[NAFEX] Questions about using Carbaryl (Sevin) to drastically thin apples.

Steve sdw12986 at aol.com
Sun Jun 14 13:06:39 EDT 2009

Replying to my own post...
I tried it Saturday. I decided to mix up only a quart of Sevin spray 
because the tree in question isn't that big and I didn't want to waste 
the stuff.
I sprayed the parts of the tree that are hard to reach fist, to make 
sure those areas got covered. I purposely did not spray one big branch 
to see for myself if the thinning only happened where the spray touched. 
(It's a low branch and I can thin that branch by hand later.)
I carefully looked at the weather radar on my computer. I looked at the 
hour by hour forecast on weather.com. Nothing coming on the radar and 
the forecast said zero % chance of rain at noon, 1 PM, 2Pm, then a 15% 
chance at 3. Back to zero at 5 PM and finally 40% starting at 6. 
Everything told me that if I sprayed (it was late morning, just before 
noon) the Carbaryl would have several hours of quality time on the 
apples before there was any serious chance of rain. Well, you guessed 
it. Half an hour later I felt some light sprinkles. I figured it would 
stop in just a moment. Minutes later, it was just raining and it rained 
all day, taking a brief break at 3 then it stopped at 9PM.
The whole thing was probably a waste of time. Today it's supposed to 
rain but it's calm and sunny.  ;-(


Steve wrote:
> It's pretty easy to find info on the web about thinning apples with 
> Sevin. I think there is even information about that on my container of 
> Sevin. I have a couple of questions beyond the normal use and I wonder 
> if anyone here has answers for me.
> 1. Can Sevin be used to thin just one part of a tree? In other words, 
> does it work mostly where you spray, or does the spray stress the entire 
> tree, causing fruit drop even on areas with little or no spray contact?
> 2. Is it possible to purposely cause a nearly 100% drop of fruit? I have 
> a tree that I would love to have drop all the developing fruit. This is 
> a tree I asked about, here, over a year ago. It has damage to the bark 
> near the ground so that it is partly girdled.* Due to that damage, it 
> puts on little vegetative growth but flowers profusely. It is loaded 
> with small apples. Most are only the size of a pea right now. Some are 3 
> times that size. The reason for this size difference is that I have 
> grafted different varieties to this tree. The early bloomers are bigger. 
> Since I have been working on this multi graft tree for years, I hate to 
> just cut it down and start over. Obviously, I'm thinking that removing 
> all fruit would relieve it from the stress of fruit bearing and maybe 
> help it recover.
> I figure time is against me right now. The apples are getting bigger and 
> it has been cool. Even now, the forecast is for barely 70 degrees and I 
> believe apples thin better if it is warm.
> Steve in the Adirondacks (zone 4a on the maps, colder most years)
> *(Most replies to that post figured it was borer damage. After watching 
> the tree for over a year, I saw no evidence that borers caused the 
> trouble. Certainly, no borers entered the actual wood. The post was used 
> in a recent issue of Pomona. I was going to say which issue and page. I 
> would have sworn it was either the Winter of Spring 2009 issue  but 
> after looking carefully, I don't see it anywhere.)

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