Downy mildew of rose
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 [...] They cause lesions on the upper leaf surface, bordered by the veins, which are first yellow and then turn brown. On the underside of the leaf fluffy growth [...] For most downy mildews, the optimum temperature is around 15 °C. The closer the temperature is to these 15 °C , the shorter the leaf wetness period that