Early Response (2018–2020) to the Threat of Spotted Lanternfly, Lycorma delicatula (Hemiptera: Fulgoridae) in Pennsylvania

Abstract

Spotted lanternfly (SLF), Lycorma delicatula (Hemiptera: Fulgoridae) is an invasive planthopper first detected in the United States in one county in Pennsylvania in September 2014. As of October 2020, 43 counties in nine states are under quarantine due to the presence of SLF in those areas, and it has been detected in 10 additional states. The greatest economic impacts from SLF have been reported from grape growers, nurseries, and Christmas tree growers, and it is considered a nuisance pest by residents. Because this insect feeds on over 70 species of herbaceous and woody trees and plants, it has the potential to cause wide ranging damage across agricultural, urban, suburban, and forested landscapes. Due to these widespread impacts, SLF management has demanded cooperation at local, state, regional, and national levels. However, the immediate response to the threat of SLF in Pennsylvania during the early phases of the infestation was a catalyst for initiating these efforts, and this response was coordinated via a partnership between the Pennsylvania Department of Agriculture, the U.S. Department of Agriculture Animal and Plant Health Inspection Service, and the Pennsylvania State University College of Agricultural Sciences. The history of SLF in the United States is recounted, highlighting the early priorities that emerged. The resulting actions taken in 2018–2020 in response to these priorities, which involved research, Extension, and public awareness are summarized, and areas in which improvements are needed that have been identified are discussed.

On 22 September 2014, a Pennsylvania Game Commission Wildlife Education Specialist reported high numbers of an unusual insect on tree-of-heaven (Ailanthus altissima (Miller) (Sapindales: Simaroubaceae)) in Berks County in eastern Pennsylvania. Pennsylvania Department of Agriculture (PDA) entomologists collected more than 100 specimens on the same day, and identified this insect as Lycorma delicatula (White) (Hemiptera: Fulgoridae) (Barringer et al. 2015). This was the first record of this invasive planthopper, now commonly referred to as the spotted lanternfly (SLF), in the United States. SLF is native to China, Vietnam, Japan, and India (Distant 1906, Dara et al. 2015, Bourgoin 2019) (although its occurrence in India is uncertain; Distant 1906); it is suspected to have been transported from its native range as egg masses to the United States on a shipment of stone (Parra et al. 2018). SLF had previously invaded South Korea in 2004 and was reported to damage grape, apple, and stone fruit, and be a nuisance pest in residential areas (Han et al. 2008, Park et al. 2009).

Because of its known pest status in South Korea, once PDA and USDA verified its identification, both agencies were quick to act on this pest. While these two agencies immediately attempted to knock down the SLF population, a more important and essential action was to establish a series of cooperative efforts aimed at controlling SLF. PDA initially focused on conducting surveys, implementing control tactics, implementing regulations to contain the insect, and prevent or minimize its potential movement, and providing scientific expertise. USDA-APHIS focused on providing a structure for and leading cooperative efforts to bring together experts and allow integration of scientific information. This agency also focused on providing a conduit for funding to support control, survey, and research activities.

The effective management and mitigation of any invasive species require cooperation among agencies and a basic understanding of the pest's biology. The threat from SLF in particular, demanded cooperation for its control, due to several aspects of its biology and impacts. These are summarized as follows:

SLF feeds on over 70 different species of trees and plants (Dara et al. 2015), and its preferences are relative to what plants are available at a given time and within a given area. Because of this behavior, as SLF expands into new areas, it has the potential to incur new impacts (e.g., feed on new hosts or more heavily feed on more commonly available hosts), possibly exerting economic damage to new sectors.

Very little was known about the SLF's biology and management. As a pest, it is very unusual for its feeding guild. That is, while many other sap-feeding insects similarly feed upon a broad range of hosts, SLF is unusual in that it feeds upon herbaceous plants (primarily as nymphs) as well as woody plants and trees (as later instars and adults) cutting across many plant families (Urban 2020). As a result of this feeding habit, SLF moves across multiple habitats and impacts hosts in extremely diverse landscapes (agricultural, suburban, urban, managed, and natural forested areas).

