Soil application of elemental sulphur as a control of Phytophthora cinnamomi root and heart rot of pineapple

Abstract

Preplant soil applications of elemental sulphur controlled root and heart rot of pineapple (Ananas comosus) caused by Phytophthora cinnamomi. A pH value below 3.8, which is required to limit the activity of P. cinnamomi, did not adversely affect vegetative growth of pineapple plants. Leaf calcium levels fell in sulphured soils, and natural flowering was inhibited. An application rate of 1200 kg ha-1 elemental sulphur has been recommended for soils with low buffering capacity. Aluminium sulphate and ammonium sulphate were not as effective as sulphur, possibly because they did not reduce soil pH below 3.8. Dolomitic limestone did not affect disease incidence. In one experiment the fungicides captafol and ethazol were as effective as sulphur. Covering pineapple beds with black polythene sheeting increased root and heart rot.