[NAFEX] Apple Curly Leaf ?

dmnorton at royaloakfarmorchard.com dmnorton at royaloakfarmorchard.com
Thu Jul 12 11:25:11 EDT 2007


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.  

Dennis Norton
Royal Oak Farm Orchard
http://www.royaloakfarmorchard.com
http://www.theorchardkeeper.blogspot.com
http://www.revivalhymn.com
  ----- Original Message ----- 
  From: Joe Boles 
  To: North American Fruit Explorers 
  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.
  http://ohioline.osu.edu/hyg-fact/3000/3001.html
  http://utahpests.usu.edu/plantdiseases/images/uploads/Fruit/applepm2.jpg
  http://plant-disease.ippc.orst.edu/plant_images/ApplePMGroupShot.jpg
  http://www.gov.mb.ca/agriculture/crops/diseases/images/fac50s00j.jpg
  http://www.inra.fr/hyp3/images/6034461.jpg


    ----- Original Message ----- 
    From: dmnorton at royaloakfarmorchard.com 
    To: North American Fruit Explorers 
    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 at yahoo.com>
    To: "North American Fruit Explorers" <nafex at 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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