May 15 2017


Study on Tamarixia in glasshouses

May 2017

The TomatoesNZ board also approved a funding contribution for a Lincoln University post-doctoral student to undertake some research on the use of Tamarixia, the new Tomato and Potato Psyllid (TPP) biocontrol agent,in glasshouses.

There is a belief that Tamarixia may not be useful in a glasshouse situation because biological control requires a base level population of the pest for sustenance, and growers have a “zero tolerance” for TPP.  Additionally there is the fear of introducing a Liberibacter infection, vectored by the TPP.

However, the Lincoln research group believe that Tamarixia could reduce pest numbers by 99.9%. There is also some recent NZ research showing that almost all wild TPP are not carrying Liberibacter, but instead the bacteria load increases following it’s colonisation of crops.  The post-doctoral study will look at whether Tamarixia can achieve and maintain low populations of TPP in the glasshouse, and the impact on Liberibacter presence.

At the time of writing this column, no Tamarixia had yet been released into NZ. As reported in last month’s column, the first imported batch were found to have a fungal contaminant. It is hoped that some “clean” Tamarixa will be available for release in the next couple of months.

Psyllid biocontrol project kicks off

15 March 2017

Information sheet on Tamarixia trioaze

A project to release and monitor the new tomato/potato psyllid biocontrol agent Tamarixia trioaze has kicked off.

Plant and Food Research imported the parasitoid from biocontrol supplier Koppert Mexico late last year, and are carrying out testing to ensure that it is true-to-type and free of any pathogens. The next step will be rearing sufficient numbers to release in Pukekohe during the first stage of a three-year project joint-funded by industry groups (including TomatoesNZ) and the Ministry for Primary Industry’s Sustainable Farming Fund.  There will be a grower workshop on the 21st March in Pukekohe, where growers will be able to see the parasitoid at work and learn about it’s lifecycle and how to use it.

Application approved!

21 June 2016

The EPA today released its decision to approve for release without controls the biocontrol agent Tamarixia trioaze.

The application to release Tamarixia was made by Horticulture New Zealand's Vegetable and Research Innovation Board on behalf of industry groups including Potatoes New Zealand, Tomatoes NZ, Vegetables New Zealand, the NZ Tamarillo Growers Association and Heinz-Wattie’s NZ Ltd.

 The Tomato potato psyllid has caused enormous problems for the potato, tomato, capsicum and tamarillo growers in New Zealand since it was discovered here in 2006.

Ever since then the industry has been waging a battle to control this insect pest. One option to assist with controlling this pest is to use biological controls like Tamarixia, a tiny wasp that lays its eggs on the psyllid, which then hatch and eat the psyllid.

The horticulture industry plans to release Tamarixia into areas where potato, outdoor tomato, and tamarillo are growing, which means it will also have benefits for neighbouring home gardens. To support this activity Horticulture New Zealand has successfully applied to the Ministry for Primary Industry’s Sustainable Farming Fund for funding to carry out a programme to release Tamarixia into horticultural environments.

Once an import permit has been approved by MPI, growers will also be able to independently import and release Tamarixia on their own properties.

Tamarixia is found in the USA and Mexico as a naturally occurring parasitoid of tomato potato psyllid.



Submissions now closed

25th March 2016

We will now await confirmation of the hearing date for the application (tentatively scheduled for Wellington, 3rd and 4th of May 2016).

New bio control Agent for Psyllids - have your say

11th February 2016

The Environmental protection Agency (EPA) has called for public submissions on the release of Tamarixia triozae, a new parasitoid of the Tomato Potato Psyllid (TPP), in New Zealand.

Horticulture New Zealand, in association with the Vegetable and Research Innovation board, TomatoesNZ, Potatoes NZ Inc, Vegetables NZ Inc, NZ Tamarillo Growers Assoc. Inc. and Heinz-Watties NZ Ltd. made the application to the EPA to release this new biocontrol agent.

