SLUGS ARE predicted to pose a significant threat to crops this autumn and numbers could remain high into next year, according to experts.

While slug populations may not be exceptionally high at present, numbers are unlikely to tail-off as they normally do over the winter, according to a Rothamsted Research model, funded by De Sangosse.

“The most striking aspect of the slug forecast for this year is that numbers could remain high until well into February 2006,” said Rothamsted’s Jenna Willis.

By February, she expects numbers to be similar to the same time last year, but above 2003 and 2004. “If the winter is warm and wet we will see a lot more.

Last year, the model, which uses historical and forecast weather data to predict slug populations, also predicted a large slug surge, which was later confirmed by field reports.

“But you need the right weather for slugs to do any damage, no matter how many are in the soil,” she added.

Unsettled summer conditions are responsible for the high slug threat, added De Sangosse sales and marketing manager Jean-François Testut

“This sustained high population is a development growers must prepare themselves for.”

He urges growers to pay close attention to pellet choice. “There’s a high danger that those who use poor quality pellets will find crops go into the cold winter months with no protection at all.”

He suggests using wet process bait, such as Metarex and Clartex, made from durum wheat, which swell, but stay whole in wet weather.

But independent consultant Colin Myram said there was little difference in the effectiveness of 15 brands he trialled last season.

“Some modern pellets have more finely milled metaldehyde and so use less active ingredient, which is better for the environment,” he noted.

Keep track of pest and disease threats throughout the season with FWi’s Crop Watch – weekly reports from agronomists around the country, updated every Tuesday.