North: Cold keeps disease and slugs at bay

The last month has seen some fairly unsettled weather, with cold snaps interspersed by some unseasonably mild days. The cold and frosty spells have tended to keep foliar diseases at bay and have deterred slugs from coming out of hibernation. On the easier to work ground ploughs have been out catching up on the backlog. Hopefully all operatives have been briefed on the Good Agricultural and Environmental Conditon (GAEC) requirement of not cultivating within 2m of a hedge or the top of the bank next to a watercourse.

Most winter crops will have had their phosphate and potash applications. The first top dressings of nitrogen will have been applied to winter oilseed rape and winter barley. In general winter wheat crops are not showing the same degree of urgency to get on with the nitrogen. However, as soil temperatures rise that job will rise up the priority table.

Many winter barley fields will soon be approaching the GS30 timing. There are low levels of mildew and net blotch, which need to be kept in check and no doubt rhynchosporium will rear its head if the weather turns warm and wet. A cyprodinil/morpholine mix will help to keep the resistance pressure off the triazole chemistry, which will be required later in the programme. Some more manganese at this timing will  assist in maintaining green leaf.

Oilseed rape crops always look a bit shabby coming out of winter, however, the recently applied nitrogen will soon get crops stretching. Light leaf spot is on the rise. A reasonable dose of prothioconazole and/or tebuconazole will be necessary for effective control. Add in some boron and molybdenum with this mixture. This will be the last chance to tidy up any weeds, mainly mayweed and sow thistle, so a judgement will need to be made about the economic response to any application – choice is limited.

As a result of the wet autumn many wheat crops will not have had any weed control. The earlier you can get on, the easier and cheaper it will be to achieve satisfactory control. In the main the problem will be annual meadow grass (AMG) and a range of broad-leaved weeds. A mix of a sulfonylurea plus residual partner may be required. A planned strategy for disease control will be needed to keep on top of septoria in particular, given that most varieties do not have high levels of resistance. The main requirement will be to use a mix of multisite and single site actives and, weather permitting, do not extend spray intervals. No doubt mother nature will keep us all guessing.

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