Growers have been left on tenterhooks by a disease which has triggered a biosecurity ban blocking exports of New Zealand tomatoes and capsicums.
Biosecurity New Zealand today stopped all exports of fresh tomato and capsicum until further notice, after new disease-causing bacteria were found in three commercial hothouses in the Auckland area in January.
But the pest is suspected of spreading the bacterium to tomatoes and could potentially infect potatoes, kumara, chillies, and eggplant.
And because the bacteria are likely to also feed on native plants such as poroporo and widespread weeds, they have a year-round "reservoir" for breeding outside the commercial crops.
In the short-term, growers are crippled by a lack of useful information, such as identification of the bacteria, and confirmation that the tomato and potato insect - which mysteriously turned up in New Zealand two years ago - is the vector for the pest.
What happens next will depend on whether the bacteria - reported to be new to science in New Zealand - are also found in commercial crops in customer countries, and whether growers can control the insects spreading the bacteria.
Tomato exports are worth $7.3 million annually and capsicum exports are worth $34m.
Most go to Australia where the horticulture sector has previously been reluctant to admit to the presence of pests such as fireblight.
Other important markets are Japan, the Pacific Islands, Hong Kong and the United Arab Emirates.
Biosecurity New Zealand director of border standards Tim Knox said he did not know whether the export ban will be lifted by October, when growers are due to ramp up harvests from the new crops they are now planting for export.
The withdrawal of certification was a precautionary measure until more was known about the bacteria, their transmission and distribution.
Research to answer these questions has been started and its results will help determine the feasibility of managing the disease.
"Initial findings suggest that the bacterium may be transmitted by a small insect called the tomato/potato psyllid," Mr Knox said.
Symptoms in both tomatoes and capsicums may vary across varieties and growing conditions, but include leaf curling and yellowing in tomatoes, stunting of the plant and fruit occasionally misshapen with a strawberry-like appearance.
Symptoms in capsicums include pale green or yellow leaves with spiky tips. Leaves may be misshapen, leaf stalks appear short, flowers may drop and the plant top may die back.
Movement controls would not be put in place, because symptoms had been present for several months, Mr Knox said.
The business manager for Horticulture New Zealand's tomato product and fresh vegetable product groups, Ken Robertson, told NZPA that growers urgently needed confirmation of the insects spreading the bacteria.
"The key for our growers is to get 100 percent confirmation of the vector, and then to deal to that insect," said Mr Robertson.
"If you can control the insect, then you won't have the bacteria in the glasshouses."
But if insects are spreading the bacteria, the industry's integrated pest management (IPM) strategies using biological controls rather than chemicals on crops will come to grief, because the predator insects currently used are not able to control the psyllids before they attack crops.
In the medium term, growers might have to return to using chemicals while they find and introduce more effective insect predators in glasshouses.
Chemicals have been found to be effective overseas, but growers have recently been experimenting with "softer" sprays, potentially less toxic to humans.
But it is not clear how they will avoid killing the bumble bees extensively used in commercial glasshouses to pollinate tomato crops.
If the bacteria turned out to be something widespread in customer countries, growers hoped they might quickly re-gain their export certification, Mr Robertson said.
