The mild and wet winter will have done nothing to reduce slug numbers and with April and May the principal breeding months, conservation charity BugLife has predicted that populations are set to surge.
Simon McMunn, commercial manager with slug pellet manufacturer De Sangosse, says conditions will support breeding activity so growers should be ready for high pressure come the summer.
“A mild autumn last year means populations were already at healthy levels and the mild winter will have done nothing to reduce this. With April and May representing an important peak in the breeding cycle the wet soils and mild temperatures suggest breeding activity will be high and egg survival good. This means populations are primed to increase significantly,” he says.
Slugs represent little threat to established winter crops, but where spring cereals were late to go in or have been slow to get going, an application of pellets may be required. The bigger warning however, relates to crops to be drilled this summer such as oilseed rape and the autumn sown winter cereals.
The threshold for wheat crops is four slugs per trap in stubble, but in stubble before oilseed rape, research has shown that just one slug per trap is enough to signal the need for action.
Cultivations are an important part of slug control though it will not remove the need for pellets in high risk situations.
“The decision to apply pellets should be based on the number of slugs present and the quality of the seedbed, but given current populations growers should be prepared to apply pellets at or around the time of drilling, ideally just after the crop has been rolled,” he says. “The potential for damage in high pressure situations is so great that waiting for activity to become visible means it is too late,” he adds.
It’s also important to use a high quality, wet process pellet to get sufficient active ingredient in to the slug for it to be fatal. De Sangosse’s metaldehyde and ferric phosphate products offer cost-effective means of control and are capable of delivering exceptional levels of efficacy. These, better quality pellets, such as TDS, are made with durum wheat flour to make the bait more palatable.
“Pellet size is also important to effective control. About 30 pellets per square metre is often all that is needed as slugs are free-roaming creatures capable of moving more than five metres a night and able it to detect food from 60cm away. The larger pellets offer greater ballistic performance, ensuring even coverage and a consistent spread pattern,” he adds.