Emerald Ash Borer: Research and Technology Development Meeting

From: V. Mastro and R. Reardon (compilers), Emerald Ash Borer Research and Technology Development Meeting, Romulus, Michigan, Oct 5-6, 2004. USDA Forest Service publication FHTET-2004-15.

Progress on Remote Sensing Applications for an Emerald Ash Borer Survey in 2004

David Williams1, David Bartels2, Alan Sawyer1 and Victor Mastro1

1USDA, APHIS, PPQ, Pest Survey, Detection & Exclusion Laboratory, Building 1398, W. Truck Road, Otis ANGB, MA 02542
2 USDA, APHIS, PPQ, Pest Detection, Diagnostic & Management Laboratory, Moore Air Base, Building 6414, 22675 North Moorefield Road, Edinburg, TX 78541-9398

We have made considerable progress in remote sensing surveys for emerald ash borer (EAB) survey in our second season (Summer 2004). We continue to pursue two nested objectives: to develop maps of the distribution of ash trees over areas potentially infested by EAB and, further, to develop maps of the distribution of EAB-infested trees that include multiple levels of decline. Our primary remote sensing approach continues to be hyperspectral imagery. Imagery was acquired in 2004 by SpecTIR Inc. using their HyperSpecTIR instrument, which simultaneously records reflectance of eloctromagnetic radiation from ground features over 227 narrow spectral bands ranging from the visible spectrum through the middle infrared. As in last year’s work, four basic activities are necessary to meet our objectives: image acquisition, collection of spectral signatures for ash trees and other tree species (which is treated in another abstract in this volume by D. Bartels), collection of ground truth information (including precise locations) of ash trees and other vegetation recorded in the imagery, and image analysis and map development.

Images were acquired over three long flight lines in southern Michigan and three flight lines in northwestern Ohio. Individual flight lines covered areas about 2 km in width and 1540 km in length. Imagery was collected over all the areas at two times during the summer: midsummer (9 July 2004) and late summer (22-23 August 2004). These times were chosen to represent periods of relatively low stress due to beetle activity and water availability and of relatively high stress, respectively. The spatial resolution of sample pixels on the ground was 1 m for the longest flight line and 2 m for the remaining lines. The quality of imagery collected in 2004 was vastly superior to that in 2003 in terms of its high resolution, low spatial distortion, and greater precision of georeferencing. Ground truth data were collected during several periods in the growing season. Precise locations were obtained for almost 300 ash trees in various states of decline and over 400 trees of other species in the images using both GPS and identification directly on hard copies of the digital images. Analysis of the imagery is underway as of this writing (October 2004). It is being carried out by a group of scientists with considerable expertise in hyperspectral analysis, including personnel from Clark University, ITT Aerospace, and the USDA Forest Service.

The Feasibility of Using Hyperspectral Remote Sensing for Differentiating Hardwood Tree Species and Stressed Ash Trees

David W. Bartels, USDA APHIS PPQ CPHST, Pest Detection, Diagnostics, and Management Laboratory Moore Air Base, Bldg. 6414, 22675 N. Moorefield Rd., Edinburg, Texas 78541

Emergency response programs for agents such as emerald ash borer (EAB) could benefit greatly from vegetation mapping to locate susceptible tree species and stressed trees within urban and rural environments. Currently, detection surveys rely on visual identification of beetles and/or visible damage. Visual surveys are often inefficient and labor-intensive with surveyors first identifying susceptible tree species and then examining individual trees for signs of beetles. The goal of this project is look at hyperspectral remote sensing tools to enhance the survey and detection methods for EAB. Working with a hand-held spectrometer, the project focuses on two main questions: Can hyperspectral imagery be used to separate ash trees from other hardwood species and can it separate stressed ash trees from healthy ash trees? By building a spectral library of different hardwood tree species at different stages of phenology over the growing season, the project will be able to determine the feasibility of distinguishing tree species using spectral characteristics. The project will also contribute to a spectral library of ash trees with a range of EAB infestation as well as trees stressed by manual girdling and herbicide injections.

