4 December 1998

Ramularia on the rampage in northern crop

A NEW cereal disease which has hit northern spring barley crops has been keeping plant pathologists on their toes over recent months.

It was first seen in barley trials in the Scottish Borders last year where it caused brown spots on upper leaves, which eventually coalesced, killing the leaves entirely.

The symptoms appeared late in the season and hit yields hard, SAC pathologist Stuart Wale told the HGCA Agronomy Roadshow in Perth last week.

Initially pollen scorch was blamed. But German scientists subsequently identified the cause of the disease as the Ramularia fungus, more commonly a problem of sugar beet.

"It took a long time to isolate the pathogen, and we dont know a lot about it," admitted Dr Wale. But it has now been found in areas as far apart as Lincolnshire and Inverness.

The new disease has already prompted the withdrawal of one variety currently undergoing official trials, and Landlord, the new spring barley provisionally recommended for the north east of the UK has been severely affected.

Another worrying factor is that Chariot spring barley is also susceptible. "Chariot is used as the base for many new varieties, so we will need to look at the genetics very carefully," commented SACs cereal specialist David Cranstoun.

The disease seems to be related to net blotch and as with net blotch a flag-leaf fungicide is recommended. "Amistar, one of the few fungicides active against net blotch, seems to be effective against Ramularia," Dr Cranstoun advised. &#42