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Guests in the Garden

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Even though it’s just November it’s not too early to become familiar with those guests in the garden—bugs and other critters. Not all insects are pests; some are beneficial and they’re actually on your side.

Slugs do some good by processing dead and decaying leaves and turning them back into organic material that enhances the soil. They are also food, in their infant form, to things like centipedes and ground beetles. If you want to get rid of them you can use enviro-friendly baits containing ferric phosphate, a natural compound found in soil. Look for Scott’s EcoSense Slug and Snail Bait or Safer’s Slug and Snail Bait, both toxic to mollusks but safe for humans, pets, birds and insects. You can also use copper barrier strips around plants which deters slugs by giving them a slight electric shock. You can also pour a small amount of beer into a container. Sink the container into the ground. Slugs are attracted by the smell of yeast and drink themselves to death.

Ground Beetles live under boards, stones and logs and eat caterpillars and other soft-bellied grubs, such as baby slugs and cutworms as well as some insects in leaf matter. Mostly nocturnal, ground beetles pop up during the day when accidentally disturbed. Rather than stomping on them, try to encourage them by putting down mulch or planting ground covers to protect the soil.

Centipedes are fast moving, can be aggressive, and not afraid to give you a nip. They will attack creatures far bigger than themselves, especially slugs, grubs and insects in their infancy. Centipedes have legs (about 30, not 100) sticking out at the sides. The millipede, by comparison, is a very different creature; more wormlike, slow moving with a habit of rolling into a ball for defense rather than running away. They do more good than harm.

Spittlebugs are tiny green creatures which live in a protective foamy substance sometimes called “cuckoo spit.” They do minor damage to plants by sucking sap from the leaf stems and causing growth to be stunted. Wait a few weeks and they will be done. If you have a lot of them, first try washing them off with a jet of water. If the problem persists, use insecticidal soap.

Earwigs are fast moving insects with a pair of pincer-like appendages at the tip of the abdomen. They nibble holes in flower petals, but also nosh on aphids, grubs and soft-bellied insects. You can trap them by stuffing crumpled newspaper into an upside down flower pot. Shake them into a bucket of soapy water to drown them, or relocate them.

Ladybugs are one of the gardener’s friends. The only reason they will leave is if your garden has not enough food. You can buy bags of ladybugs but the moment you release them they often fly to the neighbour’s garden where there is a better banquet. Ladybugs will eat all the aphids you can provide, unless you have ants stopping them.

Green lacewing gobbles up copious amounts of spider mites, leafhoppers, caterpillars and thrips. Lacewings are also known as aphid lions because of their voracious appetite. Attract them by planting flowers rich in pollen and nectar (feverfew, yarrow, daisies).

Aphids live in colonies and feed on the stems of plants, especially roses. They are often herded  by ants that milk them for their sweet secretions. Wash them off the plant with a jet of water from a hose. Once they hit the ground, they are unable to climb back up. Another solution is to attract beneficial predators, such as ladybugs, lacewings, aphid parasites (aphidius) and aphid midgets (aphidoletes) or spray with an insecticide soap.

Ants thrive in places where it is dry and there is rotting wood and plenty of leaf matter and where they can be left undisturbed. The key is to reduce the population to a tolerable number by finding the nest and killing the colony by pouring boiling water on it or by using an ant spray. In July, winged queen ants spill out of their nests to mate and form new colonies. There are various sprays and baits on the market. Some contain pyrethrum, the botanical insecticide found naturally in chrysanthemums. Others contain permethrin, a common synthetic chemical that kills ants on contact. Other ant-killers have D-Trans allethrin and benzisothiazolinone. Powder baits contain ant-killing dust such as carbaryl. The best solution is to keep reducing the populations to a tolerable size.

(Adapted from Steve Whysall, May 5, 2012)