Plant roots rot. Remove and discard infected plants. Let soil dry between watering and plant only in well drained soil. Leaves have a speckled appearance. Dry, brown blotches develop.
Leaves distort and fall off.
Buds and flowers are covered with a gray mould. Pink and yellow mould may cover all parts of the tuber and roots will rot. Try not to injure the tubers. Discard roots that show decay. Soil should be well-drained and high in organic matter.