Progress 10/01/19 to 09/30/20
Outputs
Target Audience:Target audiences during this reporting period included producers of specialty crops, withemphasis ontree fruit producers in the Mid-Atlantic region, and members of the entomological science and research community in the United States. Students are also included in the target audience. Changes/Problems:Covid-19 restrictions limited the ability to make proress on Objective 4 of this study during this reporting period. What opportunities for training and professional development has the project provided?Graduate students Whitney Hadden (Ph.D.) and Jared Dyer (M.S.) increased their experience with field experimentation, data collection,and data analysis/interpretation, and both delivered presentations at professional conferences during the performance period. How have the results been disseminated to communities of interest?During the performance period, the PI presented an update to Mid-Atlantic and northeasterntree fruit producers on the status and results of Trissolcus japonicus redistribution efforts in the eastern USA, at the annual Mid-Atlantic Fruit and Vegetable Convention at Hershey, PA. Graduate students presented the results of their research at the 95th Annual Cumberland-Shenandoah Fruit Workers Conference, Winchester, VA. What do you plan to do during the next reporting period to accomplish the goals?In 2021, we will continue our surveillance for T. japonicus, native BMSB parasitoids, and BMSBat the nine sites at which T. japonicus was released. Given that the T. japonicus released thus farwere from laboratory populations that had been in culture for multiple generations, in spring 2021 we will attempt to propagate large numbers of T. japonicus from field-sourced populations, for release at these sitesduring the 2021 growing season. The season-long study examining the correlation between captures of T. japonicus and BMSB will be repeated in 2021, as will the study comparing T. japonicus captures in traps at lower and mid-canopy locations. Graduate students will present their research at the Entomological Society of America Eastern Branch Conference in March, 2021.The PI will update Virginia tree fruit producers on the status of our T. japonicus redistribution efforts at off-season and in-season Extension meetings. We anticipate submitting at least threemanuscripts from theseprojects during the next reporting period.
Impacts
What was accomplished under these goals?
We are engaged in projects involving the redistribution of and optimized surveillance methods for Trissolcus japonicus, an Asian egg parasitoid of brown marmorated stink bug (BMSB), toward promoting improvedbiological control of BMSB in affected crops in Virginia.During this reporting period, we again conducted surveillance for T.japonicusat nine sites in Virginia at which it was released in 2018 and 2020. Trissolcus japonicuswas detected at two of these sites in 2020, compared with four sitesin 2019. That it was detected at two of the same sites in both 2019 and 2020 is encouraging, suggesting its persistence at those locations. However,we can only speculate as to the underlying reasons for thedisappointing findingthat its detections were lower in 2020 than in 2019, and continued surveillance at these sites may reveal new insights into whether andhow quickly it reaches detectable levels.Several studies were conducted in a region of northern Virginia where T. japonicus is well-established, yielding combined captures ofover500 individuals. These studies, which examinedthe effect of several olfactory stimuli associated with BMSB (i.e.BMSB egg masses, the BMSB defensive compound n-tridecane, and BMSB pheromone)on captures of T. japonicus in yellow sticky traps deployed in the canopy of BMSB host trees, yieldedno significant treatment effects. These findings demonstrate that the effectiveness and sensitivity of yellow sticky traps for this purposewill not be improved by baiting them with any of these stimuli.We did not find that the location of these traps in the tree canopy affected T. japonicus captures. In summary, our results to date indicate that yellow sticky traps alonearean effective and efficient surveillance tool for T. japonicus when deployed in the lower canopy of host trees. 1. Determine the contribution by native predators and parasitoids to the biological control of the brown marmorated stink bug (differences between species, and distribution among habitats and regions). In 2020, we conducted extensivesurveillance for native parasitoids of brown marmorated stink (BMSB) bug at nineteen sites spanning most of the commercial treefruit production regions betweennorthern andsouthwestVirginia. At all sites, several native BMSB parasitoids were detected, including (most commonly), Trissolcus euschisti, Trissolcus brochymenae, and Telenomus podisi. With the exception of sites in Frederick county (northern Virginia), where the Asian species, Trissolcus japonicus, predominated,these three native parasitoid speciespredominated elsewhere in Virginia. 