Progress 08/14/15 to 08/13/20
Outputs
Target Audience:Outreach and dissemination of this project's findings targets stakeholders which include private citizens and associations, homeowners, foresters from state lands and water company managers, land trust managers, town conservation commissions and arborists. Public interest is high and recent findings have clarified the role of winters on HWA abundance and spread, and provided management recommendations on the urban landscape level. Following severe winters, guidance is provided to reduce the need for prophylactic chemical treatments for HWA control, which should only be necessary where resurgence is detected. A strategy of implementing small scale releases of S. tsugae for biological control is being developed and applied in collaboration with different stakeholders and provides HWA management options where chemicals cannot be applied, such as on reservoir watershed forests and sensitive conservation areas.Outreach and dissemination of this project's findings targets stakeholders which include private citizens and associations, homeowners, foresters from state lands and water company managers, land trust managers, town conservation commissions and arborists. Public interest is high and recent findings have clarified the role of winters on HWA abundance and spread, and provided management recommendations on the urban landscape level. Following severe winters, guidance is provided to reduce the need for prophylactic chemical treatments for HWA control, which should only be necessary where resurgence is detected. A strategy of implementing small scale releases of S. tsugae for biological control is being developed and applied in collaboration with different stakeholders and provides HWA management options where chemicals cannot be applied, such as on reservoir watershed forests and sensitive conservation areas.Outreach and dissemination of this project's findings targets stakeholders which include private citizens and associations, homeowners, foresters from state lands and water company managers, land trust managers, town conservation commissions and arborists. Public interest is high and recent findings have clarified the role of winters on HWA abundance and spread, and provided management recommendations on the urban landscape level. Following severe winters, guidance is provided to reduce the need for prophylactic chemical treatments for HWA control, which should only be necessary where resurgence is detected. A strategy of implementing small scale releases of S. tsugae for biological control is being developed and applied in collaboration with different stakeholders and provides HWA management options where chemicals cannot be applied, such as on reservoir watershed forests and sensitive conservation areas. Changes/Problems:The pandemic restrictions of Covid 19 in 2020 posed several challenges to the continuation of safe essential data collection but most of the crown assessments were completed. Tree core sampling could not progress. Reduced laboratory access also affected S. tsugae colony rearing and maintenance and testing of volatile attractants. What opportunities for training and professional development has the project provided?ArcGIS software has been updated to produce digital maps of biological control sites and for the overlaying of other geographic and climate data for analyses in future planned collaborations with Connecticut state forester GIS specialists. Tree coring with an increment borer is being developed as another approach to analyses of hemlock growth rates. How have the results been disseminated to communities of interest?Results and guidance on the implementation of biological control of HWA with S. tsugae have been disseminated via presentations, posters, interviews, podcasts, videos, responses to calls and email enquiries throughout the past year. Updated HWA biological control poster handouts and factsheets have been widely distributed to foresters, the public and other relevant stakeholders throughout the year via email or in person. The PI has also provided hemlock resource evaluations and consultations to stakeholders from conservation commissions, land trusts, state, private and municipal forest managers. A HWA webpage at the Connecticut Agricultural Experiment Station website is updated regularly and provides links to CAES publications on hemlocks, biological control and other related information. Publications from this research project are also posted on the website ResearchGate for wider public access and have reached many stakeholders and members of the scientific community. In 2020, posters on the project were posted online for a virtual CAES Plant Science Day due to pandemic restrictions, and included links to a recent newspaper interview and a video on the project by Localmotives from Columbus, Ohio. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
Impact: Data on hemlock crown health collected over 4 years documented the resilience and ability to recover rapidly from drought and insect attack under favorable environmental conditions. Goal 1) Hemlock Crown Assessments Annual assessments of hemlock health of S. tsugae biological control release sites in Connecticut wereconducted inwinter through spring 2020, completing the fourth year of consecutive field data collections on hemlock crown health in a wide range of forest sites. Population levels of HWA and EHS in Connecticut Forests Long term studies have shown that populations of HWA in Connecticut are strongly influenced by the frequency of severe winters which can decimate HWA and reduce infestations by varying degrees in the different climatic divisions of Connecticut. However, the winter of 2019-2020 was the sixth warmest in 125 years with no sub-zero daily minimum temperatures from December 2019 through February 2020, resulting in no winter mortality of HWA. Following this very warm winter, resurgence and reinvasion of HWA in some areas was recorded in late winter and early spring 2020, particularly in northeastern cand southeastern Connecticut. Other patchy new HWA infestations were observed in some central areas, especially along rivers, near lakes and reservoirs and even in isolated pockets in northern forests on the border with neighboring states. Homeowner reports of HWA have also increased indicating resurgence in suburban areas in 2020. Additional random sampling of 18 other hemlock forests statewide continued through the fall of 2019 into winter 2020 with 541 samples collected and evaluated for hemlock recovery, HWA and EHS infestations. Samples indicated the patchy resurgence of light to moderate HWA in a third of the sites sampled (32.6%) while 59% of sites had medium to very high levels of EHS, and these included sites east of the Connecticut River, indicating further spread. Samples also indicated new shoot production in the majority of tips. Other stressors on hemlock The main abiotic stressor impacting Connecticut's hemlock forests in recent years as the climate changes has been more frequent significant drought. This project has spanned 2 significant drought periods, impacting moisture-sensitive hemlocks. The severe to extreme drought throughout Connecticut from late 2015-early 2017 was followed by 2018, the 4th wettest year since 1895 for Connecticut in all climate divisions. A wet 2019 spring was followed by below normal precipitation in summer and fall. A warm and rainy 2020 winter, was then followed by another extreme spring and ongoing summer drought. Severe drought stress from 2015-2017 had impacted hemlocks, especially on marginal sites with poor soils, and in combination with heavy EHS infestations, not HWA, resulted in secondary hemlock borer outbreaks on weakened trees in several sites, especially on rocky ridgetops in 2017. However, Connecticut 2019 crown data from this project showed that above normal high precipitation in 2018 was favorable to more rapid hemlock recovery from extreme drought then previously understood, enabling improvement in crown health from drought and insect damage, even in marginal sites two years post drought. 