Brown wood ant

Taxonomic position: The brown wood ant (Lasius brunneus) belongs to the order Hymenoptera, family Formicidae. Although common in woodland environments, this species is considered a significant pest in orchards and private gardens due to its habit of nesting in wooden structures and living trees.

Biology and life cycle: The colony is typically monogynous, meaning it is headed by a single queen. These ants are known for their preference for nesting in dead or decaying wood, often choosing locations in the trunks of deciduous trees. Their foraging activity involves exploring the canopy, where they tend to sap-sucking insects.

Target crops: They primarily infest fruit trees, including apple, pear, cherry, and plum trees. They are particularly drawn to trees that have existing wounds, such as sunscald, pruning scars, or areas of decay, but they can gradually weaken the structural integrity of otherwise healthy trees over several years.

Damage and harmfulness: The structural damage caused by gallery formation within the wood can lead to tree instability and decline. Furthermore, these ants are major promoters of aphid populations. By protecting aphids from predators, they facilitate the mass infestation of these sap-suckers, which causes leaves to curl, inhibits shoot growth, and promotes the growth of sooty mold.

Control measures:

• Regular pruning and removal of dead or rotting wood to eliminate nesting sites.
• Proper sealing of cavities and deep fissures in tree trunks using wound dressings.
• Installation of sticky barriers on trunks to prevent ants from reaching the canopy.
• Effective management of aphid populations using biological or chemical control agents.
• Deployment of bait stations with slow-acting insecticides to reduce the colony size.