Attracting the Good Bugs
The ladybird is almost universally recognised as the ‘good bug’ in our gardens. But did you know that there are hundreds of beneficial insects (or good bugs), reptiles, spiders and microbes, maybe even thousands, hard at work in our gardens?
Or to be honest, they should be there but they might not be because they could have been wiped out by poisons (even organic ones), insufficient food (too few flowers), no shelter (mulch) or a lack of water.
“In the long term,” says agricultural scientist Johan Gerber, “these organisms play a role in the natural control of pests in the garden.” Johan is a tireless campaigner for environmentally responsible gardening. For any gardener wanting to share the garden space in a mutually beneficial way, his book, The Garden Guardian’s guide to environmentally responsible garden care, is both instructive and inspiring. Restoring the balance The use of pesticides is a major reason for the lack of beneficial insects in the garden, but not the only reason, says Johan. Low-maintenance gardens consisting mainly of evergreen shrubs, extensive paved or built areas, limited plant diversity, barren soil, and the absence of water, mulch, compost heaps, shrubs, grass and trees for shelter, does not create a conducive space for the various forms of natural wildlife.
Not using any pesticides is obviously the safest option. If pests are a problem, especially in the vegetable garden, spray only the infested plants with an insecticide that specifically targets the pest. “Never spray each and every plant just for the sake of spraying,” says Johan.
Some other pointers:
- Broad-spectrum insecticides for large beetles generally eradicate many beneficial predatory insects.
- Even when using an organic insecticide, read the enclosed pamphlet for its actions and secondary effects. For instance, an insecticide containing natural pyrethrin will kill adult ladybirds on contact.
- Insecticides containing garlic act as repellents.
- Canola oil or other oil has a smothering action but can adversely affect spiders.
- Pesticides that are least likely to harm beneficial insects are biological insecticides such as those containing Bacillus thuringiensis var. kurstaki (Margaret Roberts Biological Caterpillar Insecticide) for eradicating leaf-eating caterpillars.
- Use natural methods where possible. Wash off the pests with a strong jet of water, remove by hand, and interplant with trap crops (nasturtiums, fennel) that draw pests away from the crop. Healthy soil produces strong, healthy plants that withstand pest damage.
- Look for a product like Larvae Pro from Ecobuz, which is a biological bacteria that contains a protein that when ingested stops the Lepidopteran larvae pests from eating. This product is host specific so beneficial insects are not harmed.
More flowers Equals More Good Bugs
This sounds crazy, but you need flowers to attract the baddies (aphids, red spider mite, caterpillar larvae, mealybug) as well as flying insects if you want the good bugs. That is because they provide food for predatory ladybirds, lacewings, pirate bugs, bee flies, parasitic flies and wasps, as well as dragonflies, mantids and chameleons that prey on flying insects. Flowers are also the major source of food (nectar) for pollinators and beneficial predators like parasitic wasps and birds. Flowers with easily accessible pollen are best, such as daisy types (Shasta daisy), coreopsis, cosmos, hibiscus, salvias, flowering herbs like dill, fennel, tansy, yarrow, borage, golden rod, roses (especially single or double roses) marigolds and indigenous shrubs and grasses. The more variety the better.
Water Attracts Good Bugs
Beneficial predators like dragonflies and damselflies need water to complete their life cycles. Water attracts butterflies, whose larvae acts as bait, as well as frogs and toads, which are highly effective hunters. Wildlife-friendly water features include ponds, birdbaths, wet areas, shallow drinking basins, and slow-bubbling water features.
Many insects seek shelter under mulch, in piles of sticks or wood, in well-rotted compost, and in decaying trees. In other words, don’t make your garden too tidy. Bug hotels are a fun way to provide upmarket accommodation but supplement it with plenty of decaying matter on the ground for the creepies and crawlies. This will attract hoverflies, bee flies and robber flies that overwinter under fallen leaves. Their larvae live in the soil or in decaying plant material. Centipedes, which are predators of soil pests, favour well-composted soil.
Lesser-known (or appreciated) good bugs
Spiders usually evoke an eek! or worse, but they are efficient predators of many insects. All should be protected, even the poisonous ones. Avoid almost all chemical insecticides and organic insecticides containing natural pyrethrins, nicotine, potassium salts and canola oil. Biological insecticides are not harmful. Spiders can be found among flowers, leaves, groundcovers and in grassy areas.
Best action: steer clear and pretend you don’t see them.
Mantids are charming creatures found mainly among shrubs and perennials. They feast on conifer aphids, amongst others, which puts them in danger because the spray for conifer aphids will also kill them. Use an insecticide to control small-bodied insects and avoid any for large beetles.
Minute pirate bugs (Orius) feed on aphids, whitefly, mites and caterpillar larvae. They like to hide out in hedges, permanent plantings and the flower bed, particularly among lacy or daisy-like flowers. Broadspectrum insecticides for large beetles will kill them.
Assassin bugs look like stinkbugs but are dark coloured in camouflage combinations of black, grey and green. They inhabit conifers, shrubs, hedges, bushes and roses, and prey on a wide range of insects, including aphids. Don’t use broad spectrum insecticides, even organic formulations containing canola oil.
Lacewings hunt down small, soft-bodied insects, and can’t resist a banquet of aphids. They are drawn to flowers, where most of their prey is to be found. They need a source of water during dry periods if they are to survive. They are identified by their two pairs of multi-veined wings that fold like a roof over their bodies.
Source: The Garden Guardian’s guide to environmentally responsible garden care by Johan Gerber (Aardvark publishers) For more information visit: www. biologicalcrophealth.co.za