SLF causes economic damage to key commodities via direct (feeding) and indirect (e.g., sooty mold growth on honeydew, substrates for egg deposition and subsequent movement) damage and also acts as a nuisance pest, particularly in residential and commercial areas. It is a relatively large insect and it aggregates in extremely high numbers making it highly visible leading to public concern and often fear or disgust.

SLF expands its range quickly, especially into new, disjunct areas that can be significant distances apart. What drives dispersal and how far the insect is capable of moving within a generation through natural dispersal mechanisms is not yet fully understood. Evidence suggests that long distance transport is primarily human-assisted because of the insect's behavior of laying eggs on living and nonliving substrates, crawling onto vehicles or materials that are being moved during the nymph stage, and flying or crawling onto vehicles and materials during the adult stage.

Because of SLF's broad host range, and the large variety of goods and vehicles upon which all life stages may hitchhike, containment of this insect demands coordination among a multitude of stakeholders in a wide variety of sectors.

Despite the initial cooperation across groups and all the efforts to contain and manage the pest, SLF has continued to spread (Fig. 1), necessitating the need to further expand upon the scope and composition of the cooperative groups required to deal with the expanding threats. Although such efforts are presently ongoing, the immediate response to the threat of SLF in Pennsylvania after the population significantly expanded in 2017 was important in initiating these subsequent efforts. To provide insights to potentially improve current efforts to manage and slow the spread of SLF within the United States, examination of this phase, from 2018 to 2020, is the focus of this current summary.

Timeline of SLF and Emergent Early Priorities

Immediately after USDA verified that the specimens collected by PDA entomologists were L. delicatula, the USDA formed a New Pest Advisory Group (NPAG) (Cooperband et al. 2015) for this species, and by November 2014 they had also issued a Pest Alert for SLF. PDA also immediately conducted delimitation surveys to determine the area under infestation from SLF. These surveys found SLF to be limited to a two square mile area (Parra et al. 2018) in six townships in Berks County in eastern Pennsylvania: Pike, Rockland, District, Earl, Washington, and Hereford (Barringer et al. 2015). In the fall of 2014, PDA established a Spotted Lanternfly Order of Quarantine (https://www.agriculture.pa.gov/Plants_Land_Water/PlantIndustry/Entomology/spotted_lanternfly/quarantine/Documents/SLF%20Q%20Order%205–2018.pdf) in these six townships (Fig. 2). In addition to publishing their own pest alert, PDA also established phone and e-mail reporting hotlines for SLF.

During 2015, PDA's mitigation efforts focused on removal of A. altissima, and establishment of remaining A. altissima trees in an infested area as trap trees. The trap trees were treated with the neonicotinoid dinotefuran (via injection or bark spray), which acts as a systemic insecticide and kills SLF that subsequently feed upon tissues within the tree. PDA also engaged in egg scraping, and trapping SLF via sticky tree bands and active SLF capture, and created a program to engage volunteers in these same activities (Spichiger 2016). Based on surveys conducted by PDA in 2015, SLF was detected in nine additional townships, and the quarantine was expanded into these areas (Fig. 2). As a result, the quarantine included townships in four counties: Berks, Bucks, Chester, and Montgomery.

In 2016, PDA continued conducting surveys and continued control efforts focused on A. altissima removal and establishment of trap trees, egg scraping, tree bands, and live capture. SLF was detected in new areas and the quarantine zone was expanded to include these areas, which encompassed 74 municipalities in six counties: Berks, Bucks, Chester, Montgomery, Lehigh, and Northampton. At the January 2017 meeting of the USDA Interagency Forum on Invasive Species, PDA reported that property management (i.e., A. altissima removal and treating of trap trees) lagged behind the spread of the pest (Spichiger 2017).

