact on the ActiveGuard cover. However, while bed bugs also avoided Aprehend-treated ActiveGuard shelters, the combined treatment induced almost complete mortality and more quickly than Aprehend-treated shelters made of the encasement-type cover. This suggests compatibility between the two integrated pest management (IPM) tools even though the bed bug's avoidance behavior would suggest otherwise. Since Aprehend is highly effective against pyrethroid-resistant bed bugs, its use would provide more effective control where bed bug populations are more resistant to the permethrin-impregnated cover.

The common bed bug (Cimex lectularius L.) is an obligate hematophagous ectoparasite that has significant impacts on human health and well-being. All life stages of bed bugs (except eggs) feed solely on blood, which is required to molt and reproduce. Bed bugs use multiple cues to locate their hosts, including heat, CO₂, and body odors. Of these cues, detection of heat appears limited to a short distance of <3 cm. However, it remains unclear if bed bugs can detect radiant heat, what structure(s) are responsible for heat detection, and if heat detection via the antennae is required for feeding. In this study, bed bug response to radiant heat was evaluated using the two-choice T-maze assay with the heat source either in contact with the surface (i.e., conduction) or not in contact (i.e., radiation) in nonantennectomized bed bugs. Further, we systematically ablated the bed bug's antennal segments (distal tip, first segment, and all four segments) and assessed their responses to heat and feeding in a unique two-choice T-maze assay and individual feeding assays, respectively. Our two-choice assays with contact to or no contact with the surface indicated that bed bugs cannot detect radiant heat. Later, we found that the distal tip of the terminal antennal segment is responsible for orientation toward a heat source. However, >50% of the bed bugs fed even when the entire antenna was removed, suggesting redundancy in sensory cues that drive feeding. These results will be used to better understand the role heat plays in bed bug host attraction and design of traps.

The nutritional status of host plants can have direct impacts on herbivore physiology and insect–plant interactions. We investigated the effect of micronutrients, including manganese, iron, zinc, and copper, on cucumber plant physiology, and on the biology and physiology of a strain of Aphis gossypii Glover selected over 12 generations to be resistant to pirimicarb. The micronutrient treatment increased the activity of superoxide dismutase, ascorbate peroxidase, guaiacol peroxidase, polyphenol oxidase, and phenylalanine ammonia-lyase in cucumber plants, and also increased levels of total phenolics, hydrogen peroxide, salicylic acid, and total chlorophyl, whereas malondialdehyde levels were unaffected. Pirimicarb-resistant cotton aphids that fed on micronutritient-amended cucumber plants expressed significantly decreased levels of acetylcholinesterase and detoxifying enzymes, specifically glutathione S-transferase, and carboxylesterase. Analysis of energy reserves in resistant A. gossypii fed on micronutritient-amended plants revealed decreases in the lipid and protein contents of aphids, whereas glycogen and carbohydrate contents showed no response. Resistant cotton aphids fed on micronutritient-amended plants showed significantly reduced fecundity, longevity, and reproductive periods, and a 1.7-fold reduction in pirimicarb LC₅₀ compared with those fed on control plants. We conclude that micronutrient amendment negatively impacts the biological performance of insecticide-resistant cotton aphids, and diminishes their resistance to pirimicarb. Both direct effects on plant health, such as enhanced inducible defenses, and indirect effects on aphid fitness, such as reduced biological performance and detoxification abilities, were implicated. Therefore, optimization of micronutrient amendments could be a useful complement to other tactics for managing insecticide-resistant A. gossypii on cucumbers, and warrants exploration in other contexts.

Field-evolved resistance to Cry3Bb1 corn by western corn rootworm, Diabrotica virgifera virgifera LeConte (Colleoptera: Chrysomellidae), has been reported in field populations in Iowa, Illinois, Nebraska, and Minnesota. Inheritance and fitness costs associated with Cry3Bb1 resistance have been determined for non-diapausing laboratory strains of western corn rootworm with either laboratory-selected resistance or field-derived resistance. However, information on inheritance and fitness costs of Cry3Bb1 resistance in the diapausing field populations is lacking. In this study, we determined the inheritance of Cry3Bb1 resistance for four diapausing field strains of western corn rootworm using plant-based bioassays. We also determined the fitness costs for eight diapausing field populations in a greenhouse experiment. We found that Cry3Bb1 resistance was an autosomal trait and that the inheritance of resistance was mostly non-recessive; however, there was some variation in the dominance of Cry3Bb1 resistance. We did not find evidence of fitness costs affecting survival to adulthood, developmental rate, or adult dry mass. However, we did detect a fitness cost affecting adult size. The results of this study will add to the current understanding of field-evolved resistance to Cry3Bb1 corn by western corn rootworm and help in developing better strategies to manage resistance.

