Growing Futures

Using sex to protect export markets

Using sex to protect export markets

Mating disruption technologies use pheromones to confuse insect pests, reducing the need for pesticide controls that may leave residues on fruits

Effective control of pests and diseases costs the New Zealand pipfruit industry around $23 million each year, but preserves market access for $360 million of apple exports. Not only do destination countries have strict phytosanitary requirements, but both governments and supermarkets are also putting added emphasis on limiting the use of chemical pesticides and reducing residues on produce.

Fighting nature with nature

Sex pheromones, the natural chemicals released by the females of many insect species to attract mates, can be used to disrupt communication between insects, reducing their ability to identify mates and subsequently leading to a reduction in the population and reduced reliance on chemical controls.

Mating disruption is used to control four apple pests in New Zealand; codling moth and three leafroller species - light brown apple moth, brownheaded and greenheaded leafrollers. Scientists have identified and isolated pheromones from these four species and developed methods for artificially synthesising these in the laboratory. These synthetic pheromones have been blended for use in a combination dispenser in apple orchards to disrupt the mating of all four species simultaneously. Growers can apply 800 dispensers per hectare in the spring and the pheromones will suppress mating in all four species for up to six months. The combination ISOMATE®4Play dispenser, developed by Plant & Food Research for manufacture by Shin-Etsu Fine Chemicals (Japan) and marketed by Etec Crop Solutions Ltd, is now used on the majority of the 2,000 hectares of New Zealand’s apple orchards employing mating disruption technologies.

Benefits for growers

Prior to mating disruption technologies, growers would use a combination of sprays for leafrollers and codling moth. The introduction of ISOMATE® CM Plus dispensers for codling moth control in 2005 reduced insecticide use in orchards by two to four applications per season. The later introduction in2007 of ISOMATE®3NZLR, a pheromone dispenser that disrupted mating of the three leafroller species, further reduced insecticide use for leafroller control by up to two applications each year. With the use of ISOMATE®4Play insecticide use for both codling moth and leafroller control has been minimised. Excellent control of both pests has been achieved on many orchards using ISOMATE®4Play dispensers with just one or two insecticide applications each season. Currently, around 30% of the New Zealand pipfruit industry are using a mating disruption system, resulting in a total saving on pesticide costs of around $670,000 per year. This also reduces the pesticide load in the environment.

Further economic benefits can be gained with the use of mating disruption. Fruit with little risk of codling moth contamination and ultra-low residues are acceptable to all markets, even those with the strictest requirements. Using mating disruption technologies, the industry can develop an uncompromised global marketing plan, transporting different sizes or grades of fruit to the most valuable markets with the knowledge that all market requirements are met. The total benefit is estimated at up to $28,000 per hectare for growers with a high proportion of crop targeted to premium markets.

The research was funded through the Sustainable Farming Fund with matching investment from the New Zealand pipfruit sector.

Created: September 2012

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