Shepherd's Needle [Scandix pecten-veneris]

Pest profile

About the pest

About the weed

It is a short, almost hairless annual, growing up to 30cm tall, with finely divided and subdivided leaves. When supported by the crop it may grow to 60cm. The flowerheads are groups of up to ten tiny white four-petalled flowers.

Key features

Young plant: The cotyledons are pointed and very long.

Flowers: As the fruits mature and extend, the flowers appear to be on top of ‘needles’.

Biology

Shepherd’s-needle is highly competitive in spring cereal crops and open crops of winter wheat, even when high levels of nitrogen are applied. It has re-appeared in some areas of the country in the last few years, preferring light soils. It can reduce combine efficiency when the stems and long seeds can become trapped. Shepherd’s needle reproduces only by seed. Seeds are dispersed mechanically from the parent plant and can also hook onto hair or clothing.

Symptoms & Diagnosis

Life cycle

Seed longevity: <1 year

Seed weight: 20 mg

Treatment

Management

The reappearance of shepherd’s-needle in cereals may be due to the reduction in the use of 2, 4-D and MCPA at high doses, but combinations of sulfonylureas with contact herbicides and hormones can be effective.