WHEAT GROWERS need to be aware of the potential threat from ergot as many crops are at the vulnerable flowering stage, one expert has warned.

While ergot incidence in wheat seed samples this year is only 1% compared to 5% last year, it could rise if conditions favour the fungus, said NIAB* pathologist, Bruce Napier.

“This is the time of year when the fungus appears on the soil surface and puffs out the infective spores onto nearby wheat plants. Spores take over the grain as it develops, resulting in the characteristic ergot growth.”

Infected grass weeds present a significant threat, as the infected florets produce a ‘honeydew’ at flowering, which releases spores that infect cereal ears at anthesis, he explained.

Cool, wet conditions during this period favour infection and lower temperatures also prolong flowering, so increasing the infection window. Once flowering is over the infection window is closed, he said.

“The fluctuation in ergot levels from year to year are most likely due to weather, but increased use of grass margins and reduced blackgrass control may contribute to increases in ergot levels,” he noted.

While cleaning of home-saved seed may help reduce the risk from infested seed lots, growers should also consider using a treatment active against the fungus, he said.

*National Institute for Agricultural Botany