Variety choice key to controlling light leaf spot

Oilseed rape growers need to select varieties with a minimum light leaf spot resistance score of 6 to prevent costly infection next season.

This harvest has seen high levels of light leaf spot affecting yield and now experts warn a good resistance score could prove critical to prevent a repeat scenario.

Philip Marr, oilseed rape specialist at distributor Agrii, says that growers will need to take a decidedly “northern” approach to future crop management, starting with variety choice.

See also: Leaf spot to blame for poor OSR yields

“Light leaf spot only becomes evident when the weather warms up in the spring, but by then, unless we have decent levels of resistance in our varieties, the triazole shift means we have precious few defences left these days,” explains Mr Marr.

He points out that with more than half the varieties on the current East & West Recommended List having a light leaf spot resistance score of less than 6, many growers may need to consider something different.

“These can clearly perform well where the disease isn’t a problem. However, on the evidence of recent years – and this season’s losses in particular – I consider the majority to be far too much of a risk for most UK growers.”

He stresses that with every kilo of yield vital to compensate for tumbling grain prices, making the most of varieties with high levels of resistance could see huge rewards next harvest.