The role of temperature in the development of blue mould (Peronospora tabacina Adam) Disease in tobacco seedlings. III. The effect of pre-inoculation temperature and of shade on plant growth and disease development

Abstract

The spread and effect on plant growth of blue mould disease of tobacco was measured on cv. Virginia Gold and SO1 under controlled conditions.

The factors considered were the effect of three pre-inoculation temperatures on response to post-inoculation temperature and the direct effects of shade under three temperature regimes.

Different pre-inoculation temperatures did not modify significantly the response to inoculation at three post-inoculation temperatures.

As post-inoculation temperature increased, the amount of stem mould decreased and the sizes of both healthy and inoculated plants increased.

The effects of pre-inoculation temperature on plant growth persisted to the end of the experiments. Only for the stem length of healthy plants was there a significant interaction with post-inoculation temperature, and even then the stem length increased for all post-inoculation temperatures.

Under the two higher temperature regimes shaded plants were smaller than unshaded. Shaded and unshaded plants held at the same temperature were equally susceptible to blue mould.