Preliminary data was collected in 2003 using an ASD FieldSpec Pro full range spectrometer and included bands from the visible spectrum to shortwave infrared (SWIR). Analysis indicates that, based on leaf signatures, tree species including oak, walnut, maple, and cherry were distinguishable from ash a high percentage of the time. Ash trees that had been girdled or treated with herbicide were also distinguishable from “healthy” ash trees at the leaf level.

During 2004, leaf-level data collections were made in replicated experimental plots set up by MSU and USDA Forest Service to look at stressed ash trees. Data was collected four times during the growing season from June to September. A large number of spectral signatures were also collected from over 15 trees species at multiple sites in Michigan during the growing season. Data will be analyzed this winter and used to help in classifying the airborne hyperspectral imagery collected by David Williams and the CPHST group at Otis, MA. Additional data sets were also collected over tree crowns using a bucket truck to provide ground truthing information for the airborne imagery.

Progress Toward Developing Trapping Techniques for the Emerald Ash Borer

Therese M. Poland1, Deborah G. McCullough2, Peter de Groot3, Gary Grant3, Linda MacDonald3, and David L. Cappaert2

1USDA Forest Service, North Central Research Station, 1407 S. Harrison Rd., Rm. 220, East Lansing, MI 48823
2Department of Entomology, Michigan State University, 243 Natural Science Building, East Lansing, MI 48824
3Canadian Forest Service, Great Lakes Forestry Centre, 1219 Queen St. E., Sault Ste. Marie, Ontario P6A 5M7 Canada

Since the 2002 discovery of emerald ash borer (EAB), Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), in southeastern Michigan and Windsor, Ontario, the distribution of this exotic insect has continued to expand. The primary infestation in Michigan currently includes 13 counties, with small isolated pockets in at least 13 other counties. Accurate delimitation of the infested area and detection of new outlier infestations is critical for regulatory officials who must establish the quarantine boundaries and implement eradication and control measures. Trapping and detection techniques would greatly enhance survey efforts to delineate the distribution of EAB and locate new infestations.

In 2003, we collected and analyzed ash leaf and bark volatiles. Electro-antennogram detection and walking bioassays were used to select candidate compounds that were tested both individually and in blends using four different trap types in the field. Trap trees (healthy, girdled, and herbicide-treated) and trap logs were also tested. Among trap trees, trap logs and baited traps tested, the girdled trees were found to be the most effective in capturing EAB.

In 2004, we identified additional potential attractants for EAB using coupled gas-chro-matography electro-antennal detection of ash volatiles. Wind tunnel and walking olfactometer bioassays were used to select the most attractive compounds for field testing. Trapping experiments using a prototype purple-panel trap and other purple trap designs were conducted to compare several potential attractants. Purple panel traps baited with a blend of host volatiles captured significantly more EAB than traps baited with various individual compounds. Trap tree studies were conducted to compare girdled, wounded, healthy, and herbicide-treated ash trees; trap trees located along the edge of a stand, within a closed canopy stand, or in open canopy conditions; and healthy or girdled trap trees baited with attractants and/or colored bands. The herbicide-treated trees were significantly more attractive than healthy ash trees; girdled and wounded trees were intermediate in attraction. Trap trees located in open canopy conditions were significantly more attractive than trap trees located along the edge of a stand or within a closed canopy stand. There were no significant differences in the number of EAB captured on trap trees with different colored bands or baited with blends of ash volatiles.

Chemical Ecology Studies on the Emerald Ash Borer

Damon Crook1, Joe Francese1, Ivich Fraser2, and Vic Mastro1

1USDA-APHIS-PPQ, Otis Pest Survey, Detection and Exclusion Laboratory, Bldg. 1398, W. Truck Rd., Otis ANGB, MA 02542
2USDA, APHIS, PPQ, 5936 Ford Ct., Brighton, MI 48116

