The fungicidal properties of certain spray-fluids, IV

Abstract

The following solutions were tested with respect to their fungicidal properties towards the “powdery,” conidial stage of Sphaerotheca Humuli on young hop-leaves in the greenhouse.(1) A solution of potassium polysulphide containing 0·092 per cent. polysulphide sulphur proved fungicidal, whilst one containing 0·066 per cent. was not quite fungicidal.(2) A solution of sodium polysulphide containing 0·12 per cent. polysulphide sulphur proved fungicidal. It seems probable that solutions of sodium and potassium polysulphides possess the same fungicidal values.(3) Lead arsenate proved to be considerably less fungicidal in action than lead thioarsenate, dicalcium arsenate or disodium arsenate. A solution of lead arsenate containing 0·1 per cent. As2O5 proved to be not quite fungicidal, while one containing 0·204 per cent. As2O5 proved fungicidal.(5) Solutions of calcium polysulphide and of lead arsenate at concentrations below fungicidal strength when mixed together proved to be fungicidal.