I was waiting for my plum tree to lose its last leaves to spray, and it just did, but the weather is not promising any warm ups anytime soon. Is it OK to do a dormant spray when temperature is about 25F during the day and 15F during night? I can use warm water in my tank sprayer and I am sure it will not freeze during spraying, but it may freeze on the branches, I guess. What are the guide lines here for winter sparying?
My experience is that the danger of spraying superior oil in freezing conditions is to green buds fresh out of dormancy. I doubt you would do damage to a tree already well into dormancy with it, but the larger question is why bother? Anything vulnerable to oil now will be much more vulnerable once the trees begin to grow and a spray now serves no functional purpose I can think of.
Spraying should always serve a specific purpose- what are you gunning for?
It is time to relax a bit, read up on pruning and plan for next spring!
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I had curl leaf on my peach this year, and I’ve been told to spray in fall with copper when it lose all the leaves. And oil I was going to add for aphids and what ever else decided to overwinter on branches. [quote=“alan, post:2, topic:8109”]
Anything vulnerable to oil now will be much more vulnerable once the trees begin to grow and a spray now serves no functional purpose I can think of.
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Why then do dormant sprays exist? I am confused 
Dormant sprays are no longer recommended for the control of aphids- a “delayed dormant” is now called for as scale and aphids become more vulnerable as they become active with first spring growth. I don’t believe an additional spray now against them would be beneficial and honestly, the aphids always show up anyway- spray in spring and they will return in a couple of weeks. Lady beetles need to eat and I consider further aphid control only potentially useful on establishing trees or trees with inadequate vigor.
The less mobile scale is more vulnerable to a single oil application to achieve annual control, but it is most vulnerable as a delayed dormant spray as well. Unless scale is already a problem on your trees- odds are it won’t become one next season anyway.
I don’t know about fall timing of copper spray for leaf curl control- I get adequate control at the two sites I manage where it is a problem by a single spray in early spring- just before first growth. Probably best to try this approach first and see if it is adequate. Even in heavy pressure areas it is likely to be enough to keep the trees productive.
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I did fall copper when I had bad spot or curl. Now I don’t have those problems so I just do a spring delayed dormant spray with copper/oil on the stone fruits and lime-sulphur/oil on the pomes.
If you have bad aphid or scale problems I would say two delayed dormant sprays a few weeks apart would be better than a spray now and a spray in the spring. These oil sprays also help reduce moth populations since eggs can overwinter on the tree, but they don’t make a significant enough dent in the numbers to think about moth reduction as a goal of the sprays.
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For pear psyla it is sometimes recommended to go 3% oil at green tip and then 1-2% around tight cluster. At half inch green 2% is often recommended for apples with scale but only 1% later- I believe because the more concentrated amount is not necessary when they are more vulnerable later and not because of phyto-toxicity concerns, but don’t quite trust my memory on that. .
Thank you Alan and Scott, I guess I will wait till spring.
Scott if you dont mind I have a few questions. 1) What oil are you using with your copper? 2) What is your timing for delayed dormant sprays? Do you start at first bud swell or green tip or something else? I had some of what I think is coryneum blight last year (i posted pics) and I want to get on top of it this year. I had planed on doing one spray at leaf fall and again in late dormant but I don’t think that is going to work now because the young trees are refusing to drop leaves so far! Even after a few hard freezes they are still holding on. Also one last thing are you also adding a sticker?
I currently use soybean oil. Basically the heaviest oil I can find, the heavier the more smothering you get. I spray at the last possible time which I believe is tight cluster for apples. I do pink for stone fruits and for pears its swollen bud since I need to nail the blister mites. With lime-sulphur I don’t use a sticker as it is absorbed. With copper I use Nufilm at a much heavier dose than the label, its dormant so there are no leaves to burn.
Just as an FYI to this thread. I’ve done dormant leaf curl spray in the spring, but now I do it in the fall and still get good control. It’s not as muddy in the fall, which is the main reason I choose to do it then, plus I have more time on the fall.
I’ve not ever had to spray dormant oil on peach trees (yet). Peach trees don’t seem to get mites here, or green peach aphid.
Isn’t the recommended dose of NuFilm 17 about 1/2 tsp per gallon or something?
I found some study that studied a NuFilm 17 rate of about 10 mL/gallon. https://www.nzpps.org/journal/62/nzpp_623390.pdf
So hey, I use somewhere between 5 and 10 mL’s of the stuff per gallon now when I spray. I have enough of the stuff to last me to the end of time, so that makes me feel like I’m using it.
For curl you also want to spray earlier, delayed dormant can be too late. I am not spraying for curl.
1/2-1 tsp per gallon is my summer rate for Nufilm. I use maybe 3-5 times that in winter. 10ml is 2tsp.
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Do they sell Nufilm in small quantities? I gallon for my 10 trees orchard seems too much . Or may be you can recommend something else that I can find in smaller packages?
Galina,
You can easily find Bonide Turbo spreader/sticker in a small bottle at local nuseries.
I found it at Weston Nursery. You can check Home Depot. I am not sure if HD or Loew carry it opr not.
Thanks!
When I started, I used Bonide. It lasted me a few years. Then, i have more trees so I’ve upgraded.
Soybean oil, wow. Is it the same stuff you buy at the grocery store? So you spray with a mix of soybean oil, nufilm sticker and copper at the pink stage for peach/nect’s. Is that correct? Thank you Scott.
Not grocery store soybean oil you need a special brand with an emulsifier in it. Golden pest spray oil is one brand.
Correct on what I sprayed in the spring.
Could a small amount of liquid dish soap be used as an emulsifier for the oil,if it was shaken when being sprayed? Brady
Scott,
This is one of them, right?
I bought it in the spring and forgot to use it!!!