SLUGS STILL pose a threat to many crops, even though recent frosty weather has slowed activity, growers have been warned.

Thinner and less advanced crops are particularly at risk and it is important to keep checking crops throughout the winter, said Shropshire-based ADAS entomologist, David Green.

“Numbers can quickly rebound given suitable conditions. With the return of warmer weather and slower crop growth, as a result of the colder soils, growers need to keep a check on things, particularly if oilseed rape crops lose leaves during the winter.”

He has found a variety of different species, but the bulk (around 60%), are adult and juvenile field slugs.

“Juveniles can cause damage as well as adults, particularly the more important damage for wheat, feeding on embryos of wheat grains causing grain hollowing and shredding of foliage later on.”

Half of sites in Bayer CropScience’s national Slugwatch are showing high populations, at 30+ per square metre and over half of these are juveniles less than 1cm long, added the firm’s agronomist, Gareth Bubb.

“Cereal crops into mid-tillering should hopefully be past the damage stage, but later drilled crops that are prior to or at early tillering, still need to be monitored.”

Slugwatch is available free at www.bayercropscience.co.uk