River birch aphids
What systemic insecticide do you recommend to treat my 3 year old river birch tree? The leaves on the younger branches are full of aphids and their eggs. There was also a 1/4 inch red and black caterpillar on one twig.
Anne Arundel County Maryland insect id
We hear about this often as it is common in our area.
Sounds confusing, but this is the work of the witch hazel gall aphid, which has a complicated life cycle.
We don't generally suggest treatment, as beneficial insects help to control it. It would be too late to do anything now anyway.
Here is a publication on River Birch, which includes information about this insect.