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BackgroundInvasive species threaten the productivity and stability of natural and managed ecosystems. Predicting the spread of invaders, which can aid in early mitigation efforts, is a major challenge, especially in the face of climate change. While ecological niche models are effective tools to assess habitat suitability for invaders, such models have rarely been created for invasive pest species with rapidly expanding ranges. Here, we leveraged a national monitoring effort from 543 sites over 3 years to assess factors mediating the occurrence and abundance of brown marmorated stink bug (BMSB, Halyomorpha halys), an invasive insect pest that has readily established throughout much of the United States.ResultsWe used maximum entropy models to estimate the suitable habitat of BMSB under several climate scenarios, and generalized boosted models to assess environmental factors that regulated BMSB abundance. Our models captured BMSB distribution and abundance with high accuracy, and predicted a 70% increase in suitable habitat under future climate scenarios. However, environmental factors that mediated the geographical distribution of BMSB were different from those driving abundance. While BMSB occurrence was most affected by winter precipitation and proximity to populated areas, BMSB abundance was influenced most strongly by evapotranspiration and solar photoperiod.ConclusionOur results suggest that linking models of establishment (occurrence) and population dynamics (abundance) offers a more effective way to forecast the spread and impact of BMSB and other invasive species than simply occurrence-based models, allowing for targeted mitigation efforts. Implications of distribution shifts under climate change are discussed. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Drosophila suzukii causes economic damage to berry and stone fruit worldwide. Laboratory-generated datasets were standardized and combined on the basis of degree days (DD), using Gompertz and Cauchy curves for survival and reproduction. Eggs transitioned to larvae at 20.3 DD; larvae to pupae at 118.1 DD; and pupae to adults at 200 DD. All adults are expected to have died at 610 DD. Oviposition initiates at 210 DD and gradually increases to a maximum of 15 eggs per DD at 410 DD and subsequently decreases to zero at 610 DD. These data were used as the basis for a DD cohort-level population model. Laboratory survival under extreme temperatures when DD did not accumulate was described by a Gompertz curve based on calendar days. We determined that the initiation of the reproductive period of late dormant field-collected female D. suzukii ranged from 50 to 800 DD from January 1. This suggests that D. suzukii females can reproduce early in the season and are probably limited by availability of early host plants. Finally, we used the DD population model to examine hypothetical stage-specific mortality effects of IPM practices from insecticides and parasitoids at the field level. We found that adulticides applied during the early season will result in the largest comparative population decrease. It is clear from model outputs that parasitism levels comparable to those found in field studies may have a limited effect on population growth. Novel parasitoid guilds could therefore be improved and would be valuable for IPM of D. suzukii.

In its native range, Trissolcus japonicus (Ashmead) (Hymenoptera: Scelionidae) is a main egg parasitoid of Halyomorpha halys (Stål) (Hemiptera; Pentatomidae). Adventive populations of this parasitoid have been spreading in Europe and North America, allowing active distribution efforts in these areas to utilize it against H. halys in agriculture. We tested exposure of adults and parasitized egg masses to residues of a range of insecticides an adjuvant that the wasp could encounter in perennial horticultural crops, and how exposure might affect key behaviors. The insecticides included Burkholderia rinojensis, Methoxyfenozide, Sulfoxaflor, and Spinosad, and the adjuvant NuFilm®P. The lethal effects were investigated after exposure for 1, 6, and 24 hours to residues applied to Munger cells using a Potter spray tower to determine mortality levels. Sulfoxaflor and Spinosad resulted in 73% and 100% mortality after 24 hours at field rates, while Methoxyfenozide caused 19% mortality at the same rate. Little mortality occurred with Burkholderia rinojensis and NuFilm®P at recommended rates after 24 hours. Regarding sublethal effects, Spinosad, Sulfoxaflor, and Burkholderia rinojensis negatively impacted reproduction. Sulfoxaflor caused a lower angular velocity in parasitoids exposed to H. halys traces. Spinosad, Methoxyfenozide, and NuFilm®P induced a significantly lower overall circadian activity. Our results showed that precision timing of insecticide sprays to pests is necessary, especially for biocontrol programs that involve the release of parasitoids such as T. japonicus. Our results also illustrate how sensor data acquisition and behavioral analysis software can be utilized to detect important sublethal effects such as circadian disruption in minute parasitoids. [ABSTRACT FROM AUTHOR]