2. Determine the potential for biological control of the brown marmorated stink bug by adventive populations of Trissolcus japonicus (development of sampling tools, monitoring establishment, and spread, inoculative releases, pre-and post-release monitoring, overall impact on BMSB populations). In conjunction with the study described above, we conducted the third year of surveillance for Trissolcus japonicus and BMSB at nine sites spanning the areas of commercial tree fruit production between northern and southwestin Virginia. Trissolcus japonicus was released at these sites on two occasions in 2018 and again (one release) in 2020. Despite detections of T. japonicus at foursites in 2019, it was detected at only two sites in 2020. BMSB populationsmonitored using pheromone-baited traps at all sites indicated substantial populations that should be adequate to support the establishment of T. japonicus. Other studies that wereconductedexclusively in Frederick County, VA, where T. japonicus has been detected annually since 2015, yieldedmore than 500 captures of T. japonicus. These studiesaddressed objectives related to the effect of trap placement on T. japonicus captures and the use of olfactory stimuli associated with the presence of BMSB toimprovethe sensitivity of yellow sticky trapsfor T. japonicus surveillance. Pairs of these traps were deployed in the mature female tree of heaven, with one trap in the lower canopy and the other in mid-canopy. Traps at both canopy locations captured T. japonicus, and there was not a significant difference between them. Pairs of yellow sticky traps were deployedin the canopy of the female tree of heaven, one trap was baited with fresh BMSB egg masses and the other unbaited. Both trap treatments captured T.japonicusin numbers that were not statistically different. In a similar study, trap pairs were baited with n-tridecane, a component of the BMSB defensive secretion, or unbaited. Again, T. japonicus was captured in both trap treatments in numbers that did not separate statistically. In another study, pairs of the mature female tree of heaven were selected, with one tree per pair baited with the BMSB pheromone lure and the other unbaited. Several weeks after baiting, both trees were felled and the number of BMSB egg masses in each was determined. There were no differences in the number of BMSB egg masses found between these treatments. In a companion study,pairs of the mature female tree of heaven were selected, one wasbaited with a BMSB pheromone lure, and the other left unbaited. Several weeks after baiting, yellow sticky traps were deployed in each tree. Trissolcus japonicus was captured in traps inbaited and unbaited trees in numbers that were not statistically different. A season-long study compared captures of T. japonicus in yellow sticky traps with captures of BMSB at ten sites. T. japonicus and BMSB were captured at all sites and there was a significant correlation between captures of T. japonicus and second instar BMSB nymphs. 3. Deliver research based IPM recommendations to growers. Until T. japonicus is more widely established in Virginia and/or its impacts against BMSB havebeen documented, it is premature to discuss IPMrecommendations to growers. 4. Investigate the utility of insecticide treated netting for managing injury to crops and mitigating homeowner issues. The COVID 19 pandemic precluded hiring summer assistants in 2020, and we were unable to pursue this Objective. 5. Investigate seasonal patterns of wild host use (with special emphasis on early season hosts) Harmonic radar detection technology was used to measure the retention of tagged BMSB adults and nymphs on a number of potted tree hosts of BMSB (wild and cultivated)at different points in the 2020 growing season, under the assumption that the duration of their retention on eachcan be used as a proxy forrelative hostsuitability. Preliminary analyses suggest that overall hostacceptability/suitability was greaterduring the early season than during the late season. No differences in retention among the hosts were detected, perhaps becausethese young trees either did not bear fruit or fruit was stripped from them, for stimulus equivalency.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2020
Citation:
Akotsen-Mensah, C., B. Blaauw, B.D. Short, T.C. Leskey, J.C. Bergh, D. Polk, and A.L. Nielsen. 2020. Using IPM-CPR as a Management Program for Apple Orchards. Journal of Economic Entomology 113: 1894-1902
- Type:
Journal Articles
Status:
Published
Year Published:
2020
Citation:
Cullum, J.P., L.J. Nixon, W.R. Morrison, M.J. Raupp, P.M. Shrewsbury, P.D. Venugopal, H. Martinson, J.C. Bergh, and T.C. Leskey. 2020. Influence of landscape factors and abiotic conditions on dispersal behavior and overwintering site selection by Halyomorpha halys (Hemiptera: Pentatomidae). J. Econ. Entomol. 113: 2016-2021
- Type:
Journal Articles
Status:
Published
Year Published:
2020
Citation:
Acebes-Doria, A.L., A.M. Agnello, D.G. Alston, H. Andrews, E.H. Beers, J.C. Bergh, and 32 others. 2020. Season-long monitoring of the brown marmorated stink bug, Halyomorpha halys (St�l) (Hemiptera: Pentatomidae), throughout the United States using commercially available traps and lures. J. Econ. Entomol. 113: 159-171
- Type:
Journal Articles
Status:
Published
Year Published:
2020
Citation:
Ludwick, D., W.R. Morrison III, A.L. Acebes-Doria, A.M. Agnello, J.C. Bergh, M.L. Buffington, G.C. Hamilton, J.K. Harper, K.A. Hoelmer, G. Krawczyk, T.P. Kuhar, D.G. Pfeiffer, A.L. Nielsen, K.B. Rice, C. Rodriguez-Saona, P.W. Shearer, P.M. Shrewsbury, E.J. Talamas, J.F. Walgenbach, N.G. Wiman, and T.C. Leskey. 2020. Invasion of the brown marmorated stink bug (Hemiptera: Pentatomidae) into the USA: 14 Developing a national response to an invasive species crisis through collaborative research 15 and outreach efforts. J. IPM 11: 4; 116
- Type:
Other
Status:
Published
Year Published:
2020
Citation:
