I had to spend some time working this week (the work that pays) and as I was checking the orchard tonite, I noticed that several of my apples are now showing 1/4" fruit clusters, unbloomed, and green tip throughout the orchard. At this stage, will DO damage the fruit clusters or the new emerging growth? Temps tonite in central Ia. will be in the mid 30s but in the mid 60s tomorrow although we are supposed to get 40mph wind gusts. Did I mess up or can I still spray DO?
You can do delayed dormant up to 1/2" green, so yes. I spray very close to 1/2" green, you get the most effect with the latest dormant spray.
At this point my apple buds are barely swelling, I’m probably aligned with Minnesota this year.
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You can do a delayed dormant up to and including the point that earliest flowers just start to show some color. Nowadays, for apples, it isn’t even recommended before 1/2 inch green and is more effective for some pests at tight cluster. Earlier sprays, a 2% formulation is sometimes recommended- later 1%.
For pears it is a different story- pear blister mite is best sprayed for just before first growth. Psyla may need two applications at 2%- the second at tight cluster.
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Alan, do you mean while it still looks totally dormant? I usually wait until I see a bit of swell on the flower buds.
Looking up the apple spray recs it looks they say to do full strength up to 1/2" green and switch to half strength at tight cluster. I have done full strength at tight cluster before and not noticed any problems.
Scott
Bud swell is probably perfect, I’m certainly not the last authority. On pears I’ve heard of doing triple strength pretty late to nab those psyla although Cornell only recommends that at full dormant. When they appear they are the most horrid of pests.
Cornell does recommend spraying pear blister mite at full dormancy and not at swollen bud (for pysla they say either, just at the different concentrations). It seems Olpea had some information suggesting application at swollen bud or even first sign of green works for PBM- maybe he will chime in.
They aren’t usually much of a problem here, although when they appear my customers get annoyed.
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I just read a bunch on this subject the other day. Many say not to dormant spray after bud swell. Never mentioned why not but I figured it must be that some dormant spray mixtures are not acceptable during growth. Advisory on the subject was all over the place.
Since early bud swell is all that is evident at this point on any of my trees I sprayed. 30 min. later is was pouring down rain and washing it all away.
I sprayed Dormant oil, copper, sulfur and chlorothalonil. Hopefully 30 min. contact will do some good for something.
Appleseed, the first place I think you should go for information are sources that advise commercial fruit production in this county, such as Cornell or UC Davis- accumulating wide searches on the internet and then dividing the content to come of with some kind of average may not be very useful. Of course, before you spray you need to study the label, which will tell you when the material can be applied.
Nowadays, when people talk about oil spray, they are pretty much always talking about highly refined oil originally called sunspray but now often referred to a horticultural oil because other formulations that can only be sprayed when trees are dormant are no longer often sold (if available at all). When I buy it, I just say I need a case or more of “oil” and that’s all anyone needs to know.
One thing said on the labels of the 2.5 gallon jugs I purchase is to spray when drying conditions are good- if green tissue is present it can be damaged when there is a slight drizzle- not enough to wash oil off but enough to delay evaporation long enough to damage tender young tissue.
What will also damage buds if if you spray when tissue is frozen (temps are below freezing) or even if freezing temps arrive before the oil has had a chance to adequately evaporate. What makes these formulations different than earlier oil products (back in the '70’s, still available in the '90’s) is the manner in which they quickly evaporate.
As far as wash off from rain, a half hour is not long enough to accomplish anything, but it takes over a half inch of rain to remove enough pesticide to render the spray useless. A sticker can be helpful with this.
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Yeah…I waited as long as I did because of the freezing temps issue and then this time of year rain is always just around the corner. I used Volk oil spray and this is the first time I’ve ever bothered with oil. I did spray it during a warm period in late fall as well…same mixture.
