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Affects of Winter Now Showing in Crops

12 April 2011

SCOTLAND, UK - Winter sown cereal and oilseed rape are reaching the stage where early protective treatments are needed, SAC consultants report. Meanwhile there is good progress with sowing spring crops on the lighter land, although famers on heavier soils and flatter ground still have wetter patches to cope with.

According to SAC crop health specialist Dr Fiona Burnett those conditions have also affected winter crops, some of which are patchy. In those conditions pests have made inroads.

"At the SAC Crop Clinic growers are reporting crops with "deadhearts". These are often caused by leatherjackets and wheat bulb flies chewing out stems. While the more vigorous, better tillered plants can cope, the weaker ones can't. It is worth checking the deadhearts though. For example damage by fever fly larvae (bibionid) looks similar but they don't respond to sprays like the others."

The early winter snows have left another legacy. Their blanket protection kept out the frosts and disease has thrived. Dr Burnett has noted an increase in the amount of light leaf spot in oilseed rape in the SAC monitored commercial crops compared to a season ago.

"A key time for treatment is when the crop starts to grow away and reach welly boot tops", she says. "SAC trials show that doses can be reduced on resistant varieties like Cuillen or Emerson, but most varieties are quite susceptible and those like Flash and Mendel need robust protection."

Fiona Burnett also warns pollen beetles are on the move but should only be treated where economic treatment thresholds are exceeded.

On winter barley crops SAC consultants are seeing a mixture of diseases like rhynchosporium and net blotch, with mildew around in areas like the Black Isle and the Borders. The new sdhi fungicides like Seguris and Siltra Xpro have been very effective in trials in preventing early disease development on barley and can be used again in the season as part of a programme.

On wheat crops SAC trials show that the new chemistry is probably best kept for the main flag leaf timing, and that the main risks for wheat crops early season are septoria, eyespot and yellow rust on the weak varieties like Robigus. Dr. Burnett recommends that these are best managed at stem extension stage, using fungicides that growers are already familiar with.

"It's to early for me to forecast how all this will affect the harvest", says Burnett. "There are some excellent crops in the south but as you move north the damage left by the winter and spring is still very evident in some areas."

TheCropSite News Desk

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