Caterpillars, spiders and ants: What do unwelcome garden guests really mean?

When it comes to insect invaders in your garden, the first rule of warfare is to know your enemy, according to CBC’s gardening expert Lyndon Penner.

Tent caterpillars have place in ecosystem, gardening expert says

Tent caterpillars have been everywhere this year, with people across Saskatchewan reporting infestations. (Marc Winkler/CBC)

When it comes to insect invaders in your garden, the first rule of warfare is to know your enemy, according to CBC gardening expert Lyndon Penner.

For example, tent caterpillars have been invading their way through parts of Saskatchewan this year.

Penner reminds us that these creatures do have their place in our ecosystem, and that they provide food for birds.

"There are years where tent caterpillars demolish everything and it is a problem, but on the other hand there is a place for tent caterpillars and it just might not be at your house," said Penner.

"There's a lot of bugs that are not necessarily a problem until we get masses of them."

Penner said some creepy critters have undeserved bad reputations.

"There's so many things that we are so quick to put a label on and say, 'This is bad,'" said Penner.

"I always try and find out, when I've labelled something as bad, where does it fit in? What is the role that it plays? Who is it important to?"

Attack of the caterpillars

Tent caterpillars crawl up the wall in Raymore, Sask. (Todd Deutsch/Submitted to CBC)

Gardeners should also remember that beastly caterpillars turn into something much more beautiful, Penner said.

"I had somebody say to me once that she wanted to attract butterflies to her garden, but she also wanted to buy a pesticide so she could spray for caterpillars," said Penner.

He reminded this gardener that butterflies start off their life cycle as caterpillars.

Ants, spiders and wasps, oh my! 

Caterpillars aren't the only insects that green thumbs are warding off when gardening season comes around. The usual suspects that bring out a gardener's wrath can include ants, spiders, and wasps.

"Ants, like everything else, are good in moderation," said Penner. "Their tunneling is actually good for the soil, and aerates and loosens things."

Ants pose a problem when there are too many of them, Penner said that this means that things are too dry.

He advised that soaking your garden a couple days before working in it will push ants away to somewhere more dry.

When it comes to spiders, Penner said that they aren't the ones gardeners should truly fear. They are there to eat other insects infesting your garden.

"The only thing that spiders want is to eat other bugs, so where there's smoke there's fire," said Penner. "If you have lots of spiders, that means you have lots of bugs." 
Ants in large numbers tend to pop up in dry areas. (AFP/Getty Images)

The same thing goes for wasps. Some native wasp species are important predators of bad things in the garden. These insects are on the lookout for good food sources.

When it comes to all unwanted insects in the garden, Penner said the best thing to ask is "why are you here?"

"Everything belongs somewhere," said Penner. "It may just not suit our needs."