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Questions and Answers: USDA’s 2017 Emerald Ash Borer Survey

Q. What is the 2017 Emerald Ash Borer Survey?
Similar to surveys done in past years, the U.S. Department of Agriculture’s (USDA) 2017 Emerald Ash Borer (EAB) Survey will rely on the purple prism detection tool, or “trap,” to monitor known EAB infestations and locate other unknown EAB populations. The national survey will set about 18,000 purple prism traps in the 31 participating States. Eighteen States will not participate in the national EAB survey: Alaska, Connecticut, Delaware, Hawaii, Illinois, Indiana, Iowa, Kentucky, Maryland, Massachusetts, Missouri, New Jersey, New York, North Carolina, Ohio, Pennsylvania, Virginia, and West Virginia. Texas will conduct an independent EAB survey.

Our survey strategy will continue to use a computer-generated, risk-based sample design, along with historical program data and regulatory knowledge. This design will enable USDA to monitor the leading edge of EAB infestations, determine whether undetected pockets of infestation are present, and identify locations best suited for biological control releases.

Q. What do the EAB detection traps look like?
 The purple trap is a three-dimensional triangle or prism. It’s made out of thin, corrugated purple plastic that has been coated with non-toxic glue on all three exterior sides. The purple traps are about 24 inches long and hang vertically in ash trees. Each trap is baited with a lure on the interior to attract EAB to it. 

For trap images, go to Scroll down to the “Pest Management”
section and click on “2017 Emerald Ash Borer Survey Guidelines.”

Q. Who is involved in the 2017 EAB Survey?
The EAB survey is a collaboration involving USDA’s Animal and Plant Health Inspection Service (APHIS), State departments of agriculture or natural resources, Tribal cooperators, and the USDA survey contractor.

Q. Who is paying for the 2017 EAB Survey?
The national EAB survey is funded by USDA. If a State chooses to survey for EAB on its own, USDA will provide the survey supplies, but the costs of conducting the survey are born by the State.

Q. Why do you call the detection tools “traps?” Do they really trap EAB?
We refer to the detection tools as “traps” out of convenience. The detection tools do not catch beetles as a way to reduce or deplete populations. They simply help us detect new infestations and monitor the spread of the beetle. Through ongoing trap design research, we are continually improving our ability to locate EAB infestations.

Q. Why is the color purple significant, and what is the lure?
In the insect world, color frequently plays an important role, and EAB is no exception. In 2003, researchers began investigating EAB responses to dif¬ferent stimuli in an effort to develop an effective detec¬tion tool. Researchers discovered that EAB is attracted to a specific shade of purple—the purple trap color replicates this shade to attract the pest. Additionally, the traps are baited with a lure, using a chemical called (Z)-3-hexanol, that mimics a chemical signal that is emitted by ash trees and also attracts the beetle.

Q. How do the traps work?
In their adult stage, EABs fly around ash trees, feeding on leaves and looking for a mate. If an EAB lands on a purple trap, it will get stuck in the non-toxic glue coating. Survey crews service the traps two times: in mid-summer, to replace the lure and collect any insects stuck on them; and in the fall, to collect any suspect beetles and remove the traps.

Q. Why are the traps placed only in ash trees?
Ash trees (Fraxinus spp.) and a close relative of ash, the white fringetree (Chionanthus virginicus), are the only known host species for EAB on the North American continent. The lifecycle of EAB depends on the ash tree; the adults feed on the leaves and lay eggs in its bark crevices, and the larvae develop under its bark. As a result, EAB is drawn to ash trees. All 16 native species of ash—including green, white, and black ash—are EAB hosts. White fringetrees, however, are too small to place traps in and are only a minor host for the pest.

Q. How long will the survey take to complete?
The traps will be placed in ash trees this spring and early summer before EAB adults emerge. The traps will be monitored and remain in place throughout the summer during the beetles’ flight season. This fall, all traps will be removed.

Q. If EAB is not known to be in my State, will the traps attract EAB and draw the beetles to my State?
No, the traps do not pull beetles into an area. The traps are a detection tool to help determine if EAB is already in the area.

