East: Keep fungicide timings tight to tackle wheat disease

After a slow start, crops are growing well as they react to warming soil temperatures and recently applied fertiliser. After a blustery end to March, recent calmer days have allowed growers to keep a good pace with applications. A few light showers would be welcome to aid establishment of spring crops.

In contrast to last season, sugar beet on heavy land is emerging more evenly and the first post-emergence herbicides have been applied. Herbicide mixes that can be safely applied during emergence are helpful in the control of “difficult” weeds like knotgrass.

In cereals disease pressure is moderate; this combined with the recently well timed T0 fungicide sprays helps us feel that currently disease is being well managed. However, for continued disease control and good resistance management it is important that spray timings between T0 and T1 are tight.

Forward wheats will be approaching the T1 fungicide timing (usually, emergence of final leaf 3).  Due to the drift in sensitivity of septoria to triazoles robust T1 treatments are important, even with moderate septoria levels. We now expect to spend nearly as much at T1 as T2 (flag leaf emergence). However, this season there is scope to reduce inputs compared to last spring when septoria and rust pressure was much higher. Be careful not to be lulled into a false sense of security with current dry weather – what really matters with Septoria is the weather in late April and May.

Pollen beetle are active; more forward rapeseeds are racing through the susceptible stages and may not need treatment. However, backward crops moving slowly from green bud to open flower will be at greater risk. Non pyrethroid insecticides include thiacloprid (Biscaya), pymetrozine (Plenum) and indoxacarb (Rumo). Check individual labels for the latest timing of applications.

More forward rapeseeds are now yellow; many will receive a fungicide for sclerotinia control at 1st petal fall. The start of flowering has been relatively late which may lead to a shorter flowering period? Treatments are mainly protectant, so we are trying to coat petals before they fall. Where rapeseeds have lower yield potential (eg ravaged by cabbage stem flea beetle), compromises around the level of investment will have to be made as margins for these crops are tight.

Check bean crops for pea and bean weevil damage, many winter beans are approaching early flower and will shortly be receiving the first fungicide treatment.

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