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Zestar Disease Issue?

Posted: Fri Jun 07, 2013 6:16 am
by Mulberry Grove
I went out into my orchard yesterday and noticed that my Zestar apple trees have some type of disease or die back on the top of the central leader working its way down. The orchard was planted about a month ago and only the Zestar are showing this issue. Probably about 10 or so out of 72 Zestars have the issue. I've attached a photo of the issue. Anybody know what it is or how I can narrow it down? Thanks.

Re: Zestar Disease Issue?

Posted: Sat Jun 08, 2013 12:14 am
by OrangePippin-Richard
When the tree starts to leaf out, the initial energy comes from the buds, which then draw on the roots. This looks like the roots have not been able to keep up with the demands of the tree. This could be caused by lack of watering, not heading back the leader (in the case of dwarf trees), or competing vegetation around the planting hole. However it could be something else altogether!

Re: Zestar Disease Issue?

Posted: Sat Jun 08, 2013 5:21 am
by Mulberry Grove
I did notice that this condition does not appear on any tree that has been cut back. I only cut back the trees that were damaged in shipping. We've had plenty rain and they're irrigated, and there isn't really any vegetation in the field yet. I should have mentioned that these are semi-dwarf.

Re: Zestar Disease Issue?

Posted: Sat Jun 08, 2013 12:30 pm
by OrangePippin-Richard
You should always cut back 1-year bare-root trees on planting, with the possible exception of those on very vigorous rootstocks. The reason is that the roots get damaged during the transplanting process, and the aerial part can then put too much demand on the roots when spring starts. By cutting back, you restore the balance.