The wildlife local to California has been largely dependent on oaks for a long, long time. From squirrels, deer, all the way to black bears, the animal population has been relying on acorns for sustenance. But they aren’t the only ones feasting on these trees.Insects have been gnawing away at our oaks’ leaves and causing serious damage to the trees in the process. Damage sometimes severe enough to fully kill the tree, whether it be through direct action, or through the transmittance of bacteria, fungi, or diseases.Here is a selection of the most common threats to Californian Oaks:

California Oakworm: Once fully grown, a California Oakworm can reach up to about an inch in size. They’re yellow and black in color and can largely be found along the coast. When these caterpillars have picked a tree to feed on, they can cause it to lose large portions of its foliage. However, as they feed, they will often restrict themselves to the bottom of the leaf and leave the top untouched, which allows the majority of infested trees to survive.

Fruit-Tree Leaf Roller: The majority of Californian oaks have been infested with these critters. Fruit-tree leaf rollers are small and pale and love to munch away on newly grown leaves during Spring season. When it is time for their metamorphosis, they will roll up the tree’s leaves to use them as cocoons. A strong tree will survive such an infestation, but a sickly or stressed tree may find its demise.

Tent Caterpillar: Hairy and two inches in length, the tent caterpillar is known for using fruit trees and oaks as sites to construct their silk tent-like structures. While largely harmless to the tree itself, people often dislike the sight of these silk structures and choose to call pest control as ways of getting rid of the tent caterpillars.

Western Tussock Moth: When in their larval stage, the tussock moth will feast on all kinds of trees across California, including oaks. These caterpillars have white tufts along their backs and can cause severe defoliation on the trees they infest, and in regards to humans, their hairs can cause skin irritations and the amount of their droppings can quickly pile up.

Gall Wasp: These wasps will lay their eggs in tree tissue, including the tissue of oaks, which creates a swollen chamber as the larvae develop. While generally harmless to the tree at large, the gall wasp can cause harm to singular twigs and branches.


It is best to call in the tree care services in Bay Area to look over any issues with the oaks on your property. They have the skill and knowledge to handles such exigencies and will be able to end the pest infiltration.


Anyone who really cares about their trees knows how hard it is to find a good tree trimmer. I’ve used both major name brands, and self employed tree trimmers, and have never been very satisfied, until now. ArborWorks trimmed my trees as carefully as I would have, if I knew how to climb trees!Don McIntyre, owner, responded within two days of my call, and his estimate was fair and thorough. He personally brought the foreman of the crew to my site to go over the job the evening before the crew would actually arrive. Don also visits the site as the work is performed, to make sure everything goes smoothly.If my trees could vocalize, they’d sing about the space created for light to enter the crown, and how good it feels to have the weight off the ends of the limbs. Even neighbors have come by to complement me on how good the trees look. “Best ever”.I only wish I had known about ArborWorks sooner. It took me 32 years to find them. I hope my trees will forgive me for taking so long…
Karen K. Mountain View, CA


Arborworks Inc. Diamond Certified