Artificial sweeteners are sweet-tasting additives found in consumable products as substitutes for naturally occurring sugars. They are derived from plant extracts or manufactured by chemical synthesis. Ingestion of sweeteners by insects can lead to significant physiological effects, such as mortality, decreased fecundity, and behavioral change. Due to their low toxicity toward humans and the issues associated with conventional insecticide usage, artificial sweeteners have recently gained attention for their potential use as biorational insecticides. Here, we review their impact on insects and potential as novel insecticides.

Mosquito control districts in the United States are limited to two main classes of adulticides, pyrethroids and organophosphates, to control mosquitoes. Two adulticides used to control domestic mosquitoes are Fyfanon EW (malathion, organophosphate) and DeltaGard (deltamethrin, pyrethroid). While the effect of these pesticides on European honeybees (Apis mellifera L., Hymenoptera: Apidae) has been investigated, effects on native pollinators need additional research. The purpose of this study was to investigate the acute nontarget effects of these pesticides on Bombus impatiens Cresson (Hymenoptera: Apidae), a native North American bumble bee species, and compare these effects to wild and laboratory strains of mosquitoes (Aedes aegypti (L.) and Culex quinquefasciatus Say, Diptera: Culicidae) through field and laboratory assays. Bombus impatiens was found to be resistant to Fyfanon EW (x̄ = 6.7% mortality at 50-µg malathion per bottle) at levels that caused significant mortality to study mosquitoes (86.2 ≥ x̄ ≥ 100% mortality) in laboratory bottle bioassays. Comparatively, B. impatiens demonstrated greater mortality to DeltaGard (93.3%) at 2.5-µg deltamethrin/bottle than any mosquito colony assayed (14.1 ≥ x̄ ≥ 87.0% mortality). Only DeltaGard was tested in field applications. In the field, we observed acute effects of DeltaGard on mosquitoes and B. impatiens at 25- and 75-m distance from a truck-mounted ultra-low volume fogger, although treatment effects were not significant for B. impatiens. Additional wild-caught nontarget mortality to DeltaGard field trials was also evaluated. This study indicated that common mosquito control adulticides do cause nontarget mortality to B. impatiens but that impacts are variable depending on pesticide and further studies are needed.

Pistacia vera L. is one of the most important horticultural crops in Iran. The stink bugs Acrosternum arabicum and Brachynema germari are two of the key pests that cause significant direct and indirect damage on Pistacia vera. Egg parasitoids have been considered as potential biological control agents of pistachio green stink bugs. Among them, Trissolcus semistriatus and Psix saccharicola are the most abundant and efficient parasitoid for A. arabicum in pistachio orchards. In this study, we assessed lethal and sublethal effects of two commonly used insecticide products (fenitrothion and a binary mixture of lambda-cyhalothrin + thiamethoxam) on these two parasitoid wasps under laboratory conditions. The median lethal concentration (LC₅₀) values for fenitrothion and thiamethoxam + lambda-cyhalothrin in P. saccharicola and T. semistriatus were estimated as 1.03, 0.48 and 0.87, 0.98 mg a.i./liter, respectively. In terms of sublethal effects, insecticide treatments altered the type of functional response from type III to type II in T. semistriatus. However, P. saccharicola exhibited a type II functional to density of A. arabicum for all treatments, although attack rates were lower for insecticide-exposed wasps while handling times increased. Our results show that sublethal effects of insecticides further reduce the efficacy of biological control agents. Effective integrated pest management programs should avoid antagonistic interactions between chemical and biological control methods. The results of this study provide useful information to develop comprehensive integrated pest management programs for stink bugs in pistachio orchards.

The age-specific functional and numerical responses of Neoseiulus cucumeris Oudemans (Mesostigmata: Phytoseiidae) on eggs of the two-spotted spider mite, Tetranychus urticae Koch (Prostigmata: Tetranychidae), were assessed in the laboratory using bean leaf discs. Densities of 2, 4, 8, 16, 32, 64, and 128 prey were provided to 4- (protonymph), 6- (deutonymph), 8-, 13-, 18-, 23-, 28-, 33-, and 40-d-old N. cucumeris individuals. The functional response of 28- and 40-d-old N. cucumeris fitted type II, whereas the other ages displayed a type III functional response. The longest handling time observed at the age of 4 d was 0.515 h, whereas the shortest handling time and highest value of maximum attack rate (T/T_h) were associated with the age of the 28-d-old treatment (0.261 h and 91.95 prey/d, respectively). The numerical response of N. cucumeris showed a significant increase with increasing prey density, but its rate gradually decreased at higher densities. Therefore, the efficiency of conversion of ingested food was relatively higher at low two-spotted spider mite densities, whereas it was reduced at high two-spotted spider mite densities. The stronger functional response and predation capacity of N. cucumeris on two-spotted spider mite eggs indicated the high potential of this predatory mite as an effective biological control agent against two-spotted spider mite especially at its early and middle ages and also when higher prey densities are present.

The functional and numerical responses of Habrobracon hebetor (Say) were assessed over 30 sequential generations (G) on different densities (2, 4, 8, 16, 32, 64, and 128 fifth-instar larvae) of the Mediterranean flour moth, Ephestia kuehniella (Zeller). Seven tested generations (G2_inf, G4_inf, G6_inf, G8_inf, G10_inf, G15_inf, and G30_inf) had already been naturally infected by a fungus species, whereas only the second generation (G2) had the colonies of both infected (G2_inf) and uninfected (G2_uninf) individuals. All infected generations, as well as the uninfected generation, showed a Type III functional response. A high variation was found in the handling times (T_h) of the parasitoid through 30 sequential generations, and G10_inf had the longest handling time. The shortest handling time and the maximum estimated attack rate (T/T_h) were observed in G2_inf. No significant difference in terms of the number of parasitized hosts was found among all infected generations, as well as between G2_inf and G2_uninf. Although the handling times in G2_inf and G2_uninf were close to each other, the attack coefficient of G2_uninf was more than that of G2_inf. The attack coefficient and handling time of infected generations increased from G2_inf to G10_inf and then decreased in the higher generations. The most plausible parameters of functional response of infected generations were observed in G_inf. A negative relationship between eggs laid and host densities was observed in the infected generations (G2_inf, G4_inf, G6_inf, G8_inf, and G10_inf). G2_uninf and, among infected generations, G_inf were the best generations for practical utilization in inundative release programs.

Several agroecological and integrated pest management strategies focus on landscape management to increase complexity and foster biodiversity. However, landscape complexity does not always enhance biological control and in some cases may lead to increased pest populations. We examined the prevalence of two Bracon parasitoids, Bracon cephi Gahan and Bracon lissogaster Muesebeck (Hymenoptera: Braconidae), and their host the wheat stem sawfly Cephus cinctus Norton, a major pest of wheat. We assessed the degree of noncrop and crop host plant use and responses to landscape composition. We found no instances of parasitism by either Bracon species in our three-year, statewide winter wheat survey but found small populations of Bracon in noncrop landscapes throughout eastern and western Colorado. We used model selection to examine how local (500 m scale) and landscape (5 km scale) cover of suitable noncrop and crop habitats potentially affects abundances of Bracon and wheat stem sawfly. Our best fit model for wheat stem sawfly suggests that a decrease in noncrop cover at the landscape scale leads to an increase in wheat stem sawfly infestation. Our best fit model for Bracon parasitism suggests an increase in wheat cover at the local level results in the greatest increase in the odds of parasitism by either species of Bracon. Herbaceous cover at local and landscape scales were also significant predictors of Bracon parasitism. The results of this study suggest that pest and natural enemies respond differently to landscape composition and these responses should be evaluated before management decisions are made.

