Variety choice can smother blackgrass

Choosing the right variety could have a positive effect in reducing blackgrass populations in wheat, Masstock trials have shown.

Certain varieties were more competitive on blackgrass, the firm’s Tim Horton said.

“Robigus, for example, is very competitive while Hereward isn’t.”

The effect was on the tillering capacity of the blackgrass rather than preventing weeds emerging.

The better tillering varieties appeared to prevent blackgrass from tillering to the same extent, technical manager David Langton explained.

The difference could be as much as 30% control depending on which herbicides were used.

“If you apply a good programme the difference is irrelevant, but there are big differences with weaker ones.”

For example, a pre-emergence spray followed by a non-Atlantis mixture on Robigus gave 92% control, while in Hereward it only gave 82%.

Seed rates also had an effect. Lower seed rates could double the number of blackgrass heads per sq m.

“The benefit for growers is knowing where the pressure is going to be higher.

They may be able to target different varieties to grow in the poorest fields, or use a higher seed rate.”

It could also help prioritise which fields to spray first or which to invest in using a pre-emergence on, he said.