The role of temperature in the development of blue mould (Peronospora tabacina Adam.) disease in tobacco seedlings. II. Effect on plant growth

Abstract

Healthy tobacco plants and tobacco plants inoculated with conidia of Peronospora tabacina were subjected to a wide range of temperature conditions.

Two strains of the pathogen were used. Both affected plant growth, the greatest and most obvious effects being at night temperatures of 16–24°C.

Growth, as measured by stem length, leaf number, and leaf size in plants inoculated with strain APT2, was limited by stem necrosis rather than by leaf necrosis. There was less stem necrosis at the higher day temperatures and fewer dead leaves at all temperature regimes, with strain APT2 than with APT1. At high day temperatures, stem necrosis tended to be restricted to the region of the external phloem, with consequently less severe effects on growth.