Mealy plum aphid

The mealy plum aphid (Hyalopterus pruni) is a member of the Aphididae family within the order Hemiptera. It is a major pest for various stone fruit trees, recognized by the distinct white, mealy waxy substance that covers the bodies of the aphids and the infested foliage.

The primary hosts of this pest include the European plum, peach, nectarine, and apricot. The life cycle is host-alternating; while the spring and autumn generations reside on fruit trees, the summer generations migrate to wetlands to infest various grasses, primarily the common reed (Phragmites australis), before returning to the orchard.

Biological development starts with eggs overwintering on the bark of shoots. Once temperatures rise, the fundatrices emerge and establish massive colonies on the underside of leaves. Due to rapid asexual reproduction, population densities can reach thousands of individuals per tree in a matter of weeks during the peak of spring.

The damage caused by Hyalopterus pruni is significant. As sap-feeders, they cause leaves to roll and turn chlorotic. The honey-dew produced by the aphids covers the foliage, serving as a medium for the growth of sooty mold, which blocks sunlight and hinders photosynthesis, ultimately leading to stunted growth and reduced fruit yield.

To control this pest, monitoring is essential from the bud-burst stage. Cultural practices include pruning to improve airflow and eliminating reed beds near the orchard to disrupt the migration cycle. Chemical control involves the application of systemic insecticides early in the season, while biological control using ladybird beetles or hoverflies is highly recommended in integrated pest management programs.