Crop Watch: cold weather fails to stop septoria and rust

Unseasonably cold weather last weekend (5-6 April) has done little to stop the build up of septoria and rusts in many cereal crops, according to FWi’s team of agronomists.

Septoria levels have been building rapidly prior to T0 applications,” Neil Potts from Matford Arable in Devon said. Even Gatsby (rated seven for Septoria tritici resistance on the HGCA’s Recommended Lists) was beginning to look dirty, he said.

Brown rust was unusually prevalent in some winter barley varieties, with Sabine particularly affected, he noted. “Barleys are looking well, but are not as well-developed as usual at this time of the year.”

In Northumberland, David Cairns reported pockets of yellow rust in winter wheat. “With cool, wet conditions, it is again increasing the importance of a T0 tidy-up spray.”

Winter barley was approaching the T1 spray timing and he reminded growers of the importance of early eyespot control in that crop.

Andrew Blazey said there was “plenty of septoria” and traces of yellow and brown rust in susceptible wheat varieties in Essex, so an early fungicide application would be a must.

First wheats on thinner soils were beginning to show signs of running out of nitrogen and would receive the main nitrogen dose from this week onwards, he added.

Many agronomists, including Hampshire-based Tod Hunnisett, reminded growers of the importance of looking out for pollen beetle in oilseed rape and to only treat where spray thresholds were exceeded.

“Reports of pollen beetle have started to trickle in, but I’ve not yet seen anything worth spraying and the recent cold snap should help keep them at bay. The threat of pyrethroid resistance is still an important issue, so I’m avoiding spraying unless absolutely necessary.”

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