The emerald ash borer (EAB), Agrilus planipennis Fairmaire (Buprestidae), a native of Asia, was discovered in the USA and Canada in 2002. This serious pest of ash trees (Fraxinus sp.) infests and quickly kills trees by mining the cambium area, disrupting the tree’s nutrient transport system. As newly infested trees do not typically show distinctive external visual symptoms, there is a growing need to be able to trap adult beetles so that accurate surveying can be done. During the 2004 Michigan flight season of EAB, we collected bark and leaf volatiles from healthy and girdled ash trees using both Porapak-Q and Super-Q cartridges. We refined current collecting methods by using the very latest in ‘micro-pump’ technology. We also prepared ash leaf extracts by washing leaves in methanol and hexane. EAB adults were also aerated in chambers in an attempt to collect and identify possible sex/aggregation pheromones. Volatile components were screened for EAB antennal activity using coupled gas chromatographic electro-antennal detection (GC-EAD). Compounds that elicited antennal responses were identified by gas chromatography (GC) and mass spectrometry (MS) and tested in an olfactometer arena for behavioral activity.

Exploring the Use of Spatially-Stratified Ash Host Distribution Maps for Improving Efficiency of Emerald Ash Borer Detection

David W. MacFarlane, Benjamin D. Rubin, and Steven K. Friedman, Department of Forestry, Michigan State University, 243 Natural Science Building, East Lansing, MI 48824

An accurate description of the host landscape pattern is critical for effective strategic management of the exotic insect pest the emerald ash borer (EAB), Agrilus planipennis, because population dynamics of EAB are a landscape-scale phenomenon and spatial variability in the ecological characteristics of ash host populations should define the context for the pests behavior. Strategic survey and sampling efforts to define the spatial extent of EAB infestations in southern lower Michigan have been made difficult because, like many exotic pests, EAB has been introduced into a complex, urbanizing landscape where forest inventory and health monitoring are especially difficult. Forests and other treed areas in urbanizing landscapes are fragmented and have a complex ownership patterns—which, in the case of privately owned lands, effects access and may add a public land bias to resource inventory. These landscapes also exhibit a high degree of spatial heterogeneity in species composition and forest structure, which makes it difficult to define a common sampling scheme or extrapolate forest inventory to the whole landscape (i.e., there is no “average” condition). In this analysis, potential methods for using host-weighted stratified sampling techniques to improve the efficiency of EAB detection are discussed in relation to preliminary results from the ASHMAP project. ASHMAP has the goal of defining the specific spatial distribution and abundance of ash species over the large complex landscape of southern lower Michigan where EAB is most prominent, as well as describing the general spatial ecological niche of ash in urbanized landscapes.

Environmental Spatial Distribution Patterns of Ash in Southern Michigan

Steven Friedman, David MacFarlane, and Benjamin Rubin, Department of Forestry, Michigan State University, 243 Natural Science Building, East Lansing, MI 48824

A critical step to controlling the spread of emerald ash borer is identifying the spatial distribution patterns of its host species. Ash species distribution is hypothesized to be influenced by a complex multi-faceted soil, climatological, and lake effect spatial conditions. During the summer of 2004, field crews established 1,010 plots (three sub-plots, each) across southern-lower Michigan for surveying ash at each plot. Each plot was georeferenced using a global position system that facilitated mapping the plot locations in a geographic information system (GIS). Using a preliminary sample (933 plot records), 133 tree species are included in 25,191 tree records. Approximately 24 species are present in at least 1 percent of the plots. Ash species (white 58.8 percent, green 29.9 percent, black 10.9 percent and blue 0.28 percent) were present at 31.8 percent of the plots. Soils and digital elevation models are included in the GIS in order to associate physical environmental factors with the spatial position of the plot records. Soil physical and geochemical properties derived from SURGO are spatially associated with the soil map and plot locations. Climatological data archived by NOAA provide regionalized precipitation, temperature, and cumulative growing-degree-day surface maps. Predictive models of ash tree species distribution patterns are being developed using General Linear Modeling techniques.

