Think before you squish is the advice here. Many garden bugs are beneficial and aid organic gardening practices.
For years, well-meaning gardeners routinely maimed, swatted, sprayed and squished every bug they could get their hands on. However careful observation of nature and the move to organic practices have shown that encouraging “good” bugs, or beneficial insects (the politically correct name) is one way to give Mother Nature a hand. She was doing a fine job, however the use of pesticides, combined with overzealous tidiness resulted in loss of normal bio-diversity in our gardens.
Just as when you take antibiotics, and your doctor advises yogurt to normalize the flora within your body, the attraction of beneficials back to your garden can restore balance and harmony in your back yard.
How about “Think before you squish” as your mantra for the new season…? Remember that you may not always know why this creature is climbing the clematis, lurking on the lobelia, or sniffing your snapdragons.
It is generally agreed that aphids are “bad”. They spread disease, and cause problems throughout the garden. However, aphids need to be present on your rose bush for a week or two before the beneficial insects will show up. Recent studies show that injured plant tissue sends out distress signals (!) attracting appropriate predators. Be patient, and keep your spray trigger finger occupied with something else, like knitting.
Beneficial insects are attracted to plants from families including compositae (daisy family); the mint family (all kinds of mints, lemon balm, and more); umbelliferae (carrot family, which includes anything which makes an umbel, or umbrella-like shape in the flower head: parsley, fennel, for instance); and the brassica family, a huge family which includes cabbages, cauliflower (all the “stinky when overcooked” vegetables) oriental greens, arugula, radish and more.
All these produce flowers containing the type of nectar which beneficial insects use as fuel for flight and movement, just as humans use carbohydrates, and “bad” bugs are the protein course. Now a look at three common beneficials, and how to attract them to your garden:
You undoubtedly know these large, fast moving, shiny metallic-blue-black beetles! Their full title is predacious ground beetles. I am always dismayed to see one crushed on the sidewalk, the victim of a shoe whose owner may have had good, but misdirected, intentions. Beetles thrive in deep, loose humusy mulch, like the bouncy kind found in the woods, where leaves, coniferous needles, etc., have formed a soft carpet on the ground. They snooze underneath pieces of rotten logs and stones and are nocturnal, dining ravenously in the dark upon cutworms, root maggots, and slug eggs, miscellaneous larvae and pupae of undesirables, flea beetles, and leaf hoppers.
To attract more beetles, imitate nature. Along a shady edge, away from foot traffic, dig a ditch three to six inches deep, and a foot wide. Plant mint, or lemon balm, or even red or white clover, along the inside edges to prevent erosion and to provide low ground cover. Drop shovels of peat moss, leaf mulch, coniferous needles, whatever, here and there along the slopes, then place a couple of big, flat rocks in the ditch. The beetles will hide under the rocks in the daytime. Beetles are supposed to be attracted to the nectar of evening primrose.
AKA “hover flies”, so named because they can hover in one place, resemble slender black and yellow bees. Syrphids are important pollinators, but there is another reason to attract them: their larvae prey on many undesirable insects, and most especially, aphids. Adult syrphids drink the nectar from the flowers, lay eggs, and the larvae gobble up aphids.
With the naked eye it is possible to see eggs on the undersides of leaves near aphid colonies, laid in two symmetrical rows by the female, a hundred at a time. Once hatched, the larvae decimate aphid families in a hurry. The 1/2″ creature is often mistaken for a nasty “worm” or slug, so if you come across a legless, see-through greenish-beige creature, slightly pointy at one end, do not kill him, but wish him ‘bon appetit’! To attract syrphids, choose plants of the umbelliferae family: fennel, dill, caraway, parsley, coriander, yarrow, or allow carrots to winter over. All produce symmetrical seed-heads called umbels, which are a favourite of many beneficials.
Buckwheat, usually planted as a cover crop, can be sporadically seeded anywhere in the garden, and not only does it enrich the soil when turned in, but according to a recent Oregon State University study, the flowers are maximally attractive to syrphids. (Some people even consume buckwheat “greens” as food – check it out.) Other favourite flowers: cornflowers (bachelor buttons), marigolds, chamomile, coreopsis, and feverfew.
AKA “ladybugs”, feed heavily on aphids. If you think about purchasing them, remember…in most cases, the ladybugs go into dormancy or diapause when packaged, and when they are set free their natural instinct is to fly away. Don’t waste your money, instead attract ladybugs by your choices of plant materials. Become familiar with the ladybug in the larval stage. It looks a bit evil, like an elongated grey-black dragon with many little legs, and orange to red markings. The larvae fix themselves onto leaves, trees, or wood surfaces then pupate for about a week, emerging as the familiar round ladybug of our childhood.
All stages of ladybugs from larva to adult feed on aphids. Ladybugs are attracted to cosmos, especially white, and to goldenrod, coreopsis, fennel, yarrow and other umbelliferae. All are easily grown from seed. Lady beetles and other beneficials including the spider (yes, he is beneficial) like to lay their eggs amongst the long grass, so try to leave a strip un-mowed if you can.
It is good manners to provide your insect guests with a drink, in this case water, to wash down the aphids. This can be achieved simply: placing a plastic tray or any kind of pan in your garden and fill it with water. Put rocks in the water for them to stand on while they drink.