Benchmarking shows less chemcials used

Benchmarking shows less chemcials used on summerfruit

SummerGreen success story

A dramatic decrease in the use of organophosphate chemical use on nectarines has been recorded in Central Otago orchards. There has been a 37 percent decrease over the last four years with a 66 percent reduction in use of all insecticides on nectarines.

A team at HortResearch have been benchmarking the Summerfruit New Zealand Inc SummerGreen integrated fruit production programme in orchards during the last few years. Summerfruit orchards in Hawke's Bay, Marlborough and Central Otago have come under scrutiny.

Jill McLaren, based at HortResearch Clyde, said that in 1999 in Central Otago only the Focus Orchard was using the programme. In the following three years there was a gradual increase in adoption of the SummerGreen programme.

"Adoption of the programme has been so great that this year I have had to warn the growers they have probably gone as far as they can with insecticide reduction without putting their quality and export markets at risk," Dr McLaren said.

"The total insecticide use in Central Otago continues to be significantly higher than Hawke's Bay or Marlborough because most of Central Otago summerfruit is being grown for export with stringent quarantine requirements. Despite this, the use of organophosphate insecticides decreased since the 1999/2000 season on all crops and in all regions due to use of pest monitoring and substitution with "softer" products," she said.

Agrichemical use, pest and disease data has been collected from summerfruit orchards in each region. Agrichemical use patterns were studied with variations between growers and regions for apricots, nectarines, peaches and cherries, and plums in Hawke's Bay.

The data is to be used to identify if and where the integrated pest management programme can be improved and to provide constructive feedback to the participants and the industry. It is also useful to document improvements in agrichemical use.

In the last season fungicide use had increased due to unusually wet weather in all three regions, and contrasted with the decline in insecticide use.

Control of bacterial diseases using copper is still necessary but research is underway to help target treatments more effectively so that the number of applications can be reduced in time.

Peter Wood, HortResearch Hawke's Bay, stated that the overuse of fungicides by several growers is a concern and placed products at risk of resistance development. He said a minority of growers place the whole industry at risk of reduced or lost fungicide effectiveness through overuse.

However, Mr Wood said he also recognised the difficulty of finding acceptable alternative for use on export crops. This is an urgent issue for the industry to address. HortResearch is currently developing natural products and naturally occurring micro-organisms as biological control agents for brown rot.

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