Beneficials on farmland: identification and management guidelines (HGCA Summer 2008)

Introduction

For the farmer, insects and other invertebrates fall into two main groups: pests and beneficials. It is important to distinguish between these as beneficials control pests naturally, pollinate crops and help to maintain soil fertility.

Identification

Beneficials can be classed as:

  • pest predators which, as adults or larvae, eat pests
  • pest parasites (parasitoids) that live within the pest
  • pollinators which are important for yields of crops such as oilseed rape
  • detritivores which help break down organic matter.

The few pests that occur only pose threats to crops when adverse weather or management reduces beneficial numbers, or when conditions especially encourage the pest.

Populations of many beneficial species such as bumble bees, butterflies, moths found in noncrop and arable crop habitats have declined in recent decades.

This guide aims to help farmers and advisers identify some key beneficials, especially predators and parasites.

Note: the scales (pages 312) indicate actual sizes of organisms and do not relate to the proportions of the photographs.

Managing habitats

To encourage beneficials, four criteria need to be met:

  • Shelter
  • Alternative prey
  • Flower-rich habitat
  • Environment

Many non-crop habitats, including those produced by Entry Level and Higher Level Stewardship schemes, can support substantial populations of beneficials.

Appropriate management will encourage beneficial populations within crops. Adopting Integrated Pest Management (IPM) principles will ensure that insecticide inputs are only applied when necessary, helping to reduce spray costs and prevent insecticide resistance developing.

This guide outlines the 'SAFE' principles and describes their practical use. It provides key management options within and off-crop to encourage build-up of beneficial populations and help reverse recent declines.

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