Pest control, whether this be plant or animal pests, represents a significant on-going cost for most farmers. In the bad old days when chemical control agents for pests were limited in their application and selectivity there was a general 'scorched earth' approach that killed all organisms present, both beneficial and pests, in one swoop.
Chemical control agents have come a long way in the last 30 years with much more selectivity by the products on sale. Targeting just the pest while leaving the rest of the ecological system intact has obvious long-term environmental and productivity benefits.
As an alternative to the more traditional chemical control agents for pests the development of appropriate biological control agents for key agricultural pests in New Zealand is becoming more common place.
Put simply a biological control agent is when one organism is used to control another. The beauty of such a system is that once established, pest control of the target organism continues as long as the population of the control agent is maintained. Such control is extremely selective.
Control of the clover root weevil is an excellent example of the development and use of a biological control agent for New Zealand. Introduced accidentally in the 1990s it devastated our clover pastures in many areas of New Zealand. In order to control the clover root weevil a tiny parasitic wasp from Ireland has been introduced and is making a significant contribution to the control of this pasture pest.