Ceroplastes cirripediformis Comstock is one of the most destructive invasive pests that have caused various negative impacts to agricultural, ornamental, and greenhouse plants. Since it is time- and labor-consuming to control C. cirripediformis, habitat evaluation of this pest may be the most cost-effective method for predicting its dispersal and avoiding its outbreaks. Here, we evaluated the effects of climatic variables on distribution patterns of C. cirripediformis and produced a global risk map for its outbreak under current and future climate scenarios using the Maximum Entropy (MaxEnt) model. Our results showed that mean temperature of driest quarter (Bio 9), precipitation of coldest quarter (Bio 19), precipitation of warmest quarter (Bio 18), and mean temperature of wettest quarter (Bio 8) were the main factors influencing the current modeled distribution of C. cirripediformis, respectively, contributing 41.9, 29.4, 18.8, and 7.9%. The models predicted that, globally, potential distribution of C. cirripediformis would be across most zoogeographical regions under both current and future climate scenarios. Moreover, in the future, both the total potential distribution region and its area of highly suitable habitat are expected to expand slightly in all representative concentration pathway scenarios. The information generated from this study will contribute to better identify the impacts of climate change upon C. cirripediformis's potential distribution while also providing a scientific basis for forecasting insect pest spread and outbreaks. Furthermore, this study serves an early warning for the regions of potential distribution, predicted as highly suitable habitats for this pest, which could promote its prevention and control.

Rapid and cost-efficient identification of Naupactus species is becoming a key process for the exportation of citrus fruit from Chile and other countries, considering the quarantine regulations for some species of the cosmopolitan genus Naupactus. This study deals with the development of a fast and sensitive detection protocol for Naupactus cervinus (Coleoptera: Curculionidae) (Boheman) and Naupactus xanthographus (Coleoptera: Curculionidae) (Germar) based on multiplexTaqMan Real-time polymerase chain reaction. Both N. cervinus and N. xanthographus primer and probe sets achieved species-specific detection in a linear range from 1 pg/µl to 1 × 10^-6 pg/µl, allowing detection of as few as 160 copies of template DNA. Non-target amplifications were not detected and a panel composed of 480 test samples had 100% coincidence with the respective morphological identification.

Logs of high-value eastern black walnut (Juglans nigra L.) are commonly exported from the United States for production of veneer and lumber. Veneer logs are not debarked to minimize degradation of wood quality and reduce moisture loss. Thousand cankers disease (TCD) is caused by the walnut twig beetle (Pityophthorus juglandis Blackman) and the fungal pathogen, Geosmithia morbida M. Kolarik, E. Freeland, C. Utley and N. Tisserat sp. nov., which colonize the inner bark of Juglans species. Effective eradication of these organisms by heat or chemical fumigation treatment is required for walnut logs prior to export. Because vacuum steam is an effective and efficient means of heating round wood, its use in eliminating the TCD causal agents was evaluated using Juglans logs (12- to 44-cm small end diameter and 1.7- to 1.9-m length) fromTCD-symptomatic trees in Oregon and Washington State. Five replicate trials with three logs per load were conducted in a portable vacuum chamber to test two treatment schedules: 60°C for 60 min and 56°C for 30 min. Complete elimination of P. juglandis and G. morbida was achieved when using a minimum of 56°C at 5-cm targeted depth from bottom of bark furrow into the sapwood and held for 30 min. Treatment cycle time ranged from 298 to 576 min depending on log diameter and initial log temperature. Artificial inoculation of J. nigra trees with G. morbida within the TCD range in Pennsylvania was minimally successful in producing adequately colonized logs for experimental trials.

Successful application of the sterile insect technique (SIT), an environmentally friendly control technology, mainly depends on mass-rearing of high-quality and high-performance insects. For mass-rearing of insects, the development of artificial diets is a key component. For optimal insect growth and development, sugar is an essential nutrient as it provides energy for flight. To date, few studies have analyzed the effects of different sugar contents on the biological parameters, including the flight capacity of Grapholita molesta, a globally important economic pest. Artificial diets with different sucrose contents (0, 15, and 30 g) were evaluated in two consecutive generations. The insect flight mill was used to study the G. molesta flight capacity. The larval and pupal periods, adult longevity and pupal weight of the first-generation of G. molesta reared on artificial diets with different sucrose contents were significantly different. Insects of the second-generation had a shorter larval period, greater adult longevity, and heavier larvae and pupae in the treatment with 30 g of sucrose than using 15 g. Among the males, strong, medium, and weak flight capacities were recorded and the weakest one was observed in the diet without sucrose. Results showed that the proportion of insects with highest flight capacity increased with increasing sucrose content in insects of the second generation. It can be concluded that sucrose content is a key determinant in the biological traits, including flight capacity of G. molesta, and should be taken into consideration during the mass-rearing of the pest for SIT.

Grasshoppers have been a chronic problem for agriculture on the Canadian prairies, the northern limits of the Northern Great Plains, since settlement of the region in the mid-1800s. Grasshopper pest management tools include biological control, cultural control, and insecticides. This article describes a mechanistic, or process-based, modeling approach used to assess the development and abundance of the migratory grasshopper, Melanoplus sanguinipes (Fabricius), based on a complex of environmental drivers. The purpose of the study was to develop and validate a model (using extensive field data) to quantify the effects of interannual weather variation on M. sanguinipes development and abundance in Saskatchewan, Canada. Overall, the accuracy of model predictions improved for later instars and adults such that predictions regarding adult populations were highly similar to field-collected data. The model provides greater understanding of how M. sanguinipes oviposition is related not only to adult densities, but also to the first appearance of adults and to weather conditions during the oviposition period. The model output can be used to provide accurate within-season updates of the status of grasshopper populations in western Canada to optimize pest management.

A number of thrips species are among the most significant agricultural pests globally. Use of repellent intercrop plants is one of the key components in plant-based ‘push–pull' strategies to manage pest populations. In this study, the behavioral responses of three thrips species, Frankliniella occidentalis (Pergande), Frankliniella intonsa (Trybom), and Thrips palmi Karny (Thysanoptera: Thripidae) to Rosmarinus officinalis were investigated in Y-tube olfactometer bioassays and cage experiments. In addition, the major volatile compounds from rosemary were identified and the effect of the individual compounds on thrips behavior was evaluated. Females and males of the three thrips species were significantly repelled by the volatiles from cut rosemary leaves. The presence of rosemary plants significantly reduced settlement of females of the three thrips species and eggs laid by F. occidentalis females on target host plants. In total, 47 compounds were identified in the volatiles collected from the cut leaves of rosemary plants. The responses of the three thrips species to 10 major volatile compounds showed significant differences. However, α-pinene, the most abundant volatile, was repellent to F. occidentalis and F. intonsa. Eucalyptol, the second most abundant volatile, showed significant repellent activity to all the three thrips species. Our findings showed that rosemary is a promising repellent plant against the three thrips pests we tested, which could be a good candidate for ‘push' plants in plant-based ‘push–pull’ strategies. The identified volatile compounds that accounted for the repellent activity could be developed as repellents for sustainable thrips management.

Drosophila suzukii (Matsumura) and Zaprionus indianus (Gupta) (Diptera: Drosophilidae) are invasive pests of economic importance worldwide. This study was undertaken as a first step to investigate the interaction between visual and chemical cues on the captures of D. suzukii and Z. indianus under field conditions. Specifically, we evaluated the effect of color cardboards and their combinations on the capture of these drosophilids by attractant-baited multihole traps in blackberry and blueberry crops. Color had a significant effect on the captures of D. suzukii and Z. indianus by attractant-baited traps in both crops. Overall, attractant-baited traps with yellow and yellow + green cards captured the highest number of flies compared to attractant-baited traps using cards of other colors or without cards. Multihole traps without attractant and color cardboards caught very few flies of both species. In general, more females than male D. suzukii were captured, but no sexual differences were found in the captures of Z. indianus. The results obtained will be useful for the development of a monitoring or mass trapping system for the management of D. suzukii and Z. indianuspopulations in Mexico.

