Above: Image © Patti Adair, FreeImages.com

Spring is almost here! And that means one thing...you can get outside without having to wear six layers of cotton, wool and fur. While spring means it's actually nice outside, for a lot of us, it also means yardwork. One of these weekends you're dad's going to hand you a rake and the summer's list of chores will start to grow. If you happen to live in Ontario, you better read up, 'cause your yardwork might actually involve science this year.

The difference is that the government of Ontario has invoked a cosmetic pesticide ban. As of Earth Day, April22, 2009, dangerous pesticides will not longer be allowed on residential lawns, gardens, patios, driveways, cemeteries, parks and school yards. While this means you won't have to look out for pesky"keep off" signs while you're walking the dog, it also means you might have to pick up some new gardening techniques.

Did you know? Pesticides are killers! The World Health Organization (WHO) estimates that approximately 220 000 people die worldwide every year from pesticide poisoning. These tragedies usually occur when farmhands are exposed to agricultural applications, but regardless, using pesticides can have many different unintended 'side-effects'.

Well, maybe that's not so fun, but it's what pesticides were made for. These manufactured chemicals are designed to kill pests and insects that might have made a home in your lawn or garden. Pesticides and other chemicals can be used to kill all sorts of things: plants and flowers, insects, fungi, rodents, wildlife and occasionally, humans.

Did you know? Spraying your lawn doesn't just effect your grass — it goes right throughout the ecosystem.

For instance, if you spray something to kill a bothersome insect, you can kill the bad bug and some good ones — including ladybugs, earthworms, butterflies and many different bee species. Rainfall can wash chemical residues onto the street, down the storm drains and out into local lakes and rivers, where some pesticides are highly toxic to fish. Passing birds can also be affected by residential chemical sprays, along with neighbourhood pets, squirrels, chipmunks, rabbits and other 'urban' animals.

Try This: What's the alternative to pesticides? Fighting pests with science!

A common pest in residential lawns is the white grub, a fat, C — shaped bug with a dark head. They feed on the grass roots, causing the grass to die, and make nice big brown spots. This might cause some people to reach for a bottle of pesticide, but an ecologist would reach for a book to find a naturally occurring predator, that will do the pesticides job for free.

White grubs have many natural enemies, including nematodes, tiny microscopic worms that eat the grubs. Parasitic wasps are a particularly dreadful (alien-esque) enemy to have and there are many different species that feed exclusively on white grubs. These tiny wasps are actually more like little flying ants and don't sting humans. What they do sting is the white grub, which temporarily paralyzes it while the wasp lays one or two eggs inside the host! The grub then recovers from the sting and continues eating your grass roots, briefly...

Inside the grub, the wasp larva begins feeding on its bodily fluids. Within 2-3 weeks, the baby wasp will have consumed its entire host, at which point, it makes a cocoon from the remaining outer shell of the grub. After pupation (a stage of physical change inside the cocoon) the adult wasp emerges from the soil in search of food and another grub to lay eggs.

These marvellous specialists would classify as 'good bugs', the kind that can be easily killed by spraying pesticides. With this in mind, on Earth Day 2009, when the cosmetic pesticide ban comes into effect, we might realize that we didn't need them in the first place.

Learn More:

The World Health Organization

Find out what your province is doing

White Grubs

Nematodes

Parasitic Wasps

Darryl is a contractor in Toronto. He studied soil and crop ecology and wants to have an organic farm. In the meantime, he blogs about cooking and music.

March 21, 2009

CurioCity writer

Article written by a CurioCity expert.


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