South: Slug pressure builds

Unsettled weather has halted drilling for a while with much still to do. However, most wheat following oilseed rape is in the ground and some is starting to emerge. Seed-bed quality on the whole has been excellent although, given the unsettled conditions, not as much has been rolled as I would have liked.

Slugs are now quite easy to find in the soil profile in some fields following rape. Little seed hollowing has occurred given the good seed-beds but leaf grazing will be significant were there are high populations. I am advising the use of pellets in these situations before emergence to reduce the slug population and subsequent grazing damage.

Oilseed rape crops generally look well and establishment is the best I can remember for a number of years. This has no doubt been helped by the lack of slug activity in most areas, although my subsoiler-established crops have had far more slug pellets than any other method of establishment. This is worrying given the low slug pressure this year and the possible loss of metaldehyde in the future.

Blackgrass is romping through oilseed rape fields, although some of the pre-emergence treatments, notably Shadow (dimethenamid, metazachlor and quinmerac), are thinning it out well and holding it back. Temperatures are too high for the use of propyzamide at the moment and in thick stands of blackgrass delaying control until temperatures decline is not an option.

The only option now is to try and reduce the population using a graminicide. The only one worth using is Aramo (tepraloxydim) and I have already had some excellent results. However, it does need a water conditioner adding to the tank first and needs applying in a medium to fine spray at a maximum speed of 10kph if it stands any chance of working well.

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