Submissions are open until March 24th 2016.

Make a submission using this form or this template, or go to the EPA website.

The EPA will also accept emails directly (email:, and require at the minimum only a few sentences of support (if emailing include ‘Application APP201955’ in the subject line).

We recommend including  comments on:

• how TPP impacts your business,
• how you currently control TPP, and
• how you think Tamarixia would benefit your business, staff and community.

The submission application number is APP201955.

For additional information on making a submission: Advice for industry submitters 
For additional information on the EPA process, timelines, and a summary of the risks and benefits: EPA information for submitters

The decision-making panel will weigh up the benefits vs the risks, and the level of support that the application receives versus any objections. Supporting submissions from growers affected by TPP will be crucial when the EPA decision making committee assesses the application.

About the application 


What is Tamarixia?

Tamarixia is a small wasp that is a parasitoid of TPP. Tamarixia will actively seek out and target TPP within solanaceous crops and lay its eggs on the TPP. Once hatched, the Tamaraxia larva will consume the TPP nymph. Tamarixia is found naturally in North America and Mexico – where TPP is also found. Tamaraxia only feeds on Psylli

History - Searching for options.

Since the first detection of TPP in NZ in 2006, research has sought to understand and manage TPP in New Zealand. One aspect of this research has been to look for biological control agents. In New Zealand there are already some insects (ladybird, hover fly, and lacewing) that will feed on the tomato potato psyllid. These insects only provide limited control of TPP. To date no parasitoids of TPP have been identified already present in NZ. Tamarixia would add to the effectiveness of the other insect predators and reduce insecticide use while achieving better control of the tomato potato psyllid.

Tamarixia triozae was originally identified by US researchers as a potential BCA, and testing has been carried out in containment in New Zealand to ensure Tamarixia will not harm NZ psyllid species. That research forms the basis of the application to the EPA.

Impacts of TPP

TPP’s arrival has had a number of impacts on tomato growers:

• IPM programmes have been disrupted;
• increased costs of production due to additional pest control and pest monitoring activities, and control of other pests becoming more difficult;
• reduced yield and fruit quality in some instances;
• Increased compliance costs for exporters.

In a survey of tomato and capsicum growers it was reported that seven out of eight tomato and three out of six capsicum operators reported that IPM programmes had been disrupted due to TPP. By adding Tamarixia to the options for managing TPP, it is hoped that greenhouse industries will benefit by re-establishing IPM programmes and reducing insecticide costs. TPP can be controlled reasonably well in greenhouses using insecticides, however relying on insecticides is not the industry’s preferred option.

How would Tamarixia be used?

Mass releases of Tamarixia have been used to control TPP in greenhouse crops in North America, and release into greenhouses could be used in New Zealand. However, it is thought that the most benefit for greenhouse tomato and capsicum growers will be from a reduction in TPP levels outside of the greenhouse, and consequently a reduced likelihood of TPP entering the greenhouse.

If this application is approved Tamarixia will be reared by commercial operators for release. The Releases would then most likely be co-ordinated into potato, outdoor tomato, and tamarillo growing areas. Releases could be on a local or regional scale and would rely on the establishment of self-sustaining populations in these locations. An IPM programme will be developed so that softer chemical controls are used in order to minimise their impact on Tamarixia.

Indoor growers who experience high levels of TPP could potentially release Tamarixia into the greenhouse.

The main risk is to native psyllid species. New Zealand has a unique and diverse range of native plants and insects which includes 68 native psyllid species. As Tamarixia attacks psyllids, we recognise that there is a potential risk to native psyllid species.


To examine the potential impact of Tamarixia on native psyllid species, a set of experiments to test whether native psyllids would be attacked has been carried out (host range testing). This work was done with EPA approval in a contained facility. A mathematical model of New Zealand’s climate has also been used to understand where Tamarixia might survive and establish in New Zealand.

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