13 August 1999

Risk assessment to tackle frit flies

FRITflies can pose problems to newly established autumn sown swards, as they can climb up through soil to seedlings from up to a ploughs depth.

Considering their minute size of 3mm, this is no mean feat, says IGERs Bob Clements. "Frit flies tend to affect ryegrasses, especially Italian because it is their favourite host plant, sown in late August or early September."

To overcome their threat, a risk assessment is the best policy. "This sets out the basic facts such as time of sowing, grass species, locality and grass or arable area."

Direct drilling exacerbates frit fly threat, and action must be taken promptly. "Often by the time grass is noticably damaged it is too late. Producers should make a risk assessment which will advise whether to spray or not,"he says. &#42