Q. What happens when an EAB is found stuck on a purple trap? 
The insect is collected from the trap and is cleaned and sent to a USDA insect identifier for verification. We then communicate any verifications of EAB to the appropriate State officials.

Q. If a trap is in my area, does that mean EAB is there?
No. A trap located in your community does not mean EAB is present, it just means we are looking for the beetle. The goal of the 2017 EAB Survey is to define the outer boundaries of infested areas, locate new EAB infestations, and identify locations best suited for biological control releases.

Q. What were the results of the 2016 EAB Survey?
The 2016 survey resulted in the detection of EAB in 26 new counties outside the Federal quarantine area. The new detections occurred in Alabama, Arkansas, Delaware, Georgia, Kansas, Louisiana, Minnesota, Nebraska, Oklahoma, Tennessee, Texas, and Wisconsin.

Of these 26 new detections, 18 (69 percent) resulted from using a purple trap. The other eight (31 percent) detections resulted from an alert citizen or State partner spotting and reporting signs of EAB damage.

The 2016 survey activities continued to elevate public awareness about the EAB program. Survey personnel setting and monitoring the traps in cities and towns created opportunities for discussion. The highly visible purple traps stimulated public interest and garnered media attention. As a result of the new detections, federal and state EAB quarantines were expanded or established. These quarantines prevent the human-assisted spread of EAB by regulating the conditions under which various items, including all hardwood firewood and any ash tree material, may be transported out of the quarantined areas.

In addition, the 2016 EAB survey results gave data to support biological control management and direct field personnel to appropriate locations for parasitoid (stingless wasp) releases. Survey activities also allowed the EAB pro¬gram to monitor the outer boundaries of infested areas. This information helped guide decisions on trap placement for the EAB survey in 2017.

Q. What determines where a trap is set?
The 2017 EAB Survey uses a computer model to generate a risk-based sampling design that identifies optimal locations to survey for EAB. The model analyzes a collection of environmental variables (e.g., soil moisture, land elevation, terrain) and EAB program variables (e.g., historical EAB survey data, targeted high-risk areas, pest pathways, scientific literature). The end product is a grid map that identifies locations where the likelihood of detecting EAB is greatest, as well as locations where we can gain the most information to improve the model for future sampling.

More information is available in the 2017 EAB Survey Guidelines document. To download a copy, go to and click on “2017 EAB Survey Guidelines” under the “Pest Management” section. 

Q. What are the benefits of the risk-based survey sampling design?
The risk-based sampling design is objective, transparent, and science-based. It preselects geographic locations to deploy EAB traps where there is the highest likelihood of detecting EAB. The expected benefits of the 2017 EAB survey include:
An objective and transparent process to quantify risk and select trap locations. 

  • An increase in the number of successful EAB detections beyond the known infested area. 
  • An improvement in land managers’ capabilities to detect EAB close to the date of a new infestation. 
  • Findings of locations that are best suited to carry out biological control releases. 

Q. Will traps be set in areas not selected by the model?
Yes, some traps will be set in discretionary locations based on local conditions, involving terrain, and ash tree availability.

Q. Are the traps safe?
The traps pose no risk to people or pets, however they are covered with non-toxic glue and can be extremely sticky if touched. The traps will be in ash trees throughout the summer—please do not disturb them. If you see a trap on the ground, please call toll-free USDA EAB hotline at 1-866-322-4512 to report it. If you call outside of regular business hours, leave your name, telephone number, State, and location of the fallen trap.

Q. What can I do to support the 2017 EAB Survey program?
Please talk to your family and friends about the EAB survey to raise awareness. If you see one of the traps on the ground or damaged, call the toll-free USDA EAB hotline at 1-866-322-4512. Please become familiar with the signs and symptoms of an EAB infestation and inspect your own trees. Lastly, don’t move firewood; a prudent alternative is to only purchase USDA- or State-certified, treated, and labeled firewood. The public contributes significantly to the quality of the EAB survey and the overall program. We value your efforts and appreciate your support.

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