Orchard ermine moth

Systematic position: The Orchard ermine moth (Yponomeuta padellus) belongs to the order Lepidoptera, family Yponomeutidae. It is a well-known defoliator that often reaches outbreak levels in orchards, causing significant economic damage.

Host plants: This pest primarily affects fruit trees of the Rosaceae family. While it is most commonly found on apple trees, it also targets hawthorn, plum, cherry, pear, and sloe. In urban and forest environments, it can colonize various species of the Prunus genus.

Biology and life cycle: The moth completes one generation per year. First-instar larvae overwinter under a protective silk shield on tree branches. As temperatures rise in spring, they mine into the buds and eventually emerge to construct elaborate silk webs around the foliage, feeding gregariously inside these structures until pupation.

Nature of damage and harmfulness: The larvae are voracious leaf feeders. They skeletonize the leaves, eventually consuming the entire leaf tissue. Large webs cover entire branches, giving the tree a scorched appearance. Massive infestations result in total defoliation, severely stressing the tree, preventing fruit development, and reducing overall tree vigor.

Control measures: A successful management strategy focuses on both mechanical and chemical interventions.

• Mechanical removal and destruction of silk webs in the early stages of colony formation.
• Application of microbial insecticides, such as Bacillus thuringiensis, when larvae are young.
• Use of broad-spectrum or selective chemical insecticides during the post-dormancy period if necessary.
• Encouraging biological control by protecting natural predators and parasitoids that feed on the larvae.