Homeowners who are interested in reducing gypsy moth caterpillar numbers this summer should consider oiling or removing reachable egg masses well before the eggs begin hatching in the second half of April. Gypsy moth egg masses are tan-colored lumps about the size of a nickel or quarter, and usually contain 500 to 1,000 eggs. The egg masses can be found on any rough or protected surface including trees, houses, firewood piles, bird houses and other outdoor objects. Do NOT scrape the egg masses onto the ground or step on them or break them apart. Many of the eggs will survive and still hatch.
March is a good month to consider insecticide treatments for high-value ornamental ash trees this spring. Emerald ash borer (EAB) has been found in 42 Wisconsin counties and is expected to be more than 99% fatal to ash trees that are not protected with insecticide every 1-2 years. Many insecticides used in EAB treatments are applied between mid-April and mid-May, and now is a good time to contact a tree service or other pesticide application business if arranging for professional insecticide treatments.
Property owners with susceptible ash trees should consider a number of factors when deciding to treat their ash trees, including financial cost, tree condition and location, the shade a tree provides, its contribution to property values, and aesthetic view. Homeowners should also consider the financial cost of removing a tree that is killed by EAB, and the benefits that a dead tree no longer provides.
Emerald ash borer (Agrilus planipennis) continues to be found in new areas. Regional Forest Health Updates were not sent during the 2016/2017 winter, so the list below includes new EAB finds from the last few months. Wisconsin continues to track EAB at the municipality or township level; infested areas are shown in green on the map below. If you know you have EAB please contact us with that information so we can verify the infestation and update the maps. If your area:
- is not shaded in green on the map please contact DNR or
- is not shaded at all on the map please contact DATCP.
You can reach both agencies from the menu options when you call 1-800-462-2803. Continue reading “Emerald ash borer new locations in Wisconsin”
EAB biocontrol releases in Wisconsin will continue in 2017. Wisconsin first released parasitoids to help control emerald ash borer (Agrilus planipennis) in 2011. Our first releases in northeastern Wisconsin occurred in 2016 when we released the two larval parasitoids Tetrastichus planipennisi and Spathius galinae, as well as the egg parasitoid Oobius agrili. These parasitoids are incredibly small, but they find EAB larvae and eggs just fine, helping to reduce the population of EAB. These parasitoids will not stop EAB, but they are an additional tool we can use to slow the population growth.
Written by: Linda Williams, forest health specialist, Green Bay (Linda.Williams@Wisconsin.gov), 920-662-5172.
Looking for a financial assist in your efforts to control invasive species?
The Wisconsin Invasive Species Council website lists 61 different grant opportunities that are available from Federal and State agencies as well as private foundations. The list is searchable by applicant (tribe, government agency, company, non-profit, individual) and type of invasive organism (plant, animal, aquatic, invertebrate, disease). All but one has a link that takes you to more information or a contact person.
Why not take a few moments to explore these opportunities?
Written by: Michael Putnam, invasive plants program specialist, Madison (Michael.Putnam@wisconsin.gov), 608-266-7596.
If the weather warms up a bit, we could see eastern tent caterpillars (Malacosoma americanum) and forest tent caterpillars (Malacosoma disstria) hatching before the next forest health newsletter. These are both early spring caterpillars and hatch very soon after bud break.
Eastern tent caterpillar will make a web nest that can often be seen on wild black cherry along roadsides, although they also like to feed on crabapple, apple, and a few other species. Forest tent caterpillar does not make a web nest and prefers to feed on aspen and oak.
If you had box elder bugs or multi-colored Asian lady beetles congregating on your house last fall, you’re probably starting to notice them appearing in your house again as the weather warms this spring. Last fall they were able to find a place on/in your house to overwinter and now they are attempting to leave your house to head back into the fields where the beetles, like all ladybugs, will feed on aphids and the box elder bugs will feed on the sap of certain trees.
The invasive brown marmorated stink bug (BMSB) is establishing in Wisconsin. BMSB is an agriculture, garden and home pest. Action to control populations may be needed in coming years.
BMSB is native to eastern Asia and was first officially found in the U.S. in 2001. The discovery of BMSB juveniles and the first noted pairs of mating adults in 2016 are continued signs that this invasive pest is establishing and reproducing in Wisconsin. We also had the first reports of BMSB feeding on plants, not just overwintering in structures. We expect populations will continue to increase in coming years.
A map of counties where BMSB has been confirmed or is suspected as of October 2016 was created by P.J. Liesch, University of Wisconsin-Madison Insect Diagnostic Lab and Bill McNee, Wisconsin DNR.
For information about how to identify BMSB and how to manage nuisance populations check out these publications.
- University of Wisconsin-Extension
- BMSB look-alikes – an excellent Minnesota publication available by request.
Written by: Mike Hillstrom, forest health specialist, Wisconsin Dells (Michael.Hillstrom@Wisconsin.gov), 715-459-1371.
If you work around hemlock trees, keep an eye out for signs of hemlock woolly adelgid (HWA), an aphid-like insect that was introduced to eastern North America and is fatal to most hemlock trees.
HWA produces distinctive, small balls of white wool at the base of hemlock needles. Recently, a number of infestations have been found in western Michigan and there is a risk that the pest could spread across Lake Michigan into Wisconsin. Hemlock woolly adelgid has not been found in Wisconsin. Continue reading “Unwanted in Wisconsin: hemlock woolly adelgid”