Why is the citrus blackfly harmful?

Damage to edible crops and endangerment to plant well-being are reasons for why the citrus blackfly is harmful. The insects in question (Aleurocanthus woglumi) have piercing, sipping mouthparts for removing life-sustaining fluids from inside citrus tissues. Their feeding also provokes sooty mold from their honeydew droppings and photosynthetic and respiratory failure while decreasing yields and disfiguring appearances.