New York State Flower Industries , Inc
Leaf scorch can be a serious problem on Croft lilies and, during the late 1940's and early 1950's, many re search experiments were conducted in various parts of the country (6, 7, 8, 9, 11, 13, 14). Leaf scorch, also commonly referred to as leaf burn, tip-burn injury, and tip die-back is a physiological problem which results in the death of cells at the apex of the leaves resulting in dark brown necrotic tips (Figure 1) or in some cases semi-circular regions along the margin of the leaf (3, 8, 13). There have been a number of postulated causes of this problem, and they include the following: lithium toxicity (4), low soil pH (12), moisture im balances in the leaves (3), and mineral imbalances (3, 6, 7, 8, 11, 12, 13, 14). Many of the recommendations to alleviate the problem of scorch have been directed at avoiding these possible causes. Recent research in Florida by Conover and Poole studying leaf scorch of foliage plants indicates that perhaps the true cause of scorch is fluoride toxicity, which caused scorch on the leaves of Cordyline (1) and Dra caena (2). The effect of fluoride in causing scorch of gladiolus has been well documented by Woltz (15, 16, 17). Recently Marousky and Woltz (5, 18) reported the phytotoxicity effects of fluoride in causing leaf scorch of 'Ace' lilies.
Keywords: physiological problem necrotic tips Gladiolus Phytotoxicity high pH fluoride