I’m familiar with horticultural oils although I’ve never used them, as far as sunspray, I’ve never even heard of it. I always sprayed sulfur and chlorothalonil before bud break and am starting to think the oil is probably not going to do much for me. I think the copper is a big deal based on my reading and although I’ve always had it, I never bothered spraying it for some reason. The copper I have is kinda a pia to spray though, it wants to clog the spray nozzle although I did mix it on the heavy side. Sulfur always sprays so well, but when combined with copper it seems to bind together a bit and I dunno, maybe the oil plays a part in that as well.
Can you add a sticker to oil sprays?
I sprayed Dormant oil today for the first time. I used Bonide Horticultural oil and Bonide Turbo sticker. My trees are small but it only took a few minutes. My cherries had the most green showing on the tips. My pear is still pretty much dormant.
Yeah…and today is a good day for it. I couldn’t spray today because mommy wanted to have a Easter egg hunt with the little ones and didn’t want the yuky sulfur smell. Oddly, I kinda like the smell but only for short periods.
Did you mix anything with the oil speedster?
I did not. Other than the Turbo spreader sticker. I used 1 Tbsp of sticker, 4 Tbsp of dormant oil and a gallon of water. Of course I barely used any as you can imagine. I assume it stores just fine like that and a I can use it again next time?
Conditions were perfect for spraying. Will be around 60 today and sunny. No rain expected until Monday night.
Read up a bit on copper applications. I for whatever reason never sprayed copper before (even though I did have it), but it seems particularly adept at curtailing a lot of issues that show up later in fruit trees. Hopefully it will prove to be as useful as the research data suggests. It seems a good idea to me to combine some form of fungicide. I think copper also has some bactericidal benefits as well.
As far as I know the oil really only helps control scale and mites, smothering eggs and different over wintering larvae etc.
I’ve never had any issues with mites etc, I think because I mix sulfur in all my sprays.
I’m trying the minimalist approach since these are my first trees and Im not sure what pests I’m going to have. I don’t suspect I’ll have any bloom this year but I’m going to spray immunox after petal fall.
From what I understand the migration of PBM is the best key to control. Quite frankly, I’ve seen all kinds of different recommendations for the best time to treat it.
Last year I thought I treated pears with oil just before leaf drop in the fall, but I don’t see I wrote it down. I only have 5 pear trees and I keep them pretty small, so it’s possible I just forgot to write the spray down.
Evidently, the mite migrates from the leaves inside the bud scales close to leaf drop, which makes it very vulnerable to oil. I thought I read the mite migrates out of the bud scales for a short time around bud swell, but I can’t find that now.
Instead the only info I can find is that the mite burrows deeper in the bud scales at bud swell, which would correspond with Cornell’s rec that a full dormant spray would be preferred to a delayed dormant.
Olpea…is sulfur an effective control measure against PBM? I realize some claim that certain pear varieties are sensitive to sulfur but mine have never shown any signs of ill effect despite regular spraying with fairly heavy concentrations.
Apple,
I’ve not tried sulfur, but Davis mentions it’s an effective control against the mite.
Art Angello, entomologist from Cornell, says Sevin, Diazinon, Thionex are effective, especially when mixed w/ oil.
I’ve had good luck so far w/ just an oil spray. I hope I got my oil spray last fall. I’m thinking I did, but the years are starting to run together.
I have used sulphur with success. I may need to start using it again as I have a lot less lime-sulphur left than I thought. Or maybe I will “cook up” a batch. I think l/s is a bit better as it penetrates the tissues.
My standard PLBM spray is oil plus lime-sulphur when the flower buds start to swell. I did my spray this weekend.
Scott
Well…I should be good then since I got 2 apps of oil and sulfur… Diazinon…no kidding? I’ve never thought about Diazinon…I always thought of it as a non-edible pesticide.
Scott…do you strain it after cooking it up? When I’ve seen it made on YT it looked too thick and chunky for spraying.
I have yet to cook any up. But I think you do need to strain it. I did read the instructions recently because I will probably be cooking up some soon. Here are the ones I was going to follow.
http://homeguides.sfgate.com/make-own-lime-sulfur-spraying-fruit-trees-31331.html
Scott