Looking at weed control in oilseed rape post emergence

Farmers who have not yet applied a herbicide to oilseed rape crops should consider doing so sooner rather than later.

The early removal of weeds and volunteer cereals is extremely important to achieve high yields in oilseed rape crops.

Some research has shown that small weed populations in the early stages of oilseed rape development can lead to a loss in yield of 1-2t/ha.

There are a number of options available. For example, Belkar is one option for post-emergence and can be applied once the crop has two leaves unfolded. Once the crop moves to six leaves unfolded the rate increases.

Butisan S and Katarman, which are used pre-emergence, can also be used post emergence.

Where grass weeds and volunteer cereals are present a graminicide should be applied.

Clearfield varieties

Cleranda can only be applied to Clearfield varieties and gives control of brassica weeds, as well as problematic weeds such as groundsel, fumitory and poppies.

Cleranda achieves best control when applied to small, actively growing weeds and works best when applied to broad-leaved weeds at one to four true leaves and grass weeds at two to three true leaves.

Where charlock, chickweed and shepherd’s purse are a problem, Salsa offers control.

Flea beetle

Growers should keep an eye out for the cabbage stem flea beetle in crops. Shot holes appear in crops where the beetle is present.

In the UK, where the beetle is a major pest of oilseed rape, if 25% of the leaf has been damaged when two leaves have unfolded treatment with an insecticide is advised.

If 50% of the leaf area has been damaged when three leaves have unfolded, or if the crop is being eaten quicker, than it is growing treatment is needed.