Some Indications of a Relation of Soil Fertility and Plant Nutrition to Cane Diseases in Hawaii1

Abstract

A chemical study of cane juice and of soil conditions under which the cane is produced seems to indicate that there is a correlation between readily available plant nutrients and susceptibility to some cane diseases in Hawaii. This correlation may be either positive or negative, depending upon the factors in question. Indications seem to point to growth failure as a Pythium root-rot, induced by an unbalanced nutrition in which low phosphorus and high mineral nitrogen are more or less outstanding. This disorder seems to have been on the increase during the history of the sugar industry in Hawaii. Eye spot damage is usually associated with high mineral nitrogen and perhaps low potassium, but more especially with the former. The greatest damage is done by the runner and not so much by the immediate lesion. Brown stripe appears associated with low mineral assimilation by the cane. It may be low phosphorus, low potassium, or both; or it may be associated with an unbalanced condition of phosphorus and potassium with nitrogen. Evidence seems to indicate that the assimilation of sufficient phosphorus and potassium in a balanced relation is a great aid in minimizing the danger from this disease. Resistant varieties, as a rule, are either better feeders on the phosphorus and potassium of the soil, or are capable of making normal growth by the use of less of these nutrients in their metabolism, thus leaving more of them in solution in the juice.