Issue 5, May 28, 2013

Scouting Watch

Several borers are susceptible to control at this time throughout the state. Roundheaded appletree borer, flatheaded appletree borer, peachtree borer, and viburnum borers are all susceptible to control. The appletree borers are beetles that attack most rose family plants, including crabapple, hawthorn, serviceberry, and cotoneaster. The flatheaded appletree borer attacks other unrelated trees, including young maples. Peachtree and viburnum borers are moth borers.

Flatheaded Appletree Borer Damage to Serviceberry.

Viburnum Borer Larva and Damage.

Euonymus scale crawlers have hatched in central and southern Illinois and are susceptible to control. The lemon-yellow tiny crawlers should be visible on the leaves next week in northern Illinois where they will be susceptible to insecticidal soap, summer spray oil, and pyrethroids such as permethrin (Astro), bifenthrin (Onyx, Talstar), lambda-cyhalothrin (Scimitar), and cyfluthrin (Tempo).

Euonymus Scale Crawlers.

Aphids do well under the cool, wet weather that we have been having. Infestations are likely on birch, alder, crabapple, spirea, yellow poplar, linden, and hydrangea. As temperatures warm and the weather becomes drier, natural enemies such as parasitic wasps, lady beetles, lacewings, and syrphid flies are likely to get them under control. If insecticide control is necessary, those recommended for euonymus scale crawlers above should be effective.

Aphids on Tree Leaf.

(Phil Nixon)

Phil Nixon

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