Female gypsy moth lays an egg mass.
As of mid-July, DNR forest health staff have received reports of adult gypsy moths present as far north as Burnett County. The brown-shelled pupae and white female moths can be crushed with a stick. The remaining caterpillars will also pupate soon, and where the caterpillars are a problem, they can be crushed, drowned in soapy water, or sprayed with insecticide or insecticidal soap. Continue reading “Gypsy moth adults appearing now”
EAB emergence map as of July 10, 2017. Tan colors in the north are approaching peak emergence, light green is peak emergence, and olive is past peak emergence.
Much of Wisconsin has reached peak emergence of emerald ash borer adults.
EAB continues to be found in new areas. Wisconsin tracks EAB at the municipality or township level. Quarantine counties are shown in tan and infested areas are shown in green on the EAB Detections and Quarantine map below.
New county quarantines
New finds in counties already quarantined
EAB quarantine map. Counties shaded in tan are quarantined for EAB, green areas are townships and municipalities where EAB has actually been identified.
Written by: Linda Williams, forest health specialist, Woodruff, (Linda.Williams@wisconsin.gov), 715-356-5211 x232.
Forest health program staff and coverage areas.
The forest health specialist zones were redrawn to better align with the new integrated forester teams, areas and districts. New coverage zones will go into effect on June 25, 2017.
Central Zone: Mike Hillstrom will cover Adams, Green Lake, Juneau, Marathon, Marquette, Portage, Waushara and Wood counties. Linda Williams will cover Lincoln County. Todd Lanigan will cover Taylor County.
East Central Zone: Linda Williams will cover Brown, Menominee, Oconto, Outagamie, Shawano and Waupaca counties. Bill McNee will cover Calumet, Door, Kewaunee and Manitowoc counties.
Written by: Rebecca Gray, forest health team leader, Fitchburg (rebecca.gray@wisconsin.gov), 608-275-3273.
Adult T. planipennisi wasp collected as a pupa in Ozaukee County, May 2017. This species attacks EAB larvae beneath the bark. Actual size is 1/8” in length.
This summer, DNR staff will continue to do introductions of three natural enemy wasps that attack emerald ash borer: Tetrastichus planipennisi, Spathius galinae and Oobius agrili. The Tetrastichus and Spathius wasps attack EAB larvae beneath the bark, and the Oobius wasps attack EAB eggs on the bark surface. The tiny wasps do not sting or bite, and the public is unlikely to know they are present. Continue reading “Wasp releases to fight emerald ash borer (EAB)”
EAB peak emergence map. Tan color is approaching peak emergence, light green is peak emergence, and dark green is past peak EAB emergence. Map from June 19, 2017.
Initial emergence of Emerald ash borer (Agrilus planipennis) has begun in Wisconsin and is likely occurring throughout Wisconsin at this time. Peak emergence is approaching.
EAB continues to be found in new areas. Wisconsin continues to track EAB at the municipality or township level; quarantine counties are shown in tan and infested areas are shown in green on the map below.
New county quarantines
New finds in counties already quarantined
EAB quarantine map. Counties shaded in tan are quarantined for EAB, green areas are townships and municipalities where EAB has actually been identified.
Written by: Linda Williams, forest health specialist, Woodruff, (Linda.Williams@wisconsin.gov), 715-356-5211 x232.
Asian longhorned beetle is a large, glossy black beetle with white spots and white banding on its antennae. Photo by: Dennis Haugen on bugwood.org.
USDA APHIS continues to monitor and conduct control efforts in areas where Asian longhorned beetle is established. They recently released a statement that they were “removing 28 square miles from the Asian longhorned beetle (ALB) regulated area in the eastern part of Queens, New York”. Quarantines are usually lifted after surveys have not turned up new beetles or damage in the quarantine for a certain number of years. We do not have any infestations of Asian longhorned beetle in Wisconsin that we’re aware of, but it’s necessary to stay vigilant.
Mature gypsy moth caterpillar with distinctive blue and red dots.
