Boron Deficiency in Papaya
One of the earliest signs of boron deficiency is a mild chlorosis in mature leaves, which are brittle and liable to curl downwards. A white “latex” exudate may flow from cracks in the upper part of the trunk, from leaf stalks, and from the underside of the main veins and petioles. The death of the growing point is followed by a regeneration of the sideshoots, which ultimately die.
In fruiting plants the earliest indication of boron deficiency is flower shedding. When fruit develop, they are likely to secrete a white latex. Later the fruit become deformed and lumpy. The deformation is very probably the result of incomplete fertilization as most of the seed in the seed cavity are either abortive, poorly developed, or absent. If the symptoms begin when the fruit are very small, then most do not grow to full size.