2020 Status of 18-21 year old S. tsugae release sites in Connecticut Fourteen S. tsugae release sites (1998-2001) were assessed during winter-spring 2020, during a Covid 19 pandemic, for 2019 hemlock crown health, two years post drought. During 2018 assessments in winter-spring 2019, crown assessments on annually monitored trees in 2019 showed zero HWA at 15 monitored S. tsugae release sites, although there was slight resurgence on other stressed trees atone northeastern site. In 2019 crown assessments at these sites, HWA rebound or reinvasion was recorded at 64% of sites. Most of the HWA was on the lower crowns and understory saplings which may indicate resurgence after minimal to zero winter mortality in 2020. Drought impacts from 2015-2017 was accompanied with accelerated needle loss in hemlock stands that had heavy EHS infestations in 2018-2019. However, 64% of monitored sites still had medium to very high densities of EHS. Analyses of trends over four years showed that S. tsugae sites with high EHS infestatons had significantly thinner crowns than sites that had low or negligible EHS infestations. After 3 years from the start of an extreme drought and an abnormally wet year of 2018, 93% of sites showed significant foliar transparency improvement by 2019-2020, a recovery which equaled that of crown health in uninfested baseline sites. No fresh hemlock borer activity was recorded in winter and spring 2020. Baseline sites and the impact of elongate hemlock scale Baseline sites are hemlock stands located in the north western section of the state at high elevation with a long history of negligible EHS or HWA presence and were regarded as uninfested healthy hemlock stands in 2005. These 7 sites are assessed annually together with 15 S. tsugae sites for comparisons. In 2019, a dramatic decline in hemlock crown health was recorded in 28% of monitored baseline sites. One site on the Massachusetts border had emerging HWA infestations and decline in 2019, and 71% of baseline sites had patchy medium to very high levels of EHS. Light fresh hemlock borer activity was also recorded in some baseline sites in spring 2019. In assessments during spring 2020, EHS levels had decreased to low levels with significant crown recovery in 83% of sites. There was heavy HWA recorded on two trees at one baseline site. One dominant hemlock died from hemlock borer activity at another site. Management of resurgent HWA with biological control releases In 2017, small releases of S. tsugae, ranging from 100-400 per site, were made at four state forests, and three town, land trust and private forest preserves, where emerging infestations of HWA were detected. Sampling in fall 2019 detected HWA in 0-22% of tip samples, indicating that these releases appeared to be effective in reducing HWA infestations at all eight sites after 2 years. However, after the warm winter of 2020, major HWA resurgence was observed at one southeastern site on droughty soils. A cooperative strategy, developed by the PI with foresters and land managers of state, land trust and water company lands, implemented augmentation biological control releases of S. tsugae at 14 forest sites in spring 2020. Ladybeetles were purchased by several organizations from Tree-Savers, PA (3,200) and over 3,350 were also generously donated by Tree-Savers. In 2020, >6,500 S. tsugae were released in multiple sites around the state on state lands, public preserves and watershed forests. Since 1995, >185,000 S. tsugae have been released statewide in 37 sites, primarily state lands and public preserves. Goal 2) Improving Monitoring for S. tsugae Laboratory testing of various plant volatiles did not occur due to the covid pandemic of 2020 and limited access. Some small scale experiments indicated possible attraction to a volatile from the original native tree host of HWA in Japan, Tsuga sieboldii and further investigations are planned. Goal 3) Assessments of Impact of S. tsugae Predation from Spring to Fall Previous assessments in 2016-2017 showed that S. tsugae survived increasingly hot and humid summers, with a sustained predatory impact on HWA from spring into fall.This implementation of S. tsugae after severe winters to target resurgent HWA populations may be a feasible non-chemical and safe method available to the public through the only commercial producer of S. tsugae, Tree-Savers of Pennsylvania. Biological control of HWA is an important and economical option for public and private stakeholders who cannot or do not want to use chemicals for controlling HWA. Results from 2017 small scale releases were encouraging and instrumental in implementing a collaborative effort to implement biological control releases of S. tsugae in 2020.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2019
Citation:
Cheah, C. 2019. Climate Impacts on Eastern Hemlock Sustainability. The Habitat 31 (1): 6-7, 13-14
|
Progress 10/01/18 to 09/30/19
Outputs
Target Audience:Results from this multi-faceted approach are increasing understanding of the complex environmental and ecological interactions influencing hemlock forest impacts from hemlock woolly adelgid (HWA) in Connecticut and the implications for the long term efficacy of HWA biological control using the adelgid ladybeetle predator, Sasajiscymnus tsugae. Outreach and dissemination of the results of this research is ongoing to stakeholders which include private citizens, homeowners, water company, landscape and forest managers, arborists and nurserymen for HWA management strategies. Citizens of Connecticut are very concerned on the status of hemlocks as evidenced from the numerous enquiries submitted to this project. Recent analyses has clarified the role of winters on HWA abundance and spread, and provided management recommendations on the urban landscape level. This information on the dramatic decrease in HWA statewide is important for homeowners, state forests and parks, land trusts, natural resource and forest managers, reducing the need for prophylactic chemical treatments for HWA control, which should only be necessary where resurgence is detected. Studies are showing that resurgent HWA can also be managed and reduced by implementation of S. tsugae for biological control. This is important planning information for land and forest managers. Documenting the rapid recovery of eastern hemlocks in a changing climate of increased precipitation after extreme drought is a new finding. Hemlocks previously severely stressed by drought and increased EHS infestations can recover with ample precipitation if left to do so, even in poor sites, now that HWA, decimated by successive severe winters, is no longer a serious threat in Connecticut. There should be no need for pre-emptive salvage of healthy or recovering hemlocks. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?ArcGIS software has been acquired for training for digital mapping of sites and overlaying of geographic data for analyses.Tree coring with an increment borer and analyses ofhemlock growth rateswill benew techniques acquired. How have the results been disseminated to communities of interest?Results have been disseminated via workshops, presentations, demonstrations, tours and interviews throughout the past year. There have also been numerous email enquiries and calls about HWA, biological control and hemlocks, answered throughout the year. Updated HWA biological control poster handouts have been widely distributed to foresters, the public and other relevant stakeholders throughout the year via email and by handouts. Advisory roles to Tree-Savers, PA, and Edgerton Park, Town of New Haven, also dispense research results and technical advice on the mass rearing and implementation of S. tsugae biological control releases, and healthy hemlock maintenance and culture. CAES factsheets continue to be widely distributed in 2019 through emails, links and handouts at various meetings. Publications from this research project (below) are also posted on the website ResearchGate for wider public access and have reached many stakeholders and members of the scientific community and include the following project publications: 1) A peer reviewed journal paper published in 2017 entitled "Predicting Hemlock Woolly Adelgid Winter Mortality in Connecticut Forests by Climate Divisions." Northeastern Naturalist 24 (Special Issue 7): B90-B118 2) Connecticut Agricultural Experiment Station 2016 factsheet: "HWA Winter Mortality in Connecticut and Implications for Management and Control." 3) Connecticut Agricultural Experiment Station 2019 factsheet: "Hemlock Woolly Adelgid (HWA) and Other Factors Impacting Eastern Hemlock." Talks, interviews andpresentations given in the reporting period: Gave a workshop presentation on climate impacts on hemlock sustainability at the 41st Annual Conference of the Connecticut Association of Conservation and Inland Wetlands Commissions, November 17, 2018 at the Red Lion Hotel Cromwell (30 attendees) Was interviewed by Robert Miller of the News-Times of Danbury on the effects of the polar vortex on hemlock woolly adelgid, Jan 24, 2019 Was filmed and interviewed on the impacts of winters and climate change on hemlock woolly adelgid on eastern hemlocks by Nate Murray and Cody Pfister of Local Motives, Inc., a nonprofit organization from Ohio, which is producing video documentaries from all 50 states to communicate local perspectives on environmental issues such as climate change, January 25, 2019 Was interviewed by Patrick Skayhill, for WNPR/Connecticut Public Radio on the effects of the polar vortex on hemlock woolly adelgid, and other stressors of eastern hemlock, January 30, 2019 Gave a presentation on predictions of winter mortality of hemlock woolly adelgid at the 2019 Forest Health Monitoring workshop, New Haven to state, municipal and private foresters on March 8, 2019 (50 attendees) Gave a hemlock tour and talk to members of the West Hill Lake Club, New Hartford, March 29, 2019 (12) Gave an evening presentation on climate impacts on eastern hemlocks for the Weantinoge Land Trust at the Gunn Memorial Library, Washington, on May 14, 2019 (25 attendees) Gave a morning talk on trees under siege, with concentration on hemlocks, to the Breakfast Club at the McAuley Retirement Community, West Hartford on May 29, 2019 (35 attendees ) Submitted a report summary on HWA and hemlock conditions in Connecticut to Noel Schneeberger, Forest Health Program Leader for USDA Forest Service, for the 5th Annual Hemlock Woolly Adelgid Program Managers Meeting, July 29, 2019 in Holland, Michigan Manned an experimental plot and booth on biological control of hemlock woolly adelgid in Connecticut for the annual Connecticut Agricultural Experiment Station's Plant Science Day on August 7, 2019 What do you plan to do during the next reporting period to accomplish the goals?Outreach: Continue with more publications, presentations and workshops in 2019-2020. A HWA webpage is also near completion for the Connecticut Agricultural Experiment Station website which will centralize and provide links to the multiple years of CAES hemlock related research publications for the public.This Hemlock and HWA webpagewill facillitatemore public accessibility to relevant research findings. Data Collection: Continue with S. tsugae site visits to take tree core data, determine 2019-2020 hemlock crown assessments and document recovery after extreme and extended drought, soil type interactions, other primary and secondary pests of hemlock. Research field methods for attracting and monitoring S. tsugae in forest sites. Continue with a statewide survey of hemlock stands throughout Connecticut to document the distribution and levels of hemlock pests under changing climate conditions. Laboratory research: Continue to rear and maintain S. tsugae colony at the Windsor Valley Laboratory for experiments on potential S. tsugae attractants and behavioral investigations of responses to volatiles. The goal is to identify potential mixtures of attractants that could be used to monitor S. tsugae activity and persistence in field situations. Publications: Data analyses and preparation of manuscripts for several publications are planned.
