A second wave of Costco plant shipments has been found carrying evidence of an invasive insect that can spread a fatal grapevine disease, widening concern among California agriculture officials already trying to track down thousands of potentially infested grapevines sold this spring.
Desert willow plants shipped last week to Costco stores in Sacramento and Marin counties had viable egg masses of the glassy-winged sharpshooter on their leaves, according to state agricultural officials.
The pest does not harm people or animals, but it can spread Pierce’s disease, a bacterial infection that can kill grapevines and threaten wine and table grape production…