Sequoia pitch moth

The Sequoia pitch moth (Vespamima sequoiae) is a damaging insect species belonging to the order Lepidoptera and the family Sesiidae. These moths are well-known for their clear-wing appearance and mimicry, as they strongly resemble wasps or hornets, providing protection from avian predators.

This pest primarily attacks coniferous trees, most notably coast redwood (Sequoia sempervirens), giant sequoia (Sequoiadendron giganteum), and various species of pine and cypress. It is a significant concern for nursery owners, landscape architects, and forest managers looking after young or stressed trees.

The lifecycle typically spans one to two years depending on the climate. The female moth deposits eggs into bark crevices or near pruning wounds. Upon hatching, the larvae bore into the inner bark and cambium layer, where they feed throughout their developmental stages, often resulting in heavy pitch exudation.

The damage caused by the larvae is characterized by large, messy masses of pitch and frass accumulating on the bark surface. This activity can girdle stems, especially in young trees, leading to stunted growth, structural weakness, or complete mortality if the tree is heavily infested or girdled.

Management strategies for Vespamima sequoiae include maintaining tree vigor through proper irrigation and soil care to prevent susceptibility. Cultural control involves avoiding wounding during the peak flight season of the adults. Pheromone traps are effective for monitoring activity, and in severe nursery infestations, targeted chemical applications may be necessary during the egg-laying period.