Issue 3, May 7, 2012

Scouting Watch

Emerald ash borer adult emergence was reported from Normal in central Illinois on April 30. In previous years, adult emergence typically began in early June in that area of the state. Adults will continue to emerge in southern and central Illinois for several weeks. Thanks to Kevin Black, Growmark, for his report.

Emerald ash borer degree day map.

Bagworm should be hatching in southern Illinois. Remember that this insect balloons or blows on silk strands from tree to tree for about two weeks before settling down to feed. Although some light feeding occurs during this ballooning period, leaf damage is light. One spray applied two to three weeks after egg hatch will provide almost 100% control. Spraying earlier will typically require an additional spray to achieve control on later ballooning larvae.

Silverleaf Whitefly, Bemisia tabaci, also known as the sweetpotato whitefly, is numerous in central Illinois. The adults are less than one-eighth long and yellowish with wings covered by a white powder. They fly readily from foliage when disturbed. The smaller, oval, almost transparent nymphs feed on sap and are found on leaf undersides. Their feeding causes leaf yellowing, curling, and early drop and are primarily a pest of greenhouses and outdoor flowers. These insects overwinter in Illinois but may have survived in higher numbers due to the mild winter. Numbers currently being seen are usually not achieved until mid to late summer.

Silverleaf Whitefly adults on hibiscus.

(Phil Nixon)

Phil Nixon

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