The air in Calgary is alive with swarms of aphids.  

James Borrow, a pest management expert with the city, said the tiny bugs, which typically show up in late summer and early autumn, can harm plants.

He said gardeners can spray their plants with a high pressure garden hose to knock the insects off.

Beyond that, there’s not much people can do about aphids, Borrow said.

"There’s certain times that you can avoid them. When it’s really calm, they’re going to be out. If it’s windy, they can’t handle that," he said.

One aphid can lay 250 eggs through parthenogenesis, a form of reproduction that doesn’t require a mate. During a growing season there can be 20 to 30 generations of aphids.