The western tarnished plant bug, Lygus hesperus Knight, is an economically important pest of several agricultural crops in the western United States. It is an increasing threat to potato, Solanum tuberosum L. (Solanales: Solanaceae), in the diverse landscape of the Columbia Basin of Oregon and Washington. In this study, flight mills were used to investigate the flight capacity of L. hesperus with the aim of better understand its dispersive characteristics in the agricultural landscape. Explicitly, we investigated the effects of biological factors such as generation, gender, and body weight on the flight potential of adult L. hesperus adults collected from field populations during spring and summer of 2019 and 2020.The study flight parameters assessed were distance, activity, velocity, and diel periodicity. In 24-h flight mill assays, a clear dichotomy pattern was found in sum flown distance for adults that travelled 1 km or shorter and adults that travelled greater than 1 km. Individuals from the summer population flew farther and more actively than those from the overwintered population. Female L. hesperus flew farther and were more active compared to males. Adult body weight before the flight was directly proportional to flight distance and number of flights, but not with velocity. Overwintered L. hesperus adults lost a higher percentage of their pre-flight body weight compared to summer adults over the course of the study.To the best of our knowledge, this is the first study that demonstrated that L. hesperus summer adult population has the flight ability to disperse greater distance in the agricultural landscape than overwintered population. [ABSTRACT FROM AUTHOR]

Brown marmorated stink bug, Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), is a severe economic pest of growing importance in the United States, Canada, and Europe. While feeding damage from H. halys has been characterized in tree fruit, vegetables, and agronomic crops, less is known about the impacts of stink bugs on small fruits such as blueberries. In this study, we examined H. halys feeding on two representative early and late ripening blueberry cultivars in Oregon and New Jersey. This research examined how different densities of H. halys confined on blueberry clusters for week-long periods affected fruit quality at harvest. After fruit were ripe, we stained and quantified the number of salivary sheaths on berries as an indication of feeding pressure. Feeding by H. halys damaged the fruits by causing increased levels of external discoloration, and internal damage in the form of tissue necrosis. Exposure of berries to H. halys was also associated with decreasing berry weights and lower soluble solids in fruits. However, the different cultivars did not respond consistently to feeding pressure from H. halys. Weekly variability in feeding pressure of two of the cultivars as quantified by the number of stylet sheaths per berry was largely accounted for by environmental variables. We conclude that H. halys does have potential to severely damage blueberries and may become an important economic pest. Characterization of damage is important because correct identification of insect damage is key for successful management. [ABSTRACT FROM AUTHOR]

Simple Summary: Since 2016, the fall armyworm, an important economic pest native to tropical and subtropical regions of the Western Hemisphere, has invaded Africa and further spread rapidly into most Asian countries. The fall armyworm is highly polyphagous, but two of its major strains, the corn and the rice strains, cause severe damage in the Western Hemisphere. However, the invaded populations in Africa and Asia mostly infested the corn fields. Studies on the genetic identity of the species using two molecular markers, one nuclear gene and one mitochondrial gene, showed that the major genetic group is a heterogeneous hybrid of males from the corn strain and females from the rice strain. Moreover, a minor group of homogenous individuals from the corn strain but no homogenous individuals from the rice strain were also detected. A geographic distribution analysis at the subpopulation level indicated similar genetic diversity in Africa and Asia, suggesting fall armyworm in Africa spread into Asia without significant genetic change. The fall armyworm, Spodoptera frugiperda, is an important agricultural pest native to tropical and subtropical regions of the Western Hemisphere, and has invaded Africa and further spread into most countries of Asia within two years. Here, we analyzed the genetic variation of invaded populations by comparing the nucleotide sequences of two genes: the nuclear Z-chromosome linked gene triose phosphate isomerase (Tpi) and the mitochondrial gene cytochrome oxidase subunit I (COI) of 27 specimens collected in Africa (DR Congo, Tanzania, Uganda, and Zimbabwe) and Asia (Bangladesh, Korea, Nepal, and Vietnam). The results revealed that 25 specimens were from a heterogeneous hybrid (Tpi-corn strain and COI-rice strain; Tpi-C/COI-R) of the corn strain male and rice strain female, but two specimens were from a homogenous corn strain (Tpi-corn strain and COI-corn strain; Tpi-C/COI-C). The further analysis of the fourth exon and the fourth intron sequences of the Tpi gene identified at least four subgroups of the corn strain. These four genetic subgroups were identified in Africa and Asia, suggesting no significant genetic change due to the rapid migration within two years. Our study provides essential information for understanding the genetic diversity of fall armyworm in new habitats. [ABSTRACT FROM AUTHOR]

Halyomorpha halys (Stål), or brown marmorated stink bug (BMSB), has become a major pest and nuisance for both agricultural growers and homeowners since its arrival in North America and Europe. The nutritional ecology of BMSB is important for understanding its life history and rearing requirements. However, little is known about the nutritional status of wild populations, especially in the U.S. This research monitored the nutrient status of nymphal and adult BMSB collected from English holly in western Oregon. We measured their weight, nutrient index (weight/(prothorax × width)3), lipid, glycogen and sugar levels and egg load from May–September/October. First, glycogen and sugar levels of adults were often lowest sometime in June-August with a general increase by September. Meanwhile, their lipid levels varied without a discernible trend. Second, adult females had few eggs in May, with the highest egg load in June and July, and no eggs by September. Lastly, first and second nymphal instars were found in June, and fourth and fifth instars in September. Because nothing is known about the nutrient levels of nymphs, the reported values from this survey can assist future research on physiological responses of BMSB to treatments or environmental impacts in the field. [ABSTRACT FROM AUTHOR]