Wheat Diseases and Pests - Wheat Doctor - CIMMYT

Downy Mildew
Sclerophthora rnacrospora (Sclerospora rnacrospora)
Symptoms: Diseased plants tiller profusely; they
have short, erect, irregular, or crooked yellowish-
green culms; and the leaves are thick, erect, and
usually in whorls (35). Tillers die prematurely or
never head. If formed, the heads may be
branched, and some of the floral tissues grow into
leaflike structures (36).
Development: The disease in cereals is generally
associated with water-logged or excessively
irrigated fields. Development is enhanced if
temperatures range between lo0 and 25OC.
Infection may be initiated by inoculum in the soil,
or from diseased weed hosts, and water must be
present for infection to occur. Symptoms are most
obvious during the tilleringlstem elongation growth
stages of the host plant.
HostslDistribution: The fungus has a broad host
range, including small grain cereals, maize,
sorghum, and most grasses. It may be found
wherever soils become water-logged or are poorly
drained.
Importance: Small, localized epidemics can occur
when conditions are favorable. There have been
no reports of widespread and destructive
epidemics.