Right now, bark beetle larvae could be silently tunneling through the inner wood of your pine or fir tree – and you’d never know it until it’s too late. Once they’ve done enough damage, the tree dies, becomes a hazard, and worse, spreads the infestation to nearby trees, putting your entire landscape at risk.
We’re covering five common bark beetles found in the Greater Truckee-Tahoe Area, how they attack and kill trees, the early warning signs to look for, and how to protect your trees before the damage is irreversible.
Key Takeaways
- Five major bark beetle species threaten Lake Tahoe trees, including the mountain pine beetle, Jeffrey pine beetle, red turpentine beetle, California fivespined ips, and fir engraver beetle.
- Bark beetle larvae feed on a tree’s inner bark, cutting off its water and nutrient supply – often killing the tree in just one generation of beetle.
- Early detection signs include pitch tubes and discolored needles, so look for resin masses where beetles burrowed in, rusty or yellowing needles, boring dust, and increased woodpecker activity on your trees.
- Prevention focuses on tree health by keeping trees unstressed through proper watering during droughts, spikeless pruning, fertilization, mulching, and avoiding mechanical damage to maintain their natural beetle resistance.
- Infested trees must be removed quickly because once beetles have successfully colonized a tree, it cannot recover, and removal is the only option.
5 Bark Beetles Killing Trees in the Lake Tahoe Area
Trees in the Greater Truckee-Tahoe Area face no shortage of challenges, but few are as destructive as bark beetles. These tiny pests come in many species, and several of them can quickly weaken, kill, and spread through native pines and firs.
Here are five of the most common threats in our region so you’ll know what to watch for and how to act fast if your tree shows signs of trouble.
Photo of mountain pine beetle courtesy of Javier E. Mercado, CC BY 4.0, via Wikimedia Commons
1. Mountain Pine Beetle
The mountain pine beetle (Dendroctonus ponderosae) is a native insect that affects many of our local pines, including:
- Ponderosa pine
- Lodgepole pine
- Limber pine
However, these are not the only pines the beetle can infest, as it feeds on all pine species.
The mountain pine beetle is incredibly efficient in harming your tree, with many trees dying within one generation. They “mass attack” one tree and feed on the inner bark, killing it by girdling it and preventing the transportation of water and nutrients.
Adults bore into the tree and mate, laying eggs that develop into larvae. The larvae will continue feeding on the inner bark throughout the winter and spring. By the following summer, they will emerge from the tree as adults, colonize other nearby pines, and repeat the process.
You’ll see most of the damage from mountain pine beetles in the lower 15 feet of a tree. Look for pitch tubes, or masses of resin that emerge from the tunnels where the beetles burrowed into the tree. A pine’s needles will also turn a rusty color due to the infestation.
If the opportunistic beetles complete a mass attack, your tree may be dead by the time you notice the symptoms that something is wrong. The only thing to do for these trees is to remove and dispose of them properly to keep your property safe.
2. Jeffrey Pine Beetle
The Jeffrey pine beetle (Dendroctonus jeffreyi) is the most common pest of the Jeffrey pine, a widespread tree in our region. They are one of the largest bark beetles we know of and have been a problem in the Truckee-Tahoe area for decades.
The beetle attacks trees similarly to other bark beetles by burrowing underneath and letting the larvae feed on the inner bark. You can see adults emerge from your trees as early as April, if the weather is warm. Scientists have also observed that the beetle is more likely to cause damage after a prolonged drought.
Pitch tubes on your Jeffrey pine can help you tell if beetles have attacked. If the pitch is white or yellow, the tree has likely fought them off and pushed them out. But if the pitch tube is red and filled with sawdust-like material, the beetle has made it inside and started to colonize the tree.
Monitor your trees for any signs of the beetle and have an arborist look at them as soon as possible. Because of the extensive damage already done to the Jeffrey pine population in our area, it takes a concerted effort from all of us to protect the trees we still have.
Photo of red turpentine beetle courtesy of Joseph Berger, Bugwood.org, CC BY 3.0 US, via Wikimedia Commons
3. Red Turpentine Beetle
Red turpentine beetles (Dendroctonus valens) are widespread throughout the Greater Truckee-Tahoe Area and beyond. The red turpentine beetle (RTB) affects all pine species in our area, making them a tricky pest to contain and treat.
RTB are the largest bark beetles in North America, with some growing up to ½ inch long. They are also easier to spot than some other bark beetle species, as they have a reddish-brown color.