Dispersal of Emerald Ash Borer At Outlier Sites: Three Case Studies

Deborah G. McCullough1,2, Nathan W. Siegert1, Therese M. Poland3, David L. Cappaert1, Ivich Fraser4, and David Williams4

1Dept. of Entomology and 2Dept. of Forestry, 243 Natural Science Building, Michigan State University, East Lansing, MI 48824
3USDA Forest Service, North Central Research Station, 220 Nisbet Building, East Lansing, MI 48823
4USDA Animal and Plant Health Inspection Service, Otis Methods Laboratory, Angora Air Force Base, MA and Brighton, MI

We worked with cooperators from several state and federal agencies in 2003 and 2004 to assess dispersal of emerald ash borer (EAB), Agrilus planipennis Fairmaire, from known source points in three outlier sites. In February 2003, we felled and sampled more than 200 ash trees at an outlier site near Tipton, Michigan, where one generation of adult beetles had emerged from firewood stacked near a drainage ditch in 2002. At least 70 percent of the EAB galleries occurred on trees growing along the ditch within 100 m of the firewood pile. Galleries were occasionally found on trees that were up to 750 m north from the firewood pile, but all infested trees were growing along the ditch. More than 80 woodlot trees that were roughly 400 m east of the ditch were sampled, but no galleries were found on any of these trees. The distribution of the infested trees suggested that the drainage ditch may have facilitated directional dispersal, perhaps extending the dispersal distance. The need to collect similar data at additional sites was noted.

In February 2004, we evaluated EAB dispersal at an outlier site near Shields, Michigan that resulted when a single generation of EAB adults emerged in 2003 from ten infested nursery trees. Cooperators from the Michigan Department of Agriculture randomly selected and marked one ash tree in each 1/16-mile grid cell in a 1/2-mile radius surrounding the point source of the infestation. Trees were felled and bark windows, each a minimum of 1,000 cm2, were excavated on the upper surface of each tree. Number of bark windows sampled was based on the size of individual trees; four windows were evenly spaced from the base of the lower canopy to the upper canopy for each stem or major branch. The number of bark windows sampled ranged from 4 to 24 windows per tree. The number and stage of EAB larvae and extent of feeding were recorded for each window. We sampled 147 ash trees and found 57 EAB larvae or galleries in eight trees. No infested tree was more than 0.38 miles from the point source. More than half of the EAB larvae were on a single declining tree.

We conducted a similar project in April 2004 at an outlier site in St. Joseph, Michigan, where two to three generations of EAB had emerged from infested nursery trees. One to two ash trees were felled and sampled per 1/16-mile grid cell using methods developed at the Shields site. More than 200 trees were sampled and one or more infested trees were found in at least 14 grid cells. Trees with exit holes occurred in five grid cells, all within roughly 200 m of the point source. Trees with larvae or prepupae but no exit holes occurred in nine grid cells, located 200 to 600 m from the point source. Analysis of data from all three sites is continuing.

Studies to Develop an Emerald Ash Borer Survey Trap:
I. Trap Design, Trap Location, and Tree Damage

Joseph A. Francese1, Ivich Fraser2, David. R. Lance1, Victor C. Mastro1, Jason B. Oliver3, and Nadeer Youssef3

1USDA APHIS-PPQ Otis Pest Survey, Detection and Exclusion Lab Bldg 1398, W. Truck Road, Otis ANGB, MA 02542
2USDA APHIS-PPQ, EAB Office, 5936 Ford Court, Brighton, MI 48116
3Institute of Agricultural and Environmental Research, Tennessee State University, Otis L. Floyd Nursery Research Center, 472 Cadillac Lane, McMinnville, TN 37110

Current emerald ash borer (EAB), Agrilus planipennis Fairmaire, survey methods (e.g., tree damage surveys, trunk dissection for larvae, and trunk girdling in combination with sticky bands) are less than ideal for USDA Program surveys. To address survey issues, three trapping studies were performed from 20 June to the end of August 2004 at multiple replicated locations near the Townships of Salem, Ann Arbor and Northfield, Michigan. The objective of these studies was to develop an efficacious EAB trap that can be easily deployed for survey programs.