Peer review of document titled "Understanding Brown Marmorated Stink Bug Biology and Behavior in a New Zealand Setting" for the New Zealand Brown Marmorated Stink Bug Council
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Progress 04/23/19 to 09/30/19
Outputs
Target Audience:During this reporting period, we presented research results to producers of tree fruit crops in Virginia and to peers at scientific conferences. Changes/Problems:As mentioned previously, low numbers of BMSB moving to overwintering sites and unusually high temperatures in autumn 2019 precluded our ability to conduct studies with insecticide-treated netting. We will re-assess this objective in fall 2020. What opportunities for training and professional development has the project provided?PhD candidate, Nicole Quinn, defended her dissertation on aspects of T. japonicus foraging behavior, foraging ecology, and sampling in fall 2019. PhD student, Whitney Hadden, completed her third field season of research on BMSB population ecology and new MS student, Jared Dyer (undergraduate employee through August 2019) began working toward his thesis on T. japonicus foraging ecology and sampling. Undergraduate student, Brian Ruether, assisted with all aspects of our research on BMSB and T. japonicus in 2019. How have the results been disseminated to communities of interest?Results from the T. japonicus redistribution project in Virginia were disseminated to tree fruit grower stakeholders at in-season orchard meetings in 2019 and to researchers and extension agents at the Cumberland-Shenandoah Fruit Workers Conference in December, 2019. What do you plan to do during the next reporting period to accomplish the goals?In 2020, we will continue to monitor BMSB and T. japonicus at the 10 release sites in Virginia. At sites where T. japonicus is not detected during early season (June) monitoring, we will conduct follow-up releases of the wasp. PhD candidate, Whitney Hadden, will conduct studies using harmonic radar detection to measure the retention time of adult female BMSB released on a range of host tree species that produce fruit/seed structures at different points in the growing season. Relative retention time will be used as a proxy for BMSB preference for different hosts at different points during the season. She will also collaborate in a study using gut content analysis to evaluate the host tree species upon which adult BMSB have fed at points during the season. MS student, Jared Dyer, will conduct further studies on the foraging ecology and behavior of T. japonicus, based on a graduate studies proposal that is in development.
Impacts
What was accomplished under these goals?
During this reporting period we detected Trissoculus japonicus, the Asian egg parasitoid of brown marmorated stink bug (BMSB), at four of the ten sites at which it was released in Virginia in 2018. These were all new detections of T. japonicus, indicating that our releases in 2018 had resulted in some level of wasp establishment at some sites. This result is considered very positive by the standards of classical biocontrol programs and appears to bode well for the broader establishment and spread of T. japonicus in Virginia going forward, with positive effects on BMSB populations anticipated in the near term. We documented the seasonal phenology of T. japonicus in Virginia and demonstrated that there were not consistent effects of either BMSB host tree species or habitat type on its detection. These results will inform optimally efficient and effective surveillance of T. japonicus by other researchers in the USA, as they seek to document and track its presence, abundance, rate of spread and ultimately, impacts on BMSB populations. 1) Determine the contribution by native predators and parasitoids to the biological control of the brown marmorated stink bug (differences between species, and distribution among habitats and regions). Our research utilized yellow sticky traps for sampling T. japonicus and native egg parasitoids of BMSB in wooded habitats in Virginia. Consequently, our methods did not enable determination of which native parasitoids may have impacted/attacked BMSB if sentinel eggs had been used. However, our traps revealed the presence and relative abundance of several native species of BMSB parasitoids in these habitats, all of which are known to successfully develop on and/or attack BMSB eggs. As trapping and attack rate data for these native species are collected from different regions and habitats in the USA over time, a clearer picture of their relative contributions to BMSB population suppression is expected to emerge. 2) Determine the potential for biological control of the brown marmorated stink bug by adventive populations of Trissolcus japonicus (development of sampling tools, monitoring establishment and spread, innoculative releases, pre- and post-release monitoring, overall impact on BMSB populations). Our research continues to demonstrate that T. japonicus has established widely and appears to be increasingly abundant in Frederick county, Virginia, but not yet elsewhere in the state. While BMSB populations in Frederick county have shown continuing indications of decline in recent years, we are not yet able to directly ascribe that observation to the impacts of T. japonicus. Based on data from Asia, we expect that the impacts of T. japonicus will continue to increase where it has established, but cannot predict the period of time that will be necessary