One of the distinctive aspects of this beetle is its opportunistic nature. These beetles rarely attack healthy pines, and when they do, the damage they cause is minimal. However, when a tree is stressed or struggling from another problem, RTB can quickly kill it as it won’t have the appropriate natural defenses.
Photo of ips beetle courtesy of Sarah McCaffrey, Museum Victoria, CC BY 3.0 AU, via Wikimedia Commons
4. California Fivespined Ips
Ips beetles are a family of bark beetles that are a significant problem in the Lake Tahoe area. One of these beetles, the California fivespined ips (Ips paraconfusus), is especially damaging to our local pines when there is a drought or other stress put on local trees.
Before 1945, foresters and arborists did not consider the California fivespined ips a threat to local trees and forests. However, as the forestry industry expanded in California and included more logging of ponderosa pines, we saw how destructive it could be.
While experts have managed to control the damage it causes, we still see high mortality rates from California fivespined ips when the Greater Truckee-Tahoe Area is in a drought.
Aside from the ponderosa pine, this beetle affects numerous other pines, including:
- Sugar
- Coulter
- Digger
- Knobcone
- Monterey
- Bishop
5. Fir Engraver Beetle
The final bark beetle on our list is the fir engraver beetle (Scolytus ventralis). These pests attack many of our native firs, like the white, grand, and red firs. They also sometimes infest Douglas firs, a common tree in the Lake Tahoe area.
This beetle attacks the upper portions of the tree’s canopy and kills branches near the top. You may notice some branches looking yellow or red in the canopy, indicating damage to your tree. You can also look for signs of boring dust in the bark crevices. Additionally, extensive woodpecker activity is often a symptom of a fir engraver beetle infestation.
If you believe the fir engraver beetle has killed your tree, have an arborist look at it as soon as possible. Removing these trees promptly before the adult beetles emerge in May will prevent them from colonizing other nearby firs.
Frequently Asked Questions About Bark Beetles in the Lake Tahoe Area
To help you better understand the threat that bark beetles pose to your trees, we’ve answered some of the common questions homeowners have about them.
What are some ways a homeowner can keep their trees protected from bark beetles?
The best way to protect your trees from bark beetles is to keep them healthy, as most beetles prefer to attack already weakened trees. Some ways to keep your trees unstressed include:
- Water trees during a drought
- Avoid a company that performs spiked pruning (the holes from climbing spikes can serve as an opening for insects)
- Apply fertilizer when there is a nutrient deficiency in your soil
- Place mulch around your tree to add organic matter to the soil (just be cautious of leaving defensible space)
- Prune any competing branches in the winter
- Avoid damaging your tree with a lawn mower or string trimmer
Why should you remove bark beetle-killed trees right away?
When bark beetles kill a tree, the real threat isn’t over – it’s just beginning. The larvae feeding inside the bark will soon mature into adult beetles and spread to nearby healthy trees. Removing infested trees quickly helps stop the beetles from colonizing others, protecting the rest of your property and even your neighborhood. If a tree is already dead from bark beetles, it’s time to remove it before the damage multiplies.
Can chemical treatments save a tree from bark beetles?
Some chemical treatments are effective at killing bark beetles, but they are not always as practical as you may think. Trees can’t quickly recover from the larvae’s damage. Even if you kill the pests, the girdling of the tree will prevent it from ever recovering and eventually necessitate removal. This is why keeping your trees healthy and resistant to bark beetle colonization is vital.
Has a Bark Beetle Killed Your Tahoe Trees? Arbor Solutions Can Help!
Bark beetles may be small, but they can do a lot of damage to your tree in a short amount of time. Trees can’t recover from the damage these beetles do, meaning removal is often the only choice to protect nearby trees and your property. Removing these dead trees can be dangerous, as they usually have poor structural integrity. When you need tree removal that is safe and efficient, trust the expert team at Arbor Solutions.
Our team has the experience and equipment (like our tree removal crane) to effectively take your tree down without collateral damage to your property. We’ll also haul away all debris and leave you with a clean, danger-free yard. Call us today at 530-580-8383 or request an estimate online.
Lead Arborist James Piercy has worked in the tree service industry since moving to the Tahoe region in 1997. He has been an ISA Certified Arborist since 2004 and continues to provide expert recommendations and quality tree care throughout the region.
We publish monthly articles detailing tree care in the greater Truckee-Tahoe region. If you have a question about maintaining your trees, we may have already answered it on our Tree Care Blog.