Impacts
What was accomplished under these goals?
Goal 1) Improving Hemlock Crown Assessments Annual assessments of hemlock health of S. tsugae biological control release sites in Connecticut wereconducted infall 2018 through spring 2019. This isthe third year of consecutive field data collections on hemlock crown health in a wide range of forest sites. Population levels of HWA and EHS in Connecticut Forests Long term studies have shown that populations of HWA in Connecticut are shaped by severe winters which can decimate HWA and reduce infestations to varying degrees in the different climatic divisions of Connecticut. The winter of 2019 was moderately severe in northwest Connecticut (Division 1) and average in the northeast and central regions (Division 2) and mild in coastal Connecticut (Division 3). Daily minimum temperatures fell below 0oF in late January into early February 2019 in northwest Connecticut after an average to warm December. Minimum daily temperatures were lowest in the northwest and parts of central Connecticut. Daily temperatures did not dip below 0oF in coastal Division 3. February 2019 temperatures were warmer especially in central and coastal Connecticut. Due to the scarcity of HWA, there were insufficient sites and samples to determine HWA winter mortality statewide but from a limited number of sites analyzed, HWA mortality from winter polar vortex outbreaks in late January appeared highly variable. The highest average HWA winter mortality of 61-73% was recorded in the northwest region while HWA mortality was moderate in the northeast at 40% and low in the coastal region at 25%.A statewide survey to document changing distribution and levels of hemlock pests started in fall 2018 through 2019 and will continue into 2020. Assessments were made for levels of HWA or elongate hemlock scale (EHS), and any other occurrences of interest. Results to date show that there has been little or no resurgence of HWA in most Connecticut hemlock stands in the northwest, central and southern coastal region. The southwestern part of the state has not yet been surveyed. A handful of localized patchy HWA infestations were found in north central and northeast Connecticut, near the coast or by large bodies of water but overall, HWA remains scarce throughout the forests in Connecticut. Many hemlock stands do not appear to be infested anymore. To date, 30 sites (>750 branch tips) have been sampled through spring 2019, mainly in northern Connecticut where hemlock is most plentiful. Five sites (17% of sites) had very light HWA (0.02% of all samples). In contrast, >77% of sites sampled had medium to very high levels of EHS, and only 16% of sites had negligible levels of EHS. The overwhelming majority of random tips sampled showed excellent new shoot production in 2018 and 2019. 2019 Status of 17-20 year S. tsugae release sites in Connecticut In all 15 former S. tsugae release sites, crown assessments in 2019 showed zero HWA on annually monitored trees although there was slight resurgence on other stressed trees atone northeastern site. However, the number of former S. tsugae release sites with medium to very high elongate hemlock scale infestations increased to 67% with explosive increases in 2 new sites since the last assessment in 2018. Only 20% of all CT monitored S. tsugae sites had negligible or very low EHS levels, while the remaining 13% had patchy low to medium EHS. Drought impacts from 2015-2017 have continued to accelerate needle loss in hemlock stands that had heavy EHS infestations previously in 2017 and 2018 assessments. Recovery in these stands appear to be at a slower rate than in hemlock stands that had been previously primarily impacted by HWA alone. Baseline sites and the impact of elongate hemlock scale Baseline sites are hemlock stands located in the north western section of the state at high elevation with a long history of negligible EHS or HWA presence and were regarded as uninfested healthy hemlock stands in 2005. These 7 sites are assessed together with 15 S. tsugae sites for comparisons. In 2019, a dramatic decline in hemlock crown health was recorded in 28% of monitored baseline sites. One site on the Massachusetts border had emerging HWA infestations and decline. Since 2009, EHS has continued to increase in these sites and in 2019, 71% of sites had patchy medium to very high levels of EHS. This represents a rapid increase in EHS since assessments in 2016. Light fresh hemlock borer activity was also recorded in some baseline sites in spring 2019. Management of resurgent HWA with biological control releases After 4 successive years of heavy HWA winter mortality, HWA remained at historically low levels in most forests in 2019 throughout Connecticut. Very few pockets of HWA resurgence were found, occurring nearer the coast or near large bodies of water.To manage emerging HWA infestations, small scale biological control releases had been conducted in 7 new sites in June 2017 with a donation of 2,000 S. tsugae adults from Tree-Savers of Pennsylvania.Thesesites were re-surveyed beginning in late September 2019 to assess HWA levels since S. tsugae releases were implemented in 2017 and will be continued. Heavy precipitation enabling eastern hemlock recovery from extreme drought Main stressors impacting Connecticut's hemlock forests in recent years are changing: the severe to extreme drought throughout Connecticut from late 2015-early 2017 was the primary abiotic stressor of eastern hemlock. With consecutive years of severe winter effects on HWA resulting in reduced adelgid populations statewide, EHS infestations are now more widespread and damaging to eastern hemlocks than HWA. Extreme drought stress impacted hemlocks, especially on marginal sites with poor soils, and in combination with heavy EHS infestations, resulted in secondary hemlock borer outbreaks on weakened trees in several sites, especially on rocky ridgetops in 2016-2017. But 2018 was the 4th wettest year since 1895 for Connecticut in all climate divisions. Connecticut assessments show that above normal high precipitation is favorable to more rapid hemlock recovery then previously understood, enabling improvement in tree health from drought and insect damage, even in marginal sites. Data collected in 2019indicated hemlock recovery of all class ages and high levels of refoliation through abundant new shoot production in 2018 in all sites. From foliar transparency data, improvement in hemlock crown health in 2019was recorded in 53% of S. tsugae sites while 13% had similar crown health to 2018 and had not worsened. The remaining20% of sites had declining thinner crownswith higher EHS levels. Due to the extreme drought of 2015-2017, in , heavy hemlock borer outbreaks occurred in marginal, highly stressed sites on rocky ridges in 2017-2018 but in 2019, there was little to no expansion of hemlock borer activity at these sites. Heavy precipitation appeared to have mitigated levels of hemlock borer activity into 2019. Goal 2) Improving Monitoring for S. tsugae Laboratory testing of various plant volatiles was delayed as the laboratory colony of S. tsugae has been much reduced due to scarcity of HWA. Goal 3) Assessments of Impact of S. tsugae Predation from Spring to Fall Previous assessments in 2016-2017showed that S. tsugae survived increasingly hot and humid summers, with a sustained predatory impact on HWA from spring into fall.This implementation of S. tsugae after severe winters to HWA populations may be a feasible non-chemical and safe method of managing resurgent or new introductions of HWA and S. tsugae is available to the public through the only commercial producer, Tree-Savers of Pennsylvania. Field cage experiments to assess overwintering survival of S. tsugae in in cooperation with the Maine Forest Service and Tree-Savers of Pennsylvania did not materialize as the production and availability of S. tsugae havebeen negatively impacted by the lack of HWA for mass rearing.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2019
Citation:
Cheah, Carole 2019. Hemlock woolly adelgid (HWA) and other factors impacting eastern hemlock. Connecticut Agricultural Experiment Station Factsheet January 2019.
