The Double Threat of the Spiny Witch Hazel Gall Aphid in Bloomington, IN
Aphids are among the most common pests found on herbaceous plants, trees, and shrubs in Bloomington, IN. While they are tiny, their impact on your landscape can be significant. One particular species, the Spiny Witch Hazel Gall Aphid (Hamamelistes spinosus), can threaten your plants in two different ways.
As its name suggests, this aphid first targets witch hazel in the spring. When it feeds on flower buds, it causes the plant to form irregular spiny galls. Inside these galls, the aphids reproduce safely, protected from predators. Eventually, winged adults emerge and move to their secondary host, often the river birch (or black birch). This is why the pest is sometimes referred to as the river birch aphid.
On river birch leaves, this aphid causes distinctive puckering and wrinkling. Long furrows form in the leaves, creating sheltered crevices where the aphids live and reproduce. Immature aphids are red, while adults are mostly black, but both are covered in a white waxy substance that protects them from pathogens and sticky honeydew.
The aphid’s life cycle involves moving between witch hazel and river birch each year, overwintering in eggs or nymph stages on each host before starting again in spring.
The spiny witch hazel gall aphid can even appear alongside other aphid species on the same plant. While aphids typically are not fatal to healthy trees, their feeding can contribute to plant stress, premature leaf drop, and the growth of sooty mold from their honeydew. Heavy infestations are often noticed too late for easy control.
Contact Wells for Help With Your Garden
To reduce damage, preventive treatment in early spring with systemic insecticides labeled for aphid control, such as imidacloprid, can help keep populations in check for the season.If you have witch hazel or river birch in your Bloomington landscape, take a closer look at your leaves. Early detection is key to protecting your plants from this two-host pest. Wells Lawn Care & Landscaping can help you identify and manage pest problems before they cause serious harm.
Call Wells Lawn Care & Landscaping today at (812) 272-9336 or visit our contact page to schedule a tree and shrub health evaluation.