Jumping on the spray wagon

Just making sure its ok to combine dormant oil and copper spray. I’m a little behind with this weather and combining them would be a great time saver. Just making sure I’m not asking for trouble. Thanks for any info.

The mix is fine. If it were me, I would also mix in sticker like Bonide Turbo to help the chemical stick to trees better and longer.

Make sure temp is not below 40 F when you have oil in your tank mix.


Looks like we have maybe 3 weeks … so I can procrastinate…at least that long if I don’t get in the mood sooner on the dormant oil.

Copper, just once in 30 years,probably won’t this year either.

Just that it’s been awfully rainy lately, and usually spring here is filled with even more wet weather. Trying to hedge my bets when possible I’ve skipped sprays before and paid for it. Thanks @mamuang too for the info!

I’ve only been spraying my trees for couple of years. Always mix the two you mentioned. My trees are buried under a lot of snow this year. Waiting to see them again so I can spray. It’ll start to feel like end of winter once I go out with the sprayer.


Unless you have something major that you are treating, I would not worry too much about the copper. Copper is bad for the life in your soil, so if you are applying it thorough the year, you could be doing more harm than good.
I have started mixing my oil with silicon to form an emulsion, then mix in some water, shake really well in a jar, then add that jar to the sprayer and top off with water. This has proven better results for me. Unless you use the ready to spray stuff (costs way too much in my opinion), this makes sure that the oil and water don’t separate in your sprayer and your trees get a nice even coat. It will still separate a bit if you leave it alone for several days, but you can shake it back up to a proper homogeneous mixture easily and I have yet to find a plant that doesn’t enjoy a little extra silicon.


The silicon mixing works great with neem oil sprays during the growing season as well. I like to do neem, fish emulsion, and silicon all in one spray during the growing season.


oil/silicon… first time I’ve heard of this combo. Maybe I know it by another name that I can’t connect.

What form of silicon and where do you get this.?


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@MES111 I get it from Amazon:
Amazon.com : Liquid Silica Boost Fertilizer and Supplement by Bloom City, Quart (32 oz) Concentrated Makes 180 Gallons : Garden & Outdoor
Another benefit is that Silicon cannot be redistributed through the plant unlike other nutrients. So as a foliar spray, it helps ensure the plant has enough throughout.
How to Use Fertilizers-Silicon | Organic Gardening Blog – Grow Organic

and about using it with oil:
Integrated Pest Management | Revival Gardening

I can’t find the original article I read which goes more into the science, but if you test it out, you will see the emulsion form.

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I am confused, the original poster was obviously talking about using copper and oil as pest/disease/fungal/control. It seems he needed something more than just oil.

Your formula is using only oil with a fertilizer added. The silica seems to be for use to combat environmental weather related (from the advertising blurb “silica can help increase plant defenses from all sorts of stressors - heat, humidity, drought conditions, and more”.) stresses. Silica will do nothing to combat fungal and bacterial diseases.

Am I missing something?



sorry for the confusion, my point is that mixing silicon with oil creates an emulsion which allows for a homogeneous mixture to be applied. if you just mix oil and water, they separate, and quickly. So as you spray, you are not spraying equally to everything, unless you are continuously shaking.
The other bit is a tangent on other benefits of incorporating silicon into your spray routine.

To be clear you only need silicon or some other emulsifier if you are not using hort. oil. I am using hort. oil so don’t add silicon.

Re: copper, Regina is in Virginia and it can be pretty disease-ridden and copper is a big help some years. In Maryland I use copper some years on the peaches and plums, not on anything else though. I use lime-sulphur on the apples and pears along with the oil. I agree you don’t want to spray copper unless you really need it, it does build up in the soil.


Scott - I tried to find lime sulphur . . . and read that it is has been made unavailable. ?
I read that it was suggested for apples and pears - as you are doing. Lime sulphur was also one of the possible treatments that was recommended to me - for my pomegranate problem.
Any ideas where to look for lime sulphur?

Regina is in Virginia and it can be pretty disease-ridden.

‘Karen is too’ . . . and can attest to this statement!!! :grimacing: :joy:

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Keystone Pest Solutions is selling it now. It is 5-gallon size which is the main downside. There is also the pet dip version which you need to dilute 3-1 to get the horticultural version equivalent (or just add 1/4th the amount).

I am a big fan of lime-sulphur and I spray a lot of it in the spring. Just be careful with how caustic it is. Once you have sprayed it the risk is very low, lime an sulphur are everywhere in your orchard already.


Scott, I saw that ‘pet version’. That may be the way for me to go. One site had a warning about choosing it, though. Maybe those who did, did not dilute it properly. Thanks for the info!
With my poms . . . . what do I have to lose? The fruit was such a mess last summer. And if that fungus is allowed to ‘have it’s way in the orchard’ - the plants will all eventually die. I’m going for it!


I use Cuprofix Ultra (7 lbs)with Helena Damoil (256 oz) (for 100 gallons of water) with very good effect while things are still dormant. Last year no discernible Fireblight. Remember a little soil damage is irrelevant if Fireblight makes an appearance. (Pay attention to the Cornel model for Fireblight risk.). Of course, I do follow up with Harbour and since Phytophothera is an issue RidomilGoldSL on the roots as per the label. (Plant new trees but soak before hand in Aliette as per the label - best bet is to buy resistant root stock like G-890.). I use another hit of Damoil/Cuprofix and then Pilot 4Es (for those of us with licenses) along with Syllit, Manzate ProStick and even Merivon. Recommend highly you get the Spray Bulletin from your local land grant University - for me it is VPI and they put it out for MD. VA, and WV. Penn State has wonderful folks, like Dr. Kari Peters and of course Cornel is fantastic. (MIchigan and Minnesota are also great.)

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Yeah, way too much snow out there to think of going out with the spray wagon. Also, I ran out of horticultural oil last fall and need to buy more

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Has anyone else tried the silica amendment mentioned here? I would have thought the sand in soil would provide all that is needed, but I am always open to suggestions.

I have heard a number of references about copper build-up in the soil. What negative effect does it cause?

Copper toxicity