Study Title:
Insecticide and biocontrol treatments at Maquam Wildlife Management Area, Swanton, VT

Case Study Type: Forest health
Site Photo:
https://www.uvm.edu/nesl/system/files/webform/new_case_study/79/Picture12.jpg

Lay Summary:
Green, white and black ash within the site were becoming infested with EAB.  Parasitoid releases began in 2023 and continued into 2024.  Injections of emamectin benzoate were conducted in 2025 on black ash (male and female) at the site. Both treatments occurred to maintain ash on the landscape at this important WMA. Injected trees will be monitored for canopy health annually and will be re-treated as needed.

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-------- Site Location -------------------------------------------------------

Location:
Swanton, Vermont

Location Description:
Wildlife management area (state-owned) in northwest corner of Vermont; nearly bordering Lake Champlain

Latitude:
44.905965

Longitude:
-73.157757

Directions:
From Swanton, take Rt. 78 west across the Mississquoi River and take a left at the stop sign onto S River St.  Take the next right onto Lake St. (Rt. 36), and follow for 1.5 miles to the parking access for Swanton Beach.  Upon exiting vehicle, backtrack on Lake St. approx. 0.1 miles to a small pulloff with gate across logging road.  Follow logging road and navigate via GPS to treatment site.

Accessibility:
Site only accessible on foot

Landowner Name:
State of Vermont – Fish and Wildlife Department

Landowner phone:
+1(802) 878-1564

Landowner email: fwinformation@vermont.gov
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-------- Stand Information ---------------------------------------------------

Stand Area with Units:
20 ac. = treatment area; 32 ac. = treatment area + untreated area with mortality

Cover Type:
Ash

Primary Forest Health Threat:
emerald ash borer

Primary Pests/Disease:
emerald ash borer

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-------- Pre-treatment Conditions --------------------------------------------

Start date: Wed, 06/01/2022 - 00:00
Stand History:
https://anrmaps.vermont.gov/websites/wma/maps/Maquam%20Bay.pdf

Pre-Treatment Forest Health Issues:
EAB presence

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-------- Silviculture Prescription -------------------------------------------

Case Overview:
Multiple ash species impacted by EAB. In an effort to keep ash on the landscape, a total of 12 biocontrol releases occurred between 2023-2024, and 12 ash trees were injected with emamectin benzoate (4%) in 2025.  Treated trees will be monitored annually and re-treated when appropriate. Establishment of biocontrol parasitoids will be assessed starting in 2026.

Silviculture Objectives:
Trying to keep ash on the site 

Landowner Objectives:
Trying to keep ash on the site 

Factors Influencing Prescription Choice:
- forest health

Equipment used:
EAB parasitoids (larvae, pupae, eggs) for 3 species (Tetrastichus planipennisi, Oobius agrili, Spathius galinae)
ArborJet Quik-Air injection system and plugs
Tree-Age G4 (4% emamectin benzoate)
Power drill


Prescription Notes:
Biocontrol releases – received shipments from USDA-APHIS PPQ and released as directed, either by affixing bolts to trees, opening cups containing adults, or affixing egg containers (“oobinators”) to trees

Injections – measured DBH to inject proper amount, drilled corresponding number of holes on or near root flares, installed plugs, injected insecticide

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-------- Post-treatment ------------------------------------------------------

Post-Treatment Assessment Expected:
yes

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-------- Miscellaneous -------------------------------------------------------

Treatment Total Time:
32

Treatment Total Cost:
$1,370 for staff time and chemicals.  Injection system = $2800

Future Treatment Plans:
Will re-treat in 2027 or 2028 depending on tree condition

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-------- Statistics ----------------------------------------------------------

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-------- Contact Information -------------------------------------------------

Primary Contact:
Josh Halman

Contact Organization:
VT Dept. of Forests, Parks and Recreation

Contact Email: joshua.halman@vermont.gov
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-------- Supplementary Content -----------------------------------------------