Sulphur and phosphorus requirements of three fungi causing diseases in storage

Summary The effect of different sulphur and phosphorus compounds on the growth and reproduction of three fungi causing storage rot, viz.,Fusarium solani, Botryodiplodia ananassae andMacrophomina phaseoli has been studied. Sixteen different sources of sulphur were used and out of them magnesium sulphate was found to be most favourable for the growth and reproduction of all the three fungi. Sodium sulphite and sodium bisulphite were toxic. Potassium metabisulphite prevented growth ofF. solani and M. phaseoli while it supported moderate growth ofB. ananassae. Only magnesium sulphate could induce the sporulation ofB. ananassae while sporulation and sclerotial development ofF. solani andM. phaseoli respectively varied with the type of sulphur sources used. Optimum concentration of magnesium sulphate was also determined and it was found that the growth and sporulation ofF. solani andB. ananassae were best at 0.375 g/l and 0.75 g/l.M. phaseoli tolerated higher doses of this substance as the best growth and excellent sclerotial development were recorded at 3.0 g/l (the maximum concentration used). Phosphorus was found to be essential for the present fungi as none of them could grow in complete absence of this substance. Onthophosphates and nucleic acid, were found to be favourable sources for growth and reproduction of the 3 organisms.