An invasive pest is a non-native species which can cause damage to the economy, natural resources, or human health. The invasion of these non-native species is an escalating problem worldwide. In particular, it is estimated that ca. 50,000 nonindigenous species have been introduced into the United States, many of which have caused a total of > $100 billion losses in natural and agricultural ecosystems. Recently, two invasive pests, Halyomorpha halys (Hemiptera: Pentatomidae) and Drosophila suzukii (Diptera: Drosophilidae), have emerged as serious agricultural pests in the U.S. Both species are native to Asia, however the distributions of the pests have rapidly expanded across the U.S. causing significant economic losses especially in specialty crops, presumably due to similarities in host plant complex and climatic environments between the native and new regions. In this study, a series of research efforts to protect agriculture and the environment against H. halys and D. suzukii in the U.S. are summarized and reviewed.

Currently, the management of Riptortus pedestris (Hemiptera: Alydidae) relies mainly on insecticide application in most crop productions. However, there have been very few detailed studies concerning the potential behavioral effects of sublethal dose of insecticide. This study was conducted to address sublethal effects of five insecticides on the mobility of R. pedestris. Adult R. pedestris were individually exposed to dry residue of insecticides for 4 hours in laboratory. Tested insecticides were fenitrothion (organophosphate), etofenprox (pyrethroid), bifenthrin (pyrethroid), acetamiprid (neonicotinoid) and dinotefuran (neonicotinoid). After the exposure, vertical climbing ability and flight capacity of survived R. pedestris were evaluated and compared to water-treated control. First, the mortality of R. pedestris after the 4-h insecticide exposure was as follows: 10% for fenitrothion, 3.4% for dinotefuran, 3.4% for acetamiprid, 0% for etofenprox and 0% for bifenthrin. The vertical mobility of R. pedestris was affected differently by insecticides tested. Acetamiprid resulted in decrease (37%) in the vertical mobility, whereas dinotefuran caused increase (153%) in the ability compared to the control. There was no effect by three other insecticides on the vertical mobility. In general, tested insecticides did not affect the flight capacity of R. pedestris compared to untreated individuals. However, etofenprox resulted in increase (230%) in the flight capacity. The results of this study indicate that insecticide-treated but survived R. pedestris can show similar or even increased mobility compared to untreated individuals. This should be considered in designing insecticide application programs against of R. pedestris.

R. pedestris is a major insect pest in agricultural production, especially on soybean and tree fruit, in Korea. Currently, the management of this pest relies mainly on insecticide application in most commodities. However, the chemical controls cause numerous environmental problems. To develop sustainable management tools, it is fundamental to understand the basic biology and ecology of R. pedestris. However, the overwintering ecology of this pest is virtually unknown. In this study, we surveyed diverse landscapes including high elevation mountains soybean fields and there neighboring forests to find and characterize the overwintering sites of R. pedestris. In the field, we sampled leaf litters from 1㎡ grids to locate overwintering R. pedestris. The samples were taken every 100m altitude in the mountain areas or every 50m distance in the flat landscapes. Overwintering R. pedestris were found from 6 samples out of 137 samples. All overwintering R. pedestris were located from forested areas adjacent to urban landscapes in Seong-Nam si, Gyeong-Gi Do. Interestingly, no overwintering R. pedestris was found from in the samples collected from high elivation mountains including Yeon-In, Song-Ni, Chi-Ak, Ga-Ya, Wol-Chul. likewise, no overwintering individual was found from soybean fields and their neighboring forested areas. With caveat that the data were collected only for 1 year, our results support that R. pedestris overwinters solitary resulting in low detection rates from the samples. Given that R. pedestris typically disperse into cultivated crops with high densities, it is important to better understand environmental factors affecting the presence or absence of overwintering R. pedestrris in diverse landscapes. The knowledge would be essential to develop sustainable monitoring and management programs for this economically important pest in Korea.

