Pear root aphid

Taxonomic status. The pear root aphid (Eriosoma flavum) belongs to the order Hemiptera and the family Aphididae. It is a specialized pest that colonizes the root systems of various pome fruit trees, operating primarily underground, which distinguishes it from more common foliage-feeding aphid species.

Host plants and damage. The primary host is the pear tree. By feeding on the roots, the aphid causes the formation of galls and irregular swellings. This structural damage disrupts the plant's vascular system, hindering the absorption of nutrients and water, which ultimately leads to stunted growth, yellowing foliage, and potentially the death of the tree.

Biology and lifecycle. The lifecycle is adapted to soil conditions, where the aphids remain protected by soil particles and their own waxy secretions. They reproduce parthenogenetically, allowing populations to proliferate quickly during the growing season. The lack of exposure to sunlight and predators in the soil environment contributes to the persistence of this pest.

Nature of injury. The injury is often cryptic, as the damage occurs below ground. Visible signs on the surface include overall tree weakness, reduced terminal growth, and hypersensitivity to drought stress. Upon investigation of the root zone, one may find characteristic yellowish aphid colonies covered in a white, powdery wax substance.

Control measures. Controlling this pest requires a proactive approach centered on preventing infestation of new orchard sites. It is vital to plant certified, pest-free stock and treat roots before planting if contamination is suspected. Systemic insecticides applied to the soil are the most effective method, as they are absorbed by the roots and travel through the tree's system, targeting the aphids while they feed.

• Inspection of root systems before transplanting.
• Application of systemic insecticides to the soil zone.
• Enhancing soil health to improve tree resistance.
• Monitoring for early symptoms of nutrient deficiency in the canopy.