Dr. Phyto

Common bent

Agrostis capillaris

Diseases & pests on this plant

• pink snow mouldMicrodochium nivale

  Patches of dead seedlings emerging after snowmelt, pinkish-white fluffy mycelium covering plants in cold humid mornings, surviving plants are stunted with brown crown rot.

• dollar spot (lawn disease)Clarireedia jacksonii

  Small, round, straw-coloured sunken spots about the size of a coin (2–6 cm) that can merge into larger bleached patches; individual grass blades show a light tan lesion with a darker reddish-brown band right across the leaf; in early morning dew a fine white cobwebby mycelium can be seen. Most common on fine turf in warm days with cool dewy nights.

• red thread (lawn disease)Laetisaria fuciformis

  Irregular patches of bleached, straw-pink grass from a few cm to ~25 cm across; close up, tiny coral-pink to red gelatinous threads and branching needles bind the dead leaf tips together — the diagnostic sign; in damp weather a faint pink cotton-wool web may show. Grass is killed only at the leaf, not the root, so the lawn recovers.

• Take-all patchGaeumannomyces avenae

  Roughly circular, sunken patches 5–60 cm across, at first orange-bronze then bleached straw to grey, with the worst symptoms on bentgrass. The centre often recovers and is colonised by weeds or other grasses, giving a 'frog-eye' ring. Roots are blackened, rotted and pull away easily; worst on alkaline, sandy or newly limed soils 1–3 years after establishment.

• Grey snow mould (Typhula blight)Typhula incarnata

  Circular bleached, straw-grey to silvery patches up to about 30 cm across that appear as snow melts in late winter and early spring. Leaves within the patch are matted and water-soaked, often with a greyish-white fungal felt; the diagnostic clue is tiny hard reddish-brown to dark resting bodies (sclerotia, pinhead-sized) embedded in the dead leaves and crowns. Damage is usually to the foliage only, so affected lawns commonly recover as growth resumes.

• Moss invasion (lawn)Lawn moss invasion

  Soft, low cushions of green to yellow-green moss spread between the grass plants, especially in shaded, damp, compacted or poorly drained areas and under trees. The grass thins out, the surface feels spongy, and in winter the moss can dominate large patches, often where the lawn is mown very short.

• Turf anthracnose (basal rot and foliar blight)Colletotrichum cereale

  Irregular yellow to orange-bronze patches, often most severe on annual meadow-grass (Poa annua) under stress. Foliar blight shows reddish-brown blighting of leaves; the more damaging basal rot blackens and rots the crown and stem base so plants pull out easily. With a hand lens you can see tiny black fruiting bodies bearing stiff black hairs (setae) on dead tissue. Worst in summer on low-nitrogen, drought-stressed, compacted or close-mown turf.

• leatherjackets (crane fly larvae)Tipula paludosa

  Yellowing, thinning and dead patches of lawn that lift easily because the roots have been eaten; greyish-brown, legless, tough-skinned grubs up to ~3 cm ("leatherjackets") are found in the top few cm of soil when you lift a patch; birds, badgers or foxes tear up the turf to feed on them; damage peaks in spring as overwintered larvae feed.

• Drought dormancy (lawn)Lawn drought dormancy

  Large, irregular areas of the lawn turn uniformly straw-yellow to tan during hot, dry spells, usually starting on the sunniest, most exposed parts and over sandy or shallow soil. Footprints stay visibly pressed in (loss of springiness), but the crowns at the base of the plants remain alive and the grass greens up again after rain.

• Fairy ringMarasmius oreades

  Arcs or complete rings, from under a metre to many metres across, of dark-green, fast-growing grass, often with a band of dead or thinned turf just inside, and small tan mushrooms appearing after rain. In dry weather the ring zone becomes hydrophobic (water-repellent) so the grass there wilts and browns even when surrounding turf is green; a mushroom smell and white fungal threads are found in the thatch and soil.