Molluscicidal seed treatment of barley, wheat and perennial ryegrass to control the field slug (Deroceras reticulatum)

Abstract

The effects on the field slug (Deroceras reticulatum) of treating seeds of barley, wheat and perennial ryegrass (Lolium perenne) were investigated in laboratory experiments. Barley seeds were treated with metaldehyde and methiocarb, wheat seeds with metaldehyde, methiocarb, neem oil (azadirachtin) and saponins, and perennial ryegrass seeds with metaldehyde, methiocarb and thiocyclam hydrogen oxalate. These compounds were tested at several rates. Metaldehyde was the most effective treatment in preventing slug damage to the seeds and seedlings. The level of protection against slugs at 0.8 g a.i. kg-1 barley and 1.6 g a.i. kg-1 wheat seeds was insufficient, but 1.6 g a.i. kg-1 (barley) and 3.2 g a.i. kg-1 (wheat) gave good protection for up to 10 and 6 days, respectively, after sowing. Metaldehyde at 160 g a.i. kg1 perennial ryegrass seed also gave sufficient protection against the field slug.