Test 1 – Trap Design. A trap design test evaluated multiple sizes, colors, and shapes of traps. Most traps were made from purple or black corrugated plastic covered in Pestick insect glue. In addition, two intercept flight traps, the Lindgren funnel and the IPM Tech Intercept Panel, were tested. Also included were girdled ash trees, banded with glue-coated plastic stretch wrap (30 cm width) (i.e., Michigan Department of Agriculture—MDA— Program trap). A new purple-colored elm bark beetle trap developed by Pherotech Inc. and a purple-colored wallpaper trap (3.75 cm wide) tested in 2003 were also tested. Total EAB collections among traps were low (58 EAB). The MDA Program trap had significantly higher EAB collections than other treatments (2.4 ± 0.7 [S.E.] adult EAB/trap/ week) followed by the elm bark beetle trap (1.1 ± 0.6). All other trap treatments averaged < 0.3 EAB per trap per week. Unlike the other traps, the MDA Program and the elm bark beetle trap were both in association with ash trees. In general, traps with larger surface areas were the most effective. The Lindgren funnel and IPM Tech Panel traps, as well as another black-colored corrugated plastic trap, caught no EAB. Sticky traps were more effective than the flight intercept traps.

Test 2 – Trap Site. Traps were placed along the edge of a woodlot, 25 m into the woods, or 25 m from the woodlot in an open field. Location treatments were replicated four times. Each trap site had two Pestick–covered purple corrugated plastic strips (15 cm wide by 90 cm) that were attached to 1.3 cm rebar rod at heights of 0 to 0.9 and 2.1 to 3.0 m. Total EAB collections were very low (36 EAB). On two dates (25 June and 7 July), average EAB collections were significantly greater on traps located along the forest edge (2.1 and 1.0 EAB/trap, respectively) than in the open field or woods (³ 0.4 EAB/trap). No adult EAB were captured on traps in the wooded sites. Trap height did not significantly affect EAB capture. Although none of the traps in Test 2 were associated with ash trees, EAB collection on the forest edge traps was equivalent to the MDA Program trap in Test 1.

Test 3 – Tree Damage. The attraction of EAB to sticky traps placed on damaged and undamaged ash seedlings was investigated. Bare-root green ash (Fraxinus pennsylvanica Marshall) in three varieties (‘cimmaron’, ‘patmore’, and ‘urbanite’) ranging from 1.3 to 2.5 cm caliper were planted on 21 April at a site in South Lyon, Michigan. Trees were planted at 1.5-m intervals in rows by variety (completely randomized block design). Damage treatments consisted of severe root pruning (~30 percent) at planting, trunk scraping, crown decapitation, or girdling on 11 May 2004. Traps were purple corrugated plastic triangles (with each side 30 cm long x 15 cm wide) attached to the tree at 15 to 45 cm. Traps were covered in Pestick glue. Total EAB collections were low (153 EAB). Treatments did not significantly affect EAB collections. However, there was a trend towards more EAB being captured on girdled and trunk-scraped trees than other treatments and on the ‘urbanite’ variety.

Due to the low trap catch in these studies, it is difficult to make any definitive conclusions. The actual EAB populations in the trapping areas of these studies were unknown, so there is no estimate of the relationship between trap collection and population density. Therefore, it is unknown if low EAB trap recoveries were due to ineffective traps or low EAB populations at our trapping sites. However, it appears that traps located on the edges of woodlots performed better than traps located in open or wooded areas. The MDA Program trap was the most effective treatment among trap treatments placed solely within wooded sites. Light levels were much lower (40 to 60 times) in the wooded test sites than open or edge sites. Therefore, EAB may not distinguish trap colors in low light conditions. However, EAB may be able to locate the MDA Program trap trees in low light wooded areas due to the release of volatile attractants from girdle-damaged trees. The utilization of colored sticky traps and tree damage treatments to attract EAB may be more effective when traps are placed along the edges of woodlots, but further testing will be required to confirm this assumption.

