EVERYONE loves a bit of help in the garden, and some of the best helpers are happy to work all day, every day, for nothing.
Beneficial insects will devote their entire lives to managing pests and diseases in your garden, if you let them. They fall into three broad groups - pollinators, predators and parasites.
Pollinators fertilise flowers, increasing the productivity of fruit and vegetable crops. Predators consume pest insects as food. Parasites use pests as nurseries for their young.
Much of the pollinating work is performed by insects, most notably bees, hoverflies and butterflies. So it's important to provide nectar sources by planting flowers.
Predators include lacewings, ladybirds and hoverflies. Some of the adults feed on pollen and nectar, and some feed on insects. They lay eggs that produce predatory larvae, which feed on soft-bodied insects such as aphids, thrips, mites, scale, mealy bugs and caterpillars.
Lacewing larvae will feed for 15-20 days, eating 100 or more insects in a day. Adult ladybirds will eat several hundred aphids before mating and laying eggs on aphid-infested plants. The larvae feed on aphids as well. Some species prefer other pests, like mites, white flies, or scale insects. A few eat fungus or mildew - you might see them feeding on cucumber or zucchini leaves if you have powdery mildew. One small subfamily of ladybirds includes leaf-eating beetles. Some of these are pests, but the majority of ladybirds are beneficial predators.
Parasites deposit eggs on or into the pest or its eggs. The young feed on the host, ultimately killing it. Most parasites are either wasps or flies. Parasitic wasps and flies don't sting.
If you want to get some of these bugs working for you, there are three things you need to do.
First, reduce or eliminate the use of pesticides in your garden. Many sprays will kill good bugs as well as bad ones. There are some safe, selective pest control products on the market.
Second, provide food and shelter for the good bugs. Flowers are a source of food for many pest-controlling insects in their adult form. Many have short mouthparts, so simple open flowers or very small flowers are best. Among the favourites are coriander, fennel, dill, Italian parsley, daisies, cosmos, zinnias, dandelions, marigolds, tansy, sunflowers and more.
Lastly, learn to recognise the good bugs in all the stages of their lives, so you don't mistake them for pests.
One of the beautiful things about this approach is that it helps us to appreciate the full life cycle of the plant. Instead of cursing when the rocket or coriander goes to seed, you can now appreciate the fact that those pretty flowers will attract beneficial insects.
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