Weed & Pest Control in Newly Sown Leys

Sward Destruction

• It should be viewed as good management practice to destroy the old sward with glyphosate prior to re-seeding. This operation allows the effective control of perennial grass and broad-leaved weeds such as Couch and Docks.
• To ensure adequate weed control is achieved it is important to apply the correct dose of glyphosate under appropriate conditions. Various formulations of glyphosate are available but in general terms the more advanced formulations such as Envision will give better control of perennial weed species.

Pest Control

• Both Leatherjackets & Frit Fly can be very damaging when a newly sown ley follows a previous grass crop.
• Leatherjackets are the larva of Crane Flies (Daddy Longlegs).
• They are soil inhabiting, up to 5cm in length with thick grey-brown skin and feed on the roots and stems of grass plants at or below ground level.
• Leatherjacket damage to new leys can be devastating, re-seeds may be completely destroyed.
• Frit Fly larvae are creamy-white in colour and about 5mm in length.
• Following egg hatch the larvae tunnel into the centre of grass plants causing dead-hearts and tiller death.
• Control of both these pests can be effectively achieved using Dursban WG and treatment should be seriously considered in high risk situations. Dursban WG is residual and may be tank mixed with the glyphosate used for sward destruction.

Weed Control

• Weed control in a newly sown ley is usually necessary to ensure good establishment and to avoid a gappy sward.
• Control of seedling docks is very effective before they have become established and a good kill at this stage will greatly reduce a dock problem.
• Product choice is decided by the presence or absence of clover in the new ley.
• Clover-safe herbicides include products such as Alistell, Squire and MCPB+MCPA.
• If clover is not important then the choice of product widens considerably and an herbicide should be selected according to the weed spectrum to be controlled.
• If the field to be re-seeded is known to have a weed problem, by omitting clover from the seed mixture the weeds can be more cheaply and more effectively controlled using a broad-spectrum herbicide. Once the new ley has been tidied up it is possible to introduce clover at a later date.

Advice and recommendations for pest and weed control are available from the Wynnstay Agronomists or from Dr Simon Pope, Arable sales Manager.
Tel 01939 210555