aphids on linden tree
Hi there, I have a large basswood/linden tree in my yard that had a pretty heavy aphid infestation last year. Everyone I've called says that the newest pesticides can't be used on lindens due to the danger to bees, and that they are no longer 'certified' to use the older products. Is there anything I can do to control this problem? thanks, Rae
Benton County Oregon
The reason that the newest pesticides can't be used on lindens is that they are systemic materials which are persistent for an extended period in all parts of the tree, including the nectar. Even so, certain other products are effective and legal.
For reasonable-sized plants, a high-pressure water spray from a garden hose can forcefully wash off the aphids and their sticky excrement.
Then, too, several insecticides have low risk to people, pets, non-target insects, and the environment, among them insecticidal soap and horticultural oils. Because they kill only those insects they contact, repeat treatments will be needed.
Professional tree care services have access to effective, also legal, insecticides not available to home gardeners. Plus, such companies will have the training, experience, and equipment to successfully manage the aphids on a large tree.
It’s wise to obtain estimates for the cost and proposed treatment schedule before the aphids arrive. To do so, invite several Certified Arborists for onsite visits after which you can compare their comments and decide who you prefer to hire. You can locate nearby Certified Arborists by searching with your zipcode at www.treesaregood.org.