Maple Mites
From Dr. Stephen Franks:
Mid-summer damage to maples is often attributed to the twospotted spider mite. However, I visited several nurseries this week and found the culprit was actually the maple mite, Oligonychus aceris. This mite feeds on maples and causes severe damage to maple leaves in midsummer. Leaves are yellow and stippled and mite debris is evident on the underside of leaves. Growers report more damage on “Autumn Blaze” than other maple varieties. However it is common on October Glory and most commonly grown varieties. Management recommendations are the same as for the twospotted spider mite discussed in previous articles in the June 5, 2009 and June 26, 2009 North Carolina Pest News. However, to my knowledge no efficacy tests have been conducted on this particular species. Remember that any damage done to the leaves will remain for the rest of the season and will not be corrected by treatments, nor will the debris wash off from treatments or irrigation. Therefore, be sure to determine if live mites are present before repeating a treatment bases on damage or debris.
For additional information, see Ornamentals and Turf Insect Note No. 25 on twospotted spider mites at Twospotted Spider Mite
For more information contact your local Cooperative Extension Center and ask for the Commercial Horticulture Agent.