Available online: https://portal.ct.gov/-/media/CAES/DOCUMENTS/Publications/Fact_Sheets/Valley_Laboratory/Hemlock-Woolly-Adelgid-Factsheet-Dec-2018-Cheah-Final.pdf?la=en
Cheah, C. 2019. Climate Impacts on Eastern Hemlock Sustainability. The Habitat 31 (1): 6-7, 13-14
Cheah, C. 2016. HWA winter mortality in Connecticut: implications for
management and control. Connecticut Agricultural Experiment Station Factsheet July
2016. Available online at:
http://www.ct.gov/caes/lib/caes/documents/publications/fact_sheets/plant_pathology and_ecology/hemlock_woolly_adelgid_winter_mortality__7.12.16.pdf
|
Progress 10/01/17 to 09/30/18
Outputs
Target Audience:Results from this multi-faceted approach are increasing understanding of the complex environmental and ecological interactions influencing hemlock forest impacts from hemlock woolly adelgid (HWA) in Connecticut and the implications for the long term efficacy of HWA biological control using the adelgid predator, Sasajiscymnus tsugae. Recent analyses has clarified the role of winters on HWA abundance and spread, and provided management recommendations on the urban landscape level. Continuation of dissemination of the results of analyses of 16 years of data gathered on HWA winter mortality trends in Connecticut In 2017-2018 is ongoing to private citizens, homeowners, water company, landscape and forest managers, arborists and nurserymen for HWA management strategies in a Connecticut Agricultural Experiment Station factsheet entitled: "HWA Winter Mortality in Connecticut and Implications for Management and Control". This factsheet continues to be widely distributed in 2018 through emails, links and paper copies at various meetings. It is available online at: http://www.ct.gov/caes/lib/caes/documents/publications/fact_sheets/plant_pathology_and_ecology/hemlock_woolly_adelgid_) Another peer reviewed journal paper published in 2017 entitled "Predicting Hemlock Woolly Adelgid Winter Mortality in Connecticut Forests by Climate Divisions" Northeastern Naturalist 24 (Special Issue 7): B90-B118 is also available and is also being distributed. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?ArcGIS software has been acquired for training for digital mapping of sites and overlaying of geographic data for analyses. A HWA and Hemlock webpage is under preparation for the Connecticut Agricultural Experiment Station website. How have the results been disseminated to communities of interest?Results have been disseminated via workshops, presentations, demonstrations, tours and interviews throughout the past year Answered numerous email enquiries and calls about HWA, biological control and hemlocks throughout the year Updated and distributed HWA biological control poster handouts to foresters, the public and other relevant stakeholders throughout the year Advisory role to Tree-Savers, PA, on the rearing and evaluation of S. tsugae biological control releases Communicated research findings to the public and stakeholders via guided tours of pristine hemlocks in a private research forest, Great Mountain Forest, Norfolk, November 1, 2017 and on May 29, 2018 Communicated hemlock pest research on a guided tour of Edgerton Park, New Haven, Connecticut, to members of the public and Conservancy Board Members on May 4, 2018 resulting in an educational research release for biological control of HWA at the park, May 31, 2018 Mentored a forestry intern from Great Mountain Forest for a field research day July 19 Was interviewed by John Burgeson of the Connecticut Post on the effects of the recent cold outbreak on hemlock woolly adelgid Jan. 23, 2018 Was interviewed by William Hobbs of The Day and Experiment Station Associates on hemlocks and hemlock woolly adelgid Feb 2 and 5 Was interviewed by Will Langhorne for the Yale Daily News on the effects of the recent cold outbreak on hemlock woolly adelgid Feb. 14 Was interviewed by Judith Dreyer July 6, 2018, for a 30 minute podcast on hemlocks for the series "The Holistic Nature of Us" Gave a seminar at the Connecticut Agricultural Experiment Station on climate impacts on HWA in the Northeast Jan 31, 2018 (>50) Gave a presentation on hemlocks and other trees under siege to the New Hartford Land Trust Feb. 22 (25) Gave 2 presentations on biological control of hemlock woolly adelgid at an invasives workshop for the CT Land Conservation Conference March 17 at Wesleyan University in Middletown (40) Met with Ann Astarita, Director of the Roxbury Land Trust June 15 to check hemlocks at the biological control release site at the historic Mine Hill Preserve and talked to students and their teacher from the University of Bridgeport Summer Scholars Program on biological control of HWA (4) Gave a presentation on biological control of hemlock woolly adelgid at the University of Connecticut Hot Topics series for the Master Gardeners Program June 20 (200) which was taped and is available on the web Gave a short talk for Plant Science Day, August 8 2018, on climate impacts on hemlocks and HWA (>60) which is also available at the CAES website Met with Beverley Samuel, USDA NIFA National Program Leader, at Lockwood Farm September 19, 2018 to give a research update on biological control of hemlock woolly adelgid What do you plan to do during the next reporting period to accomplish the goals?Outreach: Continue with more publications, presentations and workshops in 2018. Complete Hemlock and HWA webpage for the CAES website for more public accessibility to research findings. Data Collection: Continue with S. tsugae site visits to take tree core data, determine 2018-2019 hemlock crown assessments and document recovery after extreme and extended drought, soil type interactions, other primary and secondary pests of hemlock. Research field methods for attracting and monitoring S. tsugae in forest sites. A new method of collection of hemlock blow-down samples is being investigated to determine presence and levels of major hemlock pests, HWA and EHS. A statewide survey is planned to document changing distribution and levels of hemlock pests under changing climate conditions. Laboratory research: Continue to rear and maintain S. tsugae colony at the Windsor Valley Laboratory for experiments on potential S. tsugae attractants and behavioral investigations of responses to volatiles. The goal is to identify potential mixtures of attractants that could be used to monitor S. tsugae activity and persistence in field situations. Also continue to research possibility of using alternative prey and artificial diet developed by Cohen and Cheah for supplementing S. tsugae survival and reproduction as HWA levels in Connecticut have been reduced to an all-time low, negatively affecting S. tsugae colony rearing and maintenance in 2018.
