Spruce giant aphid

Systematic position. The species belongs to the order Hemiptera, family Aphididae. Lachnus schwarzi is a specialized aphid species that typically colonizes spruce trees, thriving on the sap of bark and stems.

Host plants and damage. The primary host is the spruce tree (Picea species). These aphids feed on the bark of twigs and trunks, causing significant physiological stress to the tree. The loss of nutrients leads to chlorosis, stunted growth, and in severe cases, the decline of the infested conifer.

Biology and lifecycle. The lifecycle of Lachnus schwarzi involves alternating between asexual and sexual reproduction phases. Overwintering occurs in the egg stage, attached to the bark. When spring temperatures rise, nymphs emerge to begin feeding, leading to multiple generations during the growing season.

Nature of damage. A distinct characteristic of this pest is the secretion of honeydew. This substance covers the needles and bark, promoting the growth of sooty mold, which reduces the tree's photosynthetic capacity. Furthermore, the presence of ants, which defend the aphids, is a visual indicator of an infestation.

Control measures. Integrated pest management (IPM) is crucial for controlling Lachnus schwarzi.

• Application of systemic insecticides during early spring.
• Monitoring the activity of natural predators like lady beetles.
• Maintaining tree vigor through proper irrigation and fertilization.
• Mechanical removal of infested shoots in nursery settings.