Question
I have a autumn blaze maple that is about 4 years old and 30 ft tall by 20 ft wide.  I抳e been battling a chronic aphid infestation for the last three months.  My husband and I have been spraying it with water and insecticidal soap but I just can seem to get rid of them.  The tree is too tall for us to reach the top area with a sprayer. There are still little white aphids, I see some tiny orange eggs on some leaves, ants  and of course, the tree is stressed.   I have put a sticky barrier around the trunk to prevent the ants from crawling up.  I抳e read about the Bayer Advanced Tree & Shrub Insect control and I have ordered it online.  Do you have opinion about this product?  In my online research I read that horticultural oil can be effective but it抯 not recommended for some trees, such as maples.  


I would appreciate any suggestions you might have to solve this problem.  Do we need a professional to come out and treat it?



Thank you in advance for your attention.  

Answer
Pat:
It is usually not feasible nor practical for homeowners to spray this size of a tree for aphids.  We usually don't have the proper equipment that can cover the tree adequately and it will probably be expensive for a professional to do it. I expect that the ants that you mentioned are there going after the other insects rather than causing a health problem for the tree. To keep the aphids off your tree, you will probably need to spray more than once per season- (if you want to consider going the spray route).This can add on to the cost.
The Bayer product that you mentioned can be applied to the soil and taken up by the tree. It has been shown to be pretty good, but don't expect overnight results, especially on your size of a tree. Since many insects are seasonal and there are predator insects out there that usually keep the bad insects in check, we don't usually go to the expense and trouble to spray large trees for these insects, but you may want to keep these critters off- your call. If the tree is growing vigorously by good watering regimes and fertilization, the impact of the insects is minimal.

If you elect to spray, keep in mind that the leaves will be dropping soon, so you might want to wait until next spring to start. Too late this year to apply the Bayer product also, since the absorption is slowing down- start next year in the spring when leaves are forming. It will take 30-60 days for the product to get up in the tree.

If you wish, you can send me a closeup photo of these aphids for a confirmation if you like.  My next door neighbor is an entomologist.

Regards
Steve