Fungicidal effects of some chemicals on Sclerotinia trifoliorum erikss.

Authors

• Aarre Ylimäki Department of Plant Pathology, Agricultural Research Centre, Tikkurila, Finland

DOI: https://doi.org/10.23986/afsci.71742

Abstract

In efficiency tests carried out in laboratory (Table 1, Figs. 1—4) it was established that on media many chemicals had a restraining effect on the growth of the mycelia of Sclerotinia trifoliorum. In addition to PCNB preparations, TCNB substances very severely restrained the growth of mycelia and the formation of sclerotia of the fungus (Figs. 5—8). Sclerotia formed of mycelia treated with TCNB as well as with PCNB substances developed numerous sporophores which were not fertile however. The effect of both PCNB and TCNB on the mycelium of S. trifoliorum proved only restricting on the growth. It did not destroy the mycelia. The activity of the substances is dependent on the temperature and the higher effectivity of TCNB is based on its greater degree of vaporization (Tables 2—3, Figs. 2, 4 and 9). In autumn and in outdoor conditions on the field the vaporization of the substances is so small that it does not lower the effectiveness to any great extent (Tables 2-3, Fig. 9).