Impacts
What was accomplished under these goals?
Impact: Greater understanding of the interaction of complex factors impacting eastern hemlock health. Data on crown health under collection is also attesting to the resiliency and recovery of eastern hemlock under favorable environmental conditions. Goal 1) Improving Hemlock Crown Assessments The current status of eastern hemlock stands in Connecticut is being assessed after a hiatus of 8 years, in conjunction with climate monitoring, site characteristics and assessments of other biotic and abiotic stressors for a more comprehensive and integrated approach. Annual hemlock health assessments of S. tsugae biological control release sites in Connecticut were initiated in early fall 2017 and were completed in the late winter-early spring of 2018. Population levels of HWA in Connecticut Forests The winter of 2018 was severe and extreme temperatures occurred in early January 2018 after a warm December, after a weak polar vortex event brought arctic air into Connecticut, which killed a high percentage of HWA. Sudden extreme wind chills also resulted in extreme winter desiccation and injury to exposed hemlocks where whole upper crowns were defoliated from needle drop. Adelgid samples were taken from 16 sites throughout Connecticut (6 sites in Division 1, 6 sites in Division 2 and 4 sites in Division 3) from mid-January to early March 2018 and assessed for live and dead HWA. Adelgids suffered lower winter mortality in Division 1 (mean of 85%) and in coastal division 3 (mean of 88%) while Division 2 recorded the highest winter mortality of HWA ( mean of 91%). ON average, HWA winter mortality in 2018 was 88% statewide but extremely high mortality (>90%) was also recorded in 56% of sites. Management of resurgent HWA with biological control releases After 4 years (2014-2016, 2018) of heavy HWA winter mortality throughout Connecticut, HWA remained at historically low levels in most sites in the spring of 2018 throughout Connecticut. Patchy light resurgence in mid-spring 2018 was recorded in 23% of all sites and moderate resurgence in 23% of all sites. To manage emerging HWA infestations, biological control releases were conducted in 7 new sites in June 2017 with a donation of 2,000 S. tsugae adults from Tree-Savers of Greentown, Pennsylvania, the only commercial producer of S. tsugae. Releases were continued in 2018, when a new small release of S. tsugae was implemented at a coastal historic park which had been annually managed with horticultural oil sprays. Although these treatments are very effective in killing hemlock pests, complete coverage is unfeasible and occasionally a few adelgids survive the sprays, notably in 2018. The release of S. tsugae reared at the CAES Valley Laboratory, in late May 2018, was timed to impact the summer progrediens generation of HWA. Impact and survival of both predator and pest will be studied with the involvement of Edgerton Park Conservancy Board members. Impact of extreme drought Main stressors impacting Connecticut's hemlock forests in recent years are changing: the severe to extreme drought throughout Connecticut from late 2015-early 2017 was the primary abiotic stressor of eastern hemlock. This was the most serious prolonged drought period since the epic drought of mid-1960s. In coastal division 3, extreme or severe drought was the most prolonged at 22 months. In central Division 2, the drought lasted for 13 months and in division 1, northwest Connecticut, it spanned 11 months. Great stress impacted moisture-loving hemlocks, especially on marginal sites with poor soils, and in combination with heavy elongate hemlock scale (EHS) infestations, resulted in secondary hemlock borer outbreaks in several sites, especially on rocky ridgetops in 2016-2017. Impacts of scale infestations appear to be exacerbated by prolonged serious drought. The drought also exacerbated large and damaging gypsy moth outbreaks, especially in eastern Connecticut, and in one southern site, gypsy moth defoliation of eastern hemlock, adjacent to oaks, was recorded, resulting in thinner crowns. Heavy precipitation and eastern hemlock recovery Crown assessments in 2017-2018 were completed for 13 S. tsugae forest sites in the 3 climate divisions of Connecticut. A wetter than normal spring in 2017 ended the extreme drought and hemlock crown ratings showed that some trees were able to respond quickly by producing new growth in many sites. Average foliage transparencies were improved in sites in climate divisions 2 and 3 and remained similar in climate division 1 after the wet spring of 2017. In 2018, 77% of S. tsugae sites remained in fair condition in spite of the extended drought and continue to recover, compared to 46% of sites in 2016-2017. Fresh hemlock borer activity from 2016-2017 ratings did not increase in 2017-2018 ratings, indicating that heavy precipitation may have mitigated the spread of this damaging native pest. In marginal highly stressed sites on rocky ridges, heavy hemlock borer outbreaks were recorded in 15% of all sites monitored in 2017-2018 (compared to 20% in 2016-2017) and 30% of sites had moderate to high hemlock borer activity in 2017-2018, a slight reduction from 33% of sites monitored in 2016-2017. Collection of tree core data with an increment borer was attempted in July 2018 with the help of a forestry student. The abnormally high rainfall of the summer of 2018 presented technical challenges to extraction of tree core samples and will be delayed until the winter of 2018-2019. Impact of elongate hemlock scale The main insect pest of Connecticut's hemlocks is now EHS, and not HWA. Consecutive extreme winters from 2014-2016 have killed off HWA on a large scale throughout Connecticut but assessments have shown that the scale is less susceptible to cold winters. EHS has continued to encroach on higher elevation hemlock stands in northwestern CT. Combined effects of extreme drought and heavy EHS infestations have resulted in rapid tree decline through heavy needle loss, resulting in thin hemlock crowns, native hemlock borer resurgence and tree mortality, especially in marginal sites on stressed ridge tops in the northern half of the state. An interesting consequence of the drought-exacerbated heavy needle drop, was the drop in EHS levels at some sites. In general, in wetter sites, the trees fared much better and had more healthy crowns. In 2017-2018 crown ratings, 46% of sites visited had light to negligible EHS levels on the new growth while 37% had medium to very high infestations of EHS, in northern sites. Goal 2) Improving Monitoring for S. tsugae Laboratory testing is planned for winter 2019 Goal 3) Assessments of Impact of S. tsugae Predation from Spring to Fall Impact: Results indicate that implementation of S. tsugae after severe winters to HWA populations may be a feasible and safe method of managing resurgent or new introductions or invasions of HWA. Predation impact of S. tsugae in field cages were previously assessed in 2016-2017. The data showed that S. tsugae is an efficient biological control agent capable of survival during increasingly hot and humid summers, with a sustained predatory impact on HWA from spring into fall. This species is readily available to the public from a commercial producer in Pennysylvania for biological control implementation and is a valuable and economical non-chemical option for managing a damaging tree pest. Field cage experiments to assess overwintering survival of S. tsugae in Connecticut and Maine, in cooperation with the Maine Forest Service and Tree-Savers of Pennsylvania are being planned for 2019.
