The white satin moth outbreak in Lake Tahoe Nevada State Park continues to be a problem.

A survey by the Nevada Division of Forestry revealed 226 acres of infestation, ranging from minimal to heavy defoliation.  Minimal defoliation was mapped on 52 acres, with moderate areas mapped on 107 acres, and heavy areas mapped on 67 acres. 

The good news is the freezing weather in the higher elevations is triggering the insects’ transition to their over-wintering stage which results in lower trap numbers.

In late August, the second hatch of larvae occurred and sampling found high caterpillar numbers feeding in upper North Canyon, Marlette Lake, and west of Hobart Lake. Bark and leaf samples found 10-15 caterpillars per leaf, which officials say is extremely high.

The high numbers are impacting fall colors.

Scientists say moth numbers are likely to increase next year, causing more defoliation, tree stress, and tree mortality.

State officials ares researching the possibility of conducting a biological insecticide spray project next year in the park.  This a non-native invasive insect.