Four Common Tree Pests in California

Pests like bark beetles and aphids are only one of the problems you’ll encounter when it comes to caring for your trees. California is particularly prone to a wide range of pesky invaders that compromise the health of trees. 

In this post, Cut Rite Tree Service shares the four most common tree pests they see in California in their travels as a reputable tree service company in Paso Robles, CA

#1 Asian Citrus Psyllid

These tiny bugs originate from Southeast Asia and were first discovered in California in 2008. An adult Asian citrus psyllid is roughly 4 mm long, with a brown or black head, brown body, dark brown spots, and black-tipped antennae.

As the name suggests, these bugs lay their eggs in a line on the young citrus tree leaves, and the hatched larvae eat the leaves. Psyllids attack different types of citrus trees, including orange and grapefruit trees. Citrus thrives in California’s warm climate and great soil quality, so it’s easy to see how these pests spread so rapidly.

You could be dealing with an Asian citrus psyllid infestation if you notice the following:

  • Pale green blotches on the leaves of your citrus tree
  • Twig dieback
  • Tiny, underdeveloped fruit

Infested trees usually die within five years. However, you can protect your trees by spraying them with insecticides regularly.

#2 Oak Worms

Oak worms are the larvae of the tussock moths, and they’re about 0.1 to 1.0 inches long. You can easily identify them with their yellowish-green bodies, brown heads, and dark stripes along their sides.

These larvae feed on oak tree leaves. You’ll often identify an oak worm infestation by heavily chewed leaves that quickly turn brown and die. They may even cause sudden oak death by killing the leaves and hampering the tree’s ability to harvest sunlight and manufacture its food.

Concerned tree owners may effectively control oak work infestations by spraying susceptible trees during the spring. But what if the worms have already infested your tree? In that case, insecticides may fight them off applied thoroughly on a well-laid-out schedule. 

#3 California Fivespined Ips

What other tree pests are a nuisance in California? Major pests that spring to mind are the fivespined ipses, which first became a serious headache in the state during the 1940s. 

Understanding the parts of the tree affected by pests is crucial, as seen with the California fivespined ips. A male ips is about 5 mm long with a red-brown body and primarily targets the bark and vascular tissue of various pine trees, including white and sugar pines. The male beetles drill holes into the bark and release a chemical that attracts their female counterparts.

The female ipses then enter the tree, mate, and lay eggs. The eggs hatch into larvae, which tunnel into the tree’s vascular tissue. So, if you have a fivespined ips infestation, you’ll often see bore holes in the bark and yellow and red-brown needles. 

While insecticide treatments can help, many trees still succumb to the infestation.

#4 Cypress Tip Miner

This pesky moth usually lays its eggs on the cypress trees’ foliage, with the hatched caterpillars feeding on the tips of cypress tree leaves. The caterpillars are about ¼ inches long, with a yellow-green body and darker heads. They evolve into silver-brown moths. 

The signs of a cypress tip miner infestation in your tree include: 

  • General foliage dieback
  • Chew marks on the twigs and leaves
  • Leaf tips turning brown

Insecticide sprays should do the trick. 

Call Our Local Tree Experts For Pest Solutions and More

Do you need some help with tree pests in California? Is it scales, whiteflies, or fungal infections ailing your trees? Our go-to local arborist has the solutions you need.

Contact Cut Rite Tree Service at 559-320-7723 today for a free estimate. Alternatively, learn about cavities in trees and other topics on our blog.


We are a locally owned company that prides ourselves in providing the best service possible for the residents of Fresno, Clovis, Madera, Sanger, Folwer, Reedley and the surrounding areas.

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1806 N Temperance
Fresno, CA 93727


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