Romancing the gypsy moth

The plane from the Department of Agriculture makes a pass over the homestead.

The sound of airborne engines started Saturday and continued on Sunday. First to the northeast and then to the southwest. Back and forth. Back and forth. Over and over. Heard but not seen.

But by Sunday afternoon the source of the noise was in full sight overhead. A bright yellow plane from the Minnesota Department of Agriculture was flying a pattern across land surrounding the Knife River. The plane flew low -- maybe 50-100 feet above the treetops -- as it delivered its payload of gypsy moth pheromone. 

Pheromones are chemical messengers emitted by insects (and others) to communicate all sorts of things, including the readiness to mate.

The pheromone drop is part of MDA's mating disruption strategy to fight the gypsy moth, a non-native pest that has the potential to defoliate forests and stress trees to the point of death. Here's how it works: The pheromone, called Disparlure, is sandwiched in plastic flakes or embedded in waxy droplets which are then dropped over the targeted area. Female gypsy moths can't fly so they produce this pheromone to attract a mate. But with all this extra pheromone around, the males can't find the females and there is no mating, no eggs and no offspring. The strategy works sort of like employing chaperones at a high school dance.

The MDA says the treatment is effective and safe and won't harm people, pets, fish, birds or mammals.The information the MDA sent us regarding the application said the flakes and droplets stick to leaves and branches and often go unnoticed. If we hadn't been home, we never would have known as we could see no evidence of the drop.

The view toward the end of the driveway.