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		Ministry of Agriculture and Forestry Te Manatu Ahuwhenua, Ngaherehere

Issue 6 March 2001

From the Editor Recent MAF forecasts have projected horticultural export values to rise 27 percent from $1.76 billion for the year ended March 2000 to $2.23 billion for the year ending March 2005, mainly due to growth in processed fruit (mainly wine) and kiwifruit. The theme of this issue of RM Update is sustainable horticulture as a land use, and some of the challenges facing this sector. We export our horticultural products to countries that have their own strict controls with which we have to comply. These controls are designed as biosecurity and food safety measures. In addition, many consumers and supermarket chains are demanding assurances of the safety and environmental integrity of our production systems. Many of the articles in this issue highlight the importance of horticultural production systems being designed to minimise chemical residues. Integrated Fruit Production and Integrated Pest Management practices are extensively used in this sector, with careful monitoring and trace-back systems providing overall quality and safety assurances to overseas customers. I am sure you will find this issue informative. John Vaney Editor

 

In this Issue:

Integrated Winegrape Production Scheme Frost Protection – Resource Consents for Wind Machines Methyl Bromide - the Alternatives for Horticulture No-Tillage for Sustainability Alternatives Needed for Agrichemical Container Disposal Hawkes Bay Focus Orchard Raises Awareness of Sustainable Management Franklin Sustainability Project News Brief Sustainable Resource Use Policy Studies PDF Version of this document

The Greening of the Kiwifruit Industry

The following article prepared by Sandy Scarrow presents a case study on the use of sprays to control pests and diseases in the kiwifruit industry. Sandy outlines the successf implementation of a spray programme with a focus on food safety and the implementation of a programme that integrates environmental imperatives.

Historical Perspective

In 1992 ZESPRI International Ltd (ZIL, the marketing company of the New Zealand Kiwifruit Marketing Board) introduced a new mode of kiwifruit production to the growing systems in New Zealand. This production method required caref monitoring of pest levels and the use of "soft" pesticides to control pests present on the orchard with the overall aim of reducing residues in kiwifruit. This programme, largely developed by HortResearch entomology scientists, is named KiwiGreen.

The aims of KiwiGreen are to:

• retain market access; provide "reverse transparency" to ZIL clients;
• reduce the conflict that exists between rural dwellers with respect to the use of chemicals;
• show the kiwifruit industry to be environmentally responsible;
• and replace the calendar spraying system (i.e. spray only where proven need is shown).

To support growers through the process, the kiwifruit industry developed monitoring systems to be followed. Most of the post-harvest service providers offered a pest monitoring service to their kiwifruit grower clients. These Pest Monitoring Centres (PMCs) conduct the on-orchard monitoring and provide recommendations to the growers regarding appropriate corrective action to take. The cost of this monitoring was subsidised, on a reducing basis, by ZIL as an incentive to get growers involved in the scheme. The fl cost of this monitoring is now met by the grower or provided as a part of the service contract by their post-harvest operator. ZIL continues to provide a freephone advice line to enable growers or PMCs to discuss their specific pest and disease problems or emerging issues.

Figure 1 shows the trend in the conversion from conventional kiwifruit production to KiwiGreen and organic production.

Figure 1 The Trend in Conversion from Conventional Kiwifruit Production to KiwiGreen and Organic Production

The progressive conversion to either organics or KiwiGreen saw a marked decrease in the use of organophosphates and synthetic pyrethroids in kiwifruit orchards. Softer sprays (e.g. Bts and mineral oils), particarly in the later part of the season, are used to a greater degree, if a spray is used at all following the two critical sprays after flowering. The pre-harvest fungicides are no longer applied. The fungal disease that this used to control is now controlled using ctural practices. Prior to KiwiGreen implementation, it was common for orchardists to apply up to nine post-flowering sprays. It is now common for only two applications of the soft products to be used after flowering.

KiwiGreen Developments

By 1997 all kiwifruit exported by ZIL was grown under either the KiwiGreen or organic production systems. Since then work has been undertaken (partly funded by ZIL, New Zealand Fruitgrowers’ Federation Charitable Trust, MAF Policy and the Ministry for the Environment’s "Sustainable Management Fund") to develop an Environmental Management System for the production of kiwifruit, named the KiwiGreen 2000 On-Orchard Code of Practice. This programme aims to broaden KiwiGreen to incorporate the use of other orchard applications (e.g. herbicides and budburst enhancers), fertility management, ground cover management, water management and waste management. The aim of the programme has been to consider all aspects of environmental impact and endeavour to minimise the negatives and maximise the positives. KiwiGreen 2000 encompasses both varieties (Hayward and Hort 16A) and the two growing methods KiwiGreen and organic.

The KiwiGreen 2000 On-Orchard Code of Practice, at this stage, remains a research project. Decisions regarding its inclusion in the fl KiwiGreen 2000 — ZESPRI system have yet to be made.

Scientific Support

An example of the scientific support that operates alongside the implementation of these programmes is the development of a Disease Risk Prediction System as a management tool for Sclerotinia. This project is aimed at reducing fungicides used in kiwifruit orchards for the control of Sclerotinia.

Sclerotinia is a fungal pathogen that infects senescing (dying) floral tissue during flowering. Where this infected floral tissue adheres to young fruitlets, the fungal mycelium can blight the flower or, later in the season, attack the fruit, causing scarring that may lead to rejection for export or, at worst, cause field rot where fruit drops from the vines mid-season.

Scientists in HortResearch have been working with growers over the past five years to develop a prediction system to determine the degree of disease risk a particar block in an orchard may have. Initial work by the scientists confirmed opinion that the use of fungicides on kiwifruit orchards may not necessarily relate to the disease risk within the orchard. It was determined, from a small sample, that almost half of the orchards rated as low risk were applying fungicides for little or no benefit in 1998/99. Similarly, almost half of those rated as having a high risk of disease were choosing not to apply a fungicide.

Work undertaken has provided the growers trialling the disease prediction system with the confidence to not apply a fungicide if they have a low risk rating. That is, in years where weather conditions were conducive to fruit infection, growers with orchards who were rated as low risk and who did not apply a fungicide have not had problems with Sclerotinia infection. Further work is being done to refine ctural methods of disease control for growers with orchards considered to be in the medium and high-risk categories. The aim is to reduce further the use of fungicides and provide additional control options for organic growers.

KiwiGreen 2000 On-Orchard Pilot Programme

A pilot programme of growers, including some large corporate growers, has been operating under the KiwiGreen 2000 On-Orchard Code of Practice for this production season.

Growers involved in the pilot programme have had the opportunity to test the practicality of the KiwiGreen 2000 On-Orchard Code of Practice. They have also looked closely at all their orchard practices in an attempt to improve their environment outputs. An example of the changes made has been the incorporation of ground cover species into orchards to reduce problem weeds. This strategy has allowed growers to reduce, and in many cases eliminate, herbicide use, reduce the need to mow the orchard and in turn improve the physical and biological health of the soil.

Keys to Success

The keys to the success of the implementation and operation of KiwiGreen within the ZESPRI system and, it is hoped, the KiwiGreen 2000 On-Orchard Code of Practice are:

• strong market demand for the product;
• industry commitment;
• a single desk marketer enabling regation;
• sound scientific basis;
• grower support; and
• continued scientific and practical support in implementation.

 

Contact for Enquiries

Amber Duncalfe
Editor - RM Update
Ministry of Agriculture and Forestry
PO Box 2526
Wellington
NEW ZEALAND

Tel: +64 4 894 0710
Fax: +64 4 894 0745
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