Hello,

There have been a few reports of pitch mass borer in the OSU Buckeye Yard and Garden Line publications in recent years. The general recommendation is to keep the tree healthy and avoid mechanical injury to the tree. It is also recommended to remove the pitch masses and dispose of them in the trash as they often contain the larvae. This will keep their numbers down. Spraying for the pitch mass borer is difficult because the larvae is located in the pitch mass or hidden in and under the bark and the spray will not come in contact with the caterpillar. That being said, spraying is more effective in the spring when the larvae are moving on the tree trunk. There was no mention of treatment with a systemic chemical in any article that I read.

Before you commit to a chemical treatment, it is important to get an accurate identification of the insect that is invading your tree.  If you can find evidence of the larvae inside of a pitch mass or the moth itself on the tree, it would be a good idea to send a sample to the C. Wayne Ellett Plant and Pest Diagnostic Clinic, run by the Ohio State University. The PPDC can confirm the identification of the pest and make additional recommendations for up to date management and treatment. If you should decide to treat the borer with a chemical, make sure that you follow all label directions accurately. Additionally, some chemicals are restricted and need to be applied only by a certified pesticide applicator.

Unfortunately, in recent years, the Colorado Blue Spruces planted in Ohio have become increasingly stressed by the area's climate. The Blue Spruce does not do well with extreme winter temperature fluctuations, summer heat and humidity, and prolonged periods of rainy weather. As they age, the spruces' defense mechanisms weaken and they begin to be riddled with disease and pests. 

I have listed the links for the articles below. I have also listed a link for the PPDC's website if you would like to send a sample to them. If you have more questions, please write back to Ask Extension.

Betsy B. - MGV

https://ocvn.osu.edu/news/osu-buckeye-yard-garden-line

https://bygl.osu.edu/pdf/2014/BYGL-2014-21.pdf

https://web.extension.illinois.edu/focus/?problem=pitch-mass-borer

https://ppdc.osu.edu/

I sent you a follow-up email requesting the timeframe in Spring and Fall the larvae is active in Central Ohio.  Thank you.

Here is an article about spraying borer larvae. It is specifically for the Zimmerman pine moth. I don't know what kind of borer that you have in your tree.  You will have to scroll down to the article on the Zimmerman pine moth and then click on the Iowa State University link for the information.  It gives the timing as related to when specific plants are blooming in the spring and fall and that is when the larvae would be active. 

Betsy B. - MGV

https://bygl.osu.edu/pdf/2011/BYGL_August_4_2011.pdf

Good morning, carefully timed insecticide applications may be effective only if you are actively targeting the correct life stage of the insect.  Without seeing the tree and the insect, we are unable to assist you with the exact timing of when to apply your treatments.  I would suggest sending in a sample to the plant and pest diagnostic clinic or allowing a professional arborist to assist you.  Here is an additional factsheet for your reference:  https://extension.entm.purdue.edu/publications/E-256/E-256.html

Many thanks, and take care. 

Jen