Following the deregistration of lindane, several neonicotinoid insecticides have been registered as seed treatments for controlling wireworms in cereal crops. Unlike lindane, which did both, neonicotinoids provide crop protection but do not reduce wireworm populations. Hence populations of various economic species are growing in key wheat production areas of the United States and Canada, and there is a need for novel seed treatments that match the efficacy of lindane. Herein we evaluated broflanilide, a novel GABA-gated Cl- channel allosteric modulator that differs from the cyclodienes (e.g., lindane) in that it binds to a unique site in the GABA receptor. As such, broflanilide confers a new mode of insecticidal action (Group 30 MOA), and is the first meta-diamide insecticide developed. When evaluated in field trials over 7 yr at various rates, broflanilide at 5.0 g [AI]/100 kg wheat seed was as effective at protecting wheat stand from wireworm (Agriotes obscurus) injury as the current industry standard thiamethoxam at 20–30 g [AI]/100 kg seed. In addition, broflanilide at 5.0 g reduced neonate wireworms (produced from eggs laid in established wheat during the growing season) and resident wireworms (in the field at time of planting) by 73.1 and 81.1%, respectively, which is comparable to that reported for the previous industry standard lindane (75.3 and 57.6%, respectively). These studies show that broflanilide at 5.0 g [AI] will provide consistent wheat stand protection (equal to thiamethoxam at 20–30 g [AI]), and A. obscurus wireworm population reduction (equal to lindane at 59 g [AI]), and will do so at far lower dosages per hectare.

The western bean cutworm, Striacosta albicosta (Smith), is considered a major corn pest in North America. In 2009, it started invading the province of Québec (northeastern Canada). To our knowledge, there has been no evidence that this pest could overwinter in this province. In the falls of 2017 and 2018, storage totes containing mature western bean cutworm larvae were placed in the soil in three agricultural regions, in Québec, where western bean cutworm invasions are frequent and crop damage is often significant. The goal was to evaluate if western bean cutworm could resist the province's winter conditions. The storage totes were removed from the soil at different dates to estimate winter survival. Emergence cages were installed over the totes in the spring of the following year to determine whether western bean cutworm could complete its life cycle. In the spring of 2019, car shelters were also installed at two different sites to evaluate natural moth emergences in fields in which numerous mature western bean cutworm larvae and damage were reported in 2018. Western bean cutworm moth emergences occurred in both cases. These experiments constitute the first documented evidence that western bean cutworm can overwinter and complete its life cycle in Québec's cold climate. It also represents the northernmost overwintering survival for this species ever documented in North America. The western bean cutworm's ability to overwinter in Québec will have important implications for corn producers. Pest monitoring and management programs in the province of Québec will need to be adapted accordingly.

This study was conducted at the Oregon State University Hermiston Agricultural Research and Extension Center, Hermiston, Umatilla County, OR, during the 2016 and 2017 potato, Solanum tuberosum L. (Solanales: Solanaceae), growing seasons. The objective was to determine the vertical distribution of hemipteran (Bactericeracockerelli Šulc, Circulifertenellus Baker, Myzuspersicae Sulzer, Macrosiphumeuphorbiae Thomas, and Lygus spp.) and thysanopteran (Frankliniella occidentalis Pergande and Thrips tabaci Lindeman) potato pests using insect towers placed near potato fields. Towers were 8 m tall and secured to the ground with metal cables. In each tower, yellow sticky cards were mounted at 1.5 m intervals up to 7.6 m aboveground. Data were collected at 7-d intervals from mid-April until mid or end of August. This study showed that B. cockerelli, C. tenellus, M. persicae, Lygus spp., and both species of thrips were captured on sticky cards placed closest to the ground; in both years, as sticky card height increased, abundances decreased. In contrast, trapped M. euphorbiae numbers were not affected by sticky card height. To our knowledge, this is the first study in the lower Columbia Basin of Oregon that evaluated the vertical distribution of major potato pests.

Spider mite (Acari: Tetranychidae) outbreaks are common on corn grown in the arid West. Hot and dry conditions reduce mite development time, increase fecundity, and accelerate egg hatch. Climate change is predicted to increase drought incidents and produce more intense temperature patterns. Together, these environmental shifts may cause more frequent and severe spider mite infestations. Spider mite management is difficult as many commercially available acaricides are ineffective due to the development of resistance traits in field mite populations. Therefore, alternative approaches to suppress outbreaks are critically needed. Drought-tolerant plant hybrids alleviate the challenges of growing crops in water-limited environments; yet, it is unclear if drought-tolerant hybrids exposed to water stress affect mite outbreaks under these conditions. We conducted a greenhouse experiment to evaluate the effect of drought-tolerant corn hybrids on Banks grass mite [Oligonychus pratensis Banks (Acari:Tetranychidae)], a primary pest of corn, under optimal irrigation and water-stress irrigation. This was followed by a 2-yr field study investigating the effect of drought-tolerant corn hybrids exposed to the same irrigation treatments on Banks grass mite artificially infested on hybrids and resident spider mite populations. Results showed that water-stressed drought-tolerant hybrids had significantly lower Banks grass mite and resident spider mite populations than water-stressed drought-susceptible hybrids. Interestingly, water-stressed drought-tolerant hybrids had equal Banks grass mite populations to drought-susceptible and drought-tolerant hybrids under optimal irrigation. We posit that planting drought-tolerant hybrids may suppress spider mite outbreaks in water-challenged areas.

Melanaphis sacchari Zehntner is a new pest of sweet sorghum in the United States, with the potential to cause complete crop failure. In Kentucky, sweet sorghum is normally planted in early May and harvested in late August or September. Planting sweet sorghum earlier in the season may avoid damaging levels of M. sacchari that develop in late summer. In a 2-yr field study, three different planting dates separated by a month (April, May, and June) were tested for their effect on M. sacchari densities and sweet sorghum yield. April (early) planted sweet sorghum was grown in greenhouses and transplanted to the field. May (mid) and June (late) planted sweet sorghum were direct seeded in the field. Melanaphis sacchari population densities were evaluated weekly starting in June. Sweet sorghum was harvested at the onset of the hard dough stage. Plots were split into two subplots, insecticide or noninsecticide, in the second year to control for planting date effect on yield. Early-planted sweet sorghum had lower aphid densities, but had lower yield relative to mid-planting date, which had the highest yield. Insecticide drenches in 2019 reduced cumulative aphid days in mid-plantings and late plantings, but did not significantly affect yield within planting dates. Seeding sweet sorghum earlier can reduce M. sacchari densities; however, this method alone may not provide the highest yields. We documented that the recommended planting date (May) for Kentucky produced the highest yield.

The emerald ash borer (EAB), Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), native to Northeast Asia, is the most destructive invasive ash (Fraxinus spp.) pest in the United States. In the present study, we evaluated the effect of exposure of diapausing mature fourth instars (J-shaped larvae, JL) of EAB to cool temperatures, either 1.7 or 12.8°C for 1–9 mo, on their post-chill development including adult emergence, longevity, and lifetime fecundity under standard rearing conditions (26 ± 0.5°C, 16:8 h L:D). In addition, we determined the effect of different stages of the larvae chilled at 12.8°C for 3 mo on the subsequent post-chill development to EAB adults. Findings from the study revealed that a period (≥2 mo) of chill at 12.8°C is required for the termination of the EAB diapause. However, chill treatment of the larvae at the near zero temperature (1.7°C) does not result in the post-diapause larval development to adults, regardless of the chill time (1–9 mo). In addition, our results showed that chill treatment of immature young larvae (L1–L4 prior to JL) results in little production of EAB adults, indicating that EAB diapause predominantly as JL. Findings of this study may be useful to laboratory rearing of EAB from eggs through continuous generations and help us understand the pest's voltinism resulting from the diapause and post-diapause development under different climatic conditions.

