Cherry Tree Borers Question

[EverythingITouch]

For starters, I have a very brown thumb and am very new to taking care of a garden.

So I have a cherry tree infested with borers.
It’s clearly too late to save the infected limbs so I trimmed them off.
I tried digging out the borers, but there was no obvious insect in any of the hole I dug out when leads me to think they’ve done their thing and flown off.

My question is, how do I know when to spray the trunk next time around to prevent this? From what I read, you spray when the larvae are present before they’ve hatched and burrowed. I’m just not sure when exactly that is.

And also, what is the most effective insecticide to use? I’ve read pyrethrin or Triazicide.

Thanks in advance for helping a clueless soul just trying to save a tree!!

 

[cpp gardener]

Either one weekly from beginning of bloom until middle of June.

 

[DirtMechanic]

If it is shothole borers, they are using the tree to feed and cultivate a fusarium fungi which it in turn eats. It is the fungus that harms the host tree. I have had success with systemic fungicide and attacking the borer food source rather than the insect itself, and have lost trees trying a insecticide, imidacloprid, that was dripped into the root just as it merges into the trunk. They swarm, and can pull out of one tree and attack another. I suspect they let the wind direction lead them. I have not studied on other types of borers.

I paid an arborist to learn of the insecticide method and still lost 2 golden rain trees. I came up with the food source attack so be aware. The insecticide must be systemic for curative purposes once they are inside. The insecticides you mentioned are to my knowledge used on the outer surfaces.

Foliar application of agri-fos is the fastest systemic fungicide method, but get in a hurry because fall approaches and the sap transport mechanism is necessary. Also drench the roots, think 5 gallon buckets.

Penn State University says this:
"One means of reducing the acidity of phosphonic acid is to neutralize it with an alkali salt; typically potassium hydroxide (KOH). The resulting solution contains mono-and di-potassium salts of phosphorous acid (often referred to as potassium phosphite), and is the active ingredient in Alude, Magellan, Vital, Vital Sign, Resyst, and other phosphonate fungicides. Potassium phosphite is also the main ingredient in several phosphite fertilizer products, including K-Phite (0-29-26), Ele-Max Foliar Phosphite (0-28-26), and Nutri Phite P + K (0-28-26)."

Agri-Fos was the product I used on my trees.


The arborist used this type injector by drilling a 1\16th" hole at a downward angle around the base of the tree right where each root cluster merged into the trunk. Its a swollen raised area that is identifiable.