Peach-tree Borers!




With my Asian plums on peach from Raintree, I have reason to be glad PTBs aren’t in this neighborhood. Yet.


I am trapping a lot of peachtree borers this spring in my pheromone traps… I’m not sure where they are coming from, but I am a bit worried they somehow managed to find something to eat in my compost bin this last winter - I turned over the bin in mid-winter and saw many worms that looked like dead ringers for peachtree borers. I almost killed them all but thought they must be something else. Only a couple trees had frass so its not my peach trees I don’t think.

Anyway I have decided to brew a new concoction for this generation. The raw neem is expensive so I thought I would try some other oils. Also, natural oils are supposed to work better in combination. Both linseed oil (aka flax oil) and sesame oil are toxic to bugs. Linseed oil in particular you can get for cheap by the gallon. So I am going to try a mix of these three oils. I already put down a diluted neem oil plus Surround mix a few weeks ago, and the Surround seems to be pretty well-attached to the tree base, so I will probably just paint this new concoction on top. Next year I think I will do the 3-oil mix plus Surround in one go.

If you have borers I would strongly recommend getting some monitoring traps, it is when you are trapping them that you need to be treating the trunks. It varies a lot by climate, for me May is the month.

PS here is the article on plant oils for moths which had better results with combined oils: They did not use neem oil in the study.

Peach Variety Suggestions for Ohio- 5b

I wonder if insecticide granules will help. Yesterday I looked at Sevin granules that you are supposed to put in the soil to kill larvae. There were also similar granules with mint oil as the main ingredient.


Since I have had good luck with the raw neem I will be sticking with natural treatments for now. But I am a bit worried given this big wave. You need something that will last a long time, I wonder how long those granules last.

Mint is a good botanical but its very expensive per ounce. I think linseed oil is the cheapest in terms of bang per buck. I have a ton of mint in my garden though, wonder how well it would blend…


Hi Scott,

I just made a new post with my borer problem, can you please take a look at my photos and confirm that it’s just borers? I saw a larvae and the sawdust, but the lump looks like black knot. It’s on only half the trunk, not all the way around. Or is this just classic peach borer? This would be my first encounter with either problem, it’s on a 2 year old apricot tree.


I need to hit my trees with permethrin again. I sprayed everything a few weeks ago very heavy. Haven’t seen any flying around…but i know they are out there…just waiting to kill my trees.


Looks like borer egg frass is in the mix. There are two types of borers. One kind bores at the base. Another higher in the tree.

I would cut ALL of that out with a knife immediately-- down to green wood-- put it in a plastic bag and dispose offsite. Also use a coat-hanger wire and poke around in the cavity to be sure you stab any borers that might still be hiding in there. Then spray the whole trunk liberally with neam oil. Then monitor. If further attacks occur, then you might consider the difficult choice of whether to go “chemical.”

Peaches are vigorous. The tree might survive and thrive. Mine did. Good luck.


Hmm, it looks like black knot to me. Cut it out with a knife and look for live wood under the lump - if there is live wood there its black knot. If its just goo its not.


It’s been pouring rain so I haven’t been able to go out yet. Is cutting into black knot mid summer going to release spores? What are the odds that my first (seen) borers would be burrowing into my first black knot infection? Bad luck for me…


If I do discover it’s black knot, is this tree getting the axe because it cannot be saved due to the location of the knot? It’s two years old only.


Hi Scott,

Here’s a few pictures after I cut off the lump. There was the faintest tinge of the palest green but only on a small part, barely discernible. This is most of the lump removed but I took a photo for you before finishing. I couldn’t scrape all the way down to green wood because half of my trunk would be missing and it would have a hard time supporting itself.

Do you still think this is black knot, and do I have to remove the tree? I brushed pure neem on the trunk after finishing, caught two borers in the process.


It certainly wasn’t just sap, I had to saw off the lump with a kitchen knife, it was beige inside along with frass.

Appreciate your input!! :slight_smile:


I’ve never seen anything like that on my trees so I’m not sure if it was black knot or not. Given the obvious presence of borers it could well have just been a site they had been working for awhile. Hopefully it was just borers. Even if it was knot there is no problem with the tree, just keep cutting it out if you see new knot growth at the edges. If you are diligent on cutting out knots it should not spread.


As you cut more wood out your tree might need support while the trunk heals.


How far is the knot above the graft union?


Probably six inches at most.


I staked it :slight_smile: I am happy to give this guy a chance.


XCan’t believe I would find a borer on April 13!!! Too early.

I was clearing around my trees including peach trees. I found jelly goo at the base of my Autumn Star. Cut a wire from a cloth hanger and started probing for a borer hole and found it.

This time the hole went down vertically (the last time I found a borer, the hole was rather horizontal). Surprisingly, I was able to find the borer and got it out.

I did not take a pic when I found the goo but took pic of a hole and the well- stabbed borer.



Thumbs is never too late to dig the sucker out


Are you kidding? Now? July yes, but April? Wow!