Predictions of likely levels of ramularia in barley crops might be possible in the future, thanks to researchers finding a link between disease incidence and the amount of surface wetness on crops for a two-week period around GS31.

The theory had been tested at four spring barley SAC trials sites this season using Met station data, the College’s Neil Havis said. Each was drilled with the same seed stock.

At the Balruddery Farm site, near Dundee, which was hosting Cereals in Practice, and the East Lothian site around 4000min of surface wetness had been recorded during the first two weeks of June.

In contrast, 10,000min were recorded at the high-risk Lanark site, while the Midlothian site had a medium to high risk, Dr Havis said.

“When we assessed ramularia this week at each site, there was practically none here at Balruddery Farm, while up to 20% at Lanark.”

The finding confirmed a previous paper-based investigation comparing ramularia levels in trials with Met Station data, which suggested an 85% correlation between surface wetness and ramularia infection levels.

“It could mean growers are able to reduce or not spray fungicides for ramularia at low risk sites,” Dr Havis reckoned.

Other ongoing research was investigating the use of seed treatments and elicitors, he said. “We know ramularia can be seed-borne, so we’re looking at whether we can break the disease cycle with seed treatments.”

Among the treatments being investigated were biological controls, such as pseudomonas and bacillus, hot water and even microwaves, as well as chemical options.

Elicitors were compounds that could induce the natural plant defences. “We’ve looked at first generation compounds, such as saccharin, that showed some activity. This year, we’re looking at a second generation, which are polymers that form a membrane across the leaf surface, which as well as inducing host resistance, also stop spores from penetrating.”

That research was being funded partly by the Australian Grain Research Development Council, he said.