Argentine stem weevil: Farmer awareness and the effectiveness of different ryegrass/endophyte associations

Argentine stem weevil (ASW) is a highly destructive pest of ryegrass that has recently been associated with increased incidences of field damage. A survey of farmer awareness and management practices in relation to this pest was carried out. Many (47%) farmers sowed favoured plant hosts such as short-term and tetraploid ryegrasses. A field trial, undertaken near Hamilton, compared the effects on ASW larval damage of 10 different ryegrass/endophyte associations in comparison with an endophyte-free control with and without seed treatment. U2 endophyte in a diploid perennial festulolium and AR37 endophyte in a hybrid tetraploid, an Italian diploid and a tetraploid perennial ryegrass had significantly less damage (<26%) than all other treatments (>42%). NEA2 endophyte in a diploid perennial ryegrass and AR1 endophyte in short-term ryegrasses failed to protect plants from severe damage by this pest. Farmers need to be aware of the risks of ASW damage to short-term and tetraploid ryegrasses.