Publications
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Progress 10/01/16 to 09/30/17
Outputs
Target Audience:Target audience included private citizens, homeowners, water company, landscape and forest managers, arborists, nurserymen, members of thescientific community which werereached throughscientific presentations at meetings, workshops, through press interviews, the distribution of posters, factsheets and publications and field visits. Many private citizen enquiries on managing HWA in urban landscapes have also been addressed through emails, phone calls and other outreach presentations. Field visits were also made to assess hemlock stands on state, town, and municipal water company, conservation, landtrust, open spaceorganizations,private and research forest properties to advise land and forest managers of stressors affecting hemlock health andappropriate management or remediation strategies. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided? Developed a working research partnership with the Director and commercial producer of S. tsugae, Jayme Boniewicz of Tree-Savers, LLC of Greentown, PA in whichS. tsugae have been provided for experiments,and for newbiological control implementations and assessments. On June 2, 2016, made a visit to Waymart, PA, to tour the insect rearing laboratory of Tree-Savers where S. tsugae isreared on a large scale for commercial use. In June 2017, Connecticut's biological control program for HWA was revived with the release of 2,000 beetles donated by Tree-Savers at new state, private and municipal forest sites of special interest for conservation, recreation and wildlife preservation. Thisexpansion of the HWA biological control program has enabled greater cooperation andinvolvement of many more stakeholder groups.In 2017,300-400 S. tsugae beetles per site were released to manage emerging HWA infestations at 7 new sites and augmentation at a 2016 site with the participation and assistance of volunteers from the public,state and private foresters, landmanagers fromstate, town, municipal, land trust and other private researchand conservation organizations. Hemlock sites helped were at the American Legion State Forest, the Pachaug State Forest,the Burlington State Fish Hatchery to protect trout production ponds,the Nassahegon State Forest,the Algonquin State Forest, Colebrook, near a designated wilderness area, at the Mine Hill Preserve, Roxbury Land Trust, an important historical site, at Webb Mountain Park, an important camping and recreation park of theTown of Monroe, and at the Great Mountain Forest, Canaan, one of the oldest forest conservation legacy organizations, with >6,000 acres in northwest Connecticut. All new sites will be used to monitor for S. tsugae establishment and impact on HWA in a changing climate. Continued with the third year of mentoring of University of Connecticut undergraduate Nicholas Russo, whose research has focused on understanding the potential avian dispersal of HWA crawlers, using the Valley Laboratory Research Farm as one of his experimental sites. This project is also a collaboration with Dr. Morgan Tingley, and Dr. Chris Elphick, Department of Ecology and Evolutionary Biology, University of Connecticut Presented findings on winter effects on HWA and efficacy ofS. tsugae as a biological control agentat the 2017 Winter Symposium and Expo of the Connecticut Nursery and Landscape Association, the 2017 North East Natural History Conference),the CAES Forest Health Monitoring Workshop,the Connecticut Association of Biology Teachers Conference, 47th Barkhamsted Earth Day Nature Festival, Gave 4 press interviews on the biological control program for HWA using S. tsugae Continuedfield visits to municipal water company landsto identify important and damaging hemlockpests Have expanded interactions and cooperative efforts to include land trusts, open space and other conservation organizations interested in hemlock preservation Gave research overviews toNGOs, and planned and implemented 2 citizen science programs in 2017 with interested stakeholders and volunteers to 1) document breeding bird diversity in S. tsugae release sites and other hemlock sites, and 2) to map the resurgenceand impactof the native hemlock borer, Melanophila fulvoguttata, in response to drought stressedhemlocks Consulted with professional biostatistian, Dr. Michael Wininger, from Yale University, for statistical advice on data analyses and future collaborations How have the results been disseminated to communities of interest?The results have been disseminated throughout the past year through scientific presentations at meetings, workshops, posters, factsheets and publications. Many private citizen enquiries on managing HWA in urban landscapes have also been addressed through emails, phone calls and other outreach such as the annual CAES Plant Science Day. Cheah 2017 publication on 15 years of HWA winter mortality was distributed to colleagues at universities, state and federal levels through the USDA Forest Service and through ResearchGate. Cheah 2016 Factsheet on "HWAWinter Mortality in Connecticut and Implications for Management and Control" was distributed to stakeholders andcooperators and the public via email, public outreach events, workshopsand field visits. Visited and assessed the condition of hemlock stands and the potential for hemlock recovery through management of HWA at Mine Hill, Roxbury Land Trust;the Hoffman Evergreen Preserve, Avalonia Land Conservancy; and Avery Farm of the Groton Open Space Association. What do you plan to do during the next reporting period to accomplish the goals?Outreach: Continue with more publications, presentations and workshops in 2018. A workshop at the 2018 Connecticut Land Conservation Council Conference will bepresented with Tree-Savers in March 2018 to educate land trusts withbiological control options for conservation of hemlock stands Data Collection: Continue with S. tsugae sitefield workto take tree core data, determine hemlock crown assessments and recovery potential after extreme and extended drought, soil type interactions, determine the interaction and effects of other primary and secondary pests of hemlock. Research field methods for attracting and monitoring S. tsugae in forest sites Laboratory research: Continue to rear and maintain S. tsugae colony at the Windsor Valley Laboratory for experiments on potential S. tsugae attractants. Investigate S. tsugae behavioral responses to artificial and plant volatiles. The goal is to identify potential mixtures of attractants that could be used to monitor S. tsugae activity and persistence in field situations Also continue to research possibility of using alternative prey and CC artificial diet for supplementing S. tsugae survival and reproductionin collaboration with Dr. Allen Cohen, Insect Rearing Education & Research Program, North Carolina State University
Impacts
What was accomplished under these goals?
