I just noticed a problem with a newly planted dwarf apple tree. The spots look similar to scale infestation that I have had on other plants but these are yellow spots, not white as scale generally are. I would appreciate any ideas on what it is and what to do for it. Thanks, Doug.
apple rust or ceder apple rust maybe
Yes, cedar-apple rust. Compare this photo: http://branchingout.cornell.edu/picturefolder/GRAPHICSCANS/Apple_RustSpots2.jpg
Thank you - I have done a little research on this and it looks like it can be caused by galls on nearby cedar trees (or any tree in the Cypress family). I don't like using chemicals but that may be the only way to keep it from killing the tree! I also see that some varieties are immune to the disease such as Red Delicious and Arkansas Black apples. Anyone else had experience with this???
I have a lot of experience with it, given that I have a hedge of junipers [the "cedars" are actually junipers in most cases] and crabapples as well as fruit apples.
There are immune varieties of apple, but unfortunately most of these fail in the taste department. I'm trying a new one called Enterprise, but so far I haven't been able to taste it - it's fruiting for the first time this year.
The treatment is to use a fungicide spray on the apples in the spring, just as the galls are starting to develop spores. This needs to be done more than once - April and early May, here. Immunox is available to homeowners and is supposed to be effective.
Thanks L Tilton.
I found an interesting article published by the University of TN (see:www.utextension.utk.edu/publications/spfiles/SP277-A.pdf). This article also recommends using Immunox. They recommend to start the treatment just as soon as you see buds starting to grow on the apple trees and that followed up every couple of weeks until mid summer. I saw the galls on an Italian cypress tree I have in the front yard last year, but I didn't know what they were. According to the above article, the apple trees are what cause the galls to grow on the junipers (or Italian cypress in my case) and those in turn give off the harmful spores that infect the apple trees. Wow-what a vicious circle!
I did not see the Enterprise listed in the article but I would be interested in knowing how it works for you. As I mentioned, I don't like using chemicals, and if I can plant something else that's immune to the rust, I think I would prefer to do that.
