Plum aphid

Taxonomic position: The plum aphid (Brachycaudus divaricatae) belongs to the order Hemiptera and the family Aphididae. It is recognized as a significant pest of stone fruit trees, demonstrating a high degree of host specificity to plants within the Prunus genus.

Crops affected: The primary hosts are cherry plum (Prunus divaricata) and domestic plum trees. In cases of severe outbreaks, the aphid can also migrate to peach and apricot trees, causing substantial damage to commercial orchards, backyard gardens, and young nursery saplings.

Biology and life cycle: The pest overwinters as eggs located in bark crevices or near buds on young shoots. Hatching occurs in early spring, coinciding with the bud-burst stage of the host trees. Throughout the growing season, multiple generations of apterous (wingless) and alate (winged) individuals are produced, facilitating rapid dispersal across the orchard.

Damage and severity: The aphid feeds on the phloem sap of young leaves and shoots, which results in severe leaf curling, distortion, and localized discoloration (often reddening).

• Stunted growth of new shoots.
• Significant reduction in photosynthetic capacity.
• Development of sooty mold on the honeydew secreted by aphids.

Protection measures: Management strategies rely on early spring applications of dormant oils or insecticides to eliminate overwintering eggs. During the active growing season, systemic insecticides are recommended if infestation thresholds are reached. Cultural practices, such as pruning root suckers and maintaining optimal tree vigor, are crucial to reducing the aphid's ability to establish large colonies.