Cottony maple scale a messy problem

Q. I was wondering what you can tell me about cottony maple scale. I have it on my silver maple tree. I am finding out that there is a large outbreak in northern Illinois this year. Many people are suffering from this with what appears to be sap falling from the tree. My whole yard and house is covered with this sap which I found out is really called "honeydew." It is not sap from the tree, it is actually the insect defecating. My friends have this all over their cars. It is very sticky! I took a couple of leaves and the insect to Platt Hill Garden Center in Bloomingdale and they informed me what it was. We cannot even enjoy our yard this summer, it's terrible. A. An outbreak of cottony maple scale is plaguing northeastern Illinois. Since 1867 the state's residents have reported successive outbreaks lasting for two to three years. Their abundance becomes greatly reduced when natural predators, including a number of wasps and fly parasites are present. Silver maple and box elder are the primary hosts of cottony maple scale. However, infestations may be seen in other maples, white ash, hackberry, dogwood, beech, apple, oak, black walnut, linden, elm, black and honey locust as well. As they overwinter, cottony maple scales take the form of small, brown, flattened 1/8-inch long scales which attach to the bark of twigs and small branches. By spring the insects have developed into mature female scales - brown, roundish and about 1/4 inch in diameter, which look like tiny army helmets or turtle shells. During this time, the mated females produce a white egg mass, or "cotton," in which the eggs are embedded. The infected branches and twigs with the egg masses and the attached female look as if they have popcorn attached. In mid July the eggs hatch into reddish-brown crawlers which move from the branches and twigs to the leaves where they feed along the midrib or veins. By late summer, mature winged males mate with immature females and soon die because they are not able to feed. Before the leaves drop in fall, the immature females move back to the twigs to overwinter.Host trees become damaged if there are heavy scale populations causing dieback of branches and twigs. These insects feed on plant sap and excrete a thin, syrupy liquid called honeydew. The honeydew often attracts colonies of sooty mold fungi, which gives leaves, twigs, and branches a blackened, sooty appearance. Heavily attacked trees may drip honeydew on to the ground where it becomes a nuisance when it coats vehicles, furniture, sidewalks and toys. There are several ways to control cottony maple scale. Mother nature can lend a hand if you allow natural enemies such as wasps and fly parasites along with natural predators such as various species of lady beetles to help. Outbreaks generally build up over a period of 4 to 5 years on average and then disappear due to natural enemies and changing climatic conditions. Use of a dormant oil spray during the tree dormant season is estimated to kill about 90 percent of the overwintering cottony maple scales and is perhaps the best option for control. These should be applied on a day when the temperature stays above freezing for 24 hours after application. Use of dormant oil during this time also eliminates the risk of killing off beneficial insects. If trees are young and unestablished, stressed or have heavy infestation, a crawler spray may be applied to prevent dieback and decline. Sprays should be applied in July when young crawlers are present on the leaves. For more information on cottony maple scale, refer to the following publication from the University of Wisconsin Extension:http://learningstore.uwex.edu/assets/pdfs/A3123.pdf As always, read and follow directions and use pesticides wisely and safely. bull; Provided by Mary Boldan, Mary Moisand and Donna Siemro, University of Illinois Extension Master Gardeners. Send questions to Ask a Master Gardener, c/o Friendship Park Conservatory, 395 W. Algonquin Road, Des Plaines, IL 60016, (847) 298-3502 or via e-mail to cookcountymg@sbcglobal.net.