Skip to main content

Ten years ago, the towering umbrella-shaped pines that line the coasts of Liguria and Tuscany produced the crème-de-la-crème of pine nuts. Each year, the trees bore 8,000 tonnes of the delicate, elongated Mediterranean strand, one with a lemony zing that is perfect for pesto.

But today Italian pines yield less than 0.2 tonnes every year, a crash in production that has effectively wiped Italian pine nuts, or pinoli, off the gastronomy table.

The gap has not only doubled prices, producers say, but opened a market once dominated by Italy to inferior varieties.

Now, most pine nuts hail from Turkey, Portugal or, more worrisome for those who take their food seriously, China, whose tasteless version is bleached to appear more like its Mediterranean cousin.

Who's to blame for all this? A Canadian, perhaps.

THE STINK BUG STRIKES

In a reversal of the usual alien-species invasion, the Old World pines have fallen victim to Leptoglossus occidentalis, which is three centimetres long and commonly known as the western conifer seed bug or, in British Columbia, the "stink bug" - simply because it looks like a bug that emits a foul odour.

Indigenous to northwestern North America, the insect probably crawled out of wooden crates that were unloaded from planes landing in northern Italy in the late 1990s. Then, with devastating alacrity for a slow-moving insect, it travelled south along the coast and began to pierce pine cones with its sharp-tipped stylet (much like a mosquito biting your arm) and sucking their seeds dry.

Italian scientists were at a loss about what to do. The forests are national parks where the pesticide use is banned and the insect, being a foreign invader, has no natural predators.

Then last fall, an e-mail exchange put in motion a scientific collaboration so promising that it may do much more than eliminate Italy's pine-nut pest.

Even better, the country that is providing the solution is the same one that seems to have caused the problem in the first place.

PARASITOIDS TO THE RESCUE

Initially, Pio Roversi of the Research Centre for Plant Protection from Pests in Florence had little luck when started sending out electronic feelers, seeking information on research to battle the stink bug. "The first e-mail I sent, the scientist replied that she didn't study the stink bug any more," he recalls. "The second scientist I contacted had retired. So I really didn't have high hopes with Ward."

Ward Strong, a cone and seed entomologist with the B.C. government, responded with enthusiasm. He and his team are researching new ways to combat the insect because the registration for the one pesticide that controls it expires in two years for environmental reasons.

For the past eight years, they have been looking at parasitoids, tiny wasps that break a small hole in the eggs of the stink bugs, laying eggs of their own that hatch into larvae that destroy the host eggs. The goal is to safeguard "orchards" created on the West Coast to produce seeds for the Douglas fir and several other species of conifer.

According to Dr. Strong, the seed orchards are managed in much the same way fruit orchards are: Trees grow in rows, are irrigated and pruned, and then have their cones harvested. "Like an apple orchard, we get all kinds of insect pests. Apple orchards have been around for hundreds of years, so their pests are well studied," he explains. "But seed orchards are relatively recent, about 30 years old, so the pests aren't well known. We knew they were there, but it wasn't until we needed the seeds for reforestation that we started to care."

So much seed is being lost to the stink bug that it poses a threat not just to the reforestation industry, but to biodiversity. "These seed orchards are repositories of genetic diversity of trees that have been bred for decades for things like faster growth, better wood quality and even pest resistance," Dr. Strong says. "So, if we lose a seed to the Leptoglossus, it represents a major loss to the B.C. heritage."

A NATURAL SOLUTION

Employing parasitoids was exactly the kind of natural, non-chemical solution the Italians were looking for.

Last month, Dr. Strong visited the Tuscan forests with Dr. Roversi to get a first-hand look at the damage. This weekend, Dr. Roversi arrives in British Columbia to confer with Dr. Strong's team and a researcher looking into ways to prevent the stink bug from attacking Sicily's famous pistachio plantations.

Next week, Dr. Roversi will fly home with samples of the parasitoids to begin testing in a laboratory.

If all goes well, the tiny wasps will be laying their deadly eggs up and down the Tuscan coast by fall. If effective, they also could be tested in Croatia, Poland, Latvia, Belgium, France, Portugal and England - other countries showing signs of stink-bug invasion.

Success, if it comes, won't be instant.

"The pine cones take three years to produce nuts," Dr. Roversi explains. "So we hope that in three years we'll be able to protect 50 per cent of the production."

Despite potential setbacks - for example, the parasitoids also may be too dangerous to introduce if they attack other bugs and throw off the environment even more - both Dr. Roversi and Dr. Strong are optimistic.

In a world with increasing biological challenges caused by globetrotting species, they say, cross-cultural scientific pairing is the only option. "Research is not a lamp," Dr. Roversi says. "When you start, it's still dark for many years. And this new pest in Italy is a very important example. If we in Italy didn't have a colleague with experience in Canada, we wouldn't have any chance of controlling this."

Special to The Globe and Mail

Report an error

Editorial code of conduct