Effect of Nutrition on the Incidence of Drechslera incurvata Leaf Spot of Coconuts.

Abstract

Recordings were made on three experiments to determine the effect of various fertilizer nutrients on the severity of Drechslera incurvata (syn. Helminthosporium incurvatum) leaf spot disease on coconut seedlings. The results showed that the severity of D.incurvata leaf spot was related to the rate of applied nitrogen. Nitrogen fertilizers increased the susceptibility of the plant to the leaf spot disease while both potassium and phosphorus fertilizers decreased the susceptibility of the coconut seedlings. The application of sulphur fertilizer did not affect the disease severity. Growth of the seedlings, measured by total fresh weight at harvest, was markedly reduced when the leaf spot disease was severe for several months prior to harvest.