Oilseed rape crops across southern England are seeing a big rise in pest damage from cabbage stem flea beetles, with some rapeseed plants containing up to 50 beetle larvae.
Despite insecticide spraying last autumn, larvae numbers are high as the pests appear to have spread from their previous hotspots in eastern England.
“This is the first time we have seen significant larvae numbers in the early spring despite pyrethroids being applied in the autumn,” [Agronomist Richard Cromie] told Farmers Weekly.
With neonicotinoid seed dressing banned, the only treatment for the beetles is pyrethroid insecticides, but spray timing is critical to control adult beetles and resistance to the insecticides is building up.
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