Pest control in cropping systems has changed remarkably in the last twenty years, as many farmers have adopted more environmentally aware practices.

In the past controls were initiated at the sight of any insect infestation; now we are conscious of the significant roles that beneficials play in maintaining the balance of nature in fields.

Farmers now need to be aware of the roles that the variety of arthropods that we may see in crops play.

Of the thousands of insect species we see in nature, only about one per cent are pests, so the vast majority are beneficials, or just part of the natural ecosystem.

Monitoring crops for pests and beneficials, is the key to successful management, as control measures only need be taken when pests reach the point of causing economic damage.

Scouting crops regularly and recording pest and beneficial occurrence, will show when the economic thresholds have been reached.

Much scientific research has been aimed at identifying these levels, so that control measures are not wasted, and the damage is limited.

A wide range of alternative pest management practises can be effectively incorporated in conventional farming systems.

Many of these favour the maintenance of a biodiverse system that considers a whole farm, or even an area wide plan.

Strip cropping, perennial plantings, maintaining healthy soils by minimum tillage, smaller fields surrounded by natural vegetation, growing multiple crops in the one field, diverse crop rotation, using trap crops and keeping crops healthy with adequate nutrients are part of a new system of 'ecological engineering' for cropping systems.

This encourages the wide range of non pests to interact with the crops, mimicking nature.

Chemicals need to be used at critical times in these systems, but with the effect on the whole system in mind.

Using a broad spectrum chemical early in the season can disrupt the balance for the rest of the season, so care needs to be taken to select appropriate chemicals.

Some sprays may be used to attract beneficials, or to repel pests.

Some of these practices have been used for centuries of crop production, but are only now being recognised again as prudent practice.

An interesting read is Ecological Engineering for Pest Management – Advances in Habitat Manipulation for Arthropods (Gurr, Wratten & Altieri) which details some practical pest management technologies that have being shown to fit into mainstream agricultural systems.

This column appears in Agriculture Today.