Tamarillo Industry Resurgence
The tamarillo industry is bouncing back with better techniques to manage the psyllid pest
In 2010 the tamarillo industry was on its knees from widespread tree deaths caused by a biosecurity incursion which was a combination of liberibacter, a bacteria, and a vector called the tomato/potato psyllid (TPP), a small winged insect. The pest pressure has now greatly reduced, the industry has recovered and lost trees have been replanted, along with large numbers of new tree plantings as a diversification option to kiwifruit and the threat of Psa. Now some tamarillo growers are organizing themselves into a producer co-operative to handle the fruit build-up and move into added-value product development.
The $2m tamarillo industry was devastated by the tomato/potato psyllid (TPP) and an associated bacterium, liberibacter, from 2008 to 2010. Orchards in the north of the North Island lost up to 90% of their trees, with routine losses of 30-50% of trees even when preventative spray programmes targeted the spread of TPP.
It was first detected around Pukekohe in tomatoes and potatoes in 2008, and the insect spread very rapidly to all growing areas during 2009 and 2010. This was a biosecurity breach, because previously TPP were only known to be causing problems in the US. Other countries remain free of the pest. TPP lives and reproduces on all plants from the Solanaceae family, including tomatoes, potatoes, capsicums, eggplant and such weeds as nightshade.
In the three summers since the worst outbreak the TPP pressure hasn’t been as great in the main growing areas (Far North, Whangarei and Bay of Plenty) and with preventative spray programmes resulting in reduced populations of TPP, the threat has been largely neutralized. However an export barrier remains to Australia because of the lack of a suitable fumigant that does not deteriorate the shelf life of the fruit being sent there. Australia does not have TPP/liberibacter. All NZ exports of tamarillo are now going to the US. Before TPP New Zealand’s annual tamarillo production was around 750 tonnes. This halved following the TPP outbreak but has now built back up to around 450 tonnes a year.
Effective TPP control:
The summer-active TPP has been relatively scarce for the past three summers, except in the Gisborne region (where there are a lot of field tomatoes grown and large numbers of tamarillo tree losses are still being felt). Elsewhere tree losses up to 10% annually are sustainable, within the normal tree replacement rates. Even in unsprayed orchards there are not the TPP numbers seen in 2009 and 2010.
The Tamarillo Growers Association recommends an integrated pest management programme for TPP which includes a monitoring and recording process and spraying by rotating through three products: Movento/Oberon, Sparta and Avid. The last two are contact sprays and must be delivered under the leaves where the insects live. Careful use means no more than two or three sprays of one product at two-week intervals, so that by the time the second generation of insects has hatched, a different spray is being used. Both pest monitoring and active tree management (tree nutrition, pruning) are essential parts of the IPM programme. Preventative spraying where indicated must be kept up during summer because re-infestation can occur from a large number of host plants.
The tamarillo industry is expanding again with two key drivers: changing land use after PSA kiwifruit orchards have been cut out, and the high prices received for tamarillos for the past three years (when fruit volumes have been considerably reduced). The long-time large growers have replanted, using their own homegrown seedlings, often from older trees that appeared to be resistant to TPP/liberibacter. Newcomers have learned how to propagate their own seedlings or purchased them, and some very large plantings were done in Bay of Plenty and Far North. Tamarillo seedlings planted in October-December will bear fruit 16-18 months later, so there will be a big fruit volume increase in 2015.
TGA has 60 active growers and production is expected between 420 and 460t this year. TGA is aware that another 80,000 trees have been planted by new growers in the past two years and if they all survive to production it has the potential to double the annual crop.
A small number of the largest growers have formed the NZ Tamarillo Co-operative (Tam Co) for collective marketing, new packaging, promotion and new value-add uses. They are using one wholesaler and dealing with both supermarket chains, which have welcomed more structure in a small product group. Bright new point-of-sale material and pre-sale bagging of fruit have been introduced. Tam Co has also copyrighted Tiger Tams as a brand for good fruit which has mosaic virus markings on the outside, similar to marbled colours.
Co-op members are pooling fruit for large lines suitable for processing, freeze drying or pulping, because a shortage of process-grade fruit has hampered fruit, drink and food development containing tamarillos.
Tam Co is a separate organisation from the TGA.