Boron Deficiency in Sisal
The first signs of boron deficiency are yellow spots, most numerous near the tip, on both surfaces of the leaf. These are followed by the formation in the epidermis of ramifying fingerlike depressions from the leaf margin, which may later become suberized. In sand culture experiments, further symptoms have been seen. The tip of the leaf may be hooked and the leaf spine absent or reduced to a white hair. In cases of severe deficiency the growing point becomes disorganized and the leaves are short, narrow, twisted and sometimes split. The plants have a flat-topped appearance.
Boron-deficient plants may be more prone to Fusarium wilt.