Diseases

Rhizoctonia blight — Perennial ryegrass

Lolium perenne L.

A fungal disease of perennial ryegrass caused by Rhizoctonia solani and R. cerealis, manifesting as brown or yellowish patches on the turf. The pathogens infect stems and roots, although the growing point usually remains viable.

In the reference 7 varieties crop Perennial ryegrass, where this is mentioned in the description.

The causal agent of brown patch is Rhizoctonia solani, which manifests as light brown or reddish-brown patches, sometimes with a characteristic “smoke ring” on the periphery under high humidity. The disease caused by Rhizoctonia cerealis is known as “yellow patch” and appears as yellowish lesions in the form of bands or ribbons.

Patches on perennial ryegrass swards can reach from 5 to 100 cm in diameter. Pathogens exhibit activity depending on temperature regimes: R. solani progresses at temperatures above 25°C, while R. cerealis is most active in the 10–20°C range. The infection usually does not affect the growing point or the crown, which limits turf mortality.

There is no specific race classification for these pathogens suitable for variety testing. The resistance of ryegrass to this fungal complex is quantitative in nature, and specific resistance genes have not yet been identified.

General information about the subject — on the page Rhizoctonia.

Sources4

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.