MAFRD staff have been busy doing surveys in cereal fields and MCVET trials over the past several weeks. I have come across ergot in a number of winter wheat and spring wheat fields, as well as the MCVET spring wheat trials.
What is Ergot? Ergot infects many cereals and grasses, including, in order of decreasing susceptibility, rye, triticale, wheat and barley. Oats are rarely affected. Ergot symptoms become evident during kernel formation, when ergot bodies are formed in place of kernels. The ergot bodies, also called sclerotia, are formed from a hard mass of fungal mycelium. The ergot bodies have a hard protective rind on the outside, which is black to dark purple in colour. They are often elongated and protrude from the glumes of maturing heads (see photo below).
Yield reductions are usually slight. However, the ergot bodies contain toxic alkaloids that are poisonous to humans and livestock, which can result in rejection or downgrading of contaminated grain.
Conditions that favour Ergot – Ergot is most prevalent in years when cool, damp weather in late spring and early summer favour ergot germination and prolong the flowering period of cereals and grasses increasing the opportunity for ergot infection.
What are some options for managing Ergot? Unfortunately, there is not much to control ergot in the field once ergot is found. Prevention is the best management strategy.
- Harvesting techniques: Ergot levels are typically higher around the edge of the field so scout fields to determine where ergot development is the worst, such as the headlands, and harvest those areas separately. In some cases, delaying harvest of a standing crop may allow more time for ergot bodies to fall out of the head.
- Tillage: For farmers using conventional tillage, burying the crop residue and ergot bodies to a depth of approximately four centimetres can impede their germination the following spring.
- Seed cleaning: Ergot bodies are relatively easy to clean from the seed lot, but can be expensive. However, it may be worth the cost to save a grade.
- Plant clean seed: Planting seed infested with ergot bodies can spread disease to previously clean fields. There are no seed treatments effective against ergot.
- Crop rotation: Ergot bodies survive in the soil for approximately one year, so crop rotation away from cereals for one to two years is recommended.
- Sanitation: Mow around headlands or roadways to remove grasses before they flower so they do not serve as a host for the first stage of the disease cycle.
Submitted by: Pam de Rocquigny, MAFRD Cereal Crops Specialist
- Ergot of Cereals and Grasses, available at http://www.agriculture.gov.sk.ca/ergot-of-cereal-grasses
- MAFRD Website at http://www.gov.mb.ca/agriculture/crops/plant-diseases/ergot.html