Gypsy Moth Suppression Program

Alicia Wallace - Program Coordinator
Jeremy Lowell - Assistant Program Coordinator

Bay County Building
515 Center Avenue, Suite 503
Bay City, Michigan 48708-5941
Voice: (989) 895-4195

August is "Tree Check" Month for Asian Longhorned Beetles (ALB)


August is the peak time of year to spot the Asian Longhorned Beetle (ALB)as adults emerge from trees. That’s why the U.S. Department of Agriculture(USDA) is declaring August as ‘Tree Check Month.’ Checking trees for the beetleand the damage it causes is one way residents can protect their own trees andhelp USDA’s efforts to eliminate this beetle from the United States.


Asian Longhorned Beetle (ALB) is aninvasive species of beetle that attacks many species of trees. Its favored host trees are maples, birch,buckeye and willows, though it can live in many other tree species native toBay County. ALB has not been found inMichigan, however there is an area in southern Ohio near Columbus and Daytonthat is infested and a new discovered infestation in North Carolina. 

The large white spotted black adultbeetles are active in the summer and are sometimes found in swimming poolfilters. The females chew oval shapedpits into the tree to lay their eggs. Look for trees, especially maples, with dying branches. 

The round exit holes (about the size ofa standard Bic pen) and oval egg laying pits can be seen along large branchesor on the trunk of infested trees.

If you see a suspect tree or beetle,take photos, record the location, try to collect suspect beetles in a jar andreport it to the Bay County Gypsy Moth Program staff at or call 989-895-4195.



More information about the Asian Longhorn Beetle (ALB) can be found at:

2020 EAB Ash Tree Injection Treatment
Treatments to protect publicly owned Ash trees from EAB will be done by direct injection of an insecticide between June 15, 2020 and June 30, 2020. EAB treatment timing is dependent on the leaf development of the ash trees that will be treated. The ash trees need to be actively transpiring or moving water through the tree to take up the insecticide. Treatment of each tree is estimated to take from 15 minutes up to two hours. The 2020 EAB Treatment Project will treat approximately 985 ash trees and will take up to three weeks to complete. These treatments will protect the trees from EAB for three (3) years.   For more information about the 2020 EAB Treatment, please check out the EAB webpage.

2020 Bay County Spring Aerial Treatment to Control Gypsy Moths Completed

Aerial treatment to control out-break level Gypsy Moth infestations were done on the morning of Wednesday, May 27, 2020 between the hours of 6:30 a.m. and 8:00 a.m. The weather conditions, Gypsy Moth caterpillar development, and the tree leaves were conducive to successful aerial treatment application. 

  • Biological Insecticide Common Name: Foray 48B, this product is OMRI certified organic so it can be used on organic foods. Active Ingredient in the insecticide: Bacillus thuringiensis kurstaki (Btk)
  • Method of Application: Aerial application by a yellow fixed-wing airplane flying low over forested areas.
  • Areas to be treated: One wooded area in Gibson Township where the gypsy moth caterpillars will damage and defoliate local trees. Property owners in treatment areas have been notified by direct mail of the intent to treat the trees on their property. 

Maps for the 2020 Treatment Area:

Pesticide Label and Information for Foray 48B:
For further information or if you have questions, please contact Alicia Wallace, Bay County Gypsy Moth Suppression Program Coordinator, at 989-895-4195 or

Press Release for 2020 Bay County Gypsy Moth Aerial Treatment( 05/14/20)

Aerial Treatment for the suppression of Gypsy Moth in Bay County will be done between May 24 – June 5, 2020. The Bay County Gypsy Moth Suppression Program will conduct Aerial Gypsy Moth Treatment in the next few weeks at a heavily infested 381 acre woodlot in Gibson Township in northern Bay County. Monitoring surveys show that the Gypsy Moth population in that area has reached outbreak levels, and is likely to damage the trees in the area. This population may also spread to other areas of the county if not treated. 

Gypsy Moth Caterpillar Hatch Video

Baby Gypsy Moth Caterpillars are freshly hatched and ready to start eating the leaves off local trees. 



Saving Trees from Invasive Species and Promoting the Care and Management of Our Valuable Trees 

The United Nations declared 2020 as the International Year of Plant Health (IYPH). This worldwide campaign is promoting the value of our precious plant resources and the need to safeguard them against invasive pests. To celebrate IYPH, each month the Bay County Gypsy Moth Suppression Program will highlight how Bay area residents can help protect the health of our valuable trees against invasive pests.

