My neighbor's yard has hemlocks which have been dying for several years from woolly hemlock disease. About a month ago, I started seeing little white puffs (which have identified as woolly adelgids or woolly aphids) on my 16 Japanese maples. They have started looking very droopy with branches dying. The white puffs have also attacked my hollies (2 lost already), rhododendrons, and vine hydrangeas. Has anyone had experience dealing with these pests on Japanese maples? I have sprayed with generic insecticide/fungicide, insecticidal soap, and am waiting for a delivery of Imidacloprid granules for systemic control. My garden is being destroyed! Pictures of the white puffs are on leaves of a vine hydrangea. Any advice would be appreciated.
I have found something that treats wooly aphids but it will leave white spots on the leaves. It's pretty non-toxic and can be used on food plants. I tried what I thought was everything else. I did have them on a JM and it was quite effective. They are quite a plague! You may need to spray weekly for awhile.
Diatect Garden and Floral Insect Control
from Diatect International.
i noticed some white puffs on just one jm and sprayed it a couple time with a kill all bayer product that seemed to do the job. was surprised to see this on a jm to be honest. tree did not seem to suffer.
It is suprising. My beech trees (especially the 'Tricolor') were covered, but not one of my 40+ JMs had the slightest bit of woolly aphids. I do have an Acer conspicuum 'Phoenix' that has just about been done in by them, though.
Really? Someone told me that beeches were especially vulnerable to woolly aphids, so I was surprised that only the Tricolors got them. None of the other beeches did. Spider mites, on the other hand... ugh!
It never ceases to amaze me how few insects prey on JMs. Japanese Beetles don't even bother. And of all the trees in my garden that got major cutting damage in '07 from the 17-year cicada invasion, the wounds on the JMs healed up within a week! They're so much tougher than people think.