Northern WI Forest Health

Pink-Striped Oakworm Population Remains Low

Posted on by akabelowsky
Photo of a pink-striked oakworm caterpillar on a hand.

This large caterpillar, a pink-striped oakworm, has great camouflage and blends in with oak twigs very well. / Photo Credit: Linda Williams, Wisconsin DNR

By Linda Williams, DNR Forest Health Specialist, Woodruff;
Linda.Williams@wisconsin.gov or 920-360-0665

Pink-striped oakworm is a native fall defoliator. Fall defoliators affect the health of trees less than defoliators that occur in the spring.

Although literature states that high populations of this caterpillar can create significant defoliation, no defoliation was noted in the area this caterpillar was observed in Oneida County.

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Aphids Make Sticky Situation For Oak, Beech Trees

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Photo of Myzocallis oak aphids on a leaf, with an adult at the left.

Myzocallis aphids feed on the top side of oak leaves. An adult is pictured on the left. / Photo Credit: Linda Williams, Wisconsin DNR

By Linda Williams, DNR Forest Health Specialist, Woodruff; Linda.Williams@wisconsin.gov or 920-360-0665

and Bill McNee, DNR Forest Health Specialist, Oshkosh; bill.mcnee@wisconsin.gov or 920-360-0942

Aphids — and the honeydew they produce — have made their mark on trees in Wisconsin during 2023.

Midway through the summer, oak trees in areas of Vilas and Oneida counties were buzzing with activity. During September, beech trees in eastern Wisconsin became busy with a different species of aphid.

A look at the two situations:

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Pine Bark Adelgids Infest White Pines

Posted on by akabelowsky
Photo of pine bark adelgids covered in white, waxy fluff on a white pine tree.

Pine bark adelgids covered in white, waxy fluff on a white pine tree. / Photo Credit: Wisconsin DNR

Michael Hillstrom, DNR Forest Health Specialist, Fitchburg
Michael.Hillstrom@wisconsin.gov

Pine bark adelgids are tiny, aphid-like insects that suck the sap of white pines. The bugs protect themselves from predators with a fluffy, white wax covering. Pine bark adelgids generate concern when thousands of them gather on white pines to feed, making the pine bark appear covered with sap.

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