There is a wide range of pests and diseases that can attack a garden – some causing only annoying disfigurements and others resulting ultimately in death. But don’t panic – most are an opportunist, striking only when plants are stressed, and can be easily controlled or avoided.
The best way to avoid them is with good growing conditions, vigilance, and cleanliness. If you do need to resort to tougher measures, there’s usually a choice of chemical or organic controls, and the new biological pest controls are a boon. So take heart – there are many strategies to prevent pests and diseases from taking a hold and some very effective remedies if they do slip through your defenses.
Pest and disease prevention
A vigorous plant is much less likely to succumb to disease or to be crippled by pest attack, so your first step is to ensure healthy soil. Dreadful the soil you start with, you can amend it to create the fine, crumbly texture that any plant would thrive in.
Growing healthy plants
When buying plants, choose the sturdiest, healthiest specimens, and reject any that shows any sign of pest or disease attack. And once home, it’s important to grow them in the right locations. Sun-lovers like lavenders will fail in the shade and moisture-lovers like hostas will hate hot, dry places. Take care not to damage young plants, especially when planting, and keep them well watered until they become established – any check in their growth weakens them and makes them more vulnerable.
Vigilance
The sooner you spot a problem, the better. Most pests and diseases are very easy to deal with in the early stages, and prompt action prevents a minor irritation from becoming a full scale attack. A quick tour through the garden at regular intervals, will let you take stock of your plants and detect any emerging problems.
Cleanliness
Is next to Godliness and, in a garden, next to impossible. However, try to be reasonably clean and tidy. Plant debris and leaf litter are natural hiding places for slugs and snails, and diseased leaves and shoots should always be put in the trash rather than composted or left in the garden to reinfect other plants. Disinfect in a weak bleach solution any garden tools you have used on diseased plants and scrub out containers before reusing them.
Organic controls
Organic gardeners have a number of effective techniques for dealing with pests and diseases. Foremost among them is prevention by selecting disease-resistant varieties and using sound cultural practices. If problems do occur, one good defense is physical barriers, such as simple tin-foil collars around the plant stems or floating row covers to deter cutworms.
If spraying or dusting does become necessary, the chemicals used are all derived from natural sources -sulfur dust fungicide, for instance, or pyrethrum insecticide, which is made from the pyrethrum daisy. Other insecticides are based on soap – an excellent way of cleaning up the problem.
Organic gardeners cherish local wildlife as the ultimate in pest control. Birds, for instance, do a wonderful job of eating caterpillars and aphids, and frogs and toads will devour a good number of slugs. Feeders and houses for birds, ponds for frogs, and boxes for bats are all part of the organic gardener’s armory.
Smaller creatures can be equally useful. Ladybugs and their larvae prey on aphids, as do the larvae of lacewings and hover flies. These predators can be attracted to the garden by providing flowers rich in nectar and pollen, such as cosmos, marguerites, yarrow, angelica, fennel, and butterfly weed. Praying mantis nymphs and adults dine on aphids, leaf hoppers, and caterpillars. Even the much-maligned wasp is beneficial: yellow jackets eat fly larvae and beetle grubs, while tiny trichogramma wasps prey on borers, gypsy moths, whiteflies, and mealybugs.
Biological controls
This is one of the most exciting – and effective-developments in pest control, whereby the natural enemies of a specific insect are introduced into the garden. These “enemies” might include predatory insects, parasites, or microorganisms, such as bacteria or viruses.
One such control is Bacillus thuringiensis (Bt), a microbial insecticide that is deadly to certain caterpillars, mosquitoes, and beetles but harmless to other insects, mammals, and the environment. Another is Bacillus popilliae, or milky spore disease, a bacterium that kills only Japanese beetle grubs. Parasitic nematodes are used in the lawn to control beetle grubs and in the garden to combat weevils.
Biological controls are available from mail-order sources and some garden centers.
Chemical controls
These are synthetic chemical compounds and despite the current movement toward organic methods, they still have a role to play in pest and disease control, although many gardeners prefer to use them as a last resort.
Contact pesticides must come in contact with the insect to be effective, but systemic insecticides are absorbed by the plant and taken in by the insects when they feed on it. Similarly, contact fungicides act on the surface fungal spores, while systemic sprays kill any trace of the disease within the plant’s tissues.
Chemicals are the most instantly effective control method and the longest lasting. But they need to be used very carefully. Always follow the manufacturer’s instructions to the letter, keep a separate watering can or sprayer for applying them, and store them well out of the reach of children and animals.
Image: by mylifeasateenageblogger
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