The pyramided genetically modified (GM) soybean [Glycine max L. (Merr.)] MON87751 × MON87708 × MON87701 × MON89788, expressing Cry1A.105, Cry2Ab2, and Cry1Ac from Bacillus thuringiensis Berliner, was approved for commercial use in Brazil. We conducted laboratory, greenhouse, and field studies to assess the efficacy of this Bt soybean against key soybean lepidopteran pests. Neonates of Anticarsia gemmatalis (Hübner) (Lepidoptera: Erebidae), Chrysodeixis includens (Walker), and Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) were exposed to Bt proteins in diet-overlay bioassays. MON87751 × MON87708 × MON87701 × MON89788 soybean and individual components were evaluated in laboratory (leaf disc), greenhouse (high artificial infestations), and in field conditions (natural infestations). Neonates of A. gemmatalis, C. includens, and H. armigera were highly susceptible to Cry1A.105 (LC₅₀ from 0.79 to 48.22 ng/cm²), Cry2Ab2 (LC₅₀ from 1.24 to 8.36 ng/cm²), and Cry1Ac (LC₅₀ from 0.15 to 5.07 ng/cm²) in diet-overlay bioassays. In laboratory leaf disc bioassays and greenhouse trials, MON87751 × MON87708 × MON87701 × MON89788 soybean as well as the individual components were highly effective in controlling A. gemmatalis, C. includens, and H. armigera. Similarly, under field conditions, the pyramided genotypes expressing Cry1A.105, Cry2Ab2, and Cry1Ac were highly effective at protecting soybean against C. includens. We concluded that the individual Bt proteins expressed by GM soybean MON87751 × MON87708 × MON87701 × MON89788 killed all or nearly all the susceptible A. gemmatalis, C. includens, and H. armigera, fulfilling one important criterion for successfully delaying resistance to pyramided Bt crops.

Pear psyllids are major pests and the causal agents of pear decline disease in orchards. In the past two decades, their outbreaks have raised issues pertaining to invasions and taxonomic identification of the dimorphic Cacopsylla chinensis (Yang and Li) in East Asia. The present study elucidated, as an aid to quarantine management, the invasive origins, differentiation history, and putative gene flow and hybridization between C. chinensis and its sibling species Cacopsylla jukyungi (Kwon). Analyses revealed that the ancestors of C. jukyungi might have diverged from C. chinensis approximately 3.5 million yr ago (Mya) and that differentiation between C. chinensis lineages I and II probably occurred 1.5 Mya. The known overlapping distribution of C. chinensis and C. jukyungi in northeastern China and the two C. chinensis lineages in the Bohai Rim region and Taiwan could be attributed to recent population expansion after the Last Glacial Maximum and/or anthropogenic activities. Analyses of the nuclear gene demonstrated that frequent gene flow between the two C. chinensis lineages and the paraphyletic relationship between C. chinensis and C. jukyungi might be caused by incomplete lineage sorting or hybridization events. On the basis of the current distribution, it is evident that C. jukyungi is not present in middle-southern China, whereas C. chinensis is not distributed in Japan and Korea. Preventing new invasions of Cacopsylla psyllids among geographic regions through the transportation of pear scions is thus pivotal in East Asia, particularly for the possible genetic exchanges among differentiated lineages after secondary invasion events.

