North: Cool and dry reduces disease pressure in all crops

The past month has been very dry, but also cold, which has significantly reduced disease pressure in all crops. Agronomists often stress the importance of timing of crop protection inputs and so far so good, as the settled weather has allowed almost everything to be applied at the optimum timing. Some rain now would be welcome for all crops, especially those on light land, late sown wheats and spring crops.

Early sown winter wheats look very well and leaf three has emerged on the earliest sites. T1 fungicides are being applied to cover leaf three and on these lusher, early sown wheats sprays will be based on SDHI, triazole and multi-site protectant active ingredients. With the dry weather it is easy to get lulled into a false sense of security with regards to disease pressure. However, the older leaves are carrying high levels of Septoria tritici and yellow rust has been around for several weeks now, along with plenty of mildew in susceptible varieties. The gap between T0 and T1 is tighter than usual, but in many ways this is good as it maintains good disease control compared to programs where intervals become stretched.

Winter barley crops have received their T1 fungicide and the next decision will be whether they warrant any further growth regulation. The recent cold and dry weather has steadied crop growth, so perhaps the level of any further growth regulation will be reduced or not required. Winter oats are at early stem extension and mildew is the main disease present, but not requiring any control just yet.

Oilseed crops are beginning to start flowering, so attention is turning to sclerotinia fungicides. Seed weevil numbers are currently low, so hopefully an insecticide will not need to be added to the sclerotinia fungicide. Thankfully pollen beetle numbers did not get anywhere near threshold levels when the crops were at the green bud stage. Areas where pigeon grazing was severe will still need to be monitored for pollen beetle damage. Spring oilseed rape crops are emerging, so be on the lookout for flea beetle damage.

Spring beans and peas have emerged well, albeit slowly, in the cool and dry conditions. Pea and bean weevil damage has been quite prevalent, so an insecticide has been recommended to reduce adult numbers and subsequently reduce the number of larvae that can attack the plants’ roots.

Spring barley crops are desperate for some rain having established well. Earlier drilled spring barley crops on lighter land are requiring some manganese, along with a herbicide mix where weed populations are high to remove any early competition.

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