Studies on the effect of sulphuric acid upon the sclerotial germination of Sclerotinia trifoliorum Eriks

Abstract

1. This paper deals with the results of studies on the effect of sulphuric acid solutions upon the sclerotial germination of Sclerotinia trifoliorum Eriks.
2. In 5 and 10per cent sulphuric acid solutions, 1 and 3 hours treatments can not be expected to prevent sclerotial germination, but 4, 5, 7 and 10 hours treatments can be expected to sterilize sclerotia.
3. According to the concentration of sulphuric acid solution and the time of treatment, the treated parental sclerotia formed secondary small sclerotia of three types. In solutions higher than 20per cent, there is a tendency for the increase of secondary sclerotial formation as concentration increases.
4. Decay of the rind-tissue of sclerotia occurs in higher percentages as concentration increases. The injured sclerotia do not germinate directly, but form secondary sclerotia which germinate by apothecial stalks.
5. The authors considered two types of mechanisms for the sterilizing action of sulphuric acid solution: by means of penetration and of corrosion. Sulphuric acid acts mainly penetration in dilute solution, and by corrosion in strong ones.