In 2017, a number of observations made throughout the year suggested that the SLF population had significantly increased in size and potential threat. For example, in early September, researchers observed and recorded video of SLF flying in high numbers, and feeding at extremely high densities on grapevine, apple, and silver maple (Figs. 3–5). SLF feeding on apple and stonefruit trees was observed at several other sites that year, and represented the first observations of the insect feeding on these commodities in the United States. In 2017, SLF continued its expansion into new areas. In November, the quarantine zone had expanded to include 13 counties: Berks, Bucks, Carbon, Chester, Delaware, Lancaster, Lebanon, Lehigh, Monroe, Montgomery, Northampton, Philadelphia, and Schuylkill. PDA surveys determined that SLF was present on 1,685 properties (Parra et al. 2018).

On 18 October 2017, a joint hearing of the Pennsylvania Senate and House Agriculture and Rural Affairs Committee was held to publicly discuss SLF. Testimony was given by PDA, Penn State research and Extension, and county administrators and fruit and wine growers from the SLF quarantine zone (http://agriculture.pasenategop.com/101817/). Testimony from the owners of an affected winery and grape/tree fruit orchard described an almost 90% loss in grape tonnage and a corresponding loss in fruit quality which was valued at one farm at $400,000 despite several pesticide applications (by 2019, this vineyard showed complete loss of productivity, Fig. 6). They testified that they needed all possible help in the form of pesticide recommendations and research for biological control options in order for them to remain in business in the coming years due to SLF. Although research was underway seeking biological control options (e.g., Liu and Mottern 2017, Xin et al. 2021), sufficient research had not been undertaken to inform pesticide control recommendations.

To this point, PDA had been leading efforts to inform the public about SLF. Due to the increasing demand from the public for information about SLF (e.g., as evidenced by increasing numbers of calls to the PDA SLF reporting hotline), in late 2017 PDA allocated funding to Penn State in order for Penn State to hire an Extension associate solely dedicated to SLF. It also led to the creation of a partnership between USDA, PDA, and Penn State's College of Agricultural Sciences that involved creation of a Core SLF Response Team in Pennsylvania. The Extension and public awareness campaign undertaken by Penn State as part of this team were subsequently funded by USDA under Farm Bill Plant Protection Act Section 7721, which has to date included continued funding for the Penn State SLF Extension associate position.

Taken together, the events of 2017 informed the priorities that emerged in 2018, which were to: 1) perform the research needed to inform effective management techniques of SLF in impacted communities/stakeholder groups, particularly to inform pesticide recommendations, 2) deliver research-based information for SLF management to impacted stakeholder groups, and 3) develop a public awareness campaign to stop or slow the spread of SLF, including facilitating public and industry compliance with quarantine regulations. Although the second and third priorities both involve communicating information about SLF to public audiences, the second priority, of delivering research-based information to impacted stakeholder groups is a more sustained and involved educational service and therefore considered here as Extension, whereas public awareness is of shorter duration and more limited content. The following sections detail actions taken within Pennsylvania in each of these priority areas.

Research Response

In order to provide research-based recommendations for management of SLF, the primary research priority was to determine the efficacy of available pesticides against the various life stages of this pest. Therefore, in 2018 the efficacy of five ovicides was tested on SLF egg masses in laboratory and field trials, and the efficacy of 20 insecticides available for use on fruit trees and grape was tested on SLF nymphs and adults. Additionally, the efficacy of 13 pesticides available for homeowner and residential use was tested. Results of these insecticide efficacy trials were used as the basis for successfully obtaining 2 (ee) label amendments for each of 15 insecticides that added SLF to the list of pests controlled.

