Silver-spotted tiger moth

The silver-spotted tiger moth (Lophocampa argentata) is a moth species belonging to the Erebidae family. This insect is widely recognized as a significant defoliator in the coniferous forests of western North America, where it primarily affects various species of evergreen trees during its larval stage.

The primary hosts for this pest include true firs (Abies species), spruces (Picea), and Douglas-fir (Pseudotsuga menziesii). While the larvae are generalist feeders within the conifer group, their feeding habits can cause substantial damage to both ornamental trees in landscapes and commercially important timber species in forest nurseries.

The life cycle of this species is univoltine, meaning there is one generation per year. Larvae overwinter in communal silken tents constructed on the branches of the host tree. As temperatures rise in the spring, the caterpillars emerge from their tents to feed aggressively on new and old needles until they reach maturity and pupate in mid-summer.

Damage caused by the silver-spotted tiger moth is characterized by the consumption of needles, often resulting in branches appearing brown or stripped bare. The presence of dense, web-like nests is a primary indicator of an infestation. Heavy defoliation reduces tree vigor, potentially leading to stunted growth or increased susceptibility to secondary infestations like bark beetles.

Management strategies for Lophocampa argentata involve a combination of manual and chemical controls. In residential or nursery settings, removing the conspicuous larval nests by hand during the dormant season is highly effective. For larger outbreaks, biological control agents such as Bacillus thuringiensis are recommended to target the larvae while preserving beneficial predatory insects.