Hello. We have a perimeter of probably 70 arborvitae trees that have recently started dying in one patch (back right in photo). Another patch has recently started dying (left in other photo). I found the beetle in the attached pic in a small gall under the bark of one of the trees in the new patch. I’m looking for advice on how to save the remaining trees. Is this a pine bark beetle? Any help to save our trees would be immensely appreciated!!
You’ve got arborvitae borers. These borers behave very much like other borers though they tend to target American, emerald green, thuja and other arborvitae species found in the states. Technically they’re “cousins” of the more common pine bark beetles but they look very similar, do the same kind of damage and fortunately, can be controlled using our sprays.Arborvitae borers are small. As you can see by comparing them to a dime, its hard to imagine they might cause damage to any tree. But their sheer numbers along can have an impact as they work their way through the bark and trunk of a healthy tree.
Once mature, they’ll exit the host tree looking to fly off, find a mate and start laying eggs elsewhere. Typically this will happen on local, nearby trees so its smart to protect as many trees are you want to keep safe.
So what we’ve had customers do for this pest is first spray all the “healthy” looking trees with MAXXTHOR EC. Spray the infested trees last. This way any beetles trying to relocate off the infested trees will avoid any tree already sprayed. Maxxthor is fast acting, highly repellent and will last several months keeping them away.
Add 2.5 of Maxxthor to our hose end sprayer, fill it to the 5 gallon line, hook it to your hose and spray. Plan on using this much for every 2-4 trees. Our Sprayer can hold 4 times as much so you could add 10 oz of Maxxthor, fill it with water and spray it all out which would be equal to 20 gallons of mixed solution. This should be enough for 10 or more trees given the size we see in the pictures you sent.
A good HOSE END SPRAYER like this one will make the job easy since you need a lot of water to saturate the trees trunk and limbs.
Second, soil drench with PROTHOR. Plan on using 1 oz of Prothor for every 5-10 inch wide tree. Add the prothor to 3-4 gallons of water (a 5 gallon bucket works great for this job) and using a soil auger, make 5-8 holes around the trees trunk so the mixture can percolate down into the ground. Once the you have the right amount of product mixed up, pour it out in the holes letting it sink it and not run off.
We also recommend adding our liquid fertilizer to the Prothor drench. This will help any tree “get well fast”. Use 2 oz of JOY JUICE with every 1 oz of Prothor needed per tree.
Remember to get the mixture into the ground by using holes 2 feet out from the trees trunk but inside the drip line. A good EARTH AUGER will make holes evenly spaced.
Plan on doing using the Maxxthor every 3 months till the trees look good again. Usually 2 treatments gets the job done. After that, spray them once a year in the spring and you’ll be fine. Same with the Prothor, once a year, after they’re gone; two treatments the first year spaced 6 months apart.
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