Pear grass aphid

Systematic position. The pear grass aphid (Longiunguis pyrarius) belongs to the order Hemiptera and the family Aphididae. It is a specialized pest known for its host-alternating lifecycle, which allows it to thrive in diverse agricultural landscapes by exploiting both woody perennials and herbaceous plants.

Host plants. The primary host is the pear tree (Pyrus species). In summer, the aphid undergoes a migration to secondary hosts, which include various species of grasses (Poaceae). This dual-host strategy is a key biological adaptation that enables the survival and dispersal of the species across different agricultural environments.

Biology and lifecycle. The species overwinters as eggs located in the crevices of pear tree bark. As spring temperatures rise, eggs hatch into fundatrices. Throughout the season, several generations of parthenogenetic females are produced. In summer, winged forms migrate to grasses, and in autumn, a return migration to pear trees occurs for mating and egg-laying.

Nature of damage and pest status. The aphids feed on the sap of young leaves, causing them to curl, wither, and eventually turn yellow. The heavy infestation limits the growth of shoots and reduces the overall vigor of the tree. Furthermore, the aphids excrete honeydew, which promotes the growth of sooty mold, negatively impacting the tree's photosynthetic capability.

Control measures. Integrated pest management (IPM) is essential for controlling Longiunguis pyrarius. Recommended strategies include:

• Dormant oil applications in late winter to suppress overwintering egg populations.
• Monitoring orchard thresholds during the spring budding phase.
• Application of selective insecticides if aphid populations exceed economic thresholds.
• Weed management to eliminate secondary grass hosts near the orchard perimeter.