CONDITIONS FAVOUR high carry over of Septoria tritici this autumn, growers are warned.

Following high septoria pressures over last season, spore numbers have been building, according to H L Hutchinsons‘ Dick Neale.

“All the predictions are that the inoculum pressure on the new crop will be high – it must be tackled early.”

High levels of disease cycling, increased use of minimum tillage (particularly in oilseed rape) and early emergence of this season‘s crops are factors in this increased risk, he said.

“Minimum tillage leaves infected foliage near the surface.” This can then lead to spores being passed on to neighbouring crops, Mr Neale explained.

Growers using wheat varieties at risk from Septoria tritici, should use a broad spectrum treatment such as Jockey (fluquinconazole + prochloraz), he said.

Consort treated with Jockey yielded 0.33t/ha more than the same variety with a single purpose dressing and the same foliar treatment, in trials near Huntingdon.

But ADAS Boxworth‘s Bill Clark does not believe there will be any greater pressure arising from last season‘s disease levels.

“There is never a shortage of inoculum. The septoria risk this autumn is not any higher or lower than normal.”

Drilling date and winter temperatures are more important factors influencing the septoria threat, although early emerging crops from warm, moist soils could be at higher risk from septoria this year, he added.