Management of ergot in cereal crops

Reducing risk (main options):

Crop rotation:

• Reduce the use of ergot susceptible species in the rotation

Use appropriate cultivations:

• Cultivate soils to bury ergots to a depth of at least 5 cm
• Ploughing is best
• Minimum tillage is more effective than direct drilling
• Avoid cultivations that bring ergots to the soil surface in the following year

Drill high quality, clean seed:

• Use certified seed or
• Use home-saved seed, cleaned via a gravity separator or colour sorter

Reducing risk (other options):

• Use seed treatments that cite ergot suppression on the label*
• Clean machinery after working in infected fields
• Control grass weeds in non-host and host crops
• Keep records of fields with previous ergot infestations

Notes:

To reduce long-term inoculum pressures, bury ergot to a depth of 5 cm for at least a year.

There are no foliar fungicides authorised for use to manage ergot in the UK.

*Although some azole-based seed treatments have label claims about efficacy against ergot, they do not provide complete control and should be used in conjunction with other management options.

Ergot is one of only two diseases included in the UK Seed Certification Scheme for Cereals (the other disease with a regulatory standard is loose smut).

Ergot is not a true seed-borne disease, as the seed is not viable.

Reducing risk (main options):

Adapt the rotation:

• Grow a non-cereal crop in high-risk areas
• Select a less-susceptible cereal crop

Encourage a uniform crop:

• Use an appropriate seed rate
• Use variable seed rates (where appropriate)
• Sow into a good seedbed at a consistent depth
• Control establishment pests
• Ensure crop nutrition is adequate

Choose lower-risk varieties*:

• Avoid open-flowering varieties
• Avoid varieties with a long flowering period
• Avoid varieties with prolific late tillering

Notes:

Cereal crops from most to least susceptible: rye, triticale, wheat, barley and oats – infection of oats is rare.

*Information on varietal risk is limited.

No cereal varieties on the Recommended Lists (RL) are cited as having resistance to ergot infection.

When florets are closed during pollination (and for a few days afterwards) it provides a mechanical barrier to spores.

There is no reliable system to score/relate the openness of flowering to reduced infection risk.

Crops become resistant to further infection a few days after fertilisation.

Reducing risk (other options):

Avoid micronutrient deficiencies:

• Monitor copper levels on high-risk soils by soil or grain analysis (copper deficiency can cause pollen sterility)
• Monitor boron levels on high-risk soils by soil or grain analysis (boron deficiency is linked with more severe cases of ergot infection)
• Monitor soil pH (high pH reduces boron availability)

Notes:

Ensure crops receive adequate nutrition (all nutrients) to help plants withstand attack from pathogens.

Reducing risk (main options):

Control grass weeds:

• Use traditional integrated weed management approaches, including appropriate cultivations, stale seedbeds, delayed drilling, spring cropping and herbicides

Reducing risk (other options):

Manage grass margins, buffer strips and beetle banks:

• Sow later-flowering species with lower infectivity*
• Mow or top grasses (if permitted)

Notes:

Ergot affects a wide range of grasses, particularly black-grass. As black-grass flowers earlier than cereals, it is a key target for management.

Grass margins are also a source of secondary inoculum, which could infect late tillers at field edges.

Some grass species, such as cocksfoot, couch grass, timothy, tall fescue and tall oat grass, are a greater threat to cereal crops, due to their ease of infection and flowering time.

Minimise risk by sowing later-flowering grass species.

*Limited evidence available.

Reducing risk (main options):

• Identify and prioritise monitoring of higher-risk fields/areas (including grass margins)
• Harvest infected areas separately and segregate from other grain
• Check loads carefully before tipping onto a wider heap
• Also check any crops destined for home-use animal feed
• Clean contaminated grain
• Update records to track higher-risk fields/areas

Reducing risk (other options):

• Clean equipment after harvesting infected grain
• Minimise infected grain handling before cleaning, where possible

Notes:

Field headlands and tramlines are often higher-risk areas (which tend to have plants with more susceptible late and secondary tillers).

Several methods can clean grain to some degree, including gravity separation (with or without an air screen cleaner) and mechanical sieves that remove foreign bodies. Grain colour sorting systems are also available, which are used mainly by processors and within central stores.

As ergot fragments can be relatively small, it means cleaning may be only partially effective.