Whitebark pine, Pinus albicaulis Engelm., is a subalpine tree endemic to western North America. This species provides multiple ecosystem services and is suffering widespread mortality from mountain pine beetle, Dendroctonus ponderosae Hopkins. Verbenone is a pheromone produced as D. ponderosae feed, and high air concentrations of verbenone deter D. ponderosae from colonizing trees. Synthetic verbenone has been formulated into products used to prevent D. ponderosae from colonizing trees. We compared the ability of verbenone pouches and SPLAT Verb to protect individuals and small stands of P. albicaulis. With individual trees in Montana, all treated trees survived regardless of verbenone formulation and rate, whereas untreated trees suffered 70 and 90% mortality in 2015 and 2016. In plot experiments in California from 2015 to 2017, and Oregon from 2015 to 2018, verbenone was applied to trees spaced ∼10 m apart, and survival of small (12.7–23 cm DBH = diameter at 1.37 m height), medium (23.1–33 cm DBH) and large (>33 cm DBH) trees was compared. In California, where >80% of untreated trees survived, pouches increased survival ∼2 to 3% and SPLAT Verb increased survival ∼4 to 7% regardless of tree size. In Oregon, verbenone pouches and SPLAT Verb performed similarly on medium and small trees, but large trees had greater survival when treated with SPLAT Verb (∼93%) than pouches (∼82%). Compared to verbenone pouches, SPLAT Verb appears to better protect P. albicaulis from D. ponderosae.

In recent years, Protaetia brevitarsis Lewis has gradually become an important pest of several crops including grape (Vitis vinifera L.) and peach (Amygdalus persica L.) in Xinjiang, China. Toward improving trapping efficacy as part of a management program, various colors, types, and placement of traps and the use of an attractant were evaluated in field and laboratory studies. Laboratory color-choice tests and field tests indicated that P. brevitarsis adults preferred red. In trap placement tests, more adults were captured on traps placed 1 or 1.5 m above the ground and on top of the horizontal grape canopy. Before grape ripening, more adults were captured in traps placed in a 0.5-m border around the outside edge of the vineyard; during grape ripening, more were caught within the vineyard. Newly designed traps that were red, with a triangular baffle and a landing plate, were more efficient than traditional bucket-shaped traps. When P. brevitarsis adults were trapped and killed from June to July 2018, the population of P. brevitarsis adults in August to early September 2018 was significantly lower than in August to early September 2017, when adults had not been trapped and killed in the prior 2 mo.

The billbug complex, Sphenophorus spp. (Coleoptera: Curculionidae), is an important pest on the sod farms of Georgia. The feeding damage of larvae within stolons and on roots delays the sod harvest and makes it difficult to conduct machine harvests. To develop an effective management strategy, the timing of insecticide applications is critical. The activity of billbugs, especially soon after sod harvest, has not been documented, as newly emerging adults could reinfest the harvested area or adjacent nonharvested sod fields. In 2019 and 2020, adult billbugs were sampled from harvested and nonharvested areas of sod farms by using linear pitfall traps. Although a significantly greater number of billbug adults were captured from the nonharvested sod, the data showed that adults were present in the harvested sod area. To understand the direction of billbug movement in harvested and nonharvested sod, a square area was selected, and the sod inside the square was removed. Linear pitfall traps were deployed along the perimeter of square areas to collect adults from outside and inside the square. In 2020, a significantly greater number of billbug adults were collected in the traps from the nonharvested areas outside the square than from harvested area inside the square, whereas in 2019, adult captures were similar from both areas. The data documented the activity of billbugs in the areas where sod was harvested, posing a risk of infestation for both strips of nonharvested grass in the harvested area and the adjacent, nonharvested sod fields that were near harvest.

The navel orangeworm, Amyelois transitella (Walker), is the most significant pest of California almonds. Direct feeding on the kernel by the larvae causes reductions in salable crop, crop quality, and exportability. Pheromone mating disruption (MD) targeting navel orangeworm is a relatively new technique with the potential to improve management. In 2017, we used replicated ∼16-ha plots to compare the efficacy of four commercial MD systems (CheckMate, Cidetrak, Isomate, and Semios) for their relative impacts on the number of navel orangeworm in monitoring traps and crop quality. From 2017 to 2018, we conducted nine direct comparison studies in 16 to 40 ha almond orchards to compare conventional pest management programs to programs incorporating pheromone MD systems. Across all studies, MD reduced male moth captures in pheromone traps by >94%. In the efficacy study, use of mating disruption led to 35% and 53% reductions in kernel damage in Nonpareil and pollinizer cultivars, respectively, and an average increase in crop value of $370 ha^–1. In the direct comparison, kernel damage to Nonpareil and pollinizer cultivars was reduced by 65% and 78%, respectively, resulting in an average increase in crop value of $357 ha^–1. Economic analyses showed that increases in crop returns exceeded the costs of implementing MD systems with the break-even point ranging from 0.86 to 1.06% of kernel damage. These results suggest that adding MD to an existing navel orangeworm management program is a cost-effective way to reduce damage while promoting sustainable pest management practices.

Prompt responses to invasive Latrodectus spiders introduced unintentionally are needed worldwide due to their medical and ecological importance. Latrodectus species are chemically controlled using pyrethroid insecticides despite concerns about the ecological impacts of these compounds on biodiversity/ecosystems. Here, the relative sensitivities (acute toxicity: 48-h LC₅₀) of Latrodectus hasseltii Thorell and Latrodectus geometricus C.L. Koch from Japan to the conventional neurotoxic insecticide bifenthrin (pyrethroid) and a new candidate insecticide, fipronil (phenylpyrazole), were examined. Acute residual toxicity tests of these compounds in two nontarget spiders (Parasteatoda tepidariorum C.L. Koch (Araneae: Theridiidae), Badumna insignis L. Koch (Araneae: Desidae)) were conducted for comparison. To test whether bifenthrin and fipronil toxicities differed among the four spiders, corresponding species sensitivity distributions (SSDs) were compared, and hazardous concentrations were determined. Sensitivity (especially in the nontarget species) was two to four orders of magnitude higher for bifenthrin than for fipronil. The SSD patterns of the two insecticides differed significantly, with the spider communities being more sensitive to bifenthrin than to fipronil. The lethal bifenthrin concentration for Latrodectus may reduce spider populations by over 70–90%. If L. hasseltii (established throughout Japan) is targeted for effective population suppression rather than L. geometricus (with a limited distribution range) using the specified insecticide concentration (LC₅₀ value) for fipronil, less than 20% of spider communities will be impacted. Chemical operations aimed at the effective population management and subsequent eradication of invasive Latrodectus spiders while supporting local biodiversity conservation would benefit from considerations of fipronil dosages and target species sensitivities.

Chrysodeixis includens (Walker, [1858]) is one of the most important defoliator of soybean in Brazil because of its extensive geographical distribution and high tolerance to insecticides compared with other species of caterpillars. Because of this, we conducted bioassays to evaluate the efficacy of pyrethroid λ-cyhalothrin on a C. includens resistant strain (MS) and a susceptible (LAB) laboratory strain. High throughput RNA sequencing (RNA-seq) of larval head and body tissues were performed to identify potential molecular mechanisms underlying pyrethroid resistance. Insecticide bioassays showed that MS larvae exhibit 28.9-fold resistance to pyrethroid λ-cyhalothrin relative to LAB larvae. RNA-seq identified evidence of metabolic resistance in the head and body tissues: 15 cytochrome P450 transcripts of Cyp6, Cyp9, Cyp4, Cyp304, Cyp307, Cyp337, Cyp321 families, 7 glutathione-S-transferase (Gst) genes, 7 α-esterase genes from intracellular and secreted catalytic classes, and 8 UDP-glucuronosyltransferase (Ugt) were overexpressed in MS as compared with LAB larvae. We also identified overexpression of GPCR genes (CiGPCR64-like and CiGPCRMth2) in the head tissue. To validate RNA-seq results, we performed RT-qPCR to assay selected metabolic genes and confirmed their expression profiles. Specifically, CiCYP9a101v1, CiCYP6ae149, CiCYP6ae106v2, CiGSTe13, CiCOE47, and CiUGT33F21 exhibited significant overexpression in resistant MS larvae. In summary, our findings detailed potential mechanisms of metabolic detoxification underlying pyrethroid resistance in C. includens.

