Dormant Spray and Copper Spray


I thought shot hole borer is in the ambrosia beetle family. The label for Sevin mentions ambrosia beetle. This will be the first time using it so I don’t know about the effectiveness yet…


Sevin has been Carbaryl for decades so most if not all articles mentioning Sevin is referring to Carbaryl. If you use the term Sevin most people will assume it is Carbaryl. Unfortunately marketing people decided to but the name Sevin on a container for a different insecticide. Confusing.


Noted :slightly_smiling_face:



I’m not sure exactly which borer you are treating for, but will offer a few general comments.

For beetle type borers which tunnel galleries inside the trees, few insecticides are going to do much once they’re inside. They are protected against sprays. Hence why Rick mentioned sprays haven’t proven to be very effective.

The caveat is that commercial orchards generally don’t have a problem with shot hole borers because they are fairly intensely sprayed for other insect pests at the same time when various beetle borers are emerging from trees. That is, no problems when broad spectrum insecticides are being used. Small non-bearing trees generally aren’t intensely sprayed, so tend to be more subject to beetle borer attack. I rarely spray non-bearing trees except for leaf curl.

The Zeta-Cypermethrin you mention is something I use (in the commercial form it’s called Mustang Maxx). Though not specifically labeled for ambrosia beetles. It’s a powerful broad spectrum contact insecticide which is going to kill any adult beetles not already tunneled in the trees.

But it’s contact ability is going to diminish with time, so I’m doubtful with the current temps that the sprays would do you any good at this point. Depending on the beetle type, they emerge in spring or early summer. I don’t think your insecticide (sprayed now) would give you much residual when you need it.

As Tippy’s chart shows, pyrethoids (i.e. Zeta Cypermethrin) are fully compatible with copper.


I just received some research on Ambrosia beetles from a trial on apple trees in 2018.

One of the most effective treatments was something called Permanet wrapped around the lower trunks of the trees. I’m not familiar with the product but apparently is also used as a insect control netting against malaria and other insect born diseases in undeveloped countries. The net is treated with deltamethrin which is a synthetic pyrethroid I had never heard of before.

Looks like an interesting idea.

The other effective treatments were soil applied Admire (Imidacloprid), foliar Lorsban (restricted use) and foliar Cobalt which is a restricted use product I had not heard of before


I use imidacloprid if needed during the season, so I might add that to my ambrosia arsenal. They are horrible!

I do use Sevin (powder) on the low trunks. It killed live ones I had on a fig that died from them. I had cut as far as I could while allowing suckers to grow to keep the variety, so I got to see how they acted for half a season on the short stump.

My attack was in February here. They hit during the first spell that made buds want to pop. I found a paper once that confirmed that they fly that early here. That summer I watched my fig, they were active again later, too, but then died from the Sevin within a day or two.

I don’t know from experience whether protecting trees with insecticide does much. I try just out of fear, lol.

Fortunately I think I got them all that year and didn’t have any problem last year. It’s crazy how they just kill the whole tree with a few hits!


Olpea, Blueberry and Cafeaulait thank you all for the useful info. I’m not exactly sure what type of ambrosia beetle I’m dealing with. I know I had about 10-15 tiny holes on each trunk that died on me. I figured I’ll start early as to prevent them since no cure after attack. I hate to use kill it all kind of products but I can’t lose anymore of trees. After the trees flower I’m planning to spray just the trunks. No branches. I’m also covering the trunks with tree trunk wrap, hopefully that will discourage them.


I have some Bonide copper spray, I bought it a couple years ago for my tomato plants, but still have most of a jug left. It has copper octanoate (copper soap) at a very low amount- 0.08%.

Would this concentration be enough to work on my peach trees for PLC prevention? My four trees are still dormant, and we are not forecast to have any rain until Thursday. The highs will be in the 50-60s the next four days.

If it is good to use, do I spray each branch down to the trunk? Also it looks like I have some flagging tips on some of my trees, which I assume to be OFM damage. Should I prune these tips off before or after spraying?



I am not sure this will give you 100% protection. I used it in Dec 2016 and in April 2017, I had some PLC on one of my two trees then. Last year I switched to the more concentrated product from Bonide (I think it is a 10% suspension), mixed it at the high end of the recommended mixing ratio and employed NuFilm with it. I also delayed my spray to late March and I got 100% protection. Of course the later spray timing may help in your case (vs my 2016/2017 experience), but there may be some risk.


Your copper is quite not strong. For PLC you need to spray at dormant stage. No need to spray trunks for PLC but you can spray trunk for canker protection or other fungal/bacterial purposes. However, I am not sure if the product you use will be much help.

I don’t prune off OFM damage before I spray. I prune them off when I see them in the summer and fall so I could catch that larvae (sometimes) in action. It’s satisfying to cut those worms in half with my pruner.


Thanks. What percentage of copper would be sufficient? And does adding a bit of dish soap help with it staying on longer? I see @Ahmad and other folks talking about Nufilm, but I don’t have any of that yet.

Since I’ve planted my peach trees, I don’t think I’ve had any PLC. There’s been yellowing leaves, but I think that’s been because of too much rain.

From what I’ve read, now is also a good time for spraying horticultural oil?


It is the type of copper, too. I only use copper hydroxide. You may want to search for copper info here. There are several threads going in detail about it.

If you don’t have Nufilm, look for Bonide Sticker/Spreader. It comes in a small bottle. It is sold in several places.


All of the sprays you need are sold on line. My fav. Is Do your own Pest Control. Is that right guys? Living in a small city, I must buy my chems on line. Nu-film is just great. I agree with Mam!


I use 4 Tbsp per gal of the 10% formula, together with NuFilm and horticultural oil. I do not know about soap though.


Has anyone used a copper that didn’t work? I use copper ammonium from Southern AG that has completely eradicated peach leaf curl. Of course timing of spray must be at or before start of bud swell.


Is that timing specific to copper ammonium? My understanding is that copper is best applied after bud swell, before bud burst


Copper can be sprayed at different stages of fruit tree growing for different purposes. It is best to follow the label for an amount needed re. the copper product you use.


Regarding PLC the guideline from universities is the same for all types of copper. The quote from University of New Hemisphere is typical. Quote:
“The disease is controlled by applying copper soap after leaf drop in the autumn or before buds swell in the spring.”
I follow that and it works well. PLC is not difficult to control. Sulfur can also be used.


I like that one . . . ‘silently dead’. Just about sums it up! Funny! (Hi Mamuang!)


Mike and others, what is the purpose of adding Lime-Sulphur to the mix? And what exactly is that Lime-Sulphur?
Are you sure it’s compatible with other components of “Bordeaux mix”?

I used for a second year the following mix suggested to me by a person on persimmon group in FB (I added neem oil to that mix):

2 tbsp of CuPro 5000
2 tbsp of Dawn liquid detergent
2 tbsp of corn oil
1/2 cup of Clorox washing detergent
1 gallon of water

What do you think about it?