And some answers to your questions
In response to multiple phone calls to local, county, and state governmental offices, Newaygo County Emergency Services wanted to share the following information obtained from subject matter experts at the MSU Extension Office, Michigan Department of Agriculture and Rural Development, and the Michigan Department of Natural Resources.
What you can do now and over the Summer
May - August:
Wrap trees with sticky barrier bands to trap caterpillars as they move up and down the trunks.
*Follow precautions stated in the article to protect your trees from damage.
Wrap trees with folded burlap barrier bands to trap the caterpillars: https://fyi.extension.wisc.edu/
May - August:
Manage gypsy moth caterpillars, pupae, and moth populations.
- Drop caterpillars into a bucket of soapy water and let sit for 48 hours. (Caution: their hairs can be irritating.)
- Spray caterpillars and moths directly with a strong mixture of dish soap and water. (Caution: can make deck surfaces slippery.)
- Monitor and maintain barrier bands.
Gypsy Moth Facts from the Experts
MSU’s Professors of Entomology and Michigan Department of Agriculture and Rural Development (MDARD) Pesticide & Plant Pest Management Division have shared the following information with the Newaygo County Emergency Services Department:
- Some townships assess a millage (an invasive species millage), as do several counties and property owner associations that use funding to address the concern of the day, whether that be gypsy moths or something else.
- It is too late to spray using more selective, lower-risk pesticides.?
There may be harder chemistries available that could still be effective as the caterpillars get larger, but the window is gone.
- There is a good chance populations will collapse this year, but we can’t be sure, and in any case it will likely be location-specific. The very dry spring is not helping matters because the fungus that controls gypsy moth thrives in a wet environment. We’ll know more in late summer when females emerge and begin laying eggs. Wimpy females and small egg masses mean a declining population.
- The cost-share program years ago was complicated, but had to be due to federal requirements on threatened & endangered species reviews and the aerial pesticide application requirements, especially safety issues for the applicators flying the planes.
The DNR informed our office that gypsy moth populations have been naturalized into Michigan’s landscape. Local outbreaks are normally attributed to drought, old age or stressed trees in general and rarely cause mortality in stands with healthy vigorous trees. In hot, dry weather, water prized trees defoliated by gypsy moth.
-Run a sprinkler for about an hour in the morning, soaking the ground under the spread of the branches.
Per the DNR, after a year or two of heavy defoliation, populations tend to collapse on their own with no spray programs in place. Furthermore, large spray programs can cause communities to become reliant on spray programs forcing them to spray more often as they disrupt the “natural” gypsy moth cycle.
Why doesn't the County or my Local Township have a Spray Program?
The State of Michigan has not funded a gypsy moth spray program, which was a cost share program through MDARD and the Forestry Service, since the early 1990s. Our research shows that some counties are spraying limited areas and using dedicated mileages to do so. The cost as stated below is not conducive to large areas. Based on cost comparables from other jurisdictions who sprayed earlier this year, County Administration calculated that to do the whole county would be over $82 million. 1800 acres or just under 3 sq miles is $250k.
Roscommon County does have a Gypsy Moth Suppression Program. It is a millage administered by the MSU Extension Office supported and has been since the federal assistance was eliminated years ago. Their support staff person developed the attached landowner management strategies that outline the life cycle of gypsy moth and provide links to details for burlap banding and duct tape barriers.
The DNR and their partners at the MSU Extension also released some valuable information last year regarding gypsy moths: https://www.canr.msu.edu/news/gypsy-moth-caterpillars-are-out-and-about. Another link that provides a great place to start is this site: https://www.canr.msu.edu/ipm/invasive_species/Gypsy-Moth/index. Both of these links to the MSU resources in particular have information on the best way for homeowners to tackle the gypsy moth issue.
What if I want to spray my own property?
Pesticide applicators licensed in Michigan:
CROP CARE COMPANY LLC, out of SHELBY, MI. 231-861-2210.
The substance they use is Bacillus Thuringiensis, used since the 1920’s.
If they want to handle it on their own (there is no funding that I am aware of State or Local) here is the info…
To address a gypsy moth infestation in a handful of individual trees, homeowners can purchase a spray containing Bacillus thuringiensis var. kurstaki (Btk), a bacterium that naturally occurs in the soil but can be lethal to certain caterpillars and moths. Be sure to follow label directions exactly. The best time to spray is when caterpillars are small, usually through mid-June. When caterpillars are massing, spraying tree trunks with a mixture of dish soap and water or scraping caterpillars into a bucket of soap and water also are effective.
Is it possible to buy Btk to spray caterpillars in my own garden?
Yes, several commercially available Btk products can be used to control caterpillars on shade trees, fruit trees or plants in the garden. Both liquid formulations and wettable powders are available from local garden stores. Be sure to follow the directions on the label. To contact an expert in your area, visit https://extension.msu.edu/experts, or call 888-MSUE4MI (888-678-3464).
The Btk formulation used for gypsy moth spray programs in Michigan is certified by the Organic Materials Review Institute (OMRI), a national nonprofit organization that approves products for organic growers, as regulated by the USDA National Organic Program. Btk is commonly used by organic gardeners and farmers, as well as some conventional farmers, to control caterpillar pests of fruits and vegetables.
To learn more about gypsy moth caterpillars, visit the MSU Extension website. More detailed information is available in this MSUE bulletin that covers the Btk management for gypsy moth.
For more information about the DNR’s Forest Health Program or to view last year’s Forest Health Highlights report for Michigan, visit Michigan.gov/ForestHealth.