The white-backed planthopper, Sogatella furcifera (Horváth), causes substantial damage to crops by direct feeding or virus transmission, especially southern rice black-streaked dwarf virus, which poses a serious threat to rice production. Cycloxaprid, a novel cis-nitromethylene neonicotinoid insecticide, has high efficacy against rice planthoppers, including imidacloprid-resistant populations. However, information about the influence of cycloxaprid on S. furcifera (Hemiptera: Delphacidae) at the molecular level is limited. Here, by de novo transcriptome sequencing and assembly, we constructed two transcriptomes of S. furcifera and profiled the changes in gene expression in response to cycloxaprid at the transcription level. We identified 157,906,456 nucleotides and 131,601 unigenes using the Illumina technology from cycloxaprid-treated and untreated S. furcifera. In total, 38,534 unigenes matched known proteins in at least one database, accounting for 29.28% of the total unigenes. The number of coding DNA sequences was 28,546 and that of amino acid sequences in the coding region was 22,299. In total, 15,868 simple sequence repeats (SSRs) were identified. The trinucleotide repeats accounted for 45.1% (7,157) of the total SSRs and (AAG/CTT)n were the most frequent motif. There were 359 differentially expressed genes that might have been induced by cycloxaprid. There were 131 upregulated and 228 downregulated genes. Twenty-two unigenes might be involved in resistance against cycloxaprid, such as cytochrome P450, glutathione S-transferase (GST), acid phosphatase (ACP), and cadherin. Our study provides vital information on cycloxaprid-induced resistance mechanisms, which will be useful to analyze the molecular mechanisms of cycloxaprid resistance and may lead to the development of novel strategies to manage S. furcifera.

The diamondback moth, Plutella xylostella (Linnaeus, 1758), is one of the main pests of brassicas, and various insecticides, such as indoxacarb, are used to control it. However, frequent insecticide applications favor the selection of resistant individuals. Thus, the residual and sublethal effects of indoxacarb in two populations of P. xylostella, one collected in the field (FP) and one from the laboratory (LP), were evaluated and compared. The objective of this research was to investigate the toxicity of indoxacarb at residual and sublethal levels in a field population of P. xylostella from Brazil and a population from the laboratory. Leaf-dip bioassays showed high toxicity, with LC₅₀ values after 48 h of 3.7 and 6.9 mg/liter for the LP and FP, respectively. Sublethal effects were indicated by significant reduction in the survival of larvae, pupae, and offspring. There was an increase in foliar consumption and a decrease in adult survival in the LP, and a decrease in fecundity in the FP. For the LP and FP population, the mean values for R₀, r_m, and λ for the control treatment were significantly higher than for the treatment groups (CL₁₅ and CL₂₅). Exposure of larvae to sublethal indoxacarb concentrations significantly reduced larval and pupal survival. Larval and pupal survival decreased as the indoxacarb concentration increased. Fecundity was significantly lower for the FP at LC₁₅ (96.2 eggs per female) and LC₂₅ (69.2 eggs per female) concentrations compared with the other treatments.

As part of an insect resistance management plan to preserve Bt transgenic technology, annual monitoring of target pests is mandated to detect susceptibility changes to Bt toxins. Currently Helicoverpa zea (Boddie) monitoring involves investigating unexpected injury in Bt crop fields and collecting larvae from non-Bt host plants for laboratory diet bioassays to determine mortality responses to diagnostic concentrations of Bt toxins. To date, this monitoring approach has not detected any significant change from the known range of baseline susceptibility to Bt toxins, yet practical field-evolved resistance in H. zea populations and numerous occurrences of unexpected injury occur in Bt crops. In this study, we implemented a network of 73 sentinel sweet corn trials, spanning 16 U.S. states and 4 Canadian provinces, for monitoring changes in H. zea susceptibility to Cry and Vip3A toxins by measuring differences in ear damage and larval infestations between isogenic pairs of non-Bt and Bt hybrids over three years. This approach can monitor susceptibility changes and regional differences in other ear-feeding lepidopteran pests. Temporal changes in the field efficacy of each toxin were evidenced by comparing our current results with earlier published studies, including baseline data for each Bt trait when first commercialized. Changes in amount of ear damage showed significant increases in H. zea resistance to Cry toxins and possibly lower susceptibility to Vip3a. Our findings demonstrate that the sentinel plot approach as an in-field screen can effectively monitor phenotypic resistance and document field-evolved resistance in target pest populations, improving resistance monitoring for Bt crops.

Eastern New York State is frequently the site of Colorado potato beetle (Leptinotarsa decemlineata, Say) populations with the highest observed levels of insecticide resistance to a range of active ingredients. The dominance of a resistant phenotype will affect its rate of increase and the potential for management. On organic farms on Long Island, L. decemlineata evolved high levels of resistance to spinosad in a short period of time and that resistance has spread across the eastern part of the Island. Resistance has also emerged in other parts of the country as well. To clarify the level of dominance or recessiveness of spinosad resistance in different parts of the United States and how resistance differs in separate beetle populations, we sampled in 2010 beetle populations from Maine, Michigan, and Long Island. In addition, a highly resistant Long Island population was assessed in 2012. All populations were hybridized with a laboratory-susceptible strain to determine dominance. None of the populations sampled in 2010 were significantly different from additive resistance, but the Long Island population sampled in 2012 was not significantly different from fully recessive. Recessive inheritance of high-level resistance may help manage its increase.

Filth flies remain one of the most prevalent pest groups affecting the animal production industry. Spalangia spp. and Muscidifurax spp. are beneficial parasitic wasps that often are utilized to manage filth fly populations such as house flies, Musca domestica L. (Diptera: Muscidae), and stable flies, Stomoxys calcitrans (L.) (Diptera: Muscidae). These wasps search for filth fly pupae as hosts in areas potentially treated with insecticides, which may result in nontarget insecticide selection effects. However, research regarding resistance development in parasitic wasps such as S. cameroni Perkins (Hymenoptera: Pteromalidae) is limited. Therefore, a study was conducted to determine the potential of S. cameroni to develop resistance to the commonly used insecticide permethrin, as well as compare permethrin susceptibility among several S. cameroni strains. After 10 selected generations, susceptibility was significantly lower for the selected strain when compared with that of its unselected parent strain. A comparison of several parasitoid strains collected from different U.S. states indicated that permethrin susceptibility was not significantly different between a baseline strain and more recently established field strains. The potential implications of this previously unrecognized nontarget insecticide exposure effect on filth fly parasitoids are discussed.

The beet armyworm Spodoptera exigua (Hübner) is a serious polyphagous pest that infests vegetable crops worldwide and has rapidly developed resistance due to its long-term exposure to insecticides. The current resistance statuses to four insecticides exhibited by three field populations of beet armyworms collected in southern China from 2014 to 2018 were investigated. Monitoring data from five consecutive years demonstrated that all three tested S. exigua populations developed extremely high resistance to chlorantraniliprole in 2018 (220.58- to 2,597.39-fold). Two populations (Baiyun and Fengxian) developed low to moderate resistance to spinosad, whereas the Huangpi population remained susceptible (except in 2014, with RR of 6.11-fold). The RR of the Fengxian and Baiyun populations to indoxacarb steadily increased over the years, whereas that of the Huangpi population increased relatively slowly. The Baiyun and Fengxian populations developed moderate to high resistance to indoxacarb and methoxyfenozide, whereas the Huangpi population exhibited susceptibility to low resistance (1.06- to 6.45-fold) to indoxacarb and susceptibility to moderate resistance (1.53- to 14.22-fold) to methoxyfenozide. These results suggest that chlorantraniliprole should not be employed to control this pest in southern China. Reduced use of indoxacarb and methoxyfenozide or the use of alternating insecticides with low levels of resistance is recommended. Spinosad remains an effective insecticide for the management of S. exigua. To avoid the rapid development of insecticide resistance, rotations of insecticides with low levels of resistance and different modes of action based on the resistance patterns of S. exigua should be performed in southern China.

