Alder spittlebug

The Alder spittlebug (Clastoptera obtusa) is a small insect belonging to the order Hemiptera and the family Clastopteridae. It is primarily recognized by the characteristic frothy foam masses it produces on its host plants, which serve as a protective micro-environment for the nymphs during their development.

The insect predominantly infests alder trees, but it also colonizes other woody species including birch, oak, hazel, and viburnum. By piercing the plant tissue with their mouthparts, both nymphs and adults extract vital nutrients from the phloem, causing stress and localized physiological damage to the host.

The life cycle begins with overwintering eggs deposited on the bark of young twigs. Once nymphs hatch in the spring, they immediately start feeding and secreting a fluid that they whisk into a white, foamy spittle mass. There are five nymphal instars before the insect matures into an adult capable of flight and migration.

The primary damage caused by Clastoptera obtusa involves leaf distortion, chlorosis, and stunting of new shoot growth. In severe infestations, the drainage of plant sap leads to reduced photosynthetic capacity and the premature shedding of leaves, which significantly impacts the aesthetic and biological health of trees.

Integrated Pest Management (IPM) for the Alder spittlebug involves several strategies:

• Pruning infested twigs during dormant seasons to remove overwintering eggs.
• Applying high-pressure water sprays to dislodge and remove spittle masses early in the season.
• Monitoring for adult emergence to time chemical interventions if necessary.
• Encouraging natural predators such as lady beetles and spiders in the surrounding environment.