Growers warned of 'clear risk' of slug damage to spring crops

Growers are being urged to assess and manage the risk of damage to spring cereals following high autumn slug pressure and a mild, wet winter.

Slug populations were significant last autumn after favourable breeding conditions in September and October, according to Keith Walters, professor of pest management at Harper Adams.

His research suggests that in many fields of suitable soil types, slugs remained active through until January, when monitoring stopped, and there is a risk this activity has continued into the spring.

Spring cereals are usually considered less vulnerable to slug damage than autumn sown crops due to lower slug populations – hit by cold winter weather – and crops growing away from vulnerable growth stages quicker in warming seedbeds.

But following the absence of any hard, prolonged frost and presence of favourable soil conditions, Professor Walters warns that nothing should be taken for granted this year.

He said: “Don’t take any risks. Look very carefully at fields destined for spring cereals, monitor for slugs and be ready to act if slug populations have survived the winter.”

Richard Cromie, independent agronomist with Crop Management Partners, agrees, warning that there is a 'clear risk' this spring.

This will be heightened on farms direct drilling into trashy stubbles, or where a cover crop has preceded the spring crop and not been grazed off by livestock.

In such situations, he recommends shallow cultivation to incorporate organic matter and knock slug numbers.

A recent BASIS project trial conducted by the partnership’s trainee suggests this tactic can reduce damage in the following crop by about one-third.

“A stubble rake is better than nothing, but a 2-4in cultivation is best. It will help culturally beat some slugs up, relieve pressure on the following crop and reduce reliance on slug pellets,” Mr Cromie said.

With much land still at field capacity it could be a couple of weeks before spring cereal drillings in earnest, so there is time to identify risky fields and monitor slug populations.

However, on larger farms some crops will have to be drilled earlier into less-than-ideal seed beds increasing opportunity for seed hollowing or seedling damage.

Mr Cromie says growers should be prepared to act, targeting ferric phosphate slug pellets at problem fields or areas rather than taking a blanket approach.

“The wet autumn underlined the importance of a high quality, standard sized pellet like Sluxx HP, and should be considered if catchy conditions continue throughout the spring drilling campaign.

“That is my preferred product in wet conditions. The larger, well formulated pellets offer a longer period of protection if you have rain soon after application."