Putative mechanisms underlying spinosyn resistance have been identified in controlled studies on many species; however, mechanisms underlying field-evolved resistance and the development of a molecular diagnostic method for monitoring field resistance have lagged behind. Here, we examined levels of resistance of melon thrips, Thrips palmi Karny (Thysanoptera:Thripidae), to spinetoram as well as target site mutations in field populations across China to identify potential mechanisms and useful molecular markers for diagnostic and quantifying purposes. In resistant populations, we identified the G275E mutation, which has previously been linked to spinosyns resistance, and F314V mutation, both located in the α6 subunit of the nicotinic acetylcholine receptor. There was a strong correlation between levels of spinetoram resistance and allele frequency of G275E mutation in field-collected populations (r² = 0.84) and those reared under laboratory conditions for two to five generations (r² = 0.91). LC₅₀ ranged from 0.12 to 0.66 mg/liter in populations without G275E mutation, whereas it ranged from 33.12 to 39.91 mg/liter in most populations with a G275E mutation frequency more than 90%. Our results indicate that the field-evolved resistance of T. palmi to spinetoram in China is mainly conferred by the G275E mutation. The frequency of the G275E mutation provides a useful diagnostic for quantifying resistance levels in field populations of T. palmi.

Graphical Abstract

In the sensitive and complex chemo-sensation system of insects, chemosensory proteins (CSPs) can facilitate the transfer of chemical information and play important roles for variable behaviors of insects. We cloned the chemosensory protein AmalCSP5 from antennae of the apple buprestid beetle (Agrilus mali Matsumura), a serious invasive pest of wild apple trees. Expression profiling showed that AmalCSP5 was expressed in various tissues, suggesting its significance in multiple physiological activities and behaviors of A. mali. AmalCSP5 was preferentially expressed in female antennae and male abdomens. AmalCSP5 was able to bind a variety of test volatiles, especially alcohols and esters. AmalCSP5 exhibited good binding affinity for all five test secondary compounds (i.e., procyanidin, phlorizin, kaemferol, chlorogenic acid, and rutin), suggesting its preferential binding abilities to nonvolatile host plant secondary metabolites and critical roles in gustatory perception of nonvolatiles. Tyr27 and Ser69 of AmalCSP5 could form hydrogen bonds with hexyl benzoate and hexyl hexanoate, respectively. Procyanidin, the best ligand among all test compounds, could form hydrogen bonds with three amino acid residues (i.e., Arg7, Leu8, and Lys41) of AmalCSP5. Thus, high ligand binding affinity for AmalCSP5 seemed to be dependent mainly on the formation of hydrogen bonds. The putative key amino acid residues of AmalCSP5 can be used as molecular targets for designing and screening new attractants and repellents for A. mali. Our results provide insights into binding interactions of AmalCSP5 with volatile and nonvolatile ligands, and a firm basis for developing eco-friendly management strategies of A. mali.

The cherry-infesting fruit fly Rhagoletis cerasi Loew is a significant commercial pest in Europe that has recently invaded North America. To date, it has been trapped only in Canada and northwestern counties of New York. It has the potential to spread further and threaten production and movement of cherry commodities. Timely diagnosis of the pest will facilitate surveys and quick response to new detections. Adult morphology of the pest is distinct from other flies in North America. However, when flies are significantly damaged on traps or the immature life stages are found in fruits, molecular methods of identification are important to confirm presence and host-use records. Other than DNA sequencing of genes from flies which takes over a day to complete, there are no timely methods of molecular identification for this pest. In this study, we report the first sequence record of the internal transcribed spacer 1 (ITS1) from R. cerasi and develop two diagnostic tests for the pest based on ITS1 differences among species in North America. The tests use loop-mediated isothermal amplification (LAMP) and multiplex, conventional polymerase chain reaction (mcPCR) technologies that target the same region of the R. cerasi ITS1 sequence. Both tests performed well when tested against collections of R. cerasi from North America and Europe, generating Diagnostic Sensitivity estimates of 98.4–99.5%. Likewise, the tests had relatively high estimates of Diagnostic Specificity (97.8–100%) when tested against Rhagoletis Loew species present in North America that also use cherry as a developmental host.

The relationship between canopy defoliation by insects and yield loss in potato (Solanum tuberosum L.) has been extensively researched. However, detailed analysis of varieties with different properties and examination of methods of defoliation are still lacking. Absence of research results has led many producers to use a very conservative economic threshold (ET) of 10% defoliation in the management of insect defoliators. A series of leaf removal experiments was conducted on a determinate chipping variety of potato at different plant stages. In 2002, the highest levels of defoliation induced upon the plant canopy were 50, 30, and 75% for tuber initiation, full bloom, and plant maturity stages, respectively. In 2003, defoliation levels were increased to 70, 80, and 90% for tuber initiation, full bloom, and plant maturity, respectively. Total yield was unaffected, and no significant changes in market sized yield, or number of marketable tubers were observed at any growth stage in either year. Because the determinate variety showed remarkable ability to recover from substantial defoliation, two different methods of defoliation: hand cut (cutting the edge of leaves with scissors while avoiding the midrib) and hole punching (hole-punching leaf tissue [15.08-mm diameter] while avoiding midrib) were tested. Although total yield was unaffected, marketable yield and small potato yield were reduced, Thus, although defoliation methods must be considered, a 10% defoliation ET is exceedingly conservative and an ET of 60% for all stages of determinate chipping potato could be adopted by growers.

The rootworm Diabrotica speciosa (Germar) is native to South America and causes severe economic losses to several crops due to root feeding and disease spread. In maize (Zea mays L.), losses in production come from larval rootworm attack on plant roots resulting in plant health problems, including stalk lodging. More options for controlling this pest are needed to create well balanced, integrated pest management programs for farmers in this region. Natural sources of tolerance in maize genotypes are important for maize breeding programs, and this study investigated the expression of tolerance in several Brazilian maize landraces to D. speciosa. Plant vigor and compounds associated with plant health, including chlorophylls, carotenoids, glycine betaine, and proline were assessed for each landrace. Five landraces and one maize cultivar were selected based on their levels of antibiosis-resistance to D. speciosa that were determined in a prior screening. The percent reduction in plant growth was used as the measure of tolerance. The landrace Azteca was classified as tolerant to D. speciosa larval feeding, displaying less reduction in plant matter despite having lower plant vigor. This landrace also had higher amounts of chlorophyl and carotenoid pigments, suggesting a positive correlation between tolerance to D. speciosa and higher contents of these photosynthetic pigments. The compatible osmolytes glycine betaine and proline do not seem to be associated with tolerance in maize landraces to D. speciosa larvae. Landrace Azteca seems promising for plant breeding, and repeated field studies are needed to confirm its suitability in maize integrated pest management.

Aphis gossypii Glover (Hemiptera: Aphididae) is a polyphagous species frequently associated with the presence of sooty mold and viruses lethal to plants. The purpose of this work was to characterize possible resistance categories of cotton genotypes against A. gossypii. Initially, a preliminary test was carried out with 78 genotypes, 15 of which were selected for infestation ability assays and the determination of the cumulative aphid-day rates. Posteriorly, these genotypes were also evaluated through antixenosis and antibiosis assays. The genotypes FM 910, FM 966 LL, Mocó, Gossypium hirsutum var. punctatum L. (Malvaceae), Variedade Reba = BTK-12, Deltapine, Hi-Bred, Acala 4–42, IAC PV010-1664, IAC 21, Reba B-50 PR and FMT 709 inhibited the aphid colonization. In the infestation ability assay, G. hirsutum punctatum, IAC PV010-1664 and Acala 4–42 were the least infested. In a multiple-choice assay, Deltapine Smooth Leaf and Variedade Reba = BTK-12 were significantly less infested, suggesting antixenosis. In the antibiosis assay, Gossypium arboreum L. (Malvaceae) 1 showed the lowest number of nymphs, number of nymphs per adult per day and, number of nymphs at 10 d after the birth of the first nymph in addition to reducing the reproductive period, nymphal survival, adult longevity and, developmental time. In the FM 910, the number of nymphs produced per day and, at 10 d after the birth of the first nymph decreased, which also indicated resistance. The results obtained here are unprecedented and can be explored in breeding programs to develop insect-resistant cotton cultivars.

