Good bugs, bad bugs

Jun 28, 2012

by Judy Wall, Lanark County master gardeners

As we head into the upcoming gardening season, this is a good time to review many of the bugs in our gardens. So many of them are actually very beneficial in that they can actually help you eliminate or control the bad bugs.

The following are considered good bugs:

Lady bugs – predator of aphids, mites, thrips, whiteflies and mealybugs, to name a few.

Bees - Major pollinators

Praying Mantis prey on caterpillars, mites, leafhoppers and other soft-bodied insects.

Lacewings Larvae also eat mealy bugs, scale, spider mites, mite eggs, whiteflies, leafhoppers, small caterpillars, and thrips. Adult lacewings feed on pollen, honeydew, and mealy bugs.

Earwigs can make a holey mess of leaves, which is unsightly but doesn’t kill the plant. They eat aphids, snails and some types of larvae. Earwigs like damp, sheltered places, like mulched garden beds. They feed at night and look for a damp, sheltered spot to spend the day. Control: Start by clearing the mulch from the area where they are congregating and letting the soil get a bit dry, which will encourage them to move elsewhere.

Ground beetles - Large, long-legged, shiny blue-black or brown beetles that hide under rocks and logs during the day, and are fast-moving when disturbed. They feed on slugs, snails, cutworms, root maggots, and Colorado potato beetle larvae.

Spiders - All spiders feed on insects and are very important in preventing pest outbreaks. The spiders normally found in gardens do not move indoors, nor are they poisonous.

Millipedes - shred organic matter and mix it through the soil. This gives smaller soil organisms like fungi and bacteria greater surface area to work on, and speeds residue breakdown.

Centipedes - are also good (but ugly) bugs. These predators feed on pests such as slugs, flies and cockroaches.

Ants and Earthworms –yes even Ants. They are just as important as earthworms, when it comes to aerating the soil.

SOME OF THE BAD BUGS:

Aphids - Small, soft bodied bugs, colours vary from pink and green to black. They feed on sap in shoots, leaves, buds and flowers, which causes distortion and cupping.

Colorado Potato Beetle – Reddish orange and black larvae, yellowish, orange and black striped beetles that feed on potato, tomato and eggplants. They strip the foliage right down to the leaf veins.

Gypsy Moth – Black, brown and red larvae that feeds on roots – it will defoliate trees.

Red Lily Beetle – Orange-brown to black larvae covered in excrement; adult beetle is bright red. Larvaes do the most damage by defoliating plants such as: lilies, fritillaries, some nightshade species, tobacco plants and others.

Asian long horn beetle – Larvae bore into tree trunks of many hardwood, softwood and fruit trees.

Emerald Ash Borer attack our ash trees.

Slugs can be very damaging pests in moist, shady gardens. They feed on the leaves of many plants, especially seedlings. Later in the season they can feed on ripening fruits and vegetables. Slugs are especially numerous during rainy seasons and in well-irrigated gardens.

White grubs – Larvae feed on roots of lawn grass, etc. Adults feed on many vegetables, flowers, trees and shrubs. Control: If severe may need to buy parasitic nematodes which you apply to the soil. Clean up garden debris in fall to reduce overwintering populations.

To teach our children more about good bugs versus bad bugs, google their images on the internet, and start to think differently about the bugs around us. If we work with the good bugs, we can save ourselves plenty of time and effort in the garden.