Peronospora manshurica

Fungal Disease

Peronospora manshurica

Fungal Disease

Peronospora manshurica

Fungal Disease

Peronospora manshurica

Fungal Disease

Not all trifoliate leaves show symptoms. Infected leaves may appear mottled and grey-green with curled down edges. Prolific conidiophore production can occur on the undersurface of leaves.

Small, discrete, pale to bright yellow spots (2-8 mm diameter) are formed on the upper leaf surface. The size of the spots may vary, and more than one race of the pathogen may be present (Miller, 1953). In a heavy infection, leaves with the entire area affected may shrivel and die (Francis, 1981).Conidiophores form a greyish-purple down on the lower leaf surface beneath the spots. Pods can become infected without showing external symptoms, and the seeds invaded. Oospores develop on the seed surface and appear as a milky-white crust consisting of a mass of the hyaline spherical resting spores (Francis, 1981).