Again there’s no let up with light leaf spot (LLS) this season and growers are being advised to think about ‘topping up’ protection with flowering sprays.
ADAS plant pathologist Julie Smith says that she has seen the disease everywhere. “We’ve had reinfection and the disease is visible on leaves and stems, and that includes the more resistant varieties. Despite the lower risk prediction for the East there is plenty of it there too,” she warns.
Her biggest fear is the disease getting onto the pods. Not just because of the potential damage to crops and returns but for the risk to next season too. “We’ve seen it in the past where the disease has got into the canopy causing pod shatter and significant seed loss. It is a very damaging phase of LLS infections.
“But it is also the carryover to next season. Shattered pods will only add to the disease left on crop stubbles.”
Her advice is to opt for products effective against both LLS and Sclerotinia. “If you’ve lost the LLS battle already then it is too late, the disease will be moving through the plant. However, if you are still in a protective situation then I would look to boost LLS control given the pressure again this season,” she says.
Bayer’s Darren Adkins agrees and adds where growers are concerned about LLS they may not want to hold off until mid flowering. “The typical Sclerotinia timing might be too late if LLS is a concern so I would consider splitting sprays and bringing the first forward to early flowering. There’s no better option for both diseases than prothioconazole so I would suggest growers opt for a 0.46l/ha dose of Proline275 and monitor crops from there,” he concludes.