Key Points
- Common rust can cause yield loss in maize crops, particularly if early infection occurs on larger leaves.
- Until recently, there were no fungicides are registered in NZ for rust control on maize. Amistar SC has recently been registered. Rust resistant hybrids are widely used.
- FAR funded trials have shown that Comet (strobilurin) and Opus (triazole) increased yield of both susceptible and more resistant maize hybrids when applied at growth stage V15 (15 leaves late whorl) to VT (Tassel emergence).
- Comet and Opus are NOT registered for use on Maize.
- Growers should monitor crops to enable prompt action, and observe with-holding periods and Maximum Residue Limits (MRL‟s) if using fungicides off-label.