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.
> > 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