Weed management policy

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9.2 Research programmes

Auckland City's existing herbicide policy, ie. that herbicides should be used only where there are no practical alternatives, and the proposed principles of weed management consistent with this policy, require that on-going improvement be made in the methods used for controlling weeds. This improvement should revolve around decreasing adverse effects on the environment and human health, decreasing monetary costs, increasing efficacy, and the long-term sustainability of methods.

9.2.1 Research priorities

Research should be prioritised as follows:

1. There are no practical methods currently available for controlling a particular weed, or weed/site combination, where a priority for control has been identified.
2. The only currently available practical control methods are chemical; chemicals are used on an on-going basis.
3. The only currently available practical control methods are chemicals; but chemicals are needed only on a short-term basis, to establish sustainable non-chemical management.
4. Non-chemical methods are practical, but they have high monetary cost, and/or are not sufficiently effective.

Other criteria to consider when identifying research priorities:

• the selection of priority weeds, as per Section 7;
• opportunity for long-term sustainable control with little or no on-going input from Auckland City (for example biological control).

9.2.1.1. Particular areas requiring researching:

1. Non-herbicide methods, or failing this, lower hazardous herbicides for the following species which are difficult to control:

Red cestrum Field bindweed Wandering Jew

Green cestrum Giant bindweed Periwinkle

2. Non-herbicide control methods for the following weed species which are abundant in Auckland City and many of which currently require considerable herbicide use to achieve adequate levels of control:

African club moss Apple of Sodom Banana passionfruit Blue morning glory Elaeagnus Maderia vine/mignonette Montbretia Three-corned garlic (onion weed) Wild gladioli

Agapanthus Asparagus species (including smilax) Blackberry Climbing dock Japanese honeysuckle Mile-a-minute Stinking iris Watsonia

3. Determining effective and low toxicity stump paint herbicides, including information on the toxicity and effects of the stump paint 'mix' of Escort and glyphosate.
4. Improving turf management methods and the identification of new 'low maintenance' turf species suitable for Auckland sports fields.
5. Researching ways of controlling weeds around street trees without the on-going need for herbicide spray. This will include the position of street trees on berms, types of street trees, mowing techniques, and the use of mulch, weed mat and plastic tree surrounds.
6. Trialing non-herbicide methods to control weeds on berms and footpaths to assess their effectiveness in meeting standards of presentation required at a reasonable cost and with minimal adverse environmental effects. This will include assessing the effectiveness of straight concrete edges behind bluestone kerbing in minimising weed invasion onto kerbs.

9.2.2 Types of research

There are three levels on which continuing research into improved weed management can be undertaken:

• literature searches
• practical trials
• innovative research.

These three levels of research are not mutually exclusive; in fact all research should begin with the literature search for existing information.

9.2.2.1 Literature searches

With the international drive for herbicide use reduction that has been underway in some countries for the last ten years, there is a burgeoning literature on non-chemical and reduced chemical methods of management. Particular attention is being paid to urban vegetation management in the United States and in Britain. It is important that Auckland City staff scan these developments for new methods that may be appropriate for use in Auckland, particularly in the arena of passive and sports turf management.

However, given the nature of Auckland's climate and its particular suite of weeds, it is unlikely that Auckland City's weed control needs can all be met by this method. It should not be expected that overseas research is going to provide all, or even the majority of the solutions to Auckland's problems, particularly in dealing with weeds in natural areas.

9.2.2.2 Practical trials

Practical trialing of innovative weed management techniques is already carried out by some Auckland City staff to great effect. Examples of this include the non-chemical management of Michaels Park Reserve, and a range of approaches to revegetation of privet-dominant areas in the Orakei Basin.

This approach is likely to be the most productive in areas such as turf management and berm maintenance (for example, the trialing of mechanical techniques). It may involve application of approaches developed overseas, or it may involve ongoing development of Auckland specific methods. Council staff should be encouraged to continue to undertake appropriate trialing of improved techniques.

9.2.2.3 Innovative research

This would include such things as searching for biological controls for problem weeds. Such research is very expensive and long-term, and not appropriate for Auckland City to undertake on its own. However it is the type of research on which Auckland could collaborate with, for example, Landcare, HortResearch, and/or Auckland University. Auckland City's role is envisaged as being principally that of funding assistance to science providers for research that is regarded as a priority under the Weed Management Policy. Joint research programmes between Auckland City and other Territorial Authorities in the Region, government departments, research agencies and the private sector will share the costs of investigating the effectiveness of new weed and vegetation control technology applicable to the Auckland Region. The Ministry for the Environment's Sustainable Land Management Fund may also be of assistance, as may the Ministry of Research, Science and Technology's Public Good Science Fund.

Reviewed - October 2006