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1. Why does Roscommon County spray?

Gypsy Moth caterpillars feed on the leaves of many trees and shrubs, especially oaks. Their populations can grow so quickly that they can, in one summer, strip all the leaves off entire stands of trees, damaging them severely. When surveys indicate the population of the pest in an area is large enough to cause defoliation of trees in June, reduction action is taken. Spray treatments reduce such outbreak populations below the level at which they can cause heavy defoliation.

2. What biological insecticide is used?

A single aerial application of the microbial insecticide "Foray48B®", a brand name for Bacillus thuringiensis var. kurstaki (commonly called Btk) certified by the Organic Materials Review Institute (OMRI), a national nonprofit organization that approves products used on operations that are certified organic under the USDA National Organic Program. . The active ingredient is a naturally occurring soil bacterium that when eaten kills gypsy moth caterpillars. Btk is specific to Lepidoptera species of caterpillars that ingest it and will not harm humans, bees, birds, fish, pets, and other wildlife.

Btk is highly unlikely to cause any adverse health reactions. It is possible, but very unlikely, that very few people with severe food allergies or asthma may react to the spray. If you suffer from such conditions,common sense suggests that you leave the area or take the simple precaution of staying indoors with the windows closed while the planes are spraying to avoid direct exposure and minimize your risk of reactions. More information is available

online (PDF).

3. Was my property chosen for spraying this year?

The Roscommon County Gypsy Moth Program makes spray block maps available on the website as soon as treatment areas are finalized around the middle of February. Each year in April the parcels chosen for spraying are mailed a post card spray notice. Also, local townships have maps in their offices and a notice of spraying appears in the local newspapers.To find out if your property is in a spray block, visit the Gypsy Moth main page for the most current map.

Spray Map page.

4. When are spray blocks treated?

Spray block treatment is timed when the caterpillars are in the first 3-4 weeks of development (1st & 2nd instar) and leaves have expanded enough to intercept the spray. The timing is based on daily observations of caterpillars and leaf development. Spraying could begin in mid-May or as late as early June. Weather permitting, spraying may start at 6 a.m.in the morning and continue as long as weather conditions remain favorable. Please call the office at 989-275-7135 by mid-May for updates or visit the Gypsy Moth page.

5. Will the trees in my yard or woodlot die once the leaves are completely chewed off by the gypsy moth?

Most trees survive, but survival depends on tree vigor before defoliation and the species of tree being attacked. Healthy, vigorous trees are generally able to withstand two or three years of heavy feeding by the gypsy moth. However, yard trees that are weakened by old age, drought, competition from other trees, or insects and diseases may die after one defoliation. In addition, coniferous trees, such as pine or spruce, cannot produce new needles after defoliation. Thus complete defoliation by gypsy moth may kill these trees.

6. Why is there a Suppression Spray Program?

The goal of the Suppression Program is to protect valuable trees from mortality by controlling gypsy moth population outbreaks in areas where the gypsy moth is established.

The Suppression Program assists communities and landowners in the management of gypsy moth by providing the expertise and equipment for aerial sprays. Treatments under this program are paid for by the Roscommon County millage.

The program uses Organic Certified Foray48B® a naturally occurring soil bacteria, Bacillus thruingiensis var. kurstaki or B.t.k., applied by aerial spray.

7. How do I request spraying or apply to a Suppression Program to be sprayed if I live outside the county?

The Roscommon County Suppression Program is funded by a county-wide millage assessment on all Roscommon County property taxes. Each fall a team of gypsy moth survey personnel check private land for infestation.

If you live out-side Roscommon County’s border, contact your local county, township or municipality. Give a detailed description of where you are located and let them know about the gypsy moth infestation you are experiencing. Contact your county clerk to register your concern. Clerks are not gypsy moth specialists; however, residents typically bring their concerns to their county government through their county clerk.You may also wish to contact your local government to express interest in participating in a suppression program. Local interest is essential because a suppression program is paid for by the people it serves, so many counties will not participate without interest and involvement.

Note: Suppression Program sprays occur in May or as late as early June of each year. The areas to be sprayed are determined in September, October, and November of the previous year. Therefore, county, township and municipality suppression programs need to receive requests as early as possible.