To evaluate the timing of insecticide treatments on deterring aphids from feeding on newly sown wheat and how this impacts on final wheat yield and to evaluate the use of an insecticide seed dressing to give early aphid control.

While aphids were observed on early sown oat crops in the Hamilton district during April and early May, they did not appear to breed up and cause problems by spreading BYDV through later sown crops. BYDV was not reported as a major problem in the western
districts in 2003 and the symptoms of the disease were not observed in the trial at Hamilton. While there was a slight increase in yield where insecticide was applied on the plots it did not relate to a significant difference between any of the insecticidal treatments. The only significant differences were between the two varieties.