Diseases

Helminthosporium leaf spot of perennial ryegrass

Lolium perenne L.

A complex of fungal diseases affecting the foliage and root system of perennial ryegrass, caused by pathogens of the genera Drechslera and Bipolaris. The disease is characterized by the appearance of spots leading to premature leaf senescence and thinning of the grass stand.

In the reference 17 varieties crop Perennial ryegrass, where this is mentioned in the description.

The primary pathogens of the disease in perennial ryegrass are Drechslera dictyoides, including the specialized form f. sp. perenne, Drechslera siccans, Drechslera andersenii, and Bipolaris sorokiniana. The infection develops actively under conditions of high humidity and moderate temperatures during the spring and autumn periods.

The clinical presentation manifests as watery spots that turn dark brown with a net-like pattern, often surrounded by a chlorotic halo. Severe infection leads to the coalescing of spots, necrosis of leaf blades, and damage to the stem bases and roots, which causes the 'thinning out' effect of the sward.

Resistance of perennial ryegrass to this complex of pathogens is a quantitative trait controlled polygenically. No specific resistance genes have been identified in this crop, therefore breeding efforts are focused on selecting varieties with increased tolerance to natural and artificial inoculation.

General information about the subject — on the page Helminthosporiosis.

Sources8

Varieties of Perennial ryegrass mentioned in the description

Selection based on the description text, not on official evaluation: these data are absent from registers. For specific variety details, please refer to its profile.