Black Bent [Agrostis gigantea]

Pest Profile

About the pest

Description

It is a loosely tufted perennial grass that can grow to a height of 40 - 120cm. It has tough creeping rhizomes.

Key features

Plant: The leaves are dull, green and hairless; the blades are flat, broad and taper to a point; the sheaths are rounded and smooth.

Flowers: The large green or purplish flowerheads are upright, oval and usually open, with many branches carrying singleflowered spikelets.

Biology

Black bent can develop into dense patches which are often a problem in fields that are frequently irrigated and where weather is cool. The plants can reproduce vegetatively from fragments of rhizome.

Symptoms & Diagnosis

Life Cycle

Seed longevity: >5 years

Seed weight: 0.067 mg

Treatment

Management

Spring cropping reduces vigour. When cultivating, beware of breaking the rhizomes as black bent can root from every broken node. Glyphosate used in summer on uncropped land or pre-harvest in early harvested crops controls rhizomes. Some residual herbicides may affect the seedlings.