How to Carry out Biosurveillance:
Looking for Emerald Ash Borer with the Cerceris Wasp
General Information:
We are hoping that you will be able to collect 50 beetles over 3-4 (or more) visits to your Cerceris wasp site.
The month of July is the best time for biosurveillance, since that is when EAB is most active, but if you are
unable to collect all 50 beetles in July, finish up in August. If, during your survey work, you find a small green
beetle that looks like EAB, please call or email me right away (contact information below).
What to bring:
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Insect net
Data collection sheets
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Pencil
Vials
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Pre-printed vial labels
Sharpee marker
What to do:
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Visit your site on warm sunny days in July (preferably) and August to look for beetles that are brought in
by the wasps. Wasps hunt best on sunny days when the temperature is above 73, with peak flight time
between 11 am to 4 pm.
When you arrive at the site, note the time and temperature on your data sheet. Take out two flip-top vials.
Mark one with a “D” (for dropped beetles) and with an “S” (for stolen beetles).
At your site, walk around and roughly count the number of nests. Record this on your data sheet. This
information will let us know how the wasps are doing over time.
Pick up all dropped beetles lying on the ground around the colony and place these in the “D” vial.
Choose a group of nests in an area small enough for you (or your group) to watch. This may be between
25 and 80 nests, depending on the size of your group and how often you have done this. If you monitor
fewer than 25 nests, the beetle collection will go slowly.
Watch for wasps coming in with prey. Gently net an incoming wasp before she dives into her nest hole.
The shock of netting will usually force the wasp to drop her prey. If you see a beetle in the bottom of the
net, open the net and let the wasp crawl out and fly away. If she has not released the beetle, you can
gently pry it away from her with your fingers. Remember, she doesn’t sting.
Place these “stolen” beetles in the separate container marked “S”. A general rule is to steal no more
beetles than the number of nests you see. For example, if there are 25 nests, steal no more than 25
beetles. We don’t want to compromise the wasps by taking more.
Fill out data sheet for the day, including numbers of dropped and stolen beetles, start and finish time,
and total time spent at the nest site. Add a completed data label (use pencil or waterproof pen) to each
vial, and place the two labeled containers of beetles in the freezer until the end of summer. Be SURE both
containers are labeled.
To learn more, visit www.cerceris.info. If you have questions or concerns, please contact me:
Trish Hanson, Forest Biology Lab
Essex Junction District Office
Vermont Dept. of Forests, Parks and Recreation
111 West Street
Essex Junction, VT 05452-4695
802-879-5687
trish.hanson@state.vt.us