South: Multiple slug pellet applications required

We have finally had a sustained dry period which has at least allowed most people to finish harvest. I am not going to dwell on results, but suffice to say with months of waterlogged soils, an absence of sunshine and horrific septoria and fusarium levels, yields are the worst for many years.

Oilseed rape crops are a very mixed bag, a few crops are well established with 3-4 leaves, but most are either at expanded cotyledon or yet to emerge. Last Sunday’s rain will obviously help these struggling crops, but it will also increase the slug pressure significantly. These late emerging crops will grow away slowly and be vulnerable to slug damage for much longer than crops emerging in late August and multiple applications of slug pellets could well be needed for adequate protection.

I strongly advise growers to use a 1.5% pellet, as they are just as effective and will allow three applications at 4kg/ha before approaching the 210g/ha metaldehyde limit. The alternatives are either ferric phosphate or methiocarb-based pellets, both of which will increase costs significantly.

Phoma has not yet appeared, but given the number of wet days in August it will probably appear soon in the earliest drilled crops. It is important to remember that Phoma on small backward plants needs swift control and should not be left to fit in with other applications to the crop.

Wheat drilling has started, seed-beds should be reasonable after the recent rains, but again slugs will be a major problem especially following rape. Drilling between 35-50mm deep in fine well consolidated seed-beds will help minimise hollowing damage significantly and also provide ideal conditions for pre-emergence herbicides.  Pre-emergence programmes should be based around 240 gms of flufenacet stacking Defy (prosulfocarb), diflufenican and other actives, depending on the severity of the blackgrass.

The recent dry spell, coupled with blackgrass seed dormancy has made it difficult to get even a single chit pre-drilling. On the worst fields patience and waiting for a chit will pay dividends, but with wet subsoil and the recent rains, it will take nerves of steel to delay drilling far into October!

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