DNR Weekly News Update for July 17, 2018
Published - July 17, 2018 by the Central Office
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Fall webworms start making an appearance
MADISON--Web-like nests of fall webworm caterpillars, a common native pest active from July through September in Wisconsin, are beginning to appear in parts of the state.
"Fall webworms are rarely large enough to cause lasting damage to trees, but the presence of nests and feeding damage from caterpillars can greatly affect how the tree looks," says Todd Lanigan, forest health specialist for the Wisconsin Department of Natural Resources.
Fall webworms typically form nests of loose webbing over the tips of tree branches. A rake or pole may also be used to roll up nests and remove them from the tree. Detached nests should be placed in a container of soapy water overnight to drown caterpillars.Photo credit: DNR
The fall webworm (Hyphantrea cunea) feeds on leaves of almost all shade, fruit, and ornamental trees and shrubs, except for conifers, throughout most of the U.S. and southern Canada. They typically form nests of loose webbing over the tips of tree branches.
"Trees typically recover from feeding damage on their own, but defoliation for more than two or three years in a row could make trees more susceptible to diseases and other problems," he says.
If intervention becomes necessary, one of the easiest ways to manage fall webworms is to simply tear open the nests with a rake or pole.
"Opening the nests allows natural predators such as birds and other insects to reach caterpillars inside the otherwise impenetrable webbing," Lanigan says.
A rake or pole may also be used to roll up nests and remove them from the tree. Detached nests should be placed in a container of soapy water overnight to drown caterpillars. One may also simply scrape the nests off onto the ground and crush them to destroy the caterpillars. These actions are best undertaken in early morning or late afternoon when caterpillars are gathered in their nests.
Never attempt to burn the nests off the branches - this action will almost certainly damage the tree and may result in an uncontrolled fire and injury.
On small trees, where webbed branches are within reach, nests can be manually pruned out and destroyed. This is only practical if the webs have not become too large and the aesthetic shape of the tree will not be affected by pruning.
On larger trees, pesticide treatments might be useful. Apply appropriate pesticides while caterpillars are inside the nest in the morning or late afternoon. Chemical treatments are most effective on small, young caterpillars such as those present in late July/early August. Larger, solitary caterpillars are harder to control with pesticides. When applying pesticides, it is important to make sure that the nest is completely penetrated. Always read and follow label directions for safe use of any pesticide.
For more information on fall webworms, visit UW Extension at hort.uwex.edu/articles/webworms or Michigan State University's Extension at msue.anr.msu.edu/news/the_rise_and_fall_of_the_fall_webworm (both links exit DNR).
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Aug. 1 deadline looms for Upriver Lakes Sturgeon Spearing Drawing
OSHKOSH, Wis. -- Sturgeon spearers have until Aug. 1 to apply for a 2019 Upriver Lakes sturgeon spearing license or purchase a preference point to be used in future drawings.
Benjamin Berger's 2018 opening day fish weighing 155.6 pounds and measuring 75.6 inches. This is the heaviest fish harvested from the Winnebago System since the 2014 spearing season. Applications for the 2018 upriver lakes season must be purchased by Aug. 1.
Participation in the Upriver Lakes sturgeon spearing season on lakes Butte des Morts, Winneconne and Poygan in February 2019 is controlled through a preference point system where applicants possessing the most preference points are given priority in the drawing. As a reminder, you must apply once every three years to retain your preference points.
All applicants are notified by Oct. 1 of whether they were drawn for a license and authorized to purchase a license for the 2019 Upriver season. All applicants not drawn for an Upriver Lakes license, or those who purchase a preference point only, can still purchase a license before the Oct. 31, 2018, deadline to spear on Lake Winnebago. Spearers can only buy a license for either Lake Winnebago or the Upriver Lakes, not both.
Groups of up to four may apply together by designating a leader and using his/her Wisconsin Department of Natural Resources customer ID on all applications. Each group will carry the preference points of the group member with the fewest points.
Spearers can apply for the license drawing or purchase a preference point through Go Wild or any of our sales locations.