OATEN hay growers are being warned to monitor their crops for red leather leaf, with recent wet weather providing ideal conditions for the common foliar disease to flourish.
Red leather leaf is the most common foliar disease of oats in the medium and high rainfall zones of southeastern Australia, causing yield losses of 10-22 pc – in susceptible varieties.
But many growers do not realise the scale to which Red Leather Leaf can infiltrate crops or the damage it can inflict.
Agriculture Victoria cereal pathologist and National Hay Agronomy trial member Hari Dadu said while dry weather reduces the extent of the disease, it does not take long to re-emerge following wet weather.
“Even though this season had a late break, the disease can develop quickly, especially for those who grow oats on oats, as the disease is already there on the stubble residue,” he said.
Research conducted in Victoria last year, revealed Red Leather Leaf as the most common foliar disease of oats – visible in 80pc of crops.
Bacterial blight was the next most prevalent disease, found in 55pc of crops.
Dr Dadu also noted that every 10pc increment in infection can result in a 1pc yield loss, due to reduced biomass.
Currently there are no registered fungicides for use on Red Leather Leaf in oaten hay crops.
Growers on the lookout for Red Leather Leaf should watch for the emergence of small bluish, white dots on the leaves of oat crops, which turn a red, brown colour before merging.
“Growers should talk to their agronomists to become familiar with the signs of Red Leather Leaf and the damage it can cause late in the season,” Dr Dadu said.