Sugar beet growers warned of leaf miner attacks to crops

Sugar beet growers are being warned of leaf miner attacks to their crops.

With no approved foliar insecticide available, researchers are keen to assess the size of problem.

Damage from the pest, the larvae of the mangold fly, is being seen particularly, but not exclusively, around the Wash area and suggests that seed treatments are running out of steam.

Experts at the British Beet Research Organisation (BBRO) are looking for growers to comment about the pest, either about numbers and/or damage, to gauge the extent of the attacks.

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The first signs of damage will be large, light brown, blisters on the leaves caused by the larvae tunnelling through them. These leaves eventually turn completely brown and drop off.

The BBRO, which is jointly funded by beet growers and processor British Sugar, says in extreme situations up to 400 eggs per plant were found at the 6-8 true leaf stage.

“We are particularly concerned at this developing situation as there are no approved foliar insecticide available for subsequent control post seed treatment,” says the BBRO.

It reminds growers that dimethoate is no longer approved for use in sugar beet crops for mangold fly control.

The BBRO is currently monitoring adult mangold fly numbers from traps and will be assessing a range of insecticides in trials this year.