West: Time to consider T3 wheat fungicides

The majority of winter wheat is at or close to ear emergence stage so it is time to consider T3 fungicides. Treatment at this stage tops-up disease control on the flag leaf and keeps the developing ear clean, increasing yield and protecting grain quality.

Mycotoxin reduction, particularly on milling wheat, is now a priority at T3. In addition there is still a risk from yellow rust and in the hot dry conditions of late, brown rust is a particular risk on susceptible varieties. While the dry weather reduces the threat from septoria and late ear diseases we do not know what conditions will develop over the coming six weeks, so T3 treatments should be applied.

As the ear emerges and up to flowering we also need to be checking on calm evenings for wheat orange blossom midge. Only spray if the threshold figure is reached as chlorpyrifos is a very broad spectrum insecticide and will kill a wide range of non-target species.

T2 fungicides will be needed on spring barley and spring wheat as flag leaves emerge. Again, we may yet go into a period of wet weather, increasing disease risk.

Pollen beetle can be found in spring rape. Even where the flower buds are still deep in the foliage the beetles are already on the developing buds. The threshold is only one per plant and often two treatments are needed, 10-14 days apart.

On beans disease levels are at present very low, with little sign of chocolate spot or mildew. Rust is probably the greatest threat, given the conditions and preventative treatments should be applied.

Monitor beans for bruchid beetles as first pods are forming on both spring and winter crops. The adults move into the crop to lay eggs in late May/early June and the grubs, once hatched, can ruin the sample for human consumption. Look for the adults which are dark brown/black, with speckled grey, humped wing cases. Two sprays are needed, 14 days apart.

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