Impact: Results indicate that S. tsugae is an efficient biological control agent capable of survival during increasingly hot summers, with a sustained predatory impact on HWA from spring into fall. This species is readily available to the public from a commercial producer in Pennysylvania for biological control implementation and is a valuable and economical non-chemical option for managing a damaging tree pest. S. tsugae is able to actively adapt to the changing climate in Connecticut and the Northeast and also overwintered successfully in 2016-2017. Goal 1) Improving Hemlock Crown Assessments The current status of eastern hemlock stands in Connecticut is being assessed after a hiatus of 8 years, in conjunction with climate monitoring, site characteristics and other insect and/or disease stressors for a more comprehensive and integrated approach. After 3 consecutive years (2014-2016) of heavy winter mortality of hemlock woolly adelgid (HWA) throughout Connecticut, populations of the adelgid are still at low and patchy levels in forest hemlocks in Connecticut forests, except for protected pockets which had more snow cover in 2017and some urban areas. However, the statewide severe to extreme drought, which has lasted between 11-22 months from 2016-2017, has resulted in great stress to moisture loving hemlocks, especially on marginal sites with poor soils. Hemlock crown assessments for the 2016-2017 growing season indicated that site type had a very pronounced effect. Annual hemlock health assessments of S. tsugae biological control release sites in Connecticut were initiated in the late summer and early fall 2016 and were completed in the late winter-early spring of 2017 before the 2017 season of new shoot production: •Crown assessments in 2016 -2017 showed that eastern hemlocks in some marginal release sites exhibited acute decline, especially on northeast and northwest ridges in spite of reduced HWA populations. This severe decline is attributed primarily to cumulative heavy infestations of another exotic pest, the elongate hemlock scale (EHS), Fiorinia externa, in either single or joint infestations with HWA, exacerbated by the concurrent extended extreme drought of 2016-2017. •Largely unaffected by recent severe winters, EHS has continued to encroach on higher elevation hemlock stands, especiallyin northwestern CT. Combined effects of extreme drought and heavy EHS infestations have resulted in rapid tree decline through heavy needle loss, resulting in thin hemlock crowns, native hemlock borer resurgence and tree mortality, especially in marginal sites on stressed ridge tops in the northern half of the state. An interesting consequence of the drought-exacerbated heavy needle drop, was the drop in EHS levels at some sites. In wetter sites, the trees fared much better and had more healthy crowns. •Hemlock crown health ratings were completed in the fall of 2016 into spring 2017 at 15 of Connecticut's S. tsugae release sites 10-20 years post release, and at 6 former baseline sites at high elevation which had previously had negligible adelgid and/or EHS infestations. HWA infestations throughout Connecticut in 2016-2017 continue to be at the lowest levels in 17 years, due to 3 years of heavy winter kill. Of the 15 S. tsugae release sites evaluated, 46% remained in fair to good condition in spite of the statewide drought. Hemlock decline exacerbated by severe drought impacts was recorded in 33% of sites, hemlock borer outbreaks at 20% of sites, all ridgetops, and detected in 33% of sites monitored. •However, the drought in Connecticut was officially ended in April 2017 and heavy rains and cool temperatures have favored dramatic hemlock refoliation and recovery statewide, which is currently being documented. •Concurrently, incidences of hemlock mortality due to the secondary native pest, the hemlock borer, Melanophila fulvoguttata, were recorded during site data collection. Hemlock borer tree mortality near trails statewide are being mapped with the help of volunteers from the public as a citizen science project. Hazard trees in recreation areas are being communicated to forest and park managers for removal for public safety. Goal 2) Improving Monitoring for S. tsugae The biological control of HWA program in Connecticut was revived in June 2017 after a lapse of 10 years, in cooperation with the only commercial producer of S. tsugae, Tree-Savers, LLC, of Greentown, PA. Two thousand S. tsugae adults were donated by Tree-Savers and released at 7 new sites in Connecticut and augmented at a 2016 new site with the assistance of state, municipal, and private foresters and volunteers. These new forest sites, currently in decline from drought and previous infestations of HWA and EHS, are in town, private conservation, land trust and state lands in areas of Connecticut which have not previously received S. tsugae. These new sites will be used for field research where trial attractants can be evaluated for monitoring S. tsugae establishment, for documenting potential recovery of damaged stands, predator impact on emerging HWA populations and winter survival in a changing climate. Goal 3) Assessments of Impact of S. tsugae Predation from Spring to Fall Predation of naturally occurring stages of HWA under field environmental temperatures was measured by following individual S. tsugae adult females and males in caged containersunder field conditionsin Windsor. •Assessments of the field efficacy of S. tsugae as a biological control agent documented many advantageous attributes in 2016-2017: Bivoltine S. tsugae are effective predators which target late sistens and resurgent summer progrediens HWA, and also uniquely feed on dormant HWA N1 settlers of the subsequent sistens generation during extreme heat. This results in a long season predation impact on HWA from spring to fall. •Mature S. tsugae adults consumed >1200 HWA sistens N1 each from July to late October 2016 in field experiments when summer temperatures routinely exceeded 30°C. Projected summer to fall predation of 5,000 adult S. tsugae = 6 million HWA. Surviving adults from the field sleeve cages similarly showed steady HWA predation into December 2016. This confirms the ability of this specialist ladybeetle to survive the extended hot summer and fall conditions by predating solely on dormant HWA nymphs, an attribute which is unique to this HWA predator species. Adults also started predation of fall-developing adelgid nymphs from September - December 2016, extending the impact of predation. •Survival over the winter outside was 61.5% with the minimum daily temperature from Dec 2016-March 2017 of -11.7 °C (10.9 °F) with greater female survival (75%) than males (40%). •Surviving females oviposited readily in the spring of 2017
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2016
Citation:
Russo, N. J., Cheah C.A. S-J, Tingley, M. W. 2016. Experimental Evidence for Branch-to-Bird Transfer as a Mechanism for Avian Dispersal of the Hemlock Woolly Adelgid (Hemiptera: Adelgidae) Environmental Entomology 45:1107-1114.
