Red wood ant

The red wood ant (Latin: Formica polyctena) belongs to the order Hymenoptera and the family Formicidae. While beneficial in forest ecosystems, these ants are often considered significant pests in horticultural settings due to their complex behavioral interactions with sap-sucking insects that damage crops.

They primarily affect fruit trees, small berries, and various ornamental plants. The main issue is their symbiotic relationship with aphids, scale insects, and mealybugs. The ants actively herd and protect these pests from predators, allowing their populations to explode on your garden plants.

The biology of Formica polyctena involves a high degree of social organization. Colonies are frequently polygynous (having multiple queens), which allows for rapid expansion and high resilience against environmental changes. Workers are highly active from early spring, constantly scouting and maintaining "aphid farms" on your trees.

The damage caused by these ants is indirect but severe. By guarding aphids, they prevent natural control agents from doing their job. This leads to heavy infestations, stunted shoots, distorted leaves, and the growth of sooty mold on the honeydew secreted by aphids. The overall plant vitality significantly declines, impacting yields.

Effective management strategies include creating physical barriers like sticky bands on tree trunks to stop ants from climbing. Regular monitoring of trees for aphid clusters is essential. Biological control involves encouraging beneficial predators and using bait stations with low-toxicity borate-based substances that target the nest population.