Nymphs tend to be lighter in color than the adults, especially in spring when the first through fourth instars have little dark pigment. Antennae are pale yellow with small amounts of black on several segments. Eyes are dark red and cornicles are short. In the other two aphid species present on pecan, cornicles are absent or greatly reduced. Black pecan aphids have multiple generations each year beginning development in March and continuing into November.
Populations generally peak in fall.
The spots die and turn brown, and just a few such spots cause a leaflet to shed. Premature leaf drop results in poor nut quality and reduced bloom in subsequent seasons. Usually control is not needed until late in the season, after mid-July. At that time, treat if levels exceed an average of one black aphid per compound leaf. Apply no more than 400 gallons spray mixture per acre.