Some plant essential oil constituents, such as monoterpenoids and phenylpropanoids, are promising insecticides in some situations and for certain insect pests. They vary in their toxicity, depending on the target insect. Moths (Lepidoptera) appear susceptible to these compounds, making them of promise for use against greater wax moths (Galleria mellonella Fabricius, (Lepidoptera: Pyrallidae), GWM), an important pest of western honey bee (Apis mellifera Linnaeus. (Hymenoptera: Apidae)) colonies. We determined the LC₅₀ for GWM larvae or LD₅₀ for GWM adults of select compounds (thymol, carvacrol, (S)-(+)-carvone, estragole, citral, linalool, (S)-(–)-limonene, and γ-terpinene). Concentrations between 8 and 2,266 µg/cm³ were mixed into the diets of GWM larvae and doses ranging between 0.08 and 70.3 mg per adult were applied topically to the abdomens of GWM adults. Lethal concentrations and doses were calculated after of 72 h of exposure. All eight compounds showed insecticidal activity against all tested stages of GWMs. Thymol (LC₅₀ µg/cm³ (95% CI) = 21 [9–56], carvacrol = 46 [26–79], citral = 63 [30–134], and carvone = 76 [33–201]) had the highest toxicity toward GWM larvae. The hydrocarbons limonene (296 [231–377]), estragole (466 [354–611]), and γ-terpinene (729 [630–857]) had the lowest toxicity toward GWM larvae. Thymol had the highest toxicity towards GWM adults (LD₅₀ (CI) = 0.5 [0.4–0.8] mg/ adult). However, carvacrol (11.6 [10.1–13.6]), linalool (12.9 [9.3–17.8]), and limonene (15.8 [13.1–19.2]) were less toxic to GWM larvae. Our data show that select plant essential oil constituents are promising controls of GWM.

The rusty grain beetle, Cryptolestes ferrugineus (Stephens), is a serious pest of stored grain, which has developed high levels of resistance to phosphine. In this study, five geographically distant populations of C. ferrugineus had been collected in China, specifically in granaries where phosphine fumigant is used for pest control, and they showed a high resistance ratio up to 1,907 (LC₅₀ = 21.0 mg/liter). Then, a reference transcriptome was constructed to use as a basis for investigating the molecular mechanisms of phosphine resistance in this species, which consisted of 47,006 unigenes with a mean length of 1,090. Subsequently, the RNA-Seq analysis of individuals from the most susceptible and resistant populations led to the identification of 54 genes that are differentially expressed. GO and KEGG analysis demonstrated that genes associated with mitochondrial and respiration functions were significantly enriched. Also, the ‘structural constituent of cuticle’ term was annotated in the GO enrichment analysis and further qRT-PCR confirmed that the expression levels of nine cuticular protein genes were significantly increased in the resistant population. In conclusion, we present here a transcriptome-wide overview of gene expression changes between resistant and susceptible populations of C. ferrugineus, and this in turn documents that mitochondria and cuticular protein genes may play together a crucial role in phosphine resistance. Further gene function analysis should enable the provision of advice to expedite resistance management decisions.

Changes in almond production practices have caused sixspotted thrips, Scolothrips sexmaculatus Pergande, and the coccinellid beetle, Stethorus punctum LeConte, to replace phytoseiid mites as the dominant predators of spider mites in California almonds. We conducted a series of field studies to evaluate nine commercially available adhesive traps for S. sexmaculatus and S. punctum and found that the yellow strip trap was the most effective, least expensive, and easy to use. At peak population levels, individual cards routinely caught >1,000 S. sexmaculatus and >100 S. punctum trap^–1 week^–1. We documented that larger traps collected more S. sexmaculatus, and more S. sexmaculatus per square area, suggesting that the trap surface was attractive. We determined the number of traps needed to have 50, 70, and 90% confidence that the averages of trap captures were within 10, 30, and 50% of the population mean. Two yellow strip traps per orchard provided 90% confidence that trap captures were within 50% of the population mean if there were an average of 16.0 S. sexmaculatus trap^–1 week^–1 or 7.9 S. punctum trap^–1 week^–1. Populations required to attain the same levels of confidence using four traps per orchard were 3.9 S. sexmaculatus and 2.9 S. punctum trap^–1 week^–1. We conclude that use of the yellow strip trap to monitor for natural enemies, in combination with leaf samples for spider mites, has the potential to improve integrated pest management programs for spider mites, and assist future research to understand the biology and phenology of both predator species.

A series of tests was performed to examine the development ability of Trogoderma granarium Everts on six different sorghum milling fractions: bran, shorts, coarse grits, fine grits, red dogs, and flour. In the first bioassay, 20 adults and 20 g of each fraction were placed in vials of 60 ml at 30°C and 60% relative humidity for a period of 65 d. In the second part of the experiment, a neonate larva (1-d old) was placed in vials with 1 g of each fraction and exposed at 25, 30, and 32°C until adult emergence. Significantly more live larvae were found in bran compared with flour and to the two grain controls (soft wheat and whole wheat flour), where most dead adults were recorded. The increase in temperature reduced both the time to adult emergence and larval mortality before the appearance of the first adult. Developmental times ranged between 25.5 and 37.5 d, and 23.2 and 29.0 d for 30 and 32°C, respectively. At 25°C, larvae in the milling fractions did not reach 100% adult emergence even after almost 3 mo. However, the first adult appeared in the shorts fraction at all temperatures tested. Our results show that all sorghum milling fractions support the development of T. granarium and that the optimal temperatures for growth and development are 30 and 32°C. These results also have important implications for phytosanitary regulations and international trade, given the quarantine restrictions on this insect.

Bioassays were conducted to evaluate the effectiveness of thiamethoxam in different surfaces, against six stored-grain insects, Sitophilus granarius (L.) (Coleoptera: Curculionidae), Sitophilus oryzae (L.) (Coleoptera: Curculionidae), Tribolium confusum Jacquelin du Val (Coleoptera: Tenebrionidae), Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae), Cryptolestes ferrugineus (Stephens) (Coleoptera: Laemophloeidae), and Oryzaephilus surinamensis (L.) (Coleoptera: Silvanidae). Six different surfaces (concrete, plywood, galvanized steel, linen, plastic, and ceramic tile) treated with thiamethoxam at 0.05 and 0.1 mg/cm² were used as substrate for adult exposure. Knockdown was recorded after 1, 3, and 7 d of exposure to the treated surface, in order to calculate a Standardized Lethality Index (SLI). Knockdown counts were ranked from ‘0' to ‘4’, with ‘0' representing adult insects ‘moved generally' and ‘4’ representing dead insects. Based on the results, insect knockdown seems leading to mortality than to recovery and the SLI ranking of the target species according to their susceptibility to thiamethoxam showed that S. granarius being more susceptible and decreasing susceptibility in an order of S. oryzae > T. castaneum ≥ O. surinamenis ≥ C. ferrugineus ≥ T. confusum. In general, among the surfaces, thiamethoxam efficacy was lower on linen, wooden, and concrete surfaces, as compared to metallic and plastic surfaces. Nevertheless, at the end of 7-d exposure, all surfaces equally affected thiamethoxam toxicity.

