On a hike to Waterdog Lake and around the Lake Loop Trail with my husband and sidekick Nellie this weekend, it was apparent that the infestation California oak moths has reached a new level. The tiny brown moths flutter at about knee level at the base of the oak trees and piles of branches and leaves.
Click on the video above to view the moths in action.
In May, Patch inquired about the exploding moth population at the request of readers who had reported seeing them in the canyons and in backyard oak trees.Belmont Parks & Recreation Director Jonathan Gervais explained a bit about the California oak moth (Phryganidia californica), and the effect of these moths on oak trees.
According to Gervais, the California oak moth (Phryganidia californica) is a native insect of coastal California. The caterpillars feed upon the leaves of our native Coast Live Oak and also some deciduous trees.
The tan brown adult moths are seen in the late afternoons as they hover around infested trees with the goal of mating and laying eggs for the next generation of caterpillars. Larger outbreaks occur approximately every 8-10 years.
Since early summer, the City of Belmont has received a high volume of calls from concerned residents reporting that the California oak moths have decimated their oak trees. The city currently estimate that there are thousands of oak trees that are infested in Belmont.
"We expect the cycle to end in the next several weeks and hope it does not return in the spring time. We have not seen an outbreak like this in probably 12 to 15 years and that one was not a severe and widespread as this years. Most of the trees infested during that outbreak recovered," said Gervais via the City of Belmont website.
More information on the California oak moth:
The California oak moth (Phryganidia californica) is a native insect of coastal California. The caterpillars feed upon the leaves of our native Coast Live Oak and also some deciduous trees. During these outbreaks caterpillars are often seen suspended from silk strands, dropping to the ground, and congregating on fence posts, mail boxes, and other available platforms. In the most extreme years, the infestation may lead to severe oak defoliation.
Oaks that are simultaneously subjected to stresses caused by landscape or home construction, drought, soil compaction, or fungal infections (i.e. Sudden Oak Death Syndrome or oak root fungus) may be more seriously impacted.
The Parks and Recreation Department has been monitoring the situation but is not proposing action at this time. In addition, this is a natural process that, although destructive, is part of the natural heritage of living in a wooded community.
What residents can do
Residents concerned about a particular oak may wish to engage a certified arborist to evaluate the impact of the moths on an individual tree. Most trees will survive, but some may need additional help to make it through.Healthy oaks usually recover from these defoliation events. Age, condition of trees, as well as human caused impacts are also factors in how well oaks recover.