Note:

Images may appear blurry in some web browsers. We recommend opening newsletter links in Google Chrome.

Diplodia Shoot Blight vs. Red Pine Shoot Moth

The tip of a red pine branch is dead and hooked over like a shepherd's crook.

Scattered damage to new red pine shoots has been observed across many counties this summer. With the intermittent rains during the summer, the first thought was that Diplodia shoot blight, a fungal disease, was causing the damage. Upon a closer look, some of the shoot mortality is caused by the red pine shoot moth. From a casual glance, these two problems will look the same, so you really need to take a closer look. Read more…

Redheaded Pine Sawfly Numbers Remain Elevated In Northeastern Wisconsin

Redheaded pine sawfly larvae feeding on red pine needles. Note the needle stubs where they have eaten nearly to the base of the needle.

For the third year in a row, colonies of redheaded pine sawfly have been noted on understory red pine in northern Wisconsin, with the most reports coming from Vilas and Oneida counties. Read more…

White Pine Branch Tips Red And Wilting

Multiple white pine branch tips are brown and dead along a branch from a combination of bast scale and the disease called Caliciopsis.

White pine trees in many counties in northeast and northcentral Wisconsin have developed rusty-colored wilting needles on outer branch tips scattered throughout the tree’s crown. These dead branch tips are associated with the feeding by white pine bast scale. The scale is a tiny insect that inserts its straw-like mouthpart into the twig to suck sap from the outer layers of phloem called bast. Damage has been observed on trees over 20 feet tall this year. Read more…

Pear Slug Sawfly Defoliation: Treatment Tips

Pear slug sawfly larvae on a leaf with some areas of defoliation.

Pear slug sawflies (Caliroa cerasi) feed by scraping off the upper layer of the leaf, leaving the veins and the lower leaf surface. Severe defoliation has been observed and reported recently on crabapple, apple, mountain ash and serviceberry in Oneida, Forest and Oconto counties. The first generation occurs earlier in the summer, so the larvae and defoliation seen now are due to the second generation of the insect, which is larger than the first generation. Read more…

Fall Webworm Is Active

As we head into September, fall webworm is starting to make its presence known. This native insect feeds on deciduous trees and shrubs and appears every year in yards and forests. Fall webworm forms loose webbing over branch tips and can completely cover a small tree with webbing. You will find both live and dead caterpillars, partially eaten leaves and frass (caterpillar poop) inside the webbing. Read more…

Oak Leaves Turning Brown? There Are Several Reasons This Year.

Leaves from an oak wilt infected tree with characteristic water-soaked brown on the outer portions and green still found near the base of the lead.

Oak wilt symptoms are active right now, but so are several other oak issues that may be mistaken for oak wilt symptoms. Issues including Tubakia leaf spot, Botryosphaeria canker, kermes scale damage and mite damage are all causing problems and may be mistaken for oak wilt. Read more…