California Bark Beetle: Prevention And Causes

Since 2010, more than 129 million trees have died in the national forests of California. The reasons are varied from climate change to drought. One of the most serious culprits, however, is the California bark beetle. This pest stays in the inner bark of the host and eventually destroys the vascular system of the tree. 

The infestation of bark beetles in California rises significantly within a short time. It might be small, but this beetle can cause unprecedented tree mortality. Read on and find out more about the bark beetle, including its causes and treatment. 

Physical Characteristics of the California Bark Beetle 

The bark beetle is less than ¼-inch in length, making it hardly noticeable. They are as small as a grain of cooked rice. It has a hard body, which it uses to bore through the bark of the tree. They have a cylindrical body, which can be dark red, black, or brown. 

The Causes of Infestation 

Bark beetles have been around in California longer than its people. In a normal circumstance, they do not pose any threat. Once they start feeding on the host and it is too late to act, however, they can kill the tree. 

The infestation of the bark beetle is caused by the stress, disease, and injury in the tree. Such problems make the host more susceptible to damage. These problems are often a result of wildfire, storms, and human activity. The more stressed the tree is, the higher is the possibility of an infestation. 

The Effects of Infestation 

When bark beetles in California successfully penetrate the host, small blobs will appear on the sap of the tree. You will see reddish-brown tubes randomly in the bark. Needles will also turn reddish-brown, with the change in color starting at the top. Like in the case of South American palm weevils, bark beetles can eventually cause the death of a tree without proper intervention. 

The Best Preventive Measures 

Providers of tree service California recommend a proactive approach in the treatment of bark beetles. While using contact insecticides can help, the best thing to do is to deal with the beetle even before it becomes a significant problem. 

  • Pay attention to proper spacing when planting trees. The closer they are, the easier it is for the pests to spread. Do not grow more trees than necessary.
  • Protect the roots, trunks, and barks from potential problems. Injury to these parts will increase the likelihood of an infestation of California bark beetle. Protect against abiotic disorders, including sunburns. 
  • Proper irrigation of the outer canopy is also a must. Do this at least twice a month during drought. The amount of water needed for irrigation depends on the size and health of the tree, among other things.
  • Spraying insecticides on healthy trees can also help. Do this before a protracted drought period to minimize potential damage. Pyrethroids are amongst the most effective for the prevention of bark beetles in California.  
  • Prune trees properly. This helps increase the vigor of the tree, making it less vulnerable to infestation. If you don’t know how to do it right, get in touch with specialists in tree trimming California. Ensure proper disposal to prevent the pests from spreading. 


Q: What trees do bark beetle attack? 

A: Pines are the most common trees bark beetle attacks. Specifically, it feeds on ponderosa pine, pinyon pine, and Jeffrey pine. Incense-cedar and white fir fines are also common hosts. 

Related Post: California Pine Trees

Q: What kills bark beetles? 

A: A contact insecticide is one of the best ways to kill bark beetles. Carbaryl is one of the most common choices. The application of the latter requires high-pressure equipment. Pyrethroids are equally effective. 

Q: How do I identify bark beetles? 

A: To identify bark beetles, watch out for boring dust and pitch tubes outside of the bark of the host tree. A reddish-brown pitch tube indicates that the bark beetle has successfully penetrated the host. The needles will also change their color. 

Q: Are bark beetles dangerous? 

A: No, bark beetles are not dangerous in normal circumstances. They can only be a danger once they attack old or diseased trees. The structural integrity of the host can be compromised. Before it poses any hazard, tree removal California is recommended. 

Q: How long does it take for a bark beetle to kill a tree? 

A: It takes two to four weeks before bark beetles can kill a tree during the warmer months. During the colder months, their activity slows down. More so, killing the host is quicker the more diseased or injured the tree is. 

Local Tree Experts Overview 

In sum, the California bark beetle is a small pest that brings big problems! It feeds mostly on conifers, especially on pines. As the name implies, they attack the bark of the tree, and with successful penetration, will inevitably kill the host.

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