Sometimes the best defense is the smallest one

For 2,000 years a pest that measures about the width of a pinkie fingernail from end to end has menaced the olive trees of the Mediterranean.

In 1998, the olive fruit fly was  detected in Los Angeles; it has since managed to spread to all olive growing regions in California. That’s not good for the state since it produces nearly all of the olives grown in the country. Olive production, which can rise to as much as 166,000 short tons in a year, sunk last year to just 65,000 tons, barely half of the originally projected production figures.

Combating the Mediterranean pest has been tricky, and research into countermeasures got dissed by Sarah Palin during the recent presidential campaign.

One method being applied involves controlling the fruit fly’s population by unleashing predators, in this case wasps, into the area. The trick with unleashing a non-native species into a new territory however, is finding out whether or not the biological control can stick to its previously determined prey. Otherwise, it could become a new pest that in turn needs to be controlled.

An article in the February issue of the US Department of Agriculture’s Agricultural Research magazine features Agricultural Research Service entomologist Victoria Yokoyama, who led a team that recently unleashed a new biological weapon  to counter the olive fruit flies’ depredations in the state: an African wasp that eats the young fruit flies hatched in the olives before the flies can grow up to eat the olives themselves.

Its worth noting that Yokoyama’s team isn’t the first one to come up with a biological control for the olive fruit fly, just the most recent. A couple of years ago, researchers at UC Berkeley released a Pakistani wasp that specifically targets the olive fruit fly called Psyttalia ponerophaga in several test orchards.