In Costa Rica, tomato (Solanum lycopersicum Linnaeus) Linnaeus (Solanales: Solanaceae) is one of the crops most severely affected by the whiteflies (Hemiptera: Aleyrodidae) Trialeurodes vaporariorum (Westwood) and the Bemisia tabaci (Gennadius) species complex. The objective of this study was to monitor the spatial distribution and diversity of these species and to detect the presence of secondary bacterial endosymbionts in individuals collected in areas of intensive tomato production. In total, 628 whitefly individuals were identified to the species level using restriction analysis (PCR-RFLP) of a fragment of the mitochondrial cytochrome C oxidase I gene (mtCOI). Trialeurodes vaporariorum was the predominant species, followed by B. tabaci Mediterranean (MED). Bemisia tabaci New World (NW) and B. tabaci Middle East-Asia Minor 1 (MEAM1) were present in lower numbers. The mtCOI fragment was sequenced for 89 individuals and a single haplotype was found for each whitefly species. Using molecular markers, the 628 individuals were analyzed for the presence of four endosymbionts. Arsenophonus Gherna et al. (Enterobacterales: Morganellaceae) was most frequently associated with T. vaporariorum, whereas Wolbachia Hertig (Rickettsiales: Anaplasmataceae) and Rickettsia da Rocha-Lima (Rickettsiales: Rickettsiaceae) were associated with B. tabaci MED. This study confirmed that B. tabaci NW has not been completely displaced by the invasive species B. tabaci MED and B. tabaci MEAM1 present in the country. An association was found between whitefly species present in tomato and certain secondary endosymbionts, elevation was the most likely environmental factor to affect their frequency.

Anoplophora glabripennis (Motschulsky, 1853), native to eastern Asia, is a destructive woodborer of many ornamental species, leading to the decline and the death of the attacked trees. In outbreak areas as Europe or North America, this pest is usually identified using morphological or molecular analyses of adult or larval specimens. However, the procedures for collecting A. glabripennis specimens from infested plants are too expensive and time consuming for routine screening. A noninvasive diagnostic tool based on frass discrimination is therefore crucial for the rapid identification of A. glabripennis at different development stages in the host.This article describes a rapid diagnostic protocol based on loop-mediated isothermal amplification (LAMP). DNA extracted from A. glabripennis frass was amplified with both visual and real-time LAMP and compared with those of nontarget species.The results show that the method is reliable and accurate and therefore could be a promising diagnostic tool in phytosanitary surveys.

The seedcorn maggot Delia platura (Meigen), and the bean seed maggot Delia florilega (Zetterstedt) can cause considerable feeding damage to a wide range of cultivated crops. The recent discovery of two distinct genetic lines of D. platura, each with a unique distribution pattern overlapping only in eastern Canada, suggests the presence of a new cryptic species for the group. The reliable identification of the three species/lines in the seedcorn maggot complex is crucial to our understanding of their distribution, phenology, and respective contribution to crop damage as well as to the development of specific integrated pest management approaches. As these taxa are morphologically indistinguishable in the immature stages, we developed a high-resolution melting PCR (HRM) assay using primers amplifying a variable 96-bp PCR product in the CO1 mitochondrial gene for rapid and economical identification of specimens. The three species/lines exhibited distinguishable melting profiles based on their different T_m values (between 0.4 and 0.9°C) and identification results based on HRM and DNA sequencing were congruent for all specimens in the validation data set (n = 100). We then used the new, highly sensitive HRM assay to identify survey specimens from the seedcorn maggot complex collected in Quebec, Canada, between 2017 and 2019. Progress curves developed to document the temporal occurrence patterns of each species/lines indicate differences between taxa, with the N-line (BOLD:AAA3453) of D. platura appearing approximately 17 d before D. florilega (BOLD:ACR4394) and the H-line (BOLD:AAG2511) of D. platura.

The Asian citrus psyllid, Diaphorina citri Kuwayama, transmits the bacteria Candidatus Liberibacter associated with huanglongbing (HLB), a devastating disease of the citrus industry. The use of genetically modified plants is an alternative to control this vector. Conversely, technology based on RNA interference (RNAi) for silencing specific genes of a target insect could be attempted. This work evaluated the knockdown effect of the target genes calreticulin (DcCRT), laccase (DcLAC), and Snf7 (DcSnf7) by RNAi through feeding D. citri in Murraya paniculata leaves after the uptake of an aqueous solution with dsRNA homologous to each vector target gene. Confocal microscopy revealed the uptake of the fluorescent-labeled dsRNA by detached leaves and the symplastic movement, allowing the ingestion by the feeding insect. A reduction in the survival rate was observed only 144 h after the beginning of feeding with dsRNA targeting DcSnf7; however, no reduction in transcript accumulation. The knockdown of the DcCRT and DcLAC genes was detected only 12 and 96 h after insect feeding, respectively. Additionally, a reduction in amino acid excretion from insects fed with dsRNA targets to DcCRT and DcLAC was observed 120 h after the beginning of feeding. However, the effects of the dsRNAs tested here appear to be minimal, both at the transcriptional and phenotype levels. For most concentrations and time points, no effects were observed. Therefore, the knockdown of genes DcCRT, DcLAC, and DcSnf7 do not appear to have the potential to control of D. citri through RNAi-mediated gene silencing.

