Dormant spray, when is too late

It seems like there is never a good day to spray until it’s too late. Is it to late based on these pictures to use copper, sulfur, or dorment oil?

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Wow…things starting to wake up for you. Where are you in zone 7?
I was just outside today wondering when to do the dormant spray. Nice day today but couldn’t do it since I had my kid around plus rain in the next few days forecast. Better get started soon. Can’t help you with your question. I’m sure somebody else will…

Yes, I’m with Susu! I’m in zone 7a and my trees do not look like that until May - June. Wow!

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I’m in Nashville. I believe it is 7B. The last few years have been earlier.


My last spray of Copper against Peach Leaf Curl for Peach and Nectarines,is before the leaf buds open.
I put on dormant oil,just as I see a little color coming out on the flower buds of the Plum types,to help stop Aphids.It could probably be used earlier,but am not sure about after flowers open fully.
I’ve used micronized Sulfur for Pear Leaf Blister Mites,during full flower,with no

Thanks, it looks like I’m not too late. Now if it will stop raining.

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From my limited understanding, dormant spray should be applied when the temp. is at least 40 degrees and rain free for a 24 hour period. Today was 54 degrees and I was planning to spray, but life got in the way. The coming days are forecasted to look like this:

Thurs. 54/partly cloudy/13mph winds
Fri. 37/cloudy-windy/23mph winds 20% chance of rain
Sat. 46/sunny/7mph winds 10% chance of rain
Sun. 57/partly cloudy/15mph winds
Mon.- Fri. Mid to low 50’s 40-80% chance of rain (it will probably rain almost everyday)

So, I am thinking about spraying tomorrow. Is that a good idea?

What’s going to be sprayed?Is it going to contain a spreader/sticker?bb

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Copper for the peaches and the spray that Michael Phillips advocates on everything except the pears. That spray has neem oil in it.

A sticker will help keep the Copper on the plants,so it won’t wash off as

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Im new to spraying but decided on using a dormant oil spray this time due to scale last year.

Most references state apply while fully dormant or just slightly open.

This one states spray before buds break but if they have swelled slightly its probably ok.

This one says apply before bud break.

This one states delayed dormant, when green is 1/4 to 1/2 inch.

It’s confusing. I sprayed yesterday. Some pears and apples have just a little green showing. I hope I didn’t kill them! As I understand, the best benefit is when insects start to awaken, which is also when buds start to awaken. The most harm is when the flowers are forming.


Also the type of oil matters. Mine was not specifically dormant oil, although the label said it can be used for that. It was a finer grade, superior oil.


What plants were the Scale on?bb

Apples and pears. mostly apples. The fruit were exactly as pictured here.

Im following the WSU instructions,


When applying dormant oil and copper, should a person include a spreader/sticker as well? Does the oil serve as a spreader/sticker?

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Oil does work,but probably not as well as a designated


I think you need a surfactant (spreader) for oil and water to mix effectively. However probably a lot of oil products already contain one?

I’ve always heard the above 40 for 24 hours to spray. Some years that doesn’t leave much of a window before buds swell. So what exactly happens if I spray dormant oil lime sulfur spray or copper/oil spray on a 40 degree day and then it drops to low 20s at night? Has it been studied or just something that people do because that’s how it’s always been done?

Some of these kinds of sprays will burn tender new growth, so — as a class — they are reckoned to be damaging if applied too late. This is not true of all, however. Modern light-weight oils can be applied for some purposes to growing foliage. When used as dormant spray, horticultural oil smothers insects coming out of hibernation. Its action is mechanical rather than toxic, so it needs to be applied while pests’ respiration is increasing — above about 40° F. The latest that such benefits are obtained is about 1/4-inch green, which can be a tolerably narrow window. If you miss it, don’t sweat it. It won’t do to apply in the rain or when rain threatens of course. It won’t do to apply when the weather is too cold, when it is too hot — above 80° F, when it is too dry, when it is too humid, or when it is too windy because the emulsion will either freeze, separate, or evaporate before killing insects and their eggs.

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