IN ORDER to help growers decide whether to apply a fungicide treatment to crops in store this autumn, the Scottish Agricultural College has produced two new decision trees.

The first helps users decide if they need an into-store fungicide treatment to control disease during storage and the second helps decide if a fungicide is needed to control disease development in the subsequent crop.

Variety disease susceptibility is a key factor to consider, explained the SAC’s Stuart Wale, who developed the guides. “If a grower considers his variety to have a high susceptibility then treatment with a fungicide is recommended.

“If moderately susceptible, then additional risk factors such as disease present on seed, disease on tubers at harvest, soil contamination, harvest time, mechanical damage to tubers and soil conditions at harvest also need to be taken into account.”

Where the crop has a ware fraction to be sold, growers also need to choose the appropriate fungicide in line with any quality assurance protocol, he said.

While the overall quality of this year’s crop appears to be relatively good, growers need to ensure this is maintained throughout storage, added BASF’s seed protection manager, Jonathan Tann.

“To maintain quality, growers must consider a risk assessment for storage diseases and ask themselves if and when they should be applying a tuber fungicide.”

He suggests using Fungazil (imazalil), which has activity against Silver scurf, Skin spot, Dry rot and Gangrene. BASF recommends spraying tubers as soon as possible after harvest, preferably within 7-10 days.

A free copy of the Seed treatment decision tree is available from Dr Wale stuart.wale@sac.co.uk, or BASF’s technical hotline, 0845 602 2553.