Jack pine budworm caterpillar on jack pine. Photo: Todd Lanigan, WI DNR
I conducted surveys for jack pine budworm caterpillars and egg masses in Dunn, Eau Claire, Jackson, Monroe, Pierce, and St. Croix counties last spring (caterpillars) and this fall (egg masses). Fortunately, I did not find any caterpillars and only one egg mass on red pine in Pierce County. Based on information from these surveys, jack pine budworm should not be a problem in 2018.
Jack pine budworm egg mass on jack pine needle. Photo: Todd Lanigan, WI DNR
In Wisconsin, jack pine budworm is a pest of jack, red, and white pine. It has rarely been found on white spruce, and in those cases only when the trees were located next to an infested plantation. Jack pine budworm can cause problems in natural stands, plantations, edge plantings/aesthetic strips, yard trees, and anywhere host trees are found.
For more information on management of jack pine in the state, click here.
Written by Todd Lanigan, forest health specialist, Eau Claire. Todd.Lanigan@wisconsin.gov; 715-839-1632
Multicolored Asian ladybeetles search for places to spend the winter and often congregate in protected places. Photo: Linda Williams, WI DNR
This fall, some areas of the state saw large numbers of ladybugs (specifically multicolored Asian ladybeetles) congregating as fall gave way to colder temperatures. Box elder bugs, leaf-footed bugs (or western conifer seed bugs), and brown marmorated stink bugs were also seen congregating this fall in areas of the state where they have been found before. These insects are attracted to homes and will attempt to find a way inside to spend the winter in a protected place. The urge to look for an overwintering spot is triggered by the first hard frosts and freezes of the season, but this year we had a fabulous warm-up after a cold spell which allowed the insects ample time to congregate on houses.
A Western conifer seed bug (sometimes called leaf footed bugs) on the left, and boxelder bug on the right. These two species also congregate in the fall as they look for warm protected places to spend the winter. Photo: Linda Williams, WI DNR
If you’re having problems with these insects invading your house you can try to “build them out”. Spraying the exterior of your house with appropriate pesticides to keep them out (which will repel all insects for a time) works well but it’s recommended this is completed by the last week of September or first week of October. UW Extension offers a fact sheet that gives suggestions for keeping ladybugs out of your home. When I get calls about ladybugs or box elder bugs inside the home, I recommend vacuuming the critters up, but always avoid squishing, since squishing them will stain whatever they are crushed on. Be sure to empty vacuum bags that have ladybugs in them as the ladybugs will start to smell after they die.
It’s not unusual for me to hear of folks mixing up multicolored Asian ladybeetles with Japanese beetles … they’re two different critters. And, yes, multicolored Asian ladybeetles are indeed ladybugs. Both exotic and native ladybugs feed on aphids and scales which means that they’re beneficial, but only the exotic ones will try to spend the winter in your house or garage.
Written by: Linda Williams, forest health specialist, Woodruff. Linda.Williams@wisconsin.gov; 715-356-5211 x232
Past reports from the 1992 and 1967 WI DNR Forest Health Annual Reports
25 years ago – 1992
“European fruit lecanium (Parthenolecanium corni (Bouche))
Heavy infestations of this scale insect were reported on sugar maple twigs in Vilas and Price counties.
Jack pine budworm (Choristoneura pinus (Rohwer))
The outbreak in the northwestern counties, which began in 1991, exploded this year (Figure 16). Over 114,000 acres of jack pine were heavily defoliated in Douglas, Bayfield, Washburn and Burnett counties. Egg mass surveys indicate extremely high numbers of jack pine budworm. The area of defoliation may increase in 1993. The present defoliation is not expected to cause significant mortality except in Highland Township, but another year of heavy defoliation in the same stands could cause 10-15 percent mortality. In Highland Township, Douglas County, extremely severe feeding produced significant. mortality and top dieback on several thousand acres of jack pine. Most of these stands are being harvested this winter. Moderate to heavy defoliation also occurred in Jackson, Juneau, Eau Claire, Marinette (1,650 acres), Vilas (2,960 acres) and Oconto counties. In Marinette County, 20 acres of 70-year-old jack pine were cut to release young jack pine and white pine. Jack pine budworm was causing severe top mortality. Evidence of budworm in the northern portion of the Monroe County Forest was observed on 35-40 year old jack pine (Sections 4, 9,16, T19N, R3W). DNR foresters have silvicultural guidelines available to manage budworm-prone jack pine stands.”