The use of radar systems for entomological research offers new opportunities that allow continuous tracking of individual insects in natural settings. In particular, harmonic radar systems can be applied for small animals such as insects because the radar tag does not rely on battery power, allowing them to be light weight. To apply this technology, it is essential to develop procedures to securely attach radar tags on target insects and thereafter demonstrate no adverse effects of radar tag attachment on insect survivorship and behaviors. In this study, we developed procedures to securely attach harmonic radar tags on adult Riptortus pedestris (Fabricius) (Hemiptera: Alydidae) and verified there were no detectable adverse effects of radar tagging on R. pedestris survivorship and walking or flight capacity. With the radar technique, future studies will focus on understanding dispersal capacity and pattern of R. pedestris in diverse landscapes. This will help enhance monitoring and management programs for this pest.

Invasive species are a major threat to ecosystems and cause enormous environmental and economic losses. Although it is difficult to estimate the full extent of the environmental damage by exotic species and control costs, it is estimated that invasive species cause > $100 billion in losses per year in the United States alone. The brown marmorated stink bug (BMSB), Halyomorpha halys, is native to Asia, but has become a recent example of serious biological invasion, expecially in the US. The BMSB is a voracious eater that damages fruit, vegetable, and ornamental crops in North America. To manage this destructive invasive pest, a team of more than 50 researchers is studying the pest's biology, behavior and ecology to find management solutions for growers, seeking strategies that will protect food, environment and agricultural industry. In this study, I address how the BMSB team were able to make successful team effort to battle the invasive species with funding from the USDA's Specialty Crop Research Initiative.

Thc climate change has the potential to significantly modify the actual distribution of insect pest with unknown consequences on agricultural systems and management strategies. In this study, Thrips palmi Karny was selected to predict distribution under climate change. T. palmi was introduced and first recorded in 1993 in Korea, and has become a serious pest of vegetable and ornamental crops. The MaxEnt was applied to T. palmi to predict its potential geographic distribution in Korea and Japan under the RCP 8.5 climate changing scenario. The MaxEnt software package is one of the most popular tools for species distribution and environmental niche modeling. The habitat prediction model of T. palmi in Korea was validated by the distribution of T. palmi in Japan. Based on the MaxEnt modeling, T. palmi would expand their potential distribution to whole Korean peninsula except the alpine region in Gangwon-do and Yanggang-do and Hamgyeongbuk-do in 2070s. Therefore, the monitoring system and management strategy for T. palmi should be reconsidered and re-evaluated.

Insects reflect climate change dramatically because insects are poikilotherm and have huge biodiversity. Also, the prediction of insect distribution is very significant due to the position of this group giving diverse ecological services including their extraordinary economic importance. Accurate modeling of geographic distributions of insect species is crucial to various applications in ecology and conservation. The best performing techniques often require some parameter tuning, which may be prohibitively time-consuming to do separately for each species, or unreliable for small or biased data sets. The purpose of this study is to introduce and compare several models to predict insect distribution under climate change in Korea. This work would be helpful to researchers or decision makers by giving practical advice, for example, kinds of input/output data, applicability to GIS, to select appropriate model to predict insect distribution.

