Coldest winter for 30 years could prompt burst of spring weeds

The coldest winter for 30 years will prompt a burst of weeds in crops this spring, warns Graham Dickinson, of Rotam UK.

The long, cold spell – the coldest in Britain since 1963 – and mixed success with autumn herbicide programmes will combine to increase the threat of weeds this spring, he claims.

Autumn pre-emergence residuals have performed well in good seed-beds but some have been less effective when applied to dry soils, says Mr Dickinson.

The wet weather that followed the dry autumn meant many growers missed the opportunity to apply post-emergence holding sprays – and nothing else has been applied since.

This combination could lead to “large and variable flushes of weeds appearing in the coming weeks”, says Mr Dickinson.

Growers should not rush ahead with their weed control programmes while soil temperatures remain low, inhibiting active weed growth.

However, when weeds do start to grow, product efficacy and flexibility in timing will be key, he says.

Sulfonylurea herbicides based on metsulfuron, such as Savvy and Ergon (metsulfuron + thifensulfuron) have a wide application window from three leaves to GS39, he reminds growers.

“In addition both have good tank mixing compatibilities with PGRs and fungicides, adding to their flexibility and ease of use particularly during March and April timings.”