To date, research continues to be conducted at Penn State and USDA-APHIS on the efficacy of various ovicidal compounds (primarily oils) to treat SLF egg masses on products such as nursery stock, Christmas trees, etc. to reduce the risk of spread of SLF to new areas. Research was also needed to determine the efficacy and timing of various treatments on SLF nymphs and adults for use on ornamental trees. These research studies represent a particular challenge for several reasons: 1) ideally (to be generalizable to the size of trees SLF typically feed upon), they should be performed on mature trees (Urban 2020), 2) the timing and dosage of the treatment, particularly of systemic compounds, could potentially negatively impact nontarget arthropods (e.g., carry-over to the year following treatment could kill pollinators if there were residual systemic present in pollen and or nectar) (Blacquière et al. 2012), 3) the uptake and efficacy of treatments, particularly systemic compounds, depends upon the timing of the treatment as it relates to the metabolic activity of the tree when it is treated (Lewis 2020). To help achieve the needed research findings, Penn State Extension hired an experienced landscaping professional in 2019 to lead these studies and this work is currently underway.

Because of SLF's broad host range, particularly during earlier life stages, it became apparent that a management strategy that focused only on treating individual trees (i.e., specific A. altissima trees known to be infested by SLF during some of the insect's life cycle) might be somewhat limited. Therefore, there arose a need to focus research efforts on determining the efficacy of area-wide insecticide applications (i.e., treating all trees or foliage in a given area) against SLF, and to identify effective compounds that also have limited negative impacts on nontarget arthropods. One study performed to date found that area-wide application of a commercialized strain of the entomopathogen Beauveria bassiana was effective in suppressing populations of SLF adults in a particular area (Clifton et al. 2020). However, additional work continues to more rigorously examine the efficacy of area-wide applications of B. bassiana, as well as that of other insecticides.

Extension Response

Prior to 2018, only the two Penn State Extension educators serving the counties in eastern Pennsylvania impacted by this pest were involved in educating residents and impacted industries about SLF. However, Extension activity significantly increased in 2018 with the hiring of an Extension associate solely dedicated to SLF. The associate led the development of key factsheets and brochures on SLF management for multiple stakeholder groups (see Table 1), including those developed directly from the insecticide efficacy studies described above (i.e., ‘Spotted Lanternfly Management in Vineyards’ and ‘Spotted Lanternfly Management for Residents’). The associate coordinated with and trained other personnel (Extension Educators, Master Gardener Coordinators, Master Gardeners, Extension Faculty) to communicate a consistent message on SLF, and also created PowerPoint slides and other presentation tools for use in public meetings for SLF education. The associate continuously updated the Penn State SLF Extension website as new information became available. In 2018, Penn State Extension established an SLF call center, staffed with operators to respond to public calls received on the Penn State Extension SLF hotline. The associate led the writing and updating of the script used by call center staff and volunteers to provide consistent answers to questions on SLF.

Unfortunately, output metrics are not available prior to 2018; however, the output for these activities accomplished in 2018–2020 are summarized in Fig. 7 which shows the number of presentations made and audience size, and the stakeholder groups which received SLF presentations. Table 1 summarizes the materials distributed, as well as page views to the Penn State SLF Extension website, call center calls received and responded to, and enrollment in the SLF Permits Course (described below in Public Awareness Response).

Public Awareness Response

Penn State Extension, PDA, and USDA-APHIS worked collaboratively to develop and implement a coordinated SLF communications and marketing strategy to increase public awareness. These agencies defined distinct and complementary messaging roles to be played by each agency: Penn State Extension's main messaging focused on awareness and education, PDA managed regulatory messaging with some awareness messaging, and USDA-APHIS focused on multi-state awareness messaging. All three agencies agreed to promote the Penn State Extension SLF website and the Penn State Extension SLF hotline as the source for consistent and up-to-date research and management information in each agency's respective communications and marketing activities. The Penn State Extension SLF website includes links to PDA and USDA-APHIS websites, as well as an online reporting form for the public to report the location of SLF sightings directly to PDA. To ensure messaging was consistent with the three organization's missions and goals, all marketing materials and joint communications pieces were vetted through each organization for final approval. To demonstrate a united front in battling this pest, marketing materials were co-branded with logos from each partner organization.

