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Japanese maple disease
Japanese maple disease  
I have a lace leaf maple which is showing some kind of disease. It looks like white cotton candy around the stem. I see it on 3-4 locations. Please help.

Dear Rinji, Your Japanese maple has what looks like an infestation of scale.  Scale are small unmoving insects that suck the plant juices.  It could also be some other types of insects, but not to worry, either way the cure is simple and fairly inexpensive.  You can try to simply remove the individual spots with WD-40 and a paper towel.  Very often in minor infestations this is all you will need to do, and the problem will be solved.  However, if the tree becomes more infested you will need to spray the tree with a lightweight horticultural oil (SunSpray is fantastic for this).  Spray the entire tree, coating the leaves and especially the stems that are infested.  You will probably need to spray the tree twice about ten days apart for complete effectiveness.  But try the WD-40 and paper towel method first.  WD-40 is an oil that will penetrate the bugs exterior and make them dehydrate assuming you haven't already crushed them by the paper towel.  I hope this helps you.  Good luck, and write if you have more questions.  Melissa

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Melissa Johnston


Plant diseases, landscaping, tropical plants, roses, herbs, plant care, grafting, horticulture, plant identification, anything about plants I can likely answer.


35 years experience in various plant businesses, 1984 Certified Texas Master Gardener.

Master Gardener Association of Texas charter member

none as of yet, but I have a plant q&a book I am in process of submitting.

Magna cum laude graduate of Texas A&M, 1978

Awards and Honors
Plant growing awards, highest grade for Texas Master Gardener graduates.

Past/Present Clients
Past member of and was very highly rated. Owned landscape company in the past, Almost Paradise, and was very successful despite little equipment, no help, and no advertising. Lived well for two years until 9/11.

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