What are these spots on my pecan leaves?

Pecan    None Given

I'm from Italy and I have two little grafted pecan plants, a kiowa and a cape fear.
The cape fear is ok and grows up very well, the kiowa didn't grew up a lot and some leaves have spots.
It seems to be scab.
What do you think?
What can I do to stop it?
About 3 weeks ago I watered them with a iron fertilizer because they looked a little bit yellow.
Thank you!

Posted by: Mirko (1 point) Mirko
Posted: May 31, 2016


I think the disease could be the vine spot/Gnomonia Leaf Spot caused by fungus Gnomonia dispora or Gnomonia nerviseda. The main symptoms are appearance of smooth, dark brown to black spots in between the veins (spots are restricted by lateral veins). In case of sever infestation leaf may fall prematurely.
1. Remove the infected leaves and burn them
2. Apply recommended quantity of fertilizers

Posted by: Dr. Ravishankar Narayana (11 points) Dr. Ravishankar Narayana
Posted: June 1, 2016

Mirko commented,
Thank you!I cut affected leaves and sprayed a tebuconazole+trifloxystrobin fungicide. In this place there are a lot if vineyards but I have also two big juglans regia plants and maybe they could be affected with some diseases because some leafs have spots. Anyway, to avoid diseases due to humidity, can I prevent with fungicide sprays?Do you know what kind of fungicides I can use on pecans? Anyway, I read that this Gomonia can affect pecans with zinc deficiency and two weeks ago I noticed some leaves were yellowing, so is it possible that I have a zinc deficiency? These two weeks ww didn't had a lot of rains so I don't understand why the fungi spreaded out!
about 4 years ago.

Mirko commented,
I read that juglans regia is affected by gnomonia leptostyla. It is called here as "anthracnose" and somewhere I read it is the same as scab, so anthracnose=scab. I think gnomonia dispora is similar to gnomonia leptostyla, so I'm going to use fungicide used to treat anthracnose on juglans regia. Do you think it's ok?
about 4 years ago.

Dr. Ravishankar Narayana commented,
Generally fungicides used to control scab are recommended to control Gnomonia disease also.
about 4 years ago.

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