Within Pennsylvania, the goal of the communications and marketing strategy was to increase awareness of the threat of SLF to Pennsylvania's economy and environment. Integral to this plan was developing and targeting messaging to a variety of audiences with specific calls to action. Key messages focused on increasing awareness, helping to stop the spread of SLF outside the quarantine zone to other areas of Pennsylvania and beyond, and controlling SLF on home and business properties.

The statewide awareness messaging had multiple components. One aspect focused on raising awareness of the threat of this pest with the calls to action to spot, destroy, and report SLF sightings online through the Penn State Extension SLF website which links directly to PDA's online report form. Another component of the messaging centers on building awareness of PDA's business permitting. As part of this effort, Penn Stated Extension worked to amplify PDA's business permitting message by encouraging businesses operating in the quarantine zone to take the PDA training to receive a permit to move equipment and goods within and out of the quarantine zone. And with hundreds of Penn State employees traveling daily to and from the quarantine zone, a special communications effort was launched to promote the required permit training for faculty and staff within Penn State. Numbers enrolled in the Permits Course in 2018 and 2019 are summarized in Table 1 (enrollment number was not available for 2020, although it is known that enrollment dropped off markedly due to business shut-downs associated with the Covid-19 pandemic).

Several other messaging campaigns were directed at slowing the spread of SLF throughout Pennsylvania and beyond. The call to action for this messaging was to ‘look before you leave’ by checking personal vehicles and outdoor equipment and destroying any SLF found before traveling. Additionally, the college worked with multiple Penn State constituent groups to share the ‘stop the spread’ of the SLF message. With thousands of students, families, football fans, concert goers coming to Penn State's University Park campus throughout the year, it was imperative to make sure those visitors were not transporting SLF. Working with the alumni association, admissions, athletics, and the Penn State concert venue, steps for helping to stop the spread of SLF were communicated through various websites, e-newsletters, targeted emails, and social media.

Inside the quarantined counties, the Penn State Extension shared additional messages on SLF management options with recommendations on the use of traps or insecticides. As with other marketing messages, the calls to action were to visit the Extension SLF website for more information or to call the Extension SLF hotline. The high volume of page views reported in Table 1, particularly during the most intensive marketing campaigns (1 July 2019–30 November 2019) indicates strong usage and positive user experience. Pageviews of the SLF landing page during the same time period increased by 110% over the previous year. Much of this increase was driven by the marketing and communications efforts that directed visitors to the website. Further analysis indicates that the bounce rate (the single-page sessions divided by all sessions, or the percentage of all sessions on a site in which users viewed only a single page and left the site) was 30.6% for the entire site. This value is in the excellent range for industry standards, where 40–60% is the rough average for content sites (Longstreet 2020). On pages where the bounce rate was above industry standards (i.e., the reporting of SLF sightings page), we determined that behavior was expected, as once the users determined the life stage of the pest, they left the site and clicked through to PDA's reporting page.

A report from the media distribution and monitoring platform Meltwater for the 2020 SLF season's communications efforts indicates there were 700 media mentions of Penn State College of Agricultural Sciences and Extension, with a potential audience reach of 315M with an ad value equivalence (an estimate of what it would have cost to place an advertisement with comparable exposure) of $2.9M. The mentions represent every time the College of Agricultural Sciences or Penn State Extension is referenced by online publications (e.g., PennLive.com, the news source for the capital region, Harrisburg, PA).

Research findings were consistently shared with the public and businesses as part of the marketing and communications strategy. The communications and marketing team took the perspective that keeping a message of progress works to allay the frustrations and panic of those managing this pest on their home or business properties. Included in this messaging always was the need for continued research and funding.

A strategic mix of communications and marketing efforts were targeted by audience and location, specifically within and outside of the quarantine zone, as well as by a calendar year of messaging based on the SLF life cycle and management options. Penn State Extension coordinated efforts with USDA and PDA, as well as other partners including the Pennsylvania Department of Conservation and Natural Resources, the Pennsylvania Turnpike, and the Pennsylvania Department of Transportation to amplify this messaging (A description of the communications and marketing tactics employed in this effort is provided in Supp Table 1 [online only]).

