Slugs lurk in dry soils
2003 could be the worst year for slug problems if growers allow recent dry weather to make them complacent or prepared to take risks, Britain's arable farmers are being warned.
Contrary to expectations, slugs are continuing to be a problem in many regions despite August's record temperatures and dry seedbeds in much of the UK's arable land. Emerging and newly drilled rape seedlings could be at risk without careful consideration of appropriate pellet treatments.
In Hereford and Shropshire Technicrop's Graham Webb who advises throughout the area reports: "Evidence of slugs has been sparse during the day, but they've been emerging in numbers at night, drawn out by the dew. They were seen grazing on ears prior to harvest, which shows that high populations are about and should the weather turn, slugs could be a big problem."
Oxfordshire and Warwickshire have seen similar problems according to agronomist reports, and slug activity was observed when spraying volunteer barley. The dry conditions could make things worse still for rape as seeds struggle with the lack of moisture so could be finished off by slugs before reaching three to four leaf when plants are generally more tolerant to attack. Moreover, with larger amounts of straw being incorporated this year due to poor prices, providing a food source for slugs, and rape planting up by some 10%, populations could be set to increase.
"Rape's attractiveness to slugs is well documented and with rape planting increasing this year, many farmers may see problems in fields where traditionally slugs have not been a problem," comments Malcolm Nursey, managing director of pellet manufacturer Luxan. "Farmers should be making regular observations of their crop, test baiting to assess populations if they think it necessary, and be prepared to use a quality pellet like the leading metaldehyde brands, which are proven to provide fast and consistent control of slugs and are durable, continuing to be highly effective during periods of rain."
Further north, on Seeton Hill Farm in East Lothian Morgan Nicholl reports that although activity is low, he suspects slugs are present in fields and is not taking any chances. "In the heavier clay soils slugs can be a problem and although we invert the soil with the plough which can help kill some slugs, we're keeping a close watch in order to time pellet applications to avoid slug damage," he says.
To the east, farmers in Suffolk are taking precautionary measures with new rape crops to guard against poor emergence. "Activity isn't high, but despite the dry soils we've seen cases of leaf stripping when spraying the cereal volunteers," reports Mike Warner of Suffolk Crop Protection. "With the dry conditions leading to uneven emergence there is an increased window of attack from slugs, and with flea beetle also a problem, we've been advising an application of metaldehyde pellets at or near drilling to help get the plants up," he says.
Finally, Nursey reminds growers of the situation last year when complacency saw many rape crops lost to slugs. "Conditions were similarly dry in August 2002 and pellet treatments were held off on many farms, but with showers in September slugs resurfaced and seeds were destroyed. With the costs of re-drilling rape crops significant, seed damage is something farmers can ill afford."
