Flea beetles in patches query

17 October 1997

Flea beetles in patches query

FLEA beetles, not slugs, may be the cause of bare patches in southern wheat crops and newly sown grass leys.

That is the warning from Nick Poole of the Arable Research Centres after a very dry early autumn.

Contrary to the text book view that it is the larvae of the pest which cause the damage, ARC findings suggest the adults are to blame.

"They totally destroyed some of our herbage seed trials last year. They just fell the plants. The worrying thing is that the symptoms appear very much like those of slugs.

Anti-BYDV control

ARC is examining the effect of early anti-BYDV sprays on the adults. "We have also been looking at the use of Gammacol on an experimental area. But there is no recommendation for it at the moment."

According to ADAS wheat flea beetle larvae cause occasional problems in crops after leys and weedy stubbles. This autumns warm spell has led to more reports than usual, says Hants-based entomologist Jon Oakley.

Neither the adults, brown and about 2mm long, nor their grubs, which are creamy white with black heads, abdomens and legs, are very obvious at first sight, he says.

"In bad cases you need to do something about it." Lindane (gamma-HCH) is likely to prove more effective than chlopyrifos-based products against the larvae because they tend to attack below soil level, Mr Oakley believes.n

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