[NAFEX] Pruning and Dormant Spray

Scott Smith scott at cs.jhu.edu
Tue Feb 19 10:24:51 EST 2008

Dennis, I was concerned about your remark Re: copper sulphate because  
I have used copper as a dormant spray with oil, but I looked the  
excellent documents you cite and found that fixed copper is not a  
problem with oil; I use Kocide 2000.  My plan this year is to do a  
single combined spray of fixed copper plus dormant oil at "silver  
tip", to give both the oil and copper the best shot at nailing the  
baddies.   Does that sound like a good idea?  According to the below- 
cited guide, if fireblight was bad the previous year then copper  
should be used.  I had very bad fireblight last year, and I had used  
lime-sulphur and not copper as my dormant disease spray the previous  
winter.  Before that I had used copper plus dormant oil and had little  
fireblight troubles.


> Bill,
> Your pruning on any apple trees should be done while the trees are in
> complete dormancy.  If you have stone fruit, prune them at green tip,
> usually late March, or early April for Zone 5.  Your dormant oil  
> needs to be
> done when day temperatures get above 45 degrees and freezing temps  
> are not
> expected for at least 24 to 48 hours. For apple trees your dormant  
> oil can
> be sprayed from dormancy up to green tip.  You can never combine  
> copper
> sulfate alone with dormant oil, but your fungicide spray does not  
> need to be
> applied until green tip for apples and pink for stone fruit, so  
> there should
> be no conflict with the dormant oil and the fungicide if you do the  
> dormant
> oil prior to or at silver tip.  We do all of our pruning (which  
> began Feb.
> 4) and then do our dormant oil spray based on the 45 degree temp  
> model at
> silver tip.  We follow with copper at green tip and our fungicides  
> (captan)
> at pink to bloom.
> If you go to http://www.hort.purdue.edu/hort/ext/sfg/ you can  
> download free
> copies of the various spray guides for the Midwest that will give  
> you all
> the timing for the various sprays needed.  Hope this helps!
> Dennis Norton
> Royal Oak Farm Orchard
> http://www.royaloakfarmorchard.com
> http://www.theorchardkeeper.blogspot.com
> http://www.revivalhymn.com

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