- Type:
Journal Articles
Status:
Published
Year Published:
2017
Citation:
Cheah, C.A.S.-J. 2017. Predicting winter mortality of hemlock woolly adelgid in Connecticut by climatic divisions. Northeastern Naturalist Volume 24, Special Issue 7, 2017: Winter Ecology: Insights from Biology and History, 2017 B90-118
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2017
Citation:
Cheah, C. 2017. Climate-Change Impacts in the Northeast on HWA and its Coccinellid Predator from Japan, Sasajiscymnus tsugae. Available online at: https://www.eaglehill.us/NENHC_2018/archives/NENHC2017-oral-abstracts.pdf
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2017
Citation:
Russo, N.J., Cheah, C.A. S-J., Elphick, C.S.and Tingley, M. W. 2017. Avian Spring Migration as a Dispersal Mechanism for an Invasive Insect Pest. Abstract for an oral presentation at the 2017 Northeast Natural History Conference, 2223 April 2017, Cromwell, CT Available online at: https://www.eaglehill.us/NENHC_2018/archives/NENHC2017-oral-abstracts.pdf
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Progress 10/01/15 to 09/30/16
Outputs
Target Audience: Results from this multi-faceted approach are increasing understanding of the complex environmental and ecological interactions influencing hemlock forest impacts fromhemlock woolly adelgid (HWA) in Connecticut and the implications for the long term efficacy of HWA biological control usingthe adelgid predator,Sasajiscymnus tsugae.Recent analyses has clarified the role of winters on HWA abundance and spread, and provided management recommendations on the urban landscape level.In 2016,the results of analyses of 16 years of data gathered onHWA winter mortality trendsin Connecticutwerecommunicated to private citizens, homeowners, water company, landscape and forest managers, arborists and nurserymen for HWA management strategies in a Connecticut Agricultural Experiment Station factsheet entitled: "HWA Winter Mortalityin Connecticut andImplcations for Management and Control". This factsheet was widely distributed in 2016 through emails, links and papercopiesat various meetings. It is available online at: http://www.ct.gov/caes/lib/caes/documents/publications/fact_sheets/plant_pathology_and_ecology/hemlock_woolly_adelgid_winter_mortality__7.12.16.pdf Outreach on biocontrol of HWA with S. tsugae was continued via a workshop to increase awareness of this strategy in April 2016at theNortheastNatural History Conference in Springfield, Massachusetts, in collaboration with the only commercial producer of S. tsugae, Tree Savers in Pennsylvania, and the Carolina Land Conservancy. The workshoppresented methods of implementation and successful resultsof hemlock recovery from theimplementation of S. tsugae in small scale releases inNorth Carolinaand Pennsylvania to manage HWA. Further outreach to regional arborists and landscapers duringthe July 2016summer meeting of the Connecticut Tree Protective Association,resultedinasummer release of S. tsugae at a town park campground, Webb Mountain Park,in the south western Connecticut town of Monroe. In furthercollaboration withTree-Savers,this biocontrolmanagement strategywas communicated through information displays at the CAES Plant Science Day in August 2016. This outreach has also informed the public of the commercial availability of this biological control agent for HWA as an alternative to the use of chemical controls. Changes/Problems:Extreme reduction and statewide scarcity offield populations of HWA in Connecticut following the highest winter mortality of HWA recorded during the winter of 2016, have presented challenges to laboratory rearing of S. tsugae in 2016. A healthy and thriving colony of S. tsugae is critical to obtaining sufficient subjects for volatile experiments. What opportunities for training and professional development has the project provided? Gave an update on the effects of severe winters on elongate hemlock scale and hemlock woolly adelgid in Connecticut to federal and state cooperators at the NY/NE 2015 Forest Health Cooperators Meeting held at the Valley Laboratory, Windsorin October 2015 Gave a presentation on predicting hemlock woolly adelgid winter mortality in Connecticut at the annual Forest Health Monitoring Workshop to Connecticut foresters in March 2016 Attended and presented on HWA winter mortality during the Winter Ecology session of the Northeast Natural History Conference at Springfield, MA inApril 2016 . Gave a tour and explained methods of small scale rearing of S. tsugae at the CAES Valley Laboratory to members of Tree-Savers, PAand the Carolina Land Conservancy, April 2016 Attended and presentedexhibits on biological control of HWA at the annual summer meeting of the Connecticut Tree Protective Association, the annual field research day of the CAES at Plant Science Day in August 2016, and the Nursery and Landscape Tour of the CAES Valley Laboratory in Spetember 2016. How have the results been disseminated to communities of interest?The results have been disseminated throughout the past year through scientific presentations at meetings, workshops, posters, factsheets and publications, as listed above. Many private citizen enquiries onmanaging HWA in urban landscapes have also been addressed through emails, phone calls and other presentations. What do you plan to do during the next reporting period to accomplish the goals?Outreach: Continue with more publications, presentations and workshops in 2017. Data Collection: Continue with S. tsugae site visits to determine hemlock health,crown assessments, soil types. interactions with other primary and secondary pests of hemlock Laboratory research: Continue to rear and maintain S. tsugae colony at the Windsor ValleyLaboratory forexperimental behavioral investigations of responses to volatiles. The goal is to identify potential mixtures of attractants that could be used to monitor S. tsugae activity and persistencein field situations. Also continue to research possibility of using alternative preyandCCartificial diet for supplementing S. tsugae survival and reproduction.
Impacts
What was accomplished under these goals?
Goal 1)Improving Hemlock Crown Assessments Assessments of HWA winter population mortality in 22 Connecticutsites were also conducted in the early spring of 2016 following a brief andextreme cold snap in mid February 2016. Results showed that2016 winter mortality was the highest statewide at 97% since the assessments were initiated in 2000. As a result, forest hemlocks visually showed remarkable recovery in spring 2016 but have since been compromised by an extreme to severe extended summer drought. Annual hemlock health assessments of HWA biological control release sitesin Connecticut wereinitiated in the late summer and early fall2016 and initial results indicate moderate to heavy needle loss from dessication, possibly exacerbated by previous heavy infestations of another exotic pest, the elongate hemlock scale. Goal 2) Improving Monitoring for S. tsugae Initial experiments were performed side by side to assess for any preferential attractiveness of southern Japanese hemlock seedlings(Tsuga sieboldii).There does not appear to be any. Initial behavioral group responses to myrcene were also investigated in small cages and are inconclusive at this stage. Goal 3) Assessments of Impact of S. tsugae Predation from Spring to Fall Assessments of impact of S. tsugae predation from spring to fall in 2016 wereconducted at field temperatures at three sites in Connecticut. S. tsugae predation and reproduction were recorded on the late spring-summer progrediens generation at field temperatures in late June and July 2016,which confirmed thesecond field generation of predators. Further predation impacton the aestivating sistens generation of first instar nymphs from July-September 2016 was recorded at field temperatures.This indicated that S. tsugae was able to survive and continue continous predation on HWA during the hottest summer on record, a considerable advantage over other HWA predator species. Sleeve cages were also used to measure the impact in the field of S. tsugae paris and groupsof males and females. Surviving adults from the field were also assessed for predatory impacts on HWA first instar nymphs throughout September2016 at field temperatures and showed steady predationthroughout. This confirms the ability of this specialistladybeetle to survive the extendedand extremehot summer conditions by predating solely on dormant HWA nymphs, an attribute which is unique to this species of HWA predator.
Publications
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2016
Citation:
Cheah, C.A.S-J. 2016. Predicting Winter Mortality of Hemlock Woolly Adelgid in Connecticut
Oral presentation at the 2016 Northeast Natural History Conference
Sat. April 23 Sun. April 24, 2016 Springfield, MA
Available online at:
https://www.eaglehill.us/NENHC_2017/archives/NENHC2016-oral-abstracts.pdf
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Progress 08/14/15 to 09/30/15
Outputs
Target Audience:Communicated the goals and project objectives,provided information on hemlock woolly adelgid biological control optionsto state, private and municipal foresters, natural resource managers, conservation groups, townparks and recreation managers, private property owners through posters and email commuications. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?The P.D. is currently learning the techniques for tree coring and GIS mapping. How have the results been disseminated to communities of interest?
Nothing Reported
What do you plan to do during the next reporting period to accomplish the goals?1) Currently mass rearing the laboratory colony of S. tsugae over the fall into winter 2016 to rebuildpopulations for winter laboratory testing of more volatiles as potential attractants and for spring predation experiments in 2016. 2) Preparation of a publicationon theeffects of winters in Connecticut on HWA populations 3) Field assessments of hemlock health at selected S. tsugae release sites during the winter
Impacts
What was accomplished under these goals?
Field visits to relocate and gather preliminary data on S. tsugae release sites, former non-release matching sites and baseline uninfested siteswere initiated in late summer 2015. Estimates of tree mortality of monitored hemlockssince 2009 were made in 3 S. tsugaerelease sites.Two non-release hemlock matching sites were also relocated and GPS coordinates recorded. Additional scouting was also performed on municipal watershed forests in northern Connecticut toinspect forhemlock woolly adelgidand/or elongate hemlock scale damage to eastern hemlocks.
Publications
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