DISEASES OF SMALL GRAINS - SEPTORIA LEAF BLOTCH

Lesions may eventually cover a large portion of the leaf surface, and in some instances the entire leaf may be killed. Symptoms of Septoria leaf blotch can often be mistaken for those of other foliar diseases. Observation of fruiting bodies of the causal fungus in the diseased tissue is considered diagnostic.

Partial control of Septoria leaf blotch may be possible through use of resistant wheat varieties. However, complete control is usually not possible, because “resistant” varieties are not resistant to all Septoria spp. that cause the disease. Other methods of control include the use of pathogen-free seed, and the removal of infested wheat debris. No-till production methods tend to favor the disease because substantial amounts of wheat stubble are present that can serve as an inoculum source. A rotation away from wheat for two or more years allows time for debris decay and reduction of inoculum levels, and can help in reducing disease severity. Wider row spacing may also help reduce disease by reducing favorable high humidity conditions.