Sophisticated social behaviors in termite colonies are mainly regulated via chemical communication of a wide range of pheromones. Trail pheromones play important roles in foraging behavior and building tunnels and nests in termites. However, it is almost unclear how termites perceive trail pheromones. Here, we cloned and sequenced of olfactory co-receptor (Orco) genes from the two termites Reticulitermes chinensis Snyder (Isoptera: Rhinotermitidae) and Odontotermes formosanus (Shiraki) (Isoptera:Termitidae), and then examined their responses to trail pheromones after silencing Orco through RNA interference (RNAi). We found that Orco knockdown impaired their ability to perceive trail pheromones and resulted in the disability of following pheromone trails in the two termite species. Our locomotion behavior assays further showed that Orco knockdown significantly decreased the distance and velocity in the two termite species, but significantly increased the angular velocity and turn angle in the termite R. chinensis. These findings strongly demonstrated that Orco is essential for termites to perceive their trail pheromones, which provides a potential way to control termite pests by damaging olfactory system.

The development of maize (Zea mays L.) hybrids that are adapted to subtropical areas of North America should consider yield potential under heat and moisture stress, and reduced susceptibility to insect herbivory and disease. To aid in this process, maize hybrids (43 developmental and seven non-Bt commercial hybrids) were evaluated for severity of ear injury to Helicoverpa zea (Boddie) and Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae), susceptibility to Aspergillus flavus (Link) (Deuteromycetes: Moniliales), and yield. In subtropical Corpus Christi and College Station, TX, field experiments conducted over three years revealed significant differences among maize hybrids with the rank of the selected measurements differing across the two locations. When the location by maize hybrid interaction was not significant, variation across the main factors of maize hybrid genetics (in all cases) and location (in some cases) was detected. In 2014, a significant location by maize hybrid interaction in yield but not aflatoxin and ear injury were likely associated with differences in weather between locations. In Corpus Christi in 2015, a location by maize hybrid interaction was detected for ear injury only. Overall, experimental maize hybrids, containing the inbred line Tx777, displayed partial resistance to insect derived ear injury in both locations, and some hybrid testcrosses exhibited low rates of aflatoxin accumulation while maintaining relatively high yields. Tx777 was selected from populations originating in Bolivia and adapted to subtropical climates. The most promising hybrid testcrosses had lower ear injury and aflatoxin accumulation, and good yield under varying heat and moisture stress at the two subtropical maize growing areas in this study.

Agricultural pest infestation is as old as domestication of food crops and contributes a major share to the cost of crop production. In a transgenic pest control approach, plant production of Vip3A, an insecticidal protein from Bacillus thuringiensis, is effective against lepidopteran pests. A synthetic Vip3A gene was evaluated for efficacy against Spodoptera litura Fabricius (Lepidoptera: Noctuidae; cotton leafworm), Spodoptera exigua Hübner (Lepidoptera: Noctuidae; beet armyworm), Spodoptera frugiperda Smith (Lepidoptera: Noctuidae; fall armyworm), Helicoverpa armigera Hübner (Lepidoptera: Noctuidae; cotton bollworm), Helicoverpa zea Boddie (Lepidoptera: Noctuidae; corn earworm), Heliothis virescens Fabricius (Lepidoptera: Noctuidae; tobacco budworm), and Manduca sexta L. (Lepidoptera: Sphingidae; tobacco hornworm) in tobacco. In artificial diet assays, the concentration required to achieve 50% mortality was highest for H. zea followed by H. virescens > S. exigua > H. armigera > M. sexta > S. frugiperda > S. litura. By contrast, in bioassays with detached leaves from Vip3A transgenic tobacco, the time until 50% lethality was M. sexta > H. virescens > S. litura > H. zea > H. armigera > S. exigua. There was no significant correlation between the artificial diet and transgenic plant bioassay results. Notably, the two insect species that are best-adapted for growth on tobacco, M. sexta and H. virescens, showed the greatest time to 50% mortality on Vip3A-transgenic tobacco. Together, our results suggest that artificial diet assays may be a poor predictor of Vip3A efficacy in transgenic plants, lepidopteran species vary in their sensitivity to Vip3A in diet-dependent manner, and host plant adaptation of the targeted herbivores should be considered when designing transgenic plants for pest control.

