Danielle M. Kirkpatrick

Spotted-wing drosophila (SWD), Drosophila suzukii Matsumura (Diptera: Drosophilidae), is an invasive pest of thin-skinned fruits in the United States. Monitoring traps are an integral part of SWD integrated pest management, allowing early detection and timely management of this pest. An ideal monitoring trap should be easy to use, effective in capturing SWD, sensitive and selective to male SWD which are easy to identify due to their spotted wings, and able to predict fruit infestation from trap captures. Deli-cup-based liquid traps (grower standard), which make in-situ observations difficult, were compared with red-panel sticky traps, both baited with commercial lures (Scentry, Trécé Broad-Spectrum (BS), and Trécé High-Specificity (HS)), across several US states in blueberries (lowbush and highbush), blackberry, raspberry, and cherry crops during 2018 and 2021. Results showed that red-panel traps effectively captured SWD, were able to detect male SWD early in the season while also being selective to male SWD all season-long, and in some cases linearly related male SWD trap captures with fruit infestation. Scentry and Trécé BS lures captured similar numbers of SWD, though Trécé BS and Trécé HS were more selective for male SWD in red panel traps than liquid traps in some cases. In conclusion, due to its ease of use with less processing time, red-panel traps are promising tools for detecting and identifying male SWD in-situ and for predicting fruit infestation. However, further research is needed to refine the trap captures and fruit infestation relationship and elucidate the trap-lure interactions in berry and cherry crops.

Spotted‐wing drosophila, Drosophila suzukii Matsumura, is an invasive pest in the United States, Europe and South America. Females are able to oviposit in intact soft‐skinned fruit, resulting in significant economic losses due to larval feeding. Attracticidal spheres, originally developed for the apple maggot, Rhagoletis pomonella Walsh, have been used as a management tool for D. suzukii in a few studies, but little is known about their longevity as a killing device and their performance under varying pest densities. Here, we evaluated the efficacy of attracticidal spheres, containing 1% spinetoram, when stored for 6 and 12 months and when deployed to manage low (4 adults/plant), moderate (16 adults/plant) and high (64 adults/plant) density populations in blueberry and raspberry plants. Additionally, the effects of simulated (rainfall, sunlight and rainfall/sunlight combinations) and field‐based weathering for periods of 6 and 12 weeks on attracticidal spheres containing 1% thiamethoxam, fenpropathrin, spinetoram, methomyl, spinosad, dinotefuran and lambda‐cyhalothrin were evaluated. Sphere caps stored for up to 12 months yielded no significant decrease in mortality of exposed flies compared with spheres fitted with newly produced caps. For both raspberries and blueberries protected by 1% spinetoram attracticidal spheres, high relative densities of D. suzukii yielded significantly greater levels of infestation compared with moderate or low relative densities. Simulated and field‐based weathering yielded reduced fly mortality for most insecticide materials, indicating that spheres may need to be replaced at 6 weeks or less to maximize their efficacy. In general, attracticidal spheres can assist in the management of D. suzukii, but likely will not serve as a stand‐alone tool, particularly under high pest densities.

Halyomorpha halys (Stål), the brown marmorated stink bug, is an invasive and highly polyphagous insect that has caused serious economic injury to specialty and row crops in the United States and Europe. Here, we evaluated the effects of marking adult and nymphal H. halys with four different colors of fluorescent powder (Blaze Orange, Corona Pink, Horizon Blue, and Signal Green) on mobility and survivorship in laboratory bioassays. Adults and nymphs were marked using liquified fluorescent powder solutions and allowed to dry prior to bioassay. The presence of the marking solution had no significant effects on adult or nymphal mobility, adult survivorship, nymphal development, or adult flight capacity. We also evaluated the persistence of neon marker applied to the pronotum of H. halys adults and found this technique remained detectable for 2 wk under field conditions. Although both marking techniques are inexpensive, persist for ≥1 wk, and do not affect mortality, the neon marker method is more time-consuming, taking ~12 times longer to mark 50 adult H. halys compared with the liquified fluorescent powders. Thus, we would recommend using fluorescent powders for large-scale mark-release-recapture studies.

