MSU Urban IPM Alerts

Several caterpillars have been found causing severe defoliation to willows. These white satin moth caterpillars feed on the leaves of willows, poplars, cottonwoods, and aspens. In Montana, they have mostly been found defoliating golden willows. The caterpillars are reddish and hairy with yellow spots.

In the Schutter Lab we have been receiving many woody ornamental samples with symptoms consistent with synthetic auxin herbicide injury. This is a group of herbicides including many that are used for broadleaf weed control in lawns. 

Several reports have come in about grubs in the garden and grass. Adults are also emerging and flying to lights.
These are May/June beetles.

Montana has several home-invading weevils that come into our homes. They range from small, grey weevils (less than 3mm) to larger black beetles.

Several phone calls and emails have come in about the sculptured pine borer. It is one of the largest flatheaded borers  found in the western US. The adults that are out now are likely the result of infestations of trees that were injured or fire damaged in the summer of 2016.

Our rainy days followed by temperatures above 75°F are ideal for fire blight infection. Old cankers are beginning to seep bacteria as the pathogen grows. This UrbanAlert provides general information about fire blight and links to helpful resources, including a tool to assess your fire blight risk.

Thank you,

Katrina Mendrey and Eva Grimme

The common ticks in Montana this time of the year are the Rocky Mountain wood tick, Dermacentor andersoni and the American dog tick, Dermacentor variabilis. See the alert for further information.