Needed Improvements in the Research Response

The insecticide trials on SLF reported in Leach et al. (2019) allowed SLF to be added to the list of pests controlled for each of 15 insecticides. As such, these compounds now labeled for use on SLF provide other states and regions of the United States with immediate tools they can use against SLF as soon as a new infestation is detected. However, the immediate priority for insecticide research was to provide recommendations to grape and tree fruit growers, and to homeowners, as these were the stakeholders who directly communicated research needs in the joint public hearing of the Pennsylvania Senate and House Agriculture and Rural Affairs Committee in 2017.

However, there remain additional high priority research needs for insecticide and other management recommendations, specifically for Green Industry nurseries and landscape professionals. Although research on the efficacy of treatments for use by nurseries and landscape professionals began in 2019 (and efficacy of ovicides has continued to be actively researched from 2018 to the present), these stakeholder groups have been particularly hard hit economically by SLF. Based on the results of a 2019 nursery grower survey (Walsh & Leach unpublished), they also need management recommendations that inform them on how to comply with quarantine phytosanitary requirements.

As previously described in the Research Response above, research-based recommendations are lacking for use on ornamental trees and plants by landscaping professionals. Ornamentals insecticide efficacy trials conducted in residential suburban housing developments and other suburban areas in late 2018, and in 2019 and 2020, have demonstrated the importance of ornamental trees (primarily red and silver maple) in landscaped urban and suburban environments as sites of late season SLF feeding (beginning in early to mid-September) and egg deposition (Keller et al. 2020, Mason et al. 2020). Research-based recommendations for treating trees in landscaped settings seem essential not only for impacted nurseries and landscapers, but also critical to reducing SLF populations during a time frame when they are forming large aggregations, and in habitats that likely serve as important corridors through which SLF may spread to new areas.

Because SLF feeds on a broad range of hosts, and as a result, tends to be diffusely or patchily distributed throughout any given habitat, particularly in the earlier life stages, effective area-wide insecticide applications are needed to improve mitigation of SLF, especially in satellite populations in newly infested areas. Although limited research has been performed exploring the efficacy of area-wide application of B. bassiana (Clifton et al. 2020), which was shown to have limited negative impacts on non-target arthropods, this compound is not as immediately effective at knocking down SLF populations as pyrethroid or neonicotinoid compounds (Keller et al., in preparation). Therefore research is needed, and is currently underway, to identify insecticides that can be effectively applied via aerial or ground-based methods to suppress SLF with minimal detrimental effects to non-target organisms. Although additional research is needed to identify more sustainable management of SLF in the longer term (i.e., using biological control methods, behavioral interruption, various ‘-omics’ methods, etc.), this work is presently underway in the context of a regional USDA NIFA funded Specialty Crops Research Initiative Coordinated Agricultural Project, whose scope extends beyond the early response time frame covered in the present discussion.

Needed Improvements in the Extension Response

As shown in Fig. 7, number of presentations and audience size for SLF presentations increased from 2018 to 2019. Despite most events being virtual in 2020, the number of presentations and audience size were near the mean of those values observed in 2018 and 2019. Concerning stakeholder groups receiving these presentations, the proportion of Green Industry members and growers in attendance increased in 2019 and 2020 compared to 2018, although the largest stakeholder group in attendance was consistently the general public. The Extension response has been extensive for SLF in terms of the number and array of factsheets developed and distributed, particularly in 2018 and 2019. Achieving the high numbers of materials distributed (over 400,000 in each of the first two years) were due in part to the opportunity for SLF materials to be distributed at two large events: the Pennsylvania Farm Show (attendance estimates for 2018 and 2019 were over 500,000 visitors for each year) and Penn State's Ag Progress Days (estimated attendance for 2018 was 42,000, and for 2019 was 46,000). In 2020, materials distributed was markedly lower because SLF presentations and meetings were all virtual beginning in March, and Ag Progress Days were also virtual in 2020. Page views to the Penn State SLF Extension website more than doubled from 2018 to 2019, and increased even more in 2020. This is likely in part due to the spread of SLF into more areas and areas of high human population densities (e.g., Philadelphia) as well as the extensive Public Awareness campaign. Calls to the call center also increased across each year, likely due to these same reasons. The number enrolled in the SLF Permits Course increased substantially in 2019 from 2018, likely also due to increased public awareness. Enrollment dropped off in 2020 (although numbers were not available) presumably due to the shut-down of businesses and stay at home restrictions due to the Covid-19 pandemic.

