Rampant slugs threaten cereals despite the chill
By Andrew Blake
THE Indian summer may be at an end, but virus-bearing aphids and slugs remain a threat to cereals in many areas, according to ADAS.
Growers should not be deceived by the abrupt change to cooler conditions after last weekends sunny weather, warns Hunting-don-based John Garstang. "It may seem cool now, but the weather is still perfect for aphids and isnt cold enough to slow slugs down."
Strong volunteer regrowth on set-aside harbours plenty of potential BYDV carriers, he adds.
Flights into crops will have slowed down since the weather changed, says entomologist David Green of Wolverhampton ADAS. "But there was an enormous amount of activity over the weekend. It is worth going back to check crops. If there are winged aphids producing young there is a potential risk of virus." Pyrethroid sprays should be applied where aphids are apparent, he advises.
The market for slug pellets is much stronger than in the past two autumns, particularly north of line from the Mersey to the Wash, manufacturers report. But there should be adequate supplies of all products with prices much the same as last year, they say.
"Demand is hotting up, especially on the heavier soils," says a spokeswoman for Draza (methiocarb) maker Bayer.
Main problems are on heavy land ploughed up damp, which then dried in September, making good seed-beds hard to achieve.
Berwickshire-based grower Jim Macfarlane has had to apply far more pellets than usual to his 105ha (260 acres) of winter cereals at Edrington Mains, Foulden. All his wheat after oilseed rape has required two half doses of Optimol (metaldehyde) and nearly all the rest has had a half rate treatment. "I am horrified because I dont really like using them for environmental reasons. Last year we used none at all."
Slug slaying was in full swing on Edward Whitfields Bank House Farm, The Delph, Spalding, Lincs, earlier this week. Contract application of Draza pellets to wheat after rape resulted in a high kill rate (inset).
• Slugs rampant in north.
• Supplies not hit, says manufacturer.
• BYDV risk still real.
• Check crops for aphids and spray if aphids apparent.