Host-plant resistance (HPR) is an important tool for pest management, affording both economic and environmental benefits. The mechanisms of aphid resistance in soybean are not well understood, but likely involve the induction of the jasmonic acid (JA) pathway, and possibly other phytohormone signals involved in plant defense responses. Despite the efficacy of aphid resistance in soybean, virulent aphids have overcome this resistance through mostly unknown mechanisms. Here, we have used metabolomic tools to define the role of plant phytohormones, especially the JA pathway, in regulating interactions between aphid-resistant soybean and virulent aphids. We hypothesized that virulent aphids avoid or suppress the JA pathway to overcome aphid resistance. Our results suggested that aphid-resistant soybean increased accumulation of JA-isoleucine (JA-Ile) only when infested with avirulent aphids; virulent aphids did not cause induction of JA-Ile. Further, applying JA-Ile to aphid-resistant soybean reduced subsequent virulent aphid populations.The concentrations of other phytohormones remained unchanged due to aphid feeding, highlighting the importance of JA-Ile in this interaction.These results increase our knowledge of soybean resistance mechanisms against soybean aphids and contribute to our understanding of aphid virulence mechanisms, which will in turn promote the durability of HPR.

Yield losses caused by pests, including aphids, can be substantial in cereals. Breeding for resistance against aphids is therefore desirable for enhancing the economic and environmental sustainability of cereal production. The aim of our study was to reveal the degree of antibiosis against Metopolophium dirhodum (Walker) (Homoptera: Aphididae), in four cultivars of spring wheat, Triticum aestivum L. (‘Alicia', ‘Odeta', ‘Libertina', ‘Astrid'), and two cultivars of emmer, Triticum turgidum ssp. dicoccum (Schrank ex Schübler) Thell. (‘Rudico’, ‘Tapiruz') (both Poales: Poaceae) under controlled laboratory conditions. Using age-stage, two-sex life table, we quantified responses of M. dirhodum to each cultivar and to project population growth. The spring wheat and emmer cultivars varied in their suitability to M. dirhodum. The cultivar most susceptible to M. dirhodum was the emmer cultivar ‘Rudico'; the projected population size of M. dirhodum on this cultivar was one order of magnitude larger than those on other cultivars. The most resistant cultivar was the spring wheat cultivar ‘Libertina'. Since emmer is commonly used as a gene source for breeding T. aestivum, we advocate that care be taken to avoid the transmission of genes responsible for suitability to aphids from emmer to T. aestivum.

The fall armyworm, Spodoptera frugiperda (J.E. Smith) (Lepidoptera, Noctuidae), is a polyphagous and highly destructive agricultural pest that invaded mainland China in 2019. To facilitate research on this pest, it is important to formulate and formalize a suitable artificial diet based on local ingredients. In this study, the life histories of fall armyworm reared on corn leaves and four artificial diets were recorded. The four artificial diets used were: soybean and sucrose-based (SS), soybean and wheat germ-based (SW), chickpea and wheat germ-based (CPW), and corn and soybean-based (CNS). The intrinsic rates of increase were 0.1957, 0.1981, 0.1816, 0.1748, and 0.1464 per day in the fall armyworm populations fed corn leaves, CNS, SW, CPW, and SS, respectively. The highest fecundity (F = 1225.4 eggs per female) and net reproduction rate (R₀ = 544.7 offspring per individual) were observed for the fall armyworm reared on the CNS diet. Moreover, the developmental rate, survival rate, and fecundity were used to calculate the projection of the population growth. Projection results showed that the fall armyworm populations can increase considerably faster when fed the CNS diet compared with the other diets. In addition, the mass-rearing system showed that the most efficient and economical strategy would be to rear the fall armyworm on the CNS diet. The results indicated that the CNS diet was the most suitable diet for the fall armyworm mass rearing.

