Sounds like "Gratoan" tree - what is causing this damage

[SLESQ]

We have a lovely small orchard with more than 20 varieties of fruit bearing trees; two are what my staff call "gratoan," or it sounds like that. It could be "kratoan." When in good bloom the bright green leaves often sprout red ones; it's a real beauty.

Then we also get some really ugly "bubbles" on the green leaves. Not much to cause concern about before as the tree fruits once a year with soft-ball size luscious sweet & sour fruit with a great strong flavor.

But this year, while some fruit is seen growing, the infestation is overpowering one of the two trees (planted about 15 meters apart) as can be seen below.

Please help me identify the pest and ways to control or rid the trees of them. Thank you.

[drtreelove]

possible eriophid mite or a blister mite

http://www.unce.unr.edu/publications/files/nr/2004/FS0447.pdf

[drtreelove]

Here is a label for an organic product I use. You probably cannot get this exact product, but look at active ingredients and find a similar botanical insecticide, or combine with neem seed oil extract product as preventive. Repeated applications will be necessary.

Don't expect 100% control or for existing damage to be corrected, but new leaves should start to become clear of the problem if you keep up with your program.

Essentria_IC3_label.pdf

[Jotham79]

These are also called Wood Apple. Definitely insects making the bubbles. Take the photo to the local seed shop and they should be able to sell you the correct spray. I had trees years ago and if I remember, they didn't cause too much problem with fruiting, but I guess it depends on how bad they are.

[SLESQ]

Thank you very much for your good suggestions, I will try them both.