In the early years of our project, we were overrun by several types of aphids. Masses of tiny, brilliantly colored buggers smothered the undersides of leaves of decorative plants and baby trees. We fretted and wrung our hands, then sprayed with soapy water, but the plague continued for at least two years.
At some point, however, I realized we no longer spied large populations -- on anything.
The various herbs and companion plants we've scattered throughout the property have attracted a panoply of beneficials. Each summer, the air is abuzz and the soil is alive with unidentified creatures -- each playing a role in a complex drama. One that, evidently, is keeping aphids in check.
This all came to the fore as I recently read about commercial organic lettuce growers inter-planting alyssum to combat currant-lettuce aphids. The alyssum blossoms attract hoverflies, which devour their pollen and nectar, then lay eggs that hatch into larvae, which, in turn, stuff themselves on currant-lettuce aphids.
What had been a difficult pest to control, because these aphids colonize interior lettuce leaves, is mitigated by adding a simple flower to the mix.
Currant-lettuce aphids aren't exactly a problem in Geneva, N.Y., but I will gladly find space for alyssum to head one off. Besides, hoverfly larvae may eat something else that is.