Key Points
- Barley yellow dwarf virus (BYDV) occurs as a result of aphids flying into cereal crops (primary infection) and aphids moving and reproducing within crops (secondary infection).
- In Canterbury, aphid flight data from 7.5m high suction traps has been used as a forecast for primary BYDV infection in autumn-sown cereal crops, but there has been no forecast of secondary BYDV infection.
- In recent years increased BYDV incidence (especially 2005) not explained by primary infection data has emphasised the need to include estimates of secondary aphid infestation in future BYDV forecasts.
- New analysis of both suction trap data (a measure of primary BYDV incidence) and heat unit accumulation (a measure of secondary BYDV incidence), especially in June, July and August, shows the potential of this combined data for predicting BYDV incidence in any given season.
- Forecast risk of BYDV will be reported in Crop Action and the Aphid Watch website from June to August.