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nafex - Re: [NAFEX] Apple Curly Leaf ?

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  • From: <dmnorton@royaloakfarmorchard.com>
  • To: "North American Fruit Explorers" <nafex@lists.ibiblio.org>
  • Subject: Re: [NAFEX] Apple Curly Leaf ?
  • Date: Thu, 12 Jul 2007 10:25:11 -0500

There is one thing for sure, it is either a pest or a disease!  I have always said that fruit growing is a scientific art...or is it an artistic science?!  With over 11,000 trees now, I have seen just about everything you cna get with apple trees and peach trees.  But I still have to pull out the reference books on a daily basis.  As has been pointed out in several posts, both pests and disease can cause leaves to curl.  If it's a pest, there may be no sign at all except the "honeydew" which can be seen if you move the leaf so the sun reflrcts off the top side of the leaf.  It looks like very small drops of mineral oil.  Disease is a little easier to identify in that there are usually visible signs such as in the powdery mildew photos from the links posted.  There are 3 very good books that I would recommend for both pests and disease if you are a grower, whether in your backyard or commercially. 
 
A Pocket Guide for Scouting Apples found at http://www.ipm.msu.edu/ApplePocket.htm
A Pocket Guide for Scouting Stone Fruits found at http://www.ipm.msu.edu/Pubs_stone.htm
Diseases of Tree Fruits in the East available at http://web2.msue.msu.edu/bulletins/keywordsearch.cfm
 
I use these three references on a daily basis and highly recommend them. 
 
----- Original Message -----
From: Joe Boles
Sent: Wednesday, July 11, 2007 8:20 PM
Subject: Re: [NAFEX] Apple Curly Leaf ?

Have a look at these sites with pictures showing how powdery mildew curls up leaves.
 
 
----- Original Message -----
Sent: Wednesday, July 11, 2007 8:05 PM
Subject: Re: [NAFEX] Apple Curly Leaf ?

Del.

There are several pests that cause apple tree leaves to curl.  RAA (Rosy
Apple Aphid), PLH (Potato Leaf Hopper), and GAA (Green Apple Aphid) Looks
like your is RAA (rosy apple aphid).  Here's some info on RAA and the link
to the MSU web page that has more in-depth info
http://web1.msue.msu.edu/vanburen/fraa.htm .
Rosy apple aphid feeding often causes apple leaves to curl, starting at
petal fall. These leaves may later turn bright red. Feeding on the leaves
around fruit clusters often results in the bunching, stunting and
malformation of the developing fruit. These abnormalities become worse as
fruit develops and can eventually render the fruit unsalable.



Large aphid populations may produce large amounts of honeydew as waste from
the sap on which they feed. Honeydew excreted onto fruit will serve as a
growing ground for sooty mold fungus, which will affect the finish of the
apple. Toxins in the aphids' saliva also serve as a "stop drop," preventing
the fruits' abscission (natural separation from the tree) at normal harvest.



Hope this helps!

Dennis Norton
Royal Oak Farm Orchard
http://www.royaloakfarmorchard.com
http://www.theorchardkeeper.blogspot.com
http://www.revivalhymn.com
----- Original Message -----
From: "Del Stubbs" <northernlights2n@yahoo.com>
To: "North American Fruit Explorers" <nafex@lists.ibiblio.org>
Sent: Wednesday, July 11, 2007 8:49 AM
Subject: [NAFEX] Apple Curly Leaf ?


>
> I notice this most years on some apples, but it seems much more pronounced
> this year,
> however this year 3/4 of my couple hundred apple trees (many varieties)
> have it. I do not
> see significant insect populations on affected stems, and the new leaves
> have eventually
> come out unaffected in previous years. In looking on various apple disease
> websites I
> have seen nothing like it, so I am asking for ideas of disease, insect,
> virus,
> deficiency, etc. ....names or ideas for me to look farther into.
> It seems Nafex photo page site still cannot upload images, so  I have
> started one of
> those free photo sites for my fruit related pics, hope it works...
>
> http://www.flickr.com/photos/48198726@N00/776767030/in/set-72157600761592815/
>
> thanks, Del Stubbs,  northern Minnesota
>
> Del Stubbs  http://www.pinewoodforge.com   zone 3   N. MN



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