Studies to Develop an Emerald Ash Borer Survey Trap:
II. Comparison of Colors

Joseph A. Francese1, Ivich Fraser2, David. R. Lance1, Victor C. Mastro1, Jason B. Oliver3, and Nadeer Youssef3

1USDA APHIS PPQ Otis Pest Survey, Detection and Exclusion Lab Bldg 1398, W. Truck Road, Otis ANGB, MA 02542
2USDA APHIS PPQ, EAB Office, 5936 Ford Court, Brighton, MI 48116
3Tennessee State University, Otis L. Floyd Nursery Research Center 472 Cadillac Lane, McMinnville, TN 37110

The objective of this study is to develop a trap for EAB that would improve the sensitivity and efficiency of EAB survey and aid the overall program in achieving its goals. A four panel ‘hanging box’ trap design was employed to test four colors simultaneously. Corrugated plastic panels (0.6 cm thick) were 37.5 cm x 60.0 cm and were coated with Pestick insect trapping glue. Two sets of four colors (Black–Yellow–White–Purple and Red–Green–Navy–Silver) were tested at two heights (1.5 m and 6.1). In 2003, over 500 beetles were caught in a three-week period. More beetles were caught on purple traps than on any other color. More beetles were caught on low traps than on high traps for all colors except black and yellow. In 2004, we deployed the hanging box traps in the same arrays, but only 149 beetles were caught throughout the study. Purple-colored traps caught significantly more beetles than all other colors except white. Unlike 2003, there was no difference between traps hung at the two heights. Traps containing logs did not catch more beetles than traps without logs. Additional studies were also conducted in 2004 using a cross-vane prototype trap. Nineteen colors (including colors produced by the plastic manufacturer, purple-colored glue, glue containing small metallic objects [purple and green], metallic foil, and paints reflecting in the 400-450 nm range) were tested. Beetle catch was low, with only 95 beetles caught throughout the study. Of the treatments, purple-colored glue caught the most beetles (21) followed by glue mixed with green glitter (11) and the manufacturer’s purple (10), also used in the ‘hanging box’ study. The attraction of EAB adults to specific colors may enhance the performance of a trap baited with semiochemicals or be utilized in a control strategy.

Studies to Develop an Emerald Ash Borer Survey Trap:
III. Tree Banding

Ivich Fraser1, Joseph A. Francese2, David. R. Lance2, Victor C. Mastro2, Jason B. Oliver3, and Nadeer Youssef3

1USDA APHIS PPQ EAB 5936 Ford Court, Brighton, MI 48116
2USDA APHIS PPQ Otis Pest Survey, Detection and Exclusion Lab Bldg. 1398, W. Truck Rd., Otis ANGB, MA 02542
3Otis L. Floyd Nursery Research Center, Tennessee State University, 472 Cadillac Lane, McMinnville, TN 37110

Attraction of emerald ash borer (EAB) to girdled ash trees has been demonstrated in prior trapping studies. Other studies have demonstrated its attraction to colors such as purple. We combined the two trapping methods using colored sticky bands (clear plastic and blue, purple, yellow and clear cellophane) on trap trees (unwounded, wounded by a half girdle, and, in a separate study, completely girdled). Trends in both of these studies indicate that clear sticky bands do better at capturing adult emerald ash borer than colored bands in trap trees. In the first study mentioned, wounded–clear cellophane trap trees caught the most EAB, followed by wounded–clear plastic, then unwounded–clear cellophane and wounded–purple. The clear– cellophane trap was the only one of the four mentioned to catch significantly more than the remaining trap tree types (both yellow and blue types and unwounded–purple.) However, it did not catch significantly more than the other top three trap tree types. The results from the study of girdled trap trees showed no significant differences between trap types, with clear cellophane catching the most, then blue, clear plastic, purple, and lastly, yellow.

Problematic Agrilus Identifications from Emerald Ash Borer Trap Tree Interceptions

James E. Zablotny, USDA APHIS PPQ, Detroit, Michigan 48242

Initial trap tree studies conducted by EAB survey crews have captured many species of Agrilus. To facilitate correct species diagnosis, a protocol for cleaning and removing tanglefoot residue from specimens is provided. Seven Agrilus species are listed from Ohio and Michigan trap trees and visual characters are provided for diagnosis.