Botrytis cinerea, a grey mould on the leaf of a succulent Kalanchoe blossfeldiana. This is one of the commonest fungus diseases encountered on a range of plants from houseplants through to crops such as strawberries, tomatoes, lettuce, & grapes. It produces millions of conidia (spores) at the end of branched conidiophores. The spores are easily dislodged, carrying the infection from plant to plant rapidly.