Best weed control at pre-emergence in oilseed rape

There is a significant amount of winter oilseed rape being planted at the moment, despite heavy rain hampering ground conditions.

As these crops are planted farmers need to tackle a few things to ensure a good start – pest and weed control.

Weed control

Pre-emergence herbicides are most effective when it comes to tackling broad-leaved weeds in oilseed rape. Some pre-emergence sprays also offer control of annual meadow grass.

One advantage of the current soil conditions is that the damp soil should help the pre-emergence herbicide to perform well.

Tackling weeds early allows the crop to get off to a better start and improve establishment rates. It is recommended to apply pre-emergence herbicides within two days of planting.

However, farmers should be careful, as the crop can be affected if heavy rain occurs 48 hours after application of some pre-emergence herbicides.

Some herbicide options include Butisan S (offers some control of annual meadow grass and black grass) and Katamaran Turbo.

If high rates of Butisan S are being used, the application can be split into pre and post-emergence. Some farmers may opt to add a graminicide to the second split where grass weeds and volunteers are a problem.

Clearfield varieties should receive Cleranda herbicide to control brassica weeds, as well as problematic weeds such as groundsel, fumitory and poppies.

Where problem weeds like charlock, chickweed and shepherd’s purse are an issue post-emergence growers may consider using Salsa.

Slugs and beetles

Farmers need to keep an eye out for slugs and apply pellets where numbers are high. The recent wet weather may increase the risk.

Flea beetle is a big problem in the UK and growers should watch out for damage to leaves. Where more than 50% of leaves at early establishment have shot holes, Teagasc recommends applying a pyrethroid insecticide.

Growers should consider planting a resistant variety where turnip yellow virus (TuYV) is a problem.