Missing from the Extension response are evaluations concerning the extent to which activities and materials changed stakeholder behavior or attitudes, or resulted in the implementation of proposed management recommendations. Additional surveys of impacted growers and other stakeholder groups (e.g., nursery growers, Christmas tree growers) are planned and in some cases, instruments are being developed. However, future work will follow examples set by other invasive pest management projects (e.g., Ludwick et al. 2020) and will include conducting assessments of insecticide costs for impacted stakeholders, management costs for impacted stakeholders, nuisance surveys for homeowners, and other metrics allowing for estimation of the utility and value brought by Extension activities that are developed as needed.

Needed Improvements in the Public Awareness Response

During the course of the implementation of the public awareness response, several unanticipated issues arose that needed to be addressed by the campaign. For example, public concern was expressed for SLF egg masses laid on Christmas trees, by-catch of vertebrates and other nontarget animals on sticky band traps, expansion of the quarantine zone, etc. This required the communications and marketing teams of Penn State Extension, PDA, and USDA to develop an agreed upon set of talking points to field media and general public questions. Each set of talking points were widely distributed throughout all three organizations in order to ensure accuracy and consistency of messaging.

During the course of the public awareness campaign from 2018 to 2020, members of the communications and marketing team also recognized the need to refine messaging. For example, in areas of the quarantine zone in which SLF populations are very high, there were reports (e.g., calls to the call center or postings on social media) of people taking extreme and unsafe measures to eradicate the insect (e.g., using butane torches or other methods to burn SLF on infested trees). In response, the messaging was adjusted to avoid or reduce panic and extreme behavior in the general public. Additionally, messaging was also adjusted with respect to reporting a spotting (detection) of SLF. As the number of reports grew, PDA resources were stretched in terms of their capability to follow up with each report as appropriate, particularly within the quarantine zone, where high populations of SLF were known to be present. Messaging was changed based on the type of response that could be expected based on the location of the report, either inside or outside the quarantine zone. This messaging was agreed upon across all three organizations and shared directly with reporting individuals, and was used in news stories produced by Penn State.

The high traffic reported for the Penn State SLF Extension website, and the other output metrics reported for the outreach response demonstrate that the public awareness campaign was very effective in terms of numbers of individuals reached. However, missing from the public awareness response (as with the outreach response) was an evaluation dimension to estimate the extent to which increased public awareness was effective in changing behavior or attitudes. As previously described for Extension, these evaluation methods will be developed and implemented moving forward.

Acknowledgments

This work was funded by United States Department of Agriculture Animal and Plant Health Inspection Service Plant Protection and Quarantine under Cooperative Agreements AP18PPQS&T00C221, AP18PPQFO000C332, AP19PPQFO000C369, and AP20PPQFO000C470; the Pennsylvania Department of Agriculture under agreement 44144949; United States Department of Agriculture National Institute of Food and Agriculture Specialty Crop Research Initiative Coordinated Agricultural Project Award 2019-51181-30014; and Hatch funding [1004464] from the United States Department of Agriculture National Institute of Food and Agriculture. We wish to thank Brian Walsh, Penn State Extension, and Heather Leach, Penn State Entomology, for sharing their observations and preliminary findings that have contributed to this manuscript.

References Cited