The spotted lanternfly, Lycorma delicatula White, is an invasive planthopper (Hemiptera: Fulgoridae) that was first detected in the United States in Berks County, PA, in 2014, and has since spread in the mid-Atlantic region. This phloem-feeding pest has a broad host range, including economically important crops such as grape where their feeding causes dieback of infested plants. Monitoring the presence and abundance of L. delicatula is of utmost importance to develop pest management approaches. Current monitoring practices include sticky bands deployed on tree trunks, sometimes paired with commercially available methyl salicylate lures. A drawback associated with sticky bands is the high numbers of nontarget captures. Here, we developed traps for L. delicatula based on a circle trap originally designed for weevils. These traps are comprised of a screen funnel that wraps around the trunk of a tree and guides individuals walking up the trunk into a collection device. In 2018 and 2019, we compared circle trap designs with sticky bands in Pennsylvania and Virginia. In both years, circle trap designs yielded captures that were equivalent to or exceeded captures of L. delicatula on sticky bands. Nontarget captures were significantly lower for circle traps compared with sticky bands. Presence of a methyl salicylate lure in association with traps deployed on host trees or vertical tree-mimicking posts did not increase L. delicatula captures compared with unbaited traps. Circle traps, modified using vinyl screen and a larger collection device, present an alternative to the current approach with reduced nontarget capture for monitoring L. delicatula.

The brown marmorated stink bug, Halyomorpha halys Stål (Hemiptera: Pentatomidae), is an invasive pest that attacks specialty and row crops in North America and Europe. There has been a concerted effort to reduce frequent broad‐spectrum insecticide applications made on vulnerable crops. One tool that has emerged recently is the use of long‐lasting insecticide‐treated nets (LLINs) as a killing agent. Here, we conducted bioassays to evaluate the effect of direct contact on deltamethrin‐impregnated LLINs on the behaviour and survivorship of H. halys nymphs and adults in the laboratory. Following exposure at three different durations (1.25, 4.25 or 7.25 min), vertical and horizontal mobility of adults and nymphs and the flight capacity of adults were recorded and compared with individuals that were not exposed (control). Exposure to LLINs reduced the horizontal distance and velocity and increased the angular velocity of adults only but reduced vertical mobility of adults and nymphs. Adult flights were not significantly affected by LLIN exposure. Mortality of adults and nymphs at 7‐day post‐exposure ranged from 73% to 77% regardless of exposure time. We discuss our findings within the context of the potential for and limitations of deploying LLINs in vulnerable crops to manage H. halys populations.

The brown marmorated stink bug, Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), is a polyphagous invasive insect and currently one of the most threatening agricultural pests in the USA and globally. Nymphs are highly mobile, moving among host plants, and causing significant damage. Thus, understanding dispersal biology for all life stages is critical for the development of reliable monitoring and management programs. Here, we evaluated the influence of harmonic radar as a tool to study dispersal ecology of nymphal H. halys; we measured the impact of glues and tag attachment on survivorship and mobility in the laboratory and validated in the field that tagged and released nymphs could be tracked on baited and unbaited host and non‐host plants using harmonic radar. In the laboratory, four glues were evaluated for attaching harmonic radar tags securely to nymphs, and survivorship with attached tags was measured. There were no significant differences in survivorship or vertical and horizontal movement among nymphs with tags affixed with the glue treatments compared with the untagged control. Based on numerically greater survivorship of nymphs with tags affixed with Loctite glass glue, a field validation study of tagged nymphs released in host (apple tree) and non‐host (mowed grass) with or without H. halys pheromonal stimuli present revealed that nymphs could be successfully relocated using harmonic radar after 48 h. Among treatments, 83% of nymphs remained in baited and unbaited apple trees, 50% of nymphs remained in baited mowed grass plots, and in unbaited mowed grass plots, 17% of fifth instars, and 0% of fourth instars were retained. The absence of negative effects on mobility, survivorship, and field tracking validates that harmonic radar can be used to study dispersal ecology of nymphal H. halys.

Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), the brown marmorated stink bug, is an invasive polyphagous insect that can cause serious economic injury to specialty and row crops in the United States and globally. To date, H. halys has been managed with repeated insecticide applications. While progress has been made toward development of trap-based monitoring tools to guide management decisions, little is known regarding the trapping area over which a single pheromone-baited trap captures H. halys. We conducted single trap, multiple distance mark-release-recapture experiments; results were used to estimate trapping area for nymphs and adults in sites without host plants present (open field) and for adults in sites with host plants present (apple orchard). Plume reach for pheromone-baited sticky traps was consistently estimated to be <3 m. Maximum dispersive distance in an open field devoid of host plants was estimated to be 40 m for nymphs and 120–130 m for adults resulting in trapping areas of 0.58 ha and 4.83–5.56 ha, respectively. When traps were deployed in association with host plants within the border row of an apple orchard, adult maximum dispersive distance and trapping area was reduced to 70 m and 1.67 ha, respectively. These results indicate that the behavioral response of H. halys to pheromonal stimuli is influenced by the presence of host plants and that trapping area for pheromone-baited traps will likely change relative to the cropping system in which it is deployed. Caution should be taken when extrapolating these results, because the measured values may differ in other crop systems.

Drosophila suzukii (Matsumura) (Diptera: Drosophilidae) is a devastating global pest of berry crops and cherries. Little is understood about its biology during the winter in northern temperate regions, including potential resources that it may utilize during this period. In this study, olfactory and behavioral responses of female D. suzukii to six volatiles (methionol, acetic acid, linalool, bornyl acetate, isoamyl acetate, and geosmin) were evaluated separately for electroantennogram (EAG) and behavioral assays between summer and winter morphs. Results of EAG indicated that isoamyl acetate, acetic acid, and geosmin elicited significantly higher olfactory responses from the antennae of female summer morph D. suzukii compared with those of female winter morph D. suzukii. Winter morph D. suzukii showed reduced antennal response to the volatiles overall. Geosmin and bornyl acetate elicited significantly different behavioral responses from the two morphs in no-choice laboratory behavioral assays. T-maze behavioral assays with geosmin further revealed that summer morphs had a significant aversion, while winter morphs showed no significant aversion to geosmin. Overall, we demonstrate that responses of the two seasonally induced morphs to environmental stimuli are different, and future studies are justified to further understand how these physiological and behavioral differences may contribute to improved pest management of D. suzukii.

Drosophila suzukii Matsumura (Diptera: Drosophilidae) is currently one of the most serious invasive pests for berry crops and cherries worldwide. The development of an effective monitoring trap that is reliable at detecting small populations to guide management decisions is greatly needed. To develop a novel dry trapping system, D. suzukii were trapped under field conditions in cherry orchards and raspberry high tunnels using various baited dry trap designs that were compared with the currently available deli-cup style traps that utilize a liquid bait or drowning solution. In a test in cherry orchards, red panel and combination yellow panel plus red sphere traps captured significantly more flies than yellow panel traps when all were baited with a Scentry lure. In a separate test in cherry, red sphere traps with the Scentry lure captured significantly more flies than the deli-cup traps with the Scentry lure or with the yeast sugar bait, and red panel traps with the Scentry lure captured significantly more flies than deli-cup traps with the Scentry lure. In raspberry high tunnels, red sphere traps with the Scentry lure captured significantly more flies than deli-cup traps with the Scentry lure. Red traps baited with the same lure as clear deli-cup traps consistently captured more D. suzukii, demonstrating that traps integrating a visual cue in combination with an olfactory cue are superior tools for monitoring D. suzukii. A dry trap requires less labor and maintenance than cup traps containing a liquid, improving the ease of use of D. suzukii monitoring traps.

Central-monitoring trap, multiple point release-recapture experiments were used to interpret Drosophila suzukii (Diptera: Drosophilidae) catch in a monitoring trap baited with a Scentry Biologicals commercial D. suzukii lure deployed in Michigan tart cherry orchards. The plume reach was found to be short (D. suzukii was projected to be ca. 90 m, so as to yield a trapping area of 2.7 ha. These data were consistent across two growing seasons and provide the first information about the dispersal distance and monitoring trap efficacy in a fruit crop setting for D. suzukii. Catch data per single monitoring trap can now be used to estimate absolute pest density in cherries. Alarmingly, catching one D. suzukii in a monitoring trap translates to approximately 192 D. suzukii per trapping area of 2.7 ha (26 per acre). Thus, by the time D. suzukii catch becomes detectable, it is very probable that the population is already above the tolerable damage threshold, suggesting control measures should immediately be taken if the fruit is in a vulnerable stage. Caution should be taken when extrapolating these results from cherry because the measured values may differ in other crop systems.