19 August 1997

Frit fly warning on grass reseeds

REPORTS of greater than usual frit fly numbers mean producers should keep a close eye on grass reseeds and should consider control measures.

According to ADASs Alan Lane, high frit fly numbers in late August and early September suggests potential for significant egg laying on emerging reseeds.

"Frit fly larvae pose a risk to recently sown grass and cereals following grass. The major threat is to reseeds following grass, where flies will have laid eggs in old pasture, so larvae will be present in soils to affect reseeds."

Leaves of affected seedlings will turn yellow, and will be easy to pull out, he says. "The larvae will be found inside the plant at or below soil level; its small and white, with a dark head."

According to Mr Lane producers reseeding after grass should apply chlorpyrifos (Dursban, Spannit, Talon) to the seed-bed, or keep a close eye on the crop for signs of attack.

"When there have been frit fly concerns in the past, it is probably worthwhile applying an insecticide before or at drilling.

"Where reseeds have been attacked already, it is possible to patch areas, but I would recommend producers apply an approved insecticide to protect emerging seedlings."