We have seen an increasing number of disease pathogens and insects attacking many tree species throughout our country. In Southern California, the gold spotted oak borer, (GSOB), (Agrilus auroguttatu), first introduced in San Diego County between 1990-2000 has spread into Riverside County and is expected to spread throughout California. This pest specifically targets the Coast Live Oak and Black Oak, (Quercus agrifolia, Quercus kelloggii), both oaks comprising a major part of our red oak forests throughout California.
The adult female beetle lays eggs on host trees mainly June through September, the eggs hatch into larvae which bore through the outer bark and feed on the phloem and xylem, the interior vascular system of the tree. After several months, the larvae mature into pupae, which eventually bore from the vascular tissue just under the bark, and may be observed on the outer bark of infested trees April through July. Adult emergence follows and the beetles feed on the foliage of the infected trees throughout summer, mating and then repeating the life cycle. Continue reading “California Trees Under Attack, Are You Part of the Problem?” »