Frankliniella schultzei (Trybom) is a serious pest of melon crops and is commonly found in the main producing areas of melon in Brazil (North and Northeast regions). This pest causes significant losses, damaging plants through feeding and tospovirus vectoring. Thus, the proper management of F. schultzei is crucial to prevent economic losses, and knowledge of the within-field distribution patterns of F. schultzei can be used to improve this pest management. This study aimed to determine the within-field distribution (through semivariogram modeling and kriging interpolation) and the factors associated with F. schultzei abundance in open-field yellow melon crops. We surveyed four yellow melon fields located in Formoso do Araguaia (Tocantins state, North Brazil) for thrips abundance in various crop stages (vegetative, flowering, and fruiting) in 2015 and 2016. Twelve models were fitted and it was determined that F. schultzei counts were strongly aggregated. The median spatial dependence was 4.79 m (range 3.55 to 8.02 m). The surface maps generated by kriging depicted an edge effect in fields 3 and 4. In addition, correlation analyses indicated that air temperature and presence of surrounding cucurbits are positively associated with F. schultzei abundance in yellow melon fields. Altogether, these insights can be combined for spatially based pest management, especially when the conditions (cucurbits in the surroundings and warmer periods) are favorable to F. schultzei.

Reduction of postharvest losses is gaining increased priority in warm regions where insect infestation may cause rapid deterioration of staple commodities. Acoustic detection can be used to assess the likelihood of insect infestations in bags of grain, flour, and other commodities that are stored in small holdings in developing countries, enabling rapid targeting of treatments. A portable postharvest insect detection system was developed with the goal to provide low-cost capability to acoustically assess infestations in small-scale storage facilities. Electret microphones input pest insect sounds to a 32-bit microcontroller platform that digitized and stored the signals on a digital memory card transferable to a portable laptop computer. The insect sounds then were analyzed by custom-written software that matched their spectra to those of known pests. Infestations of Sitophilus oryzae (L) in 2.6-kg bags could be detected down to densities of 1.9 adults/kg in grain and Tribolium castaneum (Herbst) down to 3.8 adults/kg in flour in laboratory settings. Also, differences in the rates of sounds per insect in treatments with different numbers ranging from 5 to 50 insects suggested that the sound rates of adults of different species at different population densities may be noticeably affected by aggregation pheromones or other behaviorally active semiochemicals. Further testing is needed but previous experience with acoustic detection systems suggests that the prototype has potential for use in small storage facilities where early detection of infestations is difficult to provide.

Use of nonpesticidal chemicals to minimize or eliminate horn fly (Haematobia irritans) populations on cattle could be helpful in combating insecticide resistance. One recent approach is the use of natural products with repellent properties against the target pest. A rapid on-animal evaluation system that accounts for both host and pest interactions and bypasses the need for costly multiyear field assessments is needed. The objective of this study was to develop a system to quantify product repellency of horn flies on cattle in a laboratory setting. Animal pair treatment groups were utilized to assess product efficacy and carrier effects across three experimental trials. A treatment solution consisting of 3% geraniol in mineral oil was the natural product repellent. Horn fly populations on animal pairs receiving the geraniol treatment were significantly reduced when compared with untreated animal pairs. However, animal pairs receiving a mineral oil-only treatment showed reduced horn fly populations similar to animals treated with mineral oil plus geraniol. Thus, there was a strong carrier effect that could be difficult to distinguish in the field but was easily observed using laboratory methods.

Recent outbreaks of engraver beetles, Ips spp. De Geer (Coleoptera: Curculionidae; Scolytinae), in ponderosa pine, Pinus ponderosa var. scopulorum Engelm. (Pinales: Pinaceae), forests of northern Arizona have resulted in widespread tree mortality. Current treatment options, such as spraying individual P. ponderosa with insecticides or deep watering of P. ponderosa in urban and periurban settings, are limited in applicability and scale. Thinning stands to increase tree vigor is also recommended, but appropriate timing is crucial. Antiaggregation pheromones, widely used to protect high-value trees or areas against attacks by several species of Dendroctonus Erichson (Coleoptera: Curculionidae; Scolytinae), would provide a feasible alternative with less environmental impacts than current treatments. We evaluated the efficacy of the antiaggregation pheromone verbenone (4,6,6-trimethylbicyclo[3.1.1]hept-3-en-2-one) in reducing attraction of pine engraver, I. pini (Say), to funnel traps baited with their aggregation pheromone in two trapping assays. Treatments included 1) unbaited control, 2) aggregation pheromone (bait), 3) bait with verbenone deployed from a pouch, and 4) bait with verbenone deployed from a flowable and biodegradable formulation (SPLAT Verb, ISCA Technologies Inc., Riverside, CA). Unbaited traps caught no beetles. In both assays, baited traps caught significantly more I. pini than traps with either formulation of verbenone, and no significant difference was observed between the verbenone pouch and SPLAT Verb. In the second assay, we also examined responses of Temnochila chlorodia (Mannerheim) (Coleoptera: Trogositidae), a common bark beetle predator. Traps containing verbenone pouches caught significantly fewer T. chlorodia than the baited control and SPLAT Verb treatments. We conclude that verbenone shows promise for reducing tree mortality from I. pini.