for its impacts to become apparent. Our development of sampling tools and protocols for T. japonicus has improved the effectiveness and efficiency of its surveillance and monitoring in Virginia and elsewhere in the USA. Of particular importance is PhD student, Nicole Quinn's demonstration of consistent patterns of T. japonicus presence and relative abundance during the spring and summer across two consecutive seasons, which can inform the timing of sampling efforts. She also conducted the second and third years, respectively, of the effects of BMSB host tree species and habitat type on T. japonicus detections. Given that neither study indicated a consistent treatment effect, we can recommend to research colleagues that these factors are likely of less importance than the timing of surveillance for T. japonicus. Our release of T. japonicus at 10 sites in Virginia in 2018 yielded first detections at 4 sites between northern and southwestern Virginia. This result after only one year is considered very positive and continued monitoring and potentially additional releases between 2020 and 2021 are expected to yield further indications of establishment and/or new detections. Ongoing monitoring of BMSB populations at those sites may ultimately provide indications of BMSB population decreases. During the 2019 season we conducted studies examining whether baiting host trees with a BMSB aggregation pheromone lure would 1) increase the number of BMSB egg masses laid, and/or 2) increase the number of T. japonicus detections in yellow sticky traps. Both studies yielded suggestions of a positive effect, compared with unbaited control trees, but statistical analyses resulted in no significant separations in mean counts. Similarly, a study comparing yellow sticky traps with and without freshly-laid BMSB egg masses attached to them yielded suggestions of a positive effect in traps with eggs, but no statistical separation in mean T. japonicus captures. These studies are intended to 1) provide further insights into the foraging ecology of T. japonicus and 2) to explore methods by which the sensitivity of yellow sticky traps for T. japonicus surveillance might be enhanced. 3) Deliver research based IPM recommendations to growers. It is premature to provide IPM recommendations to growers about how T. japonicus populations may be promoted or conserved. This is particularly true given that this wasp is predominantly found in wooded habitats adjacent to cropland, and therefore are not exposed to pesticide applications, as they would if more commonly occurring in the crop itself. However, we continue to update our tree fruit producers about the results of our research on sampling and releasing T. japonicus and have received positive feedback from them. 4) Investigate the utility of insecticide treated netting for managing injury to crops and mitigating homeowner issues. My laboratory has focused on the potential utility of insecticide-treated netting to mitigate homeowner issues from BMSB invasion during their autumn dispersal to overwintering sites. In fall 2019, we did not pursue this objective because of unusually hot weather that was deemed to be unrepresentative and because of low numbers of dispersing BMSB at our study site. 5) Investigate seasonal patterns of wild host use (with special emphasis on early season hosts) In 2019, PhD student, Whitney Hadden, completed the second year of study on this objective, with modifications from the protocols used in 2018. A smaller section of a BMSB pheromone lure than in 2018 was used to bait small pyramid traps deployed in mid-canopy of several common BMSB host plants (black locust, tree of heaven, black cherry, mulberry, and hackberry) on alternate weeks from April through mid-October. The smaller piece of lure was an attempt to more closely mimic the pheromone signal from an individual male BMSB, thereby intending to limit the "active space" of the lure primarily to the canopy of the tree. These tree species were selected because they bear fruit or seed structures at differing points during the growing season, ranging from early to later in the season. This was intended to enable an examination and comparison of BMSB captures in relation to the presence or absence of reproductive structures during the season. Lure-baited traps were deployed for 24-hour intervals every second week in an attempt to capture a "snap-shot" of BMSB activity in each tree and to enable BMSB to naturally redistribute themselves between sampling weeks (i.e. during the absence of an aggregation pheromone lure). Results from 2019 did not yield any consistent effects of tree species on differences in BMSB captures in early, mid, or late season. BMSB adults and/or nymphs were captured in all tree species throughout most of the season.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2019
Citation:
Quinn, NF, EJ Talamas, AL Acebes-Doria, TC Leskey, and JC Bergh. 2019. Vertical sampling in tree canopies for Halyomorpha halys (Hemiptera: Pentatomidae) life stages and its egg parasitoid, Trissolcus japonicus (Hymenoptera: Scelionidae). Environ. Entomol. 48: 173-180
- Type:
Journal Articles
Status:
Published
Year Published:
2019
Citation:
Quinn, NF, EJ Talamas, TC Leskey, and JC Bergh. 2019. Sampling methods for adventive Trissolcus japonicus (Hymenoptera: Scelionidae) in a wild tree host of Halyomorpha halys (Hemiptera: Pentatomidae). J. Econ. Entomol. 112: 1997-2000
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