Leaf rust (wheat)
Leaf rust appears as small circular to oval brown pustules on the upper surface of the leaf. These pustules are scattered across the leaves randomly. Spores develop on the leaves and leaf sheaths, they do not form on the upper stem or heads of wheat plants.
Leaf rust survives over summer on green host plants such as volunteer wheat and barley. It cannot survive on stubble. Moist conditions promote the development of the disease. Early sown crops, especially when the weather is still warm, are at the greatest risk.
Under favourable environmental conditions, rust spores germinate and penetrate the wheat leaf. The fungus obtains nutrients from the leaf, and within a week to 10 days, the fungus produces more spores, which erupt through the leaf surface. These newly produced spores are wind-blown to other wheat leaves or fields, onto later sown crops, and at the end of the season, onto the over-summering hosts.
- Treat seed with a recommended seed treatment, especially where the disease can survive over summer i.e. in areas experiencing summer rainfall and irrigation zones (Quantum Pro)
- Sow resistant varieties of wheat
- Control volunteer wheat and other hosts over summer