Cephalosporium Stripe in Wheat

Cephalosporium stripe continues to be seen in many winter wheat fields in the southwest Ontario. The disease has very distinct yellow stripes that occur on the leaf blades, sheaths and stems. Over time as the tissue dies these yellow stripes will turn brown resulting in a dark band down the affected area. In severe causes two lines will develop. Often when plants are brought in by producers they refer to them as "scorched". This is a good description since the plants to have a scorched appearance especially under dry conditions. The fungus causes a vascular wilt of the plant and therefore, if you cut the nodes on infected plants the inner node tissue is brown. Examine the developing head for shriveled seed and check the low spots in the field and areas with a high clay content (which tend to be/stay wetter longer) or other stressed areas.

As is the case with many of pathogenic fungi, Cephalosporium can survive on diseased straw residue for 3 to 5 years. It is the wheat residues in the top 3 inches where the fungus survives and thus any operations that promote movement of infected straw residue back-up to the top three inches can increase disease potential. The fungus needs help in finding its way into the plant (root injury). Some common examples are frost heaving and thawing can injury roots as can root feeding insects which allow for easy movement of the fungus into the root system. The role that frost heaving plays in disease development has been used to explain why spring seeded cereals have very little Cephalosporium stripe (escape the disease).

Besides root injury there are other factors that have contributed to the problem.

1) The wet conditions late last fall and early winter which resulted in a consider amount of surface water and saturated soils. The fungus survives well under these conditions and that is one of the reasons the disease is often worse on clay soils (better water holding capacity). The cool, wet conditions this spring and early summer were ideal for the fungus to thrive and move the fungal spores to injured roots. The dry conditions that followed have increased the stress on the plants which has favoured disease development.

2) Low soil pH and organic matter favour the disease by allowing the fungus to survive longer. Check the areas with the disease for pH problems, and correct the problem if they are in the pH 4.0 to 6.0 range.

3) Reduced rotations especially a soybean-wheat rotation can increase the disease. Keep two to three years between winter cereal crops.

4) Although slight differences in varieties may exist, it is assumed that all Ontario recommended wheat varieties are susceptible to Cephalosporium stripe. Contact your seed supplier or consultant about your specific variety.

Figure 1. Cephalosporium symptoms

Figure 2. Cephalosporium wheat closeup

Figure 3. Cephalosporium infected plants

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