Biological control agents

Science programme: Applied entomology

Biological control (or biocontrol) is the "control or regulation of pest populations by natural enemies". Successful biocontrol operates at the population level, not the individual level, so biocontrol agents (species) must be able to regulate populations of a pest, rather than just eating them when they are common. Biocontrol is applied population ecology, and successful biocontrol requires detailed understanding of species interactions across three or four trophic levels:

• The plant the pest feeds on
• The pest
• The biocontrol agent
• The natural enemies of the biocontrol agent.

Most natural enemies are either parasitoids (insects that develop within or on other insects) or predators, but biocontrol agents can include specialised fungi or viruses (called entomopathogens) that kill insects.

Plant feeding insects, and the insects that attack them, comprise about 35 percent of all terrestrial life forms. In the widest environment, population regulation of phytophagous insects is critical to the survival of all life. In New Zealand’s fruit-growing industries, biocontrol is an integral part of Integrated Fruit Production and sustainable development.

Entomologists in the bioprotection team have a broad range of scientific and practical skills in biological control, including:

• Importation and release of new natural enemies
• Practical knowledge and understanding of the Biosecurity Act and the Hazardous Substances And New Organisms Act (HSNO) 
• Insect rearing
• Measuring the impacts of natural enemies
• Population ecology
• Bi- and tri- trophic interactions
• Evolutionary ecology
• Application of biocontrol to grower pest management programmes.