Hop aphid
Phorodon humuli
35 host plants
Last updated
Hop aphids colonize the new growth of Prunus species in spring, causing leaf curling and distortion starting in April through June in orchards and landscapes. The small, yellowish-green or dark aphids gather on tender leaves, which curl inward and provide shelter. You notice the distinctive curled, thickened leaves at branch terminals. Colonies can be prolific during cool springs.
Scout for curling leaves starting in April and remove affected shoots by hand from lightly infested trees. For recurring problems, apply dormant oil in late winter to suppress overwintering eggs. Once buds break, insecticidal soap or neem oil suppresses early colonies. For heavier infestations, spinosad targets aphids during curling. Populations typically decline as natural enemies become active.
Quick Reference
All these aphids are light green in color. Spirea aphid is very difficult to separate from apple aphid without high magnification, whereas apple grain aphid can be distinguished by a yellowish green stripe down the middle of the back. Apple grain aphids infest pear only in the early part of the season, while apple aphid is present all summer. Aphids suck plant sap and live in colonies on new shoots. Populations are damaging only sporadically. Damage appears as rolled leaves, stunted terminal...
Cultural Controls
- biological control Many parasites and predators attack aphid.
- Monitor the proportion of aphid mummies to unparasitized adults and the number of predators such as lady beetles.
- If the biocontrol agents appear to be gaining control, avoid sprays which would disrupt this system.
- Most products available for aphid control are highly disruptive of natural enemies.
- Management-cultural control Aphid populations tend to be higher in plants that are fertilized liberally with nitrogen.
- Prune out suckers...