Downy mildew of rose
germination free water is required. For most downy mildews, the optimum temperature is around 15 °C. The closer the temperature is to these 15 °C , the shorter [...] underside of the leaf fluffy growth appears which is first white and later turns grey-brown. This is, in fact, the sporulation of the pathogens extruding [...] from the stomata. In lettuce, the foot is infected first and this causes the plant to fall over. In cabbage the stem is also infected in severe epidemics.