Scald is a fungus disease which attacks
the leaves and heads of plants and may cause significant yield losses if it spreads
to the upper parts of the plant. In 1996, more barley scald was present in
southern Idaho than at any time in the past 20 years.
Symptoms are distinctive on leaves and appear initially as pale or bluish gray
lesions (spots). As the infection progresses, the lesions appear water soaked,
then dried and bleached beige or tan in the center with a distinct dark brown margin
and possibly a chlorotic (yellow) zone. In severe cases, the heads may also be
infected. The disease is favored by cool, moist weather.
Normally, scald is of little or no consequence in southern Idaho. If we see it at all, it
is on the lower leaves during tillering. As the weather turns warm and dry, disease
progression slows or stops. With the wet spring we had in 1996, lesions continued
to develop up the tiller to the flag leaf and, in some cases, to the head.
Control is achieved through destruction of barley residue
(on which the pathogen survives), use of pathogen-free seed, and use of resistant
varieties, when available. In some cases, use of a foliar fungicide such as Tilt
(Ciba) applied prior to beard (awn) emergence may be cost effective, especially if
the flag leaf is threatened with infection.