Throughout history mankind has grappled weighty issues: Hurst or Greaves, Stork or butter, Kylie or Danni Minogue and, in the field of integrated crop management, friend or foe? Natural enemies are on your side, so how can you pick the goodies from the baddies?

Dr Steve Ellis, (right) an entomologist with ADAS says there is help out there.

Agri-environment schemes are encouraging farmers to increase the diversity of invertebrate life in their crops.

This could be advantageous - encouraging parasites and predatory insects, but also disadvantageous - encouraging pests.

Achieving the right balance between pests and their predators/parasites is important, so it is vital to differentiate friends from foes. Contacts with farmers and agronomists suggest there is a lot of interest in this but while they are relatively skilled at identifying foes, they have less experience of identifying friends.

With this in mind, ADAS, supported by the Home Grown Cereals Authority (HGCA), has developed "Who goes there, friend or foe?" a demonstration designed to help farmers avoid friendly fire in their crops. Natural enemies provide valuable and free pest control, so improved awareness of the potential benefits of parasitic/predatory insects could mean less reliance on pesticides and reduced costs.

For example, parasitic wasps, hoverfly larvae and ladybird and lacewing adults and larvae all kill aphids.

Hoverfly larvae, lacewings and ladybirds are all predatory and simply eat their prey while parasitic wasps lay an egg inside a live aphid which hatches into a larva that effectively consumes its prey from the inside.

While it is unrealistic to expect these insects to keep crops free of pests, less pesticide may be needed to reduce numbers below damaging levels.

Improved understanding of natural enemies will also help in the development of integrated crop management. An aim of this is to minimise the impact of pesticides on non-target species and improve biodiversity.

An awareness of what beneficials are present in the crop and how they may be affecting pest populations will enable farmers to make rational and informed decisions on the need for pesticide use.

"Who goes there friend or foe?"has been held at ADAS open days at Rosemaund, Defra's research centre in Preston Wynne, and elsewhere in the UK.

Live and dead specimens of a range of beneficial insects were on view and a short quiz enabled farmers to test their knowledge.

Feedback was also sought on the level of interest in beneficial insects.

This is being analysed to determine how best to address future farmer needs.

For further information on events and open days at ADAS, call 01432 820444