Tortoiseshell butterfly

The genus Nymphalis belongs to the family Nymphalidae within the order Lepidoptera. While these butterflies are often observed as common insects in temperate climates, their larvae can sometimes be considered pests in orchards and gardens, where they cause significant defoliation of various tree species.

These insects primarily target fruit-bearing trees including apples, pears, cherries, and plums. During the larval stage, the caterpillars consume leaf tissues aggressively, which can lead to severe stress for the host plant if the infestation remains unchecked during the peak growth season.

The life cycle of Nymphalis follows a complete metamorphosis: egg, larva (caterpillar), pupa, and adult butterfly. Females lay eggs in clusters on the host plants. The larvae are gregarious, meaning they feed in groups, which allows them to strip sections of a tree very quickly as they develop.

The primary damage is the consumption of leaf blades, leaving only the larger veins or completely skeletonizing the foliage. This defoliation reduces the photosynthetic capacity of the trees, leading to lower fruit yields and a decreased ability for the tree to store carbohydrates for the following year.

To mitigate the impact of this pest, agronomists recommend:

• Monitoring tree canopies during the early spring to identify and remove egg clusters.
• Physical removal of young caterpillar colonies by pruning infested branches.
• Applying biological insecticides (such as Bacillus thuringiensis) that specifically target larvae.
• Encouraging natural predators, such as parasitic wasps and birds, which naturally regulate population levels.