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.


We hired Arborworks to remove 10 trees at our new house. There was a small overgrown forest going on. I don’t think anyone ever trimmed anything in this yard! Not only did they remove the trees and ground the stumps, they also took out our other items we had cut down ourselves.The biggest tree was almost three stories, you could see it towering over the house from the front and we have a two story house. Could not believe how efficiently they cut down that monster tree. Their guy who was in the tree – WOW he made it look easy but I know that it wasn’t! Knew what limbs to cut and where the limbs were going to fall. Was very impressed! We were there when they took all the trees out and I can tell you they definitely know what they are doing. They asked if we wanted the chips/mulch from the stump grinder otherwise they would have taken it away.I would hire them again in a heart beat and I’ve already recommended them! Great prices and GREAT service.
George R. Palo Alto, CAPalo Alto, CA


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