Green alder aphid

Systematic position. The green alder aphid (Tinocallis viridis) belongs to the order Hemiptera and the family Aphididae. It is a specialized pest that has co-evolved with its host plants, focusing its life cycle exclusively on trees of the Alnus genus.

Host plants and damage. The pest primarily infests black alder (Alnus glutinosa) and grey alder (Alnus incana). The infestation results in the withdrawal of essential plant fluids, causing chlorosis, leaf deformation, and early leaf drop. Significant populations can lead to reduced annual growth and overall tree stress.

Biology and life cycle. The life cycle is typically synchronized with the host tree phenology. The species overwinters as eggs deposited on the bark of young shoots. In early spring, stem mothers hatch, initiating several generations of wingless and winged females. As autumn approaches, sexual forms appear to produce the overwintering eggs.

Nature of damage. Aphid colonies reside mainly on the abaxial side of the leaves, frequently along the main veins. A hallmark of their activity is the secretion of honeydew, a sugary substance. This accumulation promotes the colonization of sooty mold fungi, which darkens the foliage and interferes with the tree's photosynthetic efficiency.

Protection measures. Management of Tinocallis viridis involves integrated pest management practices. Key strategies include:

• Applying contact or systemic insecticides during the early stages of infestation.
• Encouraging natural predators such as lady beetles, lacewings, and hoverflies.
• Regular monitoring of nursery trees to prevent early-season outbreaks.
• Maintaining healthy tree vigor through proper irrigation and site selection.