Click on any
image for a more
detailed view

Symptoms and Signs

Claviceps purpurea infects only the ovary of cereal and grass plants; no other part of the plant is infected. In the early stages of disease development, a sticky exudate (honeydew) consisting of host sap and conidia often appears (Figure 2). The infected ovary is replaced by a purplish-black sclerotium, commonly referred to as an ergot (Figure 3). "Ergot" is the French word for "spur." Long ago, people in France noted some resemblance between the sclerotia and the spurs on rooster legs. Size of the sclerotium is host plant dependent. They are generally 1 to 5 times larger than the host seed. Thus, the largest ergots (1-5 cm, 0.5-2 in) are found in large seeded plants such as cereal rye. The host range for C. purpurea is largely confined to members of the grass subfamily Pooideae, the cool-season grasses such as bentgrass, bluegrass, fescue, and ryegrass.

Figure 2

Figure 3

RETURN TO TOP