May is planting time for home gardeners and it is important to remember to get your seed from a reliable source. Make sure your seeds come from a reputable provider to assure that you are:

  1. Getting seeds for the plant you want

  2. Seeds that are free of disease and other contaminants

  3. Seeds that will produce healthy plants

The USDA Plant Protection and Quarantine Service has been working in collaboration with the U.S. seed industry, the National Plant Board, and academia to develop a holistic approach to systematically reduce pest contamination risks across the seed production continuum. Buying seeds approved by USDA can go a long way to ensuring that you can grow healthy plants this spring that do not contain invasive species and diseases that could harm our local horticulture.

National Tree Benefit Calculator
The National Tree Benefit Calculator is simple to use, very accessible, and should be considered a starting point when learning about and understanding a tree’s value in our community. For example, an Ash tree from the Gypsy Moth Suppression Program’s inventory and treatment operations is a 14.5 inch wide tree that is in front of a single family residence. This tree will provide overall energy, economic and ecological benefits of $141.00 annually to the home. If this same tree is well taken care of and grows up to 19.5 inches in diameter, it will provide $192.00 in annual benefits. Additional benefits of this one (1) 14.5 inch ash tree include intercepting 1,394 gallons of storm water runoff per year, raises the property value by $48 per year, reduces atmospheric carbon by 797 pounds, and conserves 223 Kilowatt hours of electricity for cooling and reduces consumption of oil or natural gas by 26thermal units – These are big benefits that grow each year as the tree matures.

To get started visit the National Tree Benefit Calculator at If you're unsure of what type of trees you have another fun tool is the Tree Identification feature on the Arbor Day organization website at or email a picture to the Gypsy Moth Program at and staff will help identify the tree.

To find out more about the value of your trees and what is being done to protect them visit the Bay County Gypsy Moth Suppression Program website at or contact Alicia Wallace, Gypsy Moth Suppression Coordinator at

Additional benefits of this 14.5 inch ash tree include:  

  • Intercepts 1,394 gallons of storm water runoff per/year.
  • Raises the property value by $48 per/year.
  • Reduces atmospheric carbon by 797 lbs.
  • Conserves 223 kilowatt hours of electricity for cooling and reduces consumption of oil or natural gas by 26 thermal units.  
To find out what benefits the trees in your yard can provide, visait the National Tree Benefit Calculator 


Letters and Landowner Authorization to Access Property for Gypsy Moth Monitoring Being Sent Out 

The Gypsy Moth Suppression Program staff are sending out letters to landowners that have woodlots and wooded areas with the best sites to successfully monitor the Gypsy Moth Populations in Bay County.  To conduct this monitoring, staff need the cooperation of landowners like you.  Letters are being sent out to landowners with a description of how and when Gypsy Moth monitoring is conducted, along with a Landowner Authorization for Gypsy Moth Monitoring Form to fill out and send back to our department by the end of September.  The Landowner Authorization for Gypsy Moth Monitoring Form will allow our staff to conduct monitoring on your property.  When we get your form with contact information, we will provide you with field report updates on what we have found in your area. By providing your e-mail address we can provide you with the field report updates electronically instead of by mail to help keep program costs down.  If you have any questions regarding this program, other invasive species, or any tree health concerns please contact the Gypsy Moth Program at 989-895-4195 or at
None of your contact information will be shared outside of our office

Gypsy Moth Update - May 2020

 Figure 1 above shows second and third
instar Gypsy Moth caterpillars feeding
on oak leaves. [Alicia Wallace, June 2019]



Gypsy Moth caterpillar numbers are up in many
parts of Michigan this summer. Our cold spring
delayed their hatching but they are already
causing defoliation and tree damage in parts
of Barry, Clare, Gladwin, Ionia, Roscommon
and Washtenaw counties. This outbreak
started in 2018 when many of the same areas
of the state had significant leaf lose last
summer due to the feeding gypsy moth
caterpillars. Aspen and oak top the list of
over 500 preferred host species on which
gypsy moth caterpillars will feed on into

Mature trees can usually withstand
gypsy moth defoliation and simply grow
more leaves; however, multiple years of
defoliation can weaken and even kill trees.

Many folks confuse the gypsy moth with a
few of our native species of hairy caterpillars
like the Eastern Tent Caterpillar and Forest
Tent Caterpillar. The Eastern Tent caterpillars
are the ones who make the nest or webs in
small under story trees like crab apple and
cherry. All three species of caterpillar feed
on a wide variety of trees in spring each year.
Unfortunately all can be present in the same
woodlot adding more stress to our trees.