Boron Deficiency in Sisal
The first signs of boron deficiency in sisal 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 leaf tip may be hooked
- 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 also be more prone to Fusarium wilt.