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Broken Borders

Words by Nick Pyke, FAR

21 February 2017

Summary

  • There are a number of biosecurity risks to cropping growers in New Zealand which need to be effectively managed.
  • In 2015/16 three incursions, velvetleaf, pea weevil and black grass, have impacted on cropping farmers, requiring significant input from the industry.
  • In future some aspects of biosecurity in New Zealand will be managed through a partnership between government and industry (GIA). The cropping industry plan to be part of GIA.
  • Biosecurity is important at the farm level and all farms should have a Farm Biosecurity Plan.

What is biosecurity?

Biosecurity is the procedures or measures designed to protect the population against harmful biological or biochemical substances. Thus it includes pre-border, border and post-border biosecurity.

Government Industry Agreements for Biosecurity

Pre-border biosecurity is largely central government's responsibility. As an industry we can outline to government our views in relation to it, but the decision making lies with government. However, under the new Government Industry Agreements for Biosecurity (GIA) system, we will have a say on what happens at the border.

GIA has been developed to manage border biosecurity including readiness and response activities. A GIA is an agreement between government (MPI) and industry that is based on shared decision making and shared costs. The cropping industry is currently developing a GIA of its own which will involve the formation of a new legal entity. Under GIA our industry will sign a Deed and develop an operational plan based on a pathway approach. Although the cropping industry is not yet a signatory to the GIA, the GIA approach was used to very effectively manage a black grass weed incursion in Canterbury.  

The final part of the biosecurity is the post-border activity. This occurs once a biological organism has established in New Zealand and GIA have agreed it is no longer realistic to eradicate or contain the problem.  At this point it becomes the industry or your farm responsibility. This is where you should have a plan in place.

Biosecurity threats to the cropping industry

Biosecurity threats to the cropping industry include organisms that affect crops directly as well as those that would affect the use of crops in New Zealand. Thus a major biosecurity threat would be foot and mouth, which may prevent movement of grains or reduce demand from a major market for crops.

Identifying specific threats is difficult. A number of weeds, pests and diseases could be selected because of the damage they cause in crops overseas, while others that are not causing a problem elsewhere in the world, could impact on New Zealand growers due to our climate, cropping systems or factors such as agrichemical resistance. This, combined with the number and range of crops grown in New Zealand makes it very difficult to develop prevention and response plans for every possible weed, pest and disease threat, which is why our preferred approach for GIA is around pathways eg wind borne plant diseases, weed contaminants of imported seeds, insect pests on imported products etc (see Table 1).

The following are a few of the weed risks for cropping in New Zealand.

  • Some populations of Lolium multiflorum (annual ryegrass) are resistant to herbicides and if these became widespread they could be a significant problem in cropping soils.
  • Wild radish is already present in New Zealand and is relatively easily managed in cropping land. However, in some parts of Australia it is a major weed, resistant to four different herbicides groups.
  • Black grass is a persistent weed in the UK and Europe where it has developed resistance to a number of herbicide groups. 

Table 1 Assessment of risk for a few different pathways.

Pathway

Weeds

Disease

Pests

Vertebrates / reptiles

Seed borne

No

High

Low

No

Grain & seed contaminants

High

High

High

Medium

On machinery

High

Medium

Low

Low

On containers or other shipping goods

High

Low

Medium

No

In containers or shipping goods

Medium

Low

High

Medium

Airborne

No

High

Medium

Low

On people

High

Medium

Low

No

2015/16: velvetleaf, pea weevil and black grass

These incursions were detected through good surveillance, but all probably should have been detected sooner if good biosecurity was in place across the industry. For all three incursions, the response has been complicated by a poor understanding of the problem and then an inability to respond in a clear time frame and poorly informed people making statements without the necessary information and therefore reducing the effectiveness of the response. Generally good collaboration has occurred for all incursions. Some of these issues will be addressed in a GIA. There is still significant activity in New Zealand in relation to all three of these incursions. 

Recent actions on pea weevil are the monitoring of the trap crops in the Wairarapa and commercial crops elsewhere in New Zealand. In December, pea weevils had been detected in all seven of the trap crops in the Wairarapa and these crops were sprayed with insecticide and herbicide to kill all weevils and remove the host. As the pest is specific to peas, removing all potential host plants from Wairarapa should eliminate this pest. In late December over 175 paddocks elsewhere in New Zealand had been monitored and no pea weevils had been found. 

Velvet leaf seedlings continue to be detected on some farms which had velvet leaf last season and it is important that surveillance of high risk sites continues. Management plans are being developed with farmers with higher risk sites to try to ensure velvet leaf does not establish. Trials plans are being developed to evaluate herbicide control of the weed. 

Surveillance also continues for blackgrass on a mid-Canterbury farm. The ryegrass straw from the paddock where the seed was detected has been contained and will be destroyed by burning and burying to prevent any seed present in the straw from being spread.

These incursions are hopefully all contained and in some cases, hopefully the problem will be eradicated. This last year a prolonged focussed eradication programme for great white butterfly in the Nelson area was successful. The pest had limited distribution in the Nelson area and the eradication effort, led by DoC with input from HortNZ, FAR, DairyNZ and the Nelson community, has ensured this pest has not established and will not be a pest on brassicas in New Zealand. This successful outcome provides greater confidence that eradication of weeds and pests can be successful if they are detected early or in small geographic areas.

Do you have a farm biosecurity plan?

The biosecurity risk you can influence most is your own property. Your biosecurity plan is to protect your farm border from incursions of pests you don’t have, which may be present in New Zealand. A robust biosecurity plan reduce the risk of many weeds, pests and diseases establishing on your property, particularly herbicide resistant weeds or weeds evolving to be better suited to New Zealand. This could result in significant cost savings for pest control and also potential markedly increase your productivity.

The first step may be to create a biosecurity plan and update it frequently.  An easy to use plan is available in the FAR Farm Environment Plan, which is available on the FAR website www.far.org.nz