Recently, it has been demonstrated in several predator-prey interactions that predators influence prey population dynamics by inducing behavioral changes in prey as well as by feeding on prey. Accumulating evidence supports that prey change habit use patterns and activity levels in repose to predation risks. In the studies reported here, we examined the resource use patterns by adult whitefly, Bemisia argentifolii (Hemiptera: Aleyrodidae) in response to its natural enemies. The first study examined whether, in the context of a trap crop system, differential predation risks among plants influence host choice patterns of adult whiteflies. We investigated whether whiteflies avoid natural enemies inhabiting a cash crop (poinsettia) and whether this behavior can be used to increase the movement of whiteflies to a trap crop (cucumber). Three natural enemies were tested: two predators, Amblyseius swirskii and Delphastus catalinae and a parasitoid Encarsia formosa. The presence of D. catalinae on cash crop induced significantly more whiteflies to disperse to predator-free trap crop, compared with cash crop with no predator. A. swirskii and E. formosa did not result in a significant increase. The second study examined habitat choice patterns by adult whiteflies in response to D. catalinae at different spatial scales. When female whiteflies were confined in small leaf-disc arenas, whiteflies significantly delayed settling on leaf-discs with predators compared those with no predators. The presence of D. catalinae altered the vertical distribution of whiteflies on cucumber plants. Whiteflies moved upward faster over time within the plant canopy when predator were present at lower canopy compared with plants with no predator. However, D. catalinae did not result in elevated between-plant movement of whiteflies in the greenhouse, compared with that with no predator. Predator avoidance behavior by adult whiteflies should be considered in the development of biological control programs.

Halyomorpha halys (Hemiptera: Pentatomidae) is an invasive species from Asia causing major economic losses in agricultural production in the United States. H. halys is also well known for nuisance problems as massive numbers of adults often invade human-made structures to overwinter inside protected environments. However, overwintering ecology of H. halys in natural landscapes is virtually unknown. We explored forested landscapes in the mid-Atlantic region to locate and characterize natural overwintering structures used by this invasive species. We also confirmed the identified overwintering structures by training and using detector canines in the natural landscapes. Overwintering H. halys were recovered from dry crevices in dead, standing trees with thick bark, particularly oak (Quercus spp.) and locust (Robinia spp.); these characteristics were shared by 11.8% of all dead trees in surveyed landscapes. Dispersal ecology of H. halys were evaluated in the laboratory and field to understand how this pest disperses among its overwintering sites, cultivated crops and wild hosts. In the laboratory, we evaluated the baseline flight capacity of H. halys using flight mill systems. Both foraging and overwintering populations flew on average 2.5 km over a day with some exceptional individuals flying >20 km. In the field, direction observations indicate that H. halys are not likely to initiate flight when temperatures are below 17oC. In addition, H. halys did not initiate flight even under very mild wind (2.4 m/s). We also evaluated the potential of using a portable harmonic radar system to individually track H. halys movements in the field. Our study demonstrates that a portable harmonic radar can be used to track adult H. halys without affecting its survival, walking mobility or flight capacity. In diverse semi-field settings, the success rates of locating radar-tagged H. halys were >85%. The knowledge of overwintering and dispersal ecology reported here would serve as baseline to develop and enhance the management programs of H. halys at landscape levels.

Understanding of dispersal ecology is a critical component to build robust and practical simulation model for insect populations. In this study, we report multifaceted approaches to examine dispersal capacity, behavior and ecology of brown marmorated stink bug (BMSB), Halyomorpha halys (Hemiptera: Pentatomidae). We first evaluated the baseline flight capacity of adults using flight mill systems in the laboratory. The results indicates that this species has strong flight capacity: adults were found yielding flight distances of >2 km in 24 hours with a small portion of the BMSB population capable of flight into double digits. In the field, we made direct observations on BMSB flight to examine free flight capacity and diurnal patterns. BMSB made flight when ambient temperature was >15 oC and flew with the speed of 3 m/s under field conditions, yielding its prevailing flight directions away from the sun’s position over a day. Dispersal capacity and behavior of nymphal stages (2nd through 5th) were also studied. In the laboratory, video image analysis indicates that all nymphal stages have strong walking capacity comparable to adults. In the field, the walking distance of 3rd and 5th instar nymphs on mowed grass was quantified based on direct observation of individuals. Under these conditions, 5th instars moved nearly two-fold greater distances compared with 3rd instars, but surface temperature affected both nymphal stages similarly. Shorter bouts of movement were common at surface temperatures below 25 oC, whereas individuals showed longer walking distances above 25 oC. These baseline knowledge on BMSB dispersal will be key to building and improving simulation model in order to predict spatiotemporal dynamics of the pest populations.