The yellow mealworm, Tenebrio molitor L., is one of the most significant insect species of economic importance for producing protein-rich food and feed. The larvae are a promising fishmeal substitute for fish feed, and a good alternative source for human nutrition. In this study, the effect of behavioral asymmetries on male mating success of T. molitor was evaluated. Males performing antennal waving (63%) when detecting a female approached the apex of the female abdomen in a comparable manner from both sides (32% from left side vs 31% from right side). Fewer males showed antennal waving and also raised the anterior part of their body (37%) during mate recognition; 14% of them approached on the apex of female abdomen from the left side, and 23% of them approached from the right side of female body. The duration of mate recognition, antennal tapping, rubbing behavior, and the whole mating sequence of males that moved on the apex of the abdomen from the left side of females was significantly lower over that of males approaching from the right side (10.7, 12.6, 16.4, and 126.1 s for left-biased males vs 12.2, 14.8, 18.6, and 139.6 s for right-biased males, respectively). Concerning mounting side, left-biased males showed a shorter duration of rubbing behavior and the whole mating sequence (15.5 and 123.2 s) over right-biased (18.9 and 138.3 s) and backside approaching males (19.4 and 144.1 s). The duration of mate recognition, antennal tapping, and copula was not affected by the presence of a male laterality bias. Overall, this study sheds light on how laterality affects mating traits and the male success of this important edible insect species.

Ecosystem services provided by insects are threatened by recent increasing global temperatures, particularly in the tropics, where insects live close to their thermal limits. Given that tolerance to high temperatures depends on individual metabolism and physiological stress response, it may also be sensitive to other stressors that are common in natural and human-modified environments, such as pollution and parasite pressure. The effects of multiple stressors could be synergistic and can be particularly relevant in insects that provide highly valuable ecosystem services, such as dung beetles in cattle pastures. Here we measured heat tolerance (critical thermal maximum, CT_max) in dung beetles exposed to ivermectin, a toxic parasiticide excreted in cattle dung, with known negative effects on coprophagous fauna, and in beetles exposed to an immune challenge. We also exposed a group of beetles to a combination of both ivermectin and immune challenge to test for potential synergistic effects of both stressors. Contrary to our predictions, CT_max did not change with ivermectin exposure, but increased in immune-challenged beetles. As found in other insects, CT_max was higher in larger beetles, highlighting the importance of body size on thermal tolerance in ectotherms. We discuss potential mechanisms responsible of increased heat tolerance in immune-challenged beetles and highlight the importance of natural and human-induced environmental pressures that now interact with global warming and threaten ecosystem services provided by wild animals.

The sugarcane borer, Diatraea saccharalis (F.), is the primary pest of sugarcane, Saccharum spp., in Louisiana. Recent evidence suggests an integrated pest management (IPM) program has reduced the pest's impact, but the success of this program has not been assessed across the industry. The level of D. saccharalis injury present at harvest was recorded from 388 billet samples from five sugar mills from 2017 to 2019. These results were used to estimate direct and indirect revenue losses from D. saccharalis on the Louisiana sugarcane industry. Insecticide use records were used to estimate control costs and determine total economic impact. The mean percentage of bored internodes was 1.1, 0.3, and 1.7% for 2017, 2018, and 2019, respectively. Direct losses from reduced sugar yield averaged US$4.6 million across years. Indirect losses across years accounted for US$3.0 million and $463,000 for insecticidal control costs and reduced milling efficiency, respectively. The total economic impact of D. saccharalis averaged $8.0 million annually during the three-year study period. This study demonstrates the efficacy of pest management implementation in reducing D. saccharalis injury and highlights the value of IPM. Our findings provide new support for the emergence of D. saccharalis management in the Louisiana sugarcane industry as a modern IPM success story.

Detection of host plant DNA from sap-feeding insects can be challenging due to potential low concentration of ingested plant DNA. Although a few previous studies have demonstrated the possibility of detecting various fragments of plant DNA from some sap-feeders, there are no protocols available for potato leafhopper, Empoasca fabae (Harris) (Hemiptera: Cicadellidae), a significant agricultural pest. In this study we focused on optimizing a DNA-based method for host plant identification of E. fabae and investigating the longevity of the ingested plant DNA as one of the potential applications of the protocol. We largely utilized and modified our previously developed PCR-based method for detecting host plant DNA from grasshopper and the spotted lanternfly gut contents. We have demonstrated that the trnL (UAA) gene can be successfully utilized for detecting ingested host plant DNA from E. fabae and determining plant DNA longevity. The developed protocol is a relatively quick and low-cost method for detecting plant DNA from E. fabae. It has a number of important applications—from determining host plants and dispersal of E. fabae to developing effective pest management strategies.

Invertebrate animal studies of methamphetamine (METH) could allow for high throughput, inexpensive, and high-animal number pharmacology and toxicology studies. We hypothesized that in Periplaneta americana cockroaches, METH would increase locomotion compared to saline and produce lethality. Lethal dose, 50% (LD₅₀) was determined with 0–1,780 µg/g (mg/kg) METH (n = 15–16/group) using logit analysis. Locomotor activity after METH (0–560 mg/kg, intra-abdominal, n = 8 per group) administration and spontaneous locomotor activity in surviving cockroaches in an open field 24 h after LD₅₀ study doses was measured with Noldus Ethovision. The LD₅₀ of METH was 823.1 mg/kg (more than 10-fold greater than the value in rats). There were significant decreases in spontaneous locomotor activity in surviving cockroaches after administration of 650 and 750 mg/kg METH (P < 0.05). While 100 mg/kg METH did not significantly increase METH locomotor activity relative to saline, 300 mg/kg METH significantly increased locomotor activity compared to saline (P < 0.05), and 560 mg/kg METH resulted in most of the cockroaches slowly moving around the open field in the supine position for most of the trial. In conclusion, METH produces pharmacological and toxicological effects in P. americana. The high availability, low cost, and relative ease of use of these animals makes them a potential, very accessible option for studying METH use disorder.

Sugarcane aphid Melanaphis sacchari Zehntner is a significant economic pest of grain sorghum in the United States. Effective monitoring and early detection are cornerstones for managing invasive pests. The recently developed binomial sequential sampling plan estimates sugarcane aphid economic thresholds (ETs) based on classification whether a 2-leaf sample unit has ≤ or ≥ 50 M. sacchari. In this study, we evaluated eight 2-leaf sampling units for potential use in the sequential sampling plan. From 2016 through 2017, whole plant counts of M. sacchari were recorded non-destructively in situ on sorghum plants from 140 fields located in five states. Plant canopies were stratified into three categories. Two leaves from each stratum were used to compare linear relationships between M. sacchari numbers per two-leaf sample unit and total M. sacchari density per plant. Analysis revealed that two randomly selected leaves from the middle stratum accounted more variation for estimating M. sacchari density when compared to two leaves from the other strata. Comparison of eight two-leaf sampling units within plant growth stages were variable in quantifying variation of M. sacchari densities. When growth stages were combined, the standard uppermost + lowermost leaf sample unit and a unit consisting of two randomly selected leaves from the middle stratum revealed little difference in their enumeration of variation in M. sacchari density. Because other sample units were either less predictive and/or more variable in estimating M. sacchari density, we suggest that the (L1+U1) sample unit remain the preferred method for appraising M. sacchari ETs.

Spotted-wing drosophila (Drosophila suzukii, (Matsumura)) is an invasive vinegar fly that has become a serious threat to soft fruit crops. Monitoring for this pest is typically performed using drowning traps baited with live yeast cultures or fermentation volatile blends. Trapping programs using these compounds provide highly variable results across production systems, geographic regions, and growing seasons. Trap competition with fruit is one hypothesis for this inconsistency. This study evaluated the trapping efficiency of yeast and wine baits in the presence and absence of small quantities of host fruits in two binary-choice laboratory experiments. The first experiment evaluated trap capture in clear 946-ml traps with easily accessible water, apple pomace, blueberry, raspberry, strawberry, cherry, or grape as competitive influences. The second experiment evaluated the same competitors, but they were made less accessible. Recapture of flies in arenas containing competitive fruit was reduced by 64–88% when fruit was ‘accessible' and from 0 to 51% when it was ‘inaccessible’ compared with arenas containing a water competitor. All fruit types provided statistically similar levels of trap interference. In the first experiment, yeast captured more flies compared with wine, whereas in the second experiment, wine captured more flies than yeast. Our results support the hypothesis that the presence of fruit or other reproductive resources will reduce trap captures and that this reduction is likely mediated by the relative accessibility of the fruit versus the trap. Thus, attempts to develop population estimates based on traps should incorporate fruit availability/accessibility.