Early drilled OSR knocked by CSFB larvae

Drilling date

In the autumn, earlier drilled crops generally showed the most promise, but now the picture is more mixed, Ms Pickering says.

“Larval numbers this year have been more variable than in recent years, but some crops have very high larval loads. Much higher pressures are being reported in early drilled crops compared to those drilled in the second half of September.

“We have found that if you have 10 larvae per plant you may get yield reductions of around 0.5 tonnes/hectare, with losses increasing with increasing larval load. However, the yield response is quite variable and some crops are able to achieve reasonable yields with high infestations. We do not understand what determines this variable tolerance and this is something we are investigating in a new AHDB and industry-funded project.”

PGR

Although there is little that can be done to mitigate yield losses, recent work on stem strength by ADAS found that lodging risk is increased if a stem has been damaged by CSFB.

“If growers have a crop that is looking fairly leafy and big, it might be worth using a PGR to reduce the risk of lodging going forward.”