Pterostoma

Pterostoma is a genus of moths belonging to the family Notodontidae, commonly known as prominents. The most representative species, Pterostoma palpina (pale prominent), is a significant defoliator found in temperate forests and woodland areas across the Northern Hemisphere.

Systematically, this genus falls under the order Lepidoptera. Adults are easily recognized by their elongated labial palpi, which extend forward, creating a distinct snout-like appearance. Their wingspan typically ranges from 40 to 50 mm, featuring cryptic coloration that provides excellent camouflage against tree bark during the daylight hours.

The larvae of the Pterostoma moth are specialized leaf-feeders. They primarily target hardwoods, including poplars, willows, and oaks. In agricultural and horticultural settings, they can cause significant damage to young saplings and nursery stock, leading to stunted growth and reduced vigor due to the loss of photosynthetic surface area.

The biological cycle involves complete metamorphosis: egg, larva, pupa, and adult. There are usually two generations per year. The insect overwinters as a pupa within the soil or in leaf litter near the host plant. Female moths deposit eggs on the undersides of leaves, and the emerging larvae begin feeding immediately, often grouping together in the early instars.

Damage management relies on early detection. Once larval activity is observed, growers should utilize appropriate insecticides. Integrated pest management (IPM) practices, such as soil cultivation around the tree base to disrupt overwintering pupae and the encouragement of natural predators like parasitic wasps and birds, are highly recommended to minimize chemical reliance.

• Regular monitoring of canopy density during spring and summer.
• Application of selective insecticides during the early larval stage.
• Removal of leaf debris to reduce overwintering sites.
• Introduction or protection of local natural enemies of larvae.