Brown maple aphid

Systematic position. Stomaphis graffii belongs to the order Hemiptera and the family Aphididae. Unlike typical leaf-feeding aphids, this species has evolved to inhabit the woody parts of trees, making it a specialized pest that is often overlooked until infestation levels become severe.

Host plants. The primary host for this species is the maple tree (Acer). The aphids specifically target the bark of the trunk and larger branches, preferring locations where the bark is rugged or damaged, which allows them easier access to the tree's phloem sap.

Biology and lifecycle. The lifecycle of Stomaphis graffii is closely tied to the host tree's physiological status. These aphids are often tended by ants, which protect them from predators in exchange for honeydew. Overwintering occurs primarily at the egg stage, tucked away in bark crevices. Once spring arrives, the eggs hatch and initiate several generations of aphid colonies.

Damage and pest impact. The feeding activity of these aphids weakens the host tree significantly, leading to stunted growth and increased susceptibility to secondary infestations, such as bark beetles or wood-decay fungi. The production of honeydew also encourages the growth of sooty mold, which creates a dark, unsightly layer on the bark and interferes with the tree's vital physiological processes.

Control measures. Management strategies for Stomaphis graffii focus on both mechanical and chemical interventions. Key methods include:

• Applying sticky bands around tree trunks to prevent ants from tending the aphids.
• Using systemic insecticides to reach the aphids feeding under or within bark layers.
• Performing dormant oil sprays to target overwintering eggs.
• Maintaining tree vigor through proper irrigation and fertilization to help the tree withstand sap loss.