Watch Out for This Pest Invading California

April 27, 2021
April 27, 2021 Ryan McFadgen

Watch Out for This Pest Invading California

If you’re a property owner in California, particularly one who cares about the health of their trees, you need to pay attention to this: A particularly stubborn species of beetle has invaded, and is devastating trees throughout the state.

It’s called the shot hole borer, and it does pretty much what it’s name implies. The non-native beetle bores into trees to create galleries, where they eat and lay their eggs. Since they can bore fairly deep into a tree, this damage prevents water and nutrients from moving effectively throughout the entire plant. And in the case of the shot hole borer, a secondary fungal infection often accompanies them. If the nutrient disruption doesn’t kill the tree, this pathogenic fungus usually does.

Trees are actually harmed even more than smaller plants, because many smaller plants don’t succumb to the fungus. And because trees provide the correct breeding ground for shot hole borers, colonies of the insect can successfully reproduce in one tree and then move to the next. If you find shot hole borers in one tree within your yard, you’re probably going to start seeing a lot more of them in more of your trees. That’s why it is so important to act quickly if you see signs of this activity.

Many of our native California trees are particularly susceptible to this destructive activity, such as:

  • Englemann oaks
  • Sycamores
  • Box elders
  • Blue palo verde
  • Big-leaf maples

Other oak and maple species can also become infested with shot hole borers, along with avocado trees, acacia trees, and many others. These species are all quite common within California, so it’s easy to see how these invasive beetles are doing so much damage.

If you witness small, round holes in the trunks of your trees, it’s time to take action. Management options for shot hole borers are unclear at this time, as scientists scurry to devise a solution. For now, heavily infested trees should be removed so that the insect’s reproductive efforts don’t spread to nearby trees in your yard.

If you suspect you should remove an infested tree, give us a call for an evaluation. We can help you decide upon the best course of action to save the other trees in your yard.




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