Cephalosporium Stripe

Washington State University bulletin

SP0004 -- 1993

Diseases of Washington Crops.

Otis C. Maloy and Debra Ann Inglis

 

Small Grains Home * Wheat Diseases * Barley Diseases

Cause

Hosts

Symptoms and Signs

Disease Cycle

Control

1997 PNW Pesticide

Recommendations

Another Picture

Other Interesting Cephalosporium Stripe sites

Cephalosporium stripe or fungus leaf stripe is a disease of winter cereals that is sporadic in its distribution and occurrence but can cause severe yield losses when it occurs. A major disease in Washington in the 1950s when 'Brevor' was widely planted, it subsided in importance with the development of 'Gaines' and 'Nugaines.' Now the disease is a problem again because of repeated planting of certain high yielding but susceptible cultivars. The disease is found most consistently in areas of eastern Washington where frost heaving, resulting from fluctuating winter temperatures, heavier soils, and higher soil moisture, damages roots.

Cause
Cephalosporium stripe is caused by Hymenula cerealis (synonym Cephalosporium gramineum). This fungus is slow growing in culture and probably in nature too. It produces tiny conidia on sporodochia in the saprophytic stage on wheat straw, but as a parasite it invades the vascular system, where it interferes with water movement. It is the only true vascular parasite known to attack wheat.

Hosts
Cephalosporium gramineum attacks most winter cereals but especially winter wheat. It invades several grasses (Bromus, Dactylis, Poa) and probably was indigenous to the region in native grasses.

Symptoms and Signs
Cephalosporium stripe is first observed in the spring as distinct yellow stripes on leaf blades, sheaths and stems. The stripes may contain thin, brown streaks (necrotic vascular tissues) surrounded by yellow. Frequently, a yellow stripe on the leaf blade continues as a single brown line down the leaf sheath (Photo 15). Nodes are darker than normal on diseased plants, and when cut lengthwise, the inner nodal tissue is brown in color. Plants are stunted and the heads are white and sterile. If any seed is set, it is usually shriveled. Diseased plants have a scorched appearance when hot weather accentuates moisture stress.

Disease Cycle
The fungus survives for as long as 4 to 5 years in undecomposed infested straw. Survival is enhanced by fungal production of antibiotic substances. Conidia, the primary inoculum, are produced on infested plant debris. The fungus enters wheat plants through wounds. Circumstantial evidence, such as escape from infection by spring-seeded cereals, suggests that roots broken by frost heaving constitute an important means of entry. The fungus then grows into and develops in the vascular system, where it can extend for several internodes up the stem. Heavy, wet soils and soils low in pH favor incidence of Cephalosporium.

Control
Cultural. Early seeding produces a more extensive root system going into the winter, and larger root systems are more likely to be damaged when the soil moves during heaving. Delayed seeding results in plants with a smaller root system less prone to such damage, but smaller plants are less winter-hardy and cover less soil for erosion prevention.
Minimum tillage leaves more infested straw on the soil surface, thus delaying straw decomposition and slowing inoculum destruction. Destroying straw by burning or by deep plowing (Table 5) reduces the amount of inoculum, but both practices run counter to soil conservation concerns. Studies in Kansas have shown that lime applied to low-pH soil reduces Cephalosporium stripe incidence. In Washington, recent disease outbreaks in previously unaffected dry areas are believed to be partly the result of a decline in soil pH due to continual use of ammonium-based fertilizers and the planting of susceptible cultivars.

Table 5. Effect of residue management on the incidence of Cephalosporium stripe in Kansas. Adapted from Bockus, W. W., J.P. O'Conner, and P.J. Raymond. 1983. Plant Disease 67:1323-1324.

*It should be noted that in the cited text there was no apparent significant difference in yield among these treatments.

In areas where Cephalosporium stripe is a consistent problem, rotation out of winter grain for at least 3 years-2 full years between winter grain-must be practiced for adequate control. Grow either legumes or spring grains instead. If spring barley is planted, do not allow volunteers to go through the winter, since the fungus can carry through on the barley (or other grass) without producing visible symptoms.

Resistance. In addition to rotating crops, growers need to plant tolerant cultivars (Table 6). 'Nugaines,' Luke,' and 'Lewjain' are the most tolerant of the commercial cultivars now available, in part because they have a high tillering capacity; some tillers can escape infection even though several stems may be infected. Avoid susceptible cultivars where the disease is a problem. 'Stephens' is among the most susceptible along with 'Hyslop' and 'McDermid.'

Table 6. Relative tolerance of major Washington wheat varieties to Cephalosporium stripe.* From the annual Winter Wheat Seed Buying Guide of the Washington State Crop Improvement Association.

*Only those varieties likely to be grown in areas where Cephalosporium stripe is common are included in this comparison.
** The index value is based on empirical observations of test plots established throughout eastern Washington. 1 = low tolerance (very poor); 5 = medium; 10 = high tolerance (good);-data not available.

References
Bruehl, G.W., T.D. Murray and R.E. Allan. 1986. Resistance of winter wheats to Cephalosporium stripe in the field. Plant Disease 70:314-316.
Love, C.S., and G.W. Bruehl. 1987. Effect of soil pH on Cephalosporium stripe in wheat. Plant Disease 71: 727-731.

Other Interesting Cephalosporium Stripe sites:
The University of Nebraska-Lincoln NebGuide describes the symptoms and causes of this disease, which can seriously reduce yields, and provides methods for its control.