The leaf-cutting ant, Atta cephalotes L. (1758), is a major herbivore with great economic impact in the Neotropics. Because of its broad range and human-mediated dissemination, the ecology of this ant has received considerable attention; however, questions concerning its population genetics, dispersal, and social structure remain unexplored. Here, we aimed to identify and provide information on molecular and statistical performance of a suite of polymorphic microsatellite markers for A. cephalotes while demonstrating their utility for further genetic studies.We designed primer sequences targeting thousands of microsatellite loci and then screened 30 of these for amplification and polymorphism. Fifteen of these loci were selected and used to evaluate their polymorphism using 74 ants sampled from 15 different nests of the same location. This set of 15 loci exhibited variation of 2–20 alleles, with a mean heterozygosity of 0.57. All loci followed Hardy–Weinberg expectations with no evidence of linkage disequilibrium, while two loci showed evidence of null alleles. Our preliminary analysis suggested substantial nest differentiation with no population viscosity within the sampled location, as well as colonies with multiple queens (polygyny) and paternity (polyandry). Our newly identified microsatellites have proven to be highly informative to investigate gene flow, social structure and reproduction of this key agricultural pest.

The efficacies of two trap types, bucket and Picusan traps, for capturing and retaining Rhynchophorus palmarum (L.), an invasive palm pest responsible for killing thousands of ornamental Canary Islands date palms (Phoenix canariensis Chabaud [Arecales: Arecaceae]) in San Diego County, CA, were compared. Digital video data were analyzed to determine how R. palmarum behavior toward each trap type affected capture and retention rates. Videography was conducted 24 h/d, 7 d/wk, for more than 7 mo resulting in 20,211 h of digital data for analysis. Weevil attraction to traps was observed only during daylight hours and no patterns in diel activity were found. Neither trap type tested captured 100% of weevils attracted to traps. Bucket traps suspended 1.5 m above the ground attracted 30% more weevils than ground deployed Picusan traps. Of those weevils attracted to bucket traps, 89% entered, 82% escaped, and 18% that entered traps were retained. Weevils that were not retained spent an average of 19 min 20 s entering and exiting entry holes and walking and flying around the bucket trap. By contrast, Picusan traps captured 89% of weevils that entered the trap.The time between weevils arriving (via walking or flight) on the sides of the Picusan trap and retention in the trap ranged between 90 and 376 s.These visual observations suggest that Picusan traps are more efficient than bucket traps for R. palmarum capture.

The small hive beetle, Aethina tumida Murray, is an invasive pest that has spread globally. Western honey bees, Apis mellifera Linnaeus (Hymenoptera: Apidae), are considered the most important host and infestations can lead to collapse of colonies. Larvae feed on honey, pollen, and brood inside the hive and leave the hive as postfeeding wandering larvae to pupate in the surrounding soil. Other host species include bumble bees, stingless bees, and solitary bees, all of which can facilitate small hive beetle reproduction and are used for greenhouse crop pollination worldwide. Here, we investigated if small hive beetles can complete their life cycle when soil is absent by pupating in plant root-supporting substrates commonly used in greenhouses. Wandering small hive beetle larvae were introduced into containers with coconut fiber, perlite, a mixture of both and stone wool substrates to investigate pupation success and development time. Sand was used as control substrate. In all but one substrate (perlite), small hive beetles developed into adults equally well as they did in the sand. Development time ranged between 23 and 37 d and was not different from that of the control. We showed that small hive beetles can pupate in greenhouse substrates. This could constitute a problem for greenhouse pollination as well as it could facilitate small hive beetle survival in areas which otherwise would be deemed unsuitable or marginal environments for small hive beetles to become established. Our study highlights the opportunistic nature of the small hive beetle as an invasive species.