Pest control workers in Toronto are confirming what most people already know — there's an abnormally large number of wasps flying around the city this summer.

The buzzing, stinging insects are driving people off patios and out of their backyards.

But there are differing opinions about what's behind the wasp explosion.

Carlo Panacci, who makes his living getting rid of the pesky insects, spent Tuesday morning knocking nests of bald-faced hornets off the vine-covered walls of a house near Mount Pleasant Road and St. Clair Avenue E.

Panacci, the owner of Cain Pest Control, says he's doing double his usual number of jobs tackling wasps.

"It's amazing. The calls just come flooding in — or swarming in, you might say — just one after another, after another. I can hardly keep up," he said.

Entomologists say the relatively mild weather last winter combined with our rainy summer made ideal conditions for this wasp season.

Panacci has another theory.

"Maybe the garbage strike. More flies, so there's an overabundance of food for them, a lot of bugs out there. I know last year was rather a wet year as well but nowhere near this many wasp calls," he says.

The wasp invasion has pushed Susan Allen and her family indoors.

"I can't remember seeing wasps like this, ever. You could stand here and just watch them buzz the ground. There's hundreds and hundreds of them in the backyard all the time," said Allen.

For Allen, that has meant missing out on eating outdoors — until now. She saw Panacci working across the street and hired him on the spot to spray a nest.