By late June, gypsy moth caterpillars will be large (>1” in length) and noticeable in most of Wisconsin. Nuisance caterpillar problems and defoliation from the caterpillars will be apparent by now, even in the far northern counties. As of mid-June, we have only had a few reports of nuisance caterpillars. This is a hopeful sign that populations will remain low in 2018. The June rainstorms will also help the Entomophaga fungus to kill gypsy moth caterpillars.
Continue reading “Large gypsy moth caterpillars now present; mating disruption treatments begin.”
Anthracnose on maple leaves. Photo by Joleen Stinson.
As anticipated, anthracnose is common on a number of deciduous tree species statewide this spring, especially maple and ash. Many of the maple samples we’ve seen also have tar spot. The cool, wet, humid conditions this spring were ideal for fungal leaf diseases. Anthracnose symptoms appear as patches of brown or black, dead leaf tissue which may cause leaves to curl or shrivel up as damage progresses. Trees may drop the infected leaves but will send out new leaves within a few weeks.
Aspen with thin crowns caused by frost damage. Photo by Bob DeBruyckere.
Damage to other species, including aspen, cottonwood and willow appears to have been caused by frost damage. These tree species likely became active and had the buds swell during the early warm up in February, then suffered damage to the buds and twigs from the cold weather thereafter. Although the damage was severe in some cases it seems that the trees produced new buds and are working on sending out additional leaves.
Significant dieback was noted in many locations around the state, including on some hybrid poplar in Shawano County, on trembling aspen in central and northern Oconto County, and on big toothed aspen in western Vilas County. We had reports of impacted aspen, cottonwood and willow from south central, southwest, central, west central and northcentral Wisconsin. Forest health specialists in Minnesota report similar damage.
Keep impacted trees healthy by watering (where possible) during hot and dry periods to help the trees recover.
Written by: Mike Hillstrom, forest health specialist, Fitchburg, (Michael.Hillstrom@wisconsin.gov), 608-513-7690
An annual or “Dog Day” cicada.
A recent article from Science Alert reported that some of the 17-year periodical cicadas associated with Brood X, have begun emerging – 4 years early! Brood X doesn’t typically emerge in Wisconsin, although it does emerge in some areas of Michigan and Illinois. The brood that emerges in a few areas of Wisconsin is Brood XIII which isn’t due to emerge again until 2024. We also have annual or “Dog Day” cicadas that emerge every summer in Wisconsin.
Cicadas are harmless, they do not bite or sting or attack people, they are not poisonous and don’t transmit disease, but they are big and the periodical cicadas emerge in huge numbers which can be quite upsetting to some people.
The problem for trees comes when the females lay their eggs. They use a stout ovipositor to puncture the twigs of small trees and shrubs, laying an egg in the slit created by the ovipositor. This damage to the tree can cause twigs to die and break off. Some young trees can be badly damaged and may lose most of their twigs and branches, they may die or be severely stunted.
An additional aggravation for many people is the very loud buzzing noise made by the males; some people refer to these insects as heat-bugs because their loud buzzing is often heard during the hottest days of the summer.
Cicadas emerge from the ground, climb an object, emerge from their exoskeleton, and leave the empty exoskeleton behind after they expand their wings and fly off.
For more info on periodical cicadas check out the Cicada Mania webpage.
Written by: Linda Williams, forest health specialist, Woodruff, (Linda.Williams@wisconsin.gov), 715-356-5211 x232.
Sapsuckers drill orderly holes through the bark into the cambium layer of the trees, causing them to bleed sap.
Sapsuckers are birds that drill orderly holes through the bark of trees. The holes go just through the bark to the cambium layer, causing the tree to bleed. The sapsuckers then return to them later that day or the next day to feed on the sap. Sapsuckers are migratory and may just pass through an area in the spring, but they will sometimes return to the same tree over multiple years, creating new rows of holes each year. Trees will attempt to grow over this damage, and in most cases are successful. Occasionally the damage is so extensive that mortality can occur from that point up. Federal regulations don’t allow you to shoot sapsuckers, so control is usually some manner of deterrent, like wrapping the main stem with hardware cloth or burlap, or hanging scare tactics in the tree.
Written by: Linda Williams, forest health specialist, Woodruff, (Linda.Williams@wisconsin.gov), 715-356-5211 x232.
