The extension office diagnosed my maple tree issue as Erineum caused by Eriophyes modestus Hodgkiss, and possibly some scorch. Apparently this mite is uncommon in the Western states, and that's why I was having trouble w/ the ID, Anyhow, the office suggested a dormant oil spray late next winter. I prefer not to spray my trees, if for no other reason than the appearance of perfoming a non-organic control. An internet search gave varying results--some say do nothing, some say oil provides poor control, others say good control. Any suggestions? Apparently the adults overwinter in the bark. Given this, is it OK to let the leaves stay where they fall? Or should I be careful to collect and dispose of them. Thank-you!!

Some of the dormant oil sprays are petroleum based, but a search can reveal many that are vegetable oil based and, theoretically, these would be more environmentally accetable. Dormant oil sprays are however acceptable organic methods of controlling many insect pests and some diseases, if applied at the proper time.