Aphid-infested tulip tree

Credit: Jupiter Images

This is a tricky problem to resolve.

The tulip tree just happens to be one of the aphid’s favourite meals so you can probably expect aphids every year to one degree or another. Biological controls are available, but the key word here is control, not elimination.

The best natural enemies are various parasitic wasps, which lay their eggs inside aphids and turn them into mummies. Keep in mind that predators and parasites only become abundant when aphids are numerous. Other natural predators are lady beetles, lacewings and syrphid flies, which are available for purchase at some garden centres.

Insecticidal soaps will also work if good foliage coverage is achieved; if possible, target both the underside and top of the leaves. These products are a temporary solution: they kill pests that are present at the time, but have little toxic residue so will not affect those that arrive on the plant after the spray. The height of your tree makes it awkward to treat yourself.

Alternatively, consider hiring a garden maintenance professional to apply a suitable treatment.

Note from GARDENWISE HORTICULTURIST CAROLYN JONES:

The Great Plant Picks tree committee discussed rescinding tulip trees because of this problem. The aphids are such a pain and the trees get so big it’s not practical for
homeowners to spray them regularly.