Late summer reseeds at risk from Frit fly

Published 24 August 12

A new 'hatch' of frit fly larvae is emerging through late august and early September posing a threat to late season reseeding, says DairyCo extension officer Chris Duller.

The frit fly lives in all grass swards in the UK and their maggots damage grass plants by boring into the centre shoot. In larger plants this damage often goes unnoticed - but in a new reseed the damage can mean huge reduction in establishment. The biggest risk is where grass follows grass, or where new seed is being stitched into an existing sward.

Treatment comes in the form of a spray with the chemical Chlorpyrifos, either prior to establishment (it can be tank mixed with RoundUp), or at emergence. With a cost of around £10/acre it is not a huge extra expense to safeguard your valuable reseed.

There is concern over the way Chlorpyrifos is currently being used in the UK and there is a major campaign to safeguard its continued availability. All users are urged to adopt a 20 meter no spray zone around water courses and to use low drift nozzles.

For anyone reseeding this autumn, either spray as a precaution against frit fly, or monitor your emerging crop very carefully and react to any damage early. The threshold for action is at around 10% of seedlings affected.