Treating woolly apple aphid
I have a small apple seedling with an infestation of woolly apple aphid. It has persisted even into these freezing temperatures. How should I treat it? Can I avoid using any toxic chemicals? Thanks!
Montgomery County Maryland
Wooly apple aphid is not an issue that we hear about very often.
It is not of great concern for mature trees, but it can be damaging to small ones, and can get on the roots as well.
Unfortunately is a difficult problem to control, as there are 9-12 generations per year.
If you have a lot of it we'd suggest pulling it out now and starting over.
If you want to take a more conservative approach and try to nurse it along, (hoping it's not already underground), you could try manually wiping off/squishing or pruning out all that you can find, and then treat with horticultural oil or soap sprays, either of which would need to be repeated every couple of weeks during the growing season.