Control of barley yellow dwarf virus in cereals

Abstract

1. Barley yellow dwarf virus (BYDV) is the most important disease affecting cereal crops in New Zealand. 2. Losses from BYDV in the total wheat crop have been up to 25 per cent in recent years. 3. Effective control of BYDV in autumn- and early winter-sown wheat in New Zealand has been achieved by 1 application of a good systemic organo-phosphate spray (Metasystox i, Rogor 40, Ekatin, or Phosdrin) at any time between late winter and late spring. 4. These spray materials applied at rates between 6 oz and 16 oz of commercial material in 9 to 15 gal of water per acre by tractor-or helicopter-mounted booms have given excellent control of BYDV and the aphid vector Rhopalosiphum padi, and increases in yield of 5 to 24 bushels of wheat per acre, even when very low or very high aphid numbers were present in the field at the time of application. 5. It is thought that the full significance of late secondary spread of BYDV in reducing yields of relatively tolerant cereals, particularly wheat and barley, has not been recognised in many countries throughout the world.