An anticipated 3,000 hectares of kiwifruit farmland could be threatened by the growing Psa disease in Chile this season.

Chile's Agriculture and Livestock Service (SAG), in conjunction with the Chilean Fruit Exporters Association (ASOEX), Fedefruta and the Chilean Kiwifruit Committee, unveiled a situation that could adversely affect the industry, if not prevented and controlled in time.

The authorities reported 30 positive cases of Psa disease in kiwifruit in the Linares Province of the Maule Region, an area where almost 45% of plantations are made up of kiwifruit.

ASOEX president Ronald Bown said the plague arrived to the country a few years ago on a small scale, adding "today we have seen with great concern how it has begun to generate in an almost exponential way, especially in the Linares area where we now have about 40 bulbs from the 6 or 7 that initially appeared."

Detecting the disease

The variety most likely to suffer from this bacterium is yellow kiwifruit, which, due to its natural mesh protection, generates a damper environment, more susceptible to vegetative growth. Furthermore, young plantations of 1-6 years may be more susceptible to the disease.

Psa can manifest through angular, brown necrotic  points on leaves surrounded by a yellow halo. Ooozing orange or reddish sap appears in August and September, with the presence of cankers, decay of buds, stems or entire plants with sores.

Each hectare comes from an investment of US$30,000, so the problem could be economically catastrophic for farmers affected by the bacteria. The only way to get rid of the disease is to bury, burn and put lime down on the plantations.

According to figures from the Chilean Kiwifruit Committee, the fruit is valued at more than US$200 million in revenue, US$50 million in direct labor, and US$1 billion in infrastructure and orchards.

Measures to prevent the spread

Bown said that New Zealand has lost 50% of its production from the disease, a scenario Chile hopes to avoid.

"If you make a projection of what could happen in Chile, we are talking about significantly higher than US$400 million in terms of investment, in terms of exports and we are already working with the authorities," he said.

While quarantine has already been ordered in the affected regions, the president of ASOEX was emphatic about the measures that both private actors and authorities should take to control the spread of the bacteria.

"We must deepen a strategic plan for the medium term. This is not a situation that we will solve in days, weeks or even years. It will take at least five years to find ways to contain or eliminate the disease," Bown said.

He also emphasized that there is no health problem or risk of illness from eating a kiwi from an infected farm.

"There is no health problem. It's  a problem of whether antibiotics can be used or not. We are not in that line, as we have always worked for our production to be as safe as possible."

Furthermore, he emphasized that a source of propagation is hygiene. Carlos Cruzat, general manager of the Chilean Kiwifruit Committee, said that preventation can be promoted by not  pruning too late into autumn to avoid the production of strong byproduct. Additionally, garden spaces must be kept clean by disinfecting wheels, tools, hands and other materials.

"We started later with Psa and therefore, we should not miss the opportunity to attack early and prevent disease among producers, exporters and government. So far there are no barriers to actually stop the disease, so, we must learn to live with it and prepare ourselves," Cruzat said.

"We are asking the private sector to take action, that it educate and act. And from the public sector, we are asking that funding be available for research, disease surveillance activities  and an increase in the budget," he said.

New Zealand as a warning

In 2010, a bacteria outbreak began in kiwifruit orchards in New Zealand and losses have been in the order of US$400 million over the last five years.

"They've spent US$400 million in research, plant health programs, license purchases for new varieties, among other things. It is estimated that in the next few years, the cost will reach US$1 billion to contain the bacteria. This cost is undertaken by the producers themselves," Cruzat said.

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