Continue reading “Of historical interest…”
Since the August newsletter, it was announced that six new counties would be quarantined for emerald ash borer (EAB). The find in Chippewa County was due to a vigilant landowner while the other finds were due to trapping by USDA APHIS.
WI counties quarantined for EAB (DATCP). Most of Wisconsin is EAB-free, including most of the northern half and the yellow areas in all
quarantined counties. EAB has been confirmed only in those cities, villages and townships
colored dark green.
Continue reading “Six new counties quarantined for EAB”
Gypsy moth egg mass
Early fall is the best time for property owners to determine whether gypsy moths will be a problem next year. Gypsy moth egg masses are tan-colored and about the size of a nickel or quarter. Egg masses will not hatch until next spring, which means landowners have plenty of time to plan to minimize gypsy moth damage next summer. New egg masses produced this year feel hard, whereas those that are older are soft and appear faded. Most egg masses will be found on tree trunks and the undersides of branches, but they can also be found on buildings, firewood piles, vehicles and other outdoor objects.
Continue reading “Look for next year’s gypsy moth infestations”
A mass emergence of winged ants. Photo by Mike Kamke.
On August 29, and again in early September, a mass emergence of winged ants occurred in southern Vilas County and some areas of northern Oneida County. Mass emergences of winged adults are part of a reproductive strategy used by ants to overwhelm predators, in the hope that a few of the new queens will mate and establish their own nests. When weather conditions are right, winged individuals from many ant colonies in an area will emerge and fly away to mate and start their own nests.
Winged ants consist of large winged females and smaller winged males, but many folks that reported these insects were concerned that they were seeing swarms of wasps since most people aren’t accustomed to seeing ants with wings. Once new queens and males fly away from the nest, they will eventually drop to the ground, shed their wings, mate and start a new nest. These events are relatively rare for folks to see as they are very short lived, with the winged ants generally being gone within a day.
Mature northern red oaks killed by oak wilt in Sawyer County. Photo by Paul Cigan
Late-summer aerial and ground surveys revealed new oak wilt infections within northern red oak stands in Rusk, Sawyer and Washburn counties. Below is an update on the finds in each of the counties.
In Rusk County, aerial detection surveys led to the confirmation of 10 new infections on county forest property. Suspected factors for these infections include spring storm damage and latent detection of past infections caused by logging damage during unrestricted spring harvesting. The county forestry department continues to use cut-stump herbicide treatments to control below-ground transmission. They plan to continue follow-up monitoring of treated pockets and have reported encouraging results to date; only a few pockets treated between 2015 and 2016 contained newly infected oaks on or near the edge of the treatment zone.
Continue reading “Oak wilt update for Rusk, Washburn, and Sawyer counties”
Oak skeletonizer is a tiny caterpillar that feeds on oak by removing just the lower layers of the leaf, leaving the paper-thin upper epidermal layer.
These two pictures are of the same leaf. In this photo, the leaf is being held up to light to show how there is one very thin layer of leaf left where oak skeletonizer was feeding.
Oak skeletonizer (Bucculatrix ainsliella) is a native insect that defoliates oak in Wisconsin. Damage was observed in most counties in northeast and central Wisconsin. There are two generations per year. Damage from the first generation this year barely showed up at all, but defoliation by the second generation became quite noticeable in late August and September. Continue reading “Oak skeletonizer showed up late this season”
Round hard galls from oak bullet gall wasps can impact growth of young oaks if the population is high enough.
There are a lot of galls on oak. One that can cause some problems at heavy densities is the oak bullet gall. These galls, sometimes called rough bullet galls, can quickly become unsightly. I usually see them on burr oak and occasionally on swamp white oak. They are caused by a gall wasp. The galls start out green-colored, eventually darkening to brown as the season progresses and the gall wasp larvae grow inside. Continue reading “Oak bullet gall”
Bronzing along the veins of this oak leaf is due to feeding mites.
In August and September, I observed bronzing due to mites feeding on some young swamp white oaks. The tops of the leaves were very bronzed along the main veins, while the undersides of the leaves remained unaffected. When looking at the leaves with my hand lens and under the microscope, I saw a very heavy infestation of mites. Mites suck plant juices from the cells of the leaf.
Continue reading “Spider mites cause bronzing on oak leaves”