I have a Pecan nut tree growing in a garden in the Boland area of the Western Cape province in South Africa. As far as I know, there is no natural pest here like pecan weevils, etc. This area has a Mediterranean climate with hot summers and cool wet winters. This is a big tree about 15 years old and has never shown any form of disease or pest of any kind. It has been producing around about 20 > 25 kg of well-formed nuts for many years now.
This year in May and June (beginning of winter here) it produced its usual crop. This year I noticed a deformity in about 5% of the fruit that I have never seen before.
The picture named "Healthy" shows how the pecans should look like. The septum is also visible when the nut is turned over to the other side, i.e. 180 degrees. This is not the case with the effected nuts.
The picture named "Diseased-1" shows the fruit body of the problem pecan rotated through 90 degrees in each subsequent photo. The septum is visible in the image named "Top" but not in the image named "Bottom". The "Bottom" image shows that the two halves of the nut are joined there (long side of the halves) instead of on the tip of the two halves. This picture also shows the strange form of the pecan with its shell intact.
The picture named "Diseased-2" shows the pecan fruit body separated into its 2 halves with the septum removed. Here it is shown clearly that the two halves are joined on the sides of each half and not at the top as in the photos show for the healthy pecan.
What could be the cause of this? I have never seen any insect on the tree. There is no pest that I can see. Maybe some sore of a fungus or deficiency in the soil? Improper pollination?
Thanks for helping me.
Pecan nut deformity. Disease, pest or deficiency?