Diseases of Rye and Triticale

Ergot
Claviceps purpurea

What to look for?
Ergot affects a range of wild grasses, tame grasses and small grain cereals world-wide. Many grasses and rye are open pollenated and are therefore very prone to ergot infection. Wheat, barley and oats are close pollenated and not usually susceptible to ergot infection. Triticale is not immune to ergot but generally much less susceptible than rye.

Copper deficiency and herbicide induced copper deficiency cause pollen sterility allowing wheat, barley and oats to be come susceptible to ergot since the sterile florets are forced to open to pick up pollen. Severe mid-season frosts and extreme drought may also cause pollen sterility in wheat, barley and oats. Ergots are very toxic to man and animals. LSD or lysergol diethylamine is derived from ergots.

Ergot infection in rye is severe under very dry weather conditions, an indication that it's main method of spread is via insects that feed on the conidial ooze in infected rye florets before transfer to uninfected open flowers.

Reservoirs of ergot infection in Alberta occur in the wild headland grasses from which infecting spores from the mushroom producing sclerotia move into the rye crop. Rye after rye can be an ergot disaster due to a build-up of the disease causing sclerotia in the soil.

Triticale - a hybrid combination of durum wheat and rye does have open florets but to a lesser degree than rye, since much of the time triticale is self-pollenated.

Photo: Duczek

Picture description Heavy ergot infection of rye. Ergots are very hard and when broken in two are purplish inside. Sclerotinia sclerotes are white inside. Mouse droppings are different when broken open.

Photo: Duczek

Picture description A single ergot generally much larger than a grain of rye although in heavy infections some ergot are grain sized or smaller.

Photo: Gossen

Picture description Severe snow mold in late March and early April on overwintered rye.

Photo: Howard

Picture description Stem smut on rye.