Bloomberg News

Cone-Sucking U.S. Invader Shrinks Mediterranean Pine-Nut Crop

March 01, 2013

The Mediterranean region’s pine-nut harvest fell 63 percent last year after an invasive insect pest from the U.S. damaged cones from Turkey to Portugal, pushing up prices for the tree seeds used to make pesto.

Gathering of pine nuts across the region declined to 905 metric tons from 2,445 tons in 2011, based on estimates from the International Nut & Dried Fruit Council, or INC. The Reus, Spain-based council had previously forecast a pine-nut crop of 2,700 tons around the Mediterranean.

“Pine-nut production in the entire Mediterranean basin has experienced a strong reduction, in both the number of pine cones and in the yield,” said Irene Girones, project coordinator at the council. “Estimates have been reduced dramatically.”

The damage was caused by the western conifer seed bug, according to Girones. The 2-centimeter (0.8-inch) bug, a native of the western U.S., feeds on pine cones and has spread across the region since it was first found in Italy in 1999, appearing in Turkey in 2009 and Portugal in 2010.

Spain’s harvest of nuts of the stone pine fell to 280 tons last year from 845 tons in 2011, whereas the INC had initially expected the crop to total 700 tons, according to Girones.

Turkey’s output fell to 350 tons from 650 tons, less than a third of the INC’s earlier forecast for a 2012 harvest of 1,100 tons. The country is the largest grower of Mediterranean stone pines outside the European Union.

Turkish Producers

“We spoke to Turkish producers who say they have only very limited quantities of pine nuts,” said Jochen Voecks, who trades the tree seeds at German dried-fruit company Michael Priestoph GmbH in Hamburg.

Portugal’s crop slipped to 125 tons from 650 tons, a quarter of what had been initially predicted, the INC estimates. Italy gathered 150 tons of pine nuts from 300 tons in 2011, according to the council.

Italian import prices for pine nuts from Turkey, the country’s main supplier, rose to 34.99 euros ($46.12) a kilogram (2.2 pounds) in December, climbing 34 percent from 26.03 euros a year earlier, Eurostat trade data show.

“This price level is not sustainable,” and users will look for cheaper alternatives if supply of the Mediterranean variety doesn’t recover, said Sven Mutke, a researcher at Madrid-based forest research center INIA-Cifor. Walnuts and cashews can be substitutes for pine nuts in pesto.

Pompeii Ruins

Pine-nut remains have been found in the ruins of Pompeii. Large stone-pine forests were planted in Italy after Papal decrees, including one in 1666 near Fregene, north of Rome, which still exists, according to the United Nations’ Food & Agriculture Organization.

The western conifer seed bug feeds on pine nuts by piercing cones and digesting the developing seeds. The bug’s feeding on stone pines causes deterioration for 50 percent of first-year pine cones and 65 percent for second-year cones, according to data collected as part of Tuscany’s forest-health monitoring project META.

“The actual impact of its damage to stone-pine cones is still under study,” Mutke said. “Where it appeared, many unripe cones abort and dry, and those cones that ripen have a very low seed output.”

Italy’s harvest of pine cones fell to 13,000 tons in 2005 from 80,000 tons in 1995, without any recovery in intermediate years, according to the country’s Pedology and Agrobiology Research Centre in Florence. Pine nuts typically make up about 4 percent of cone weight, which can drop to 2 percent due to damage by the seed bug, according to Mutke.

Cone Weevil

Endemic pests of Europe’s conifers include the cone weevil and the pine-cone moth. Global warming is also making stone pines more susceptible to a fungus called diplodia pinea, which can be spread by the western conifer seed bug, according to researchers at the University of Florence.

Mutke said there’s still uncertainty to what extent the cone losses are caused by the western conifer seed bug or other factors, particularly the Mediterranean’s increasing droughts in recent years. Spain had its second-driest summer in 60 years in 2012, according to the Agriculture Ministry weather service.

To contact the reporter on this story: Rudy Ruitenberg in Paris at

To contact the editor responsible for this story: Claudia Carpenter at

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