Cottony Maple Scales Invade Trees

The infestation of the cotton maple scale begins in June when the female lays egg masses through the summer, eventually hatching into crawlers from June through mid-July (each egg mass contains 1,000-1,500 eggs).

One of the largest and most conspicuous scale insects, the cottony maple scale, has made its mark on maple trees in the city of Dunkirk, New York. Trees along roads and residents’ yards appear to be strung with popcorn along its branches, a sign that a severe infestation is taking place.

The cottony maple scale is defined as a usually cyclical problem with damaging populations that occur irregularly, but typically can remain high for one to three years once established.

Those crawlers migrate to the underside of the host plant, being maple trees, and they insert their piercing-sucking mouthparts and feed on the sap from vascular cells of the plant. The "pest" spends the remainder of the summer feeding on leaves.

The application of horticultural oil is recommended to be used in early spring before new growth starts as a dormant treatment. Crawlers can be managed with an application of a registered insecticide made in late June and repeated according to the labels instructions in early July.

Source: Michael Rukavina, observertoday.com