Gardening Pests

Indoor Gardening

It is virtually impossible to keep your indoor garden - conservatory, greenhouse, window sill or potted plants - entirely free from pests. The goal should be to keep the level of infestation down as much as possible. The main problem is that the indoor environment provides pests with the same degree of warmth and protection from predators and the elements that benefit the plants.

Most indoor pests are 'sucking' creatures, deriving their nutrition from plant sap through specialised piercing mouthparts. Apart from the unsightly appearance of the pests themselves, the effects on the plants vary but common symptoms include:

• Slowing of growth
• Reduction in the number, size and attractiveness of flowers
• Yellowing, curling or stunting of leaves and stems
• Withering and early loss of leaves
• Sticky deposits - actually excreted by the pests - on, and under, the affected plant which hold dust and may become mildewy

Common indoor pests

Greenfly - These are also common in the outdoor garden, particularly on roses. They are comparatively large insects that are obvious to the naked eye. Plants such as fuchsia, cyclamen, cineraria, primula and basil are ready targets for these creatures.

Whiteflies - Like miniature white moths. The young are unwinged, transparent discs with protective scales. They live on the underside of leaves and transform them into sticky messes. Pelargoniums and fuchsias attract these pests.

Scale insects - The adults are brown or grey, oval or round in shape. The young are smaller, round and paler in colour. They target the underside of leaves, especially around the primary vein and leaf edges. They also like the bark of stems and branches. Again, a sticky mess results.

Mealy bugs - The bugs are covered with white fluff and sticky excrement may also be present. Find them around in the crevices and spine bases of cacti.

Red spider mite - These are microscopic in size, grouped on the underside of leaves. They may appear as red-brown, pink yellow or even white and cause a webbing and speckling effect on leaves. Fuchsia, chrysanthemum, pelargonium and impatiens (busy lizzie) are targets.

Dealing with pests

Care must be taken not to import infected plants. Since one pest or one egg may be enough to start an infestation, this is easier said than done. If possible, try to quarantine new plants for at least a month in a location well away from your existing healthy stock.

The most vulnerable plants are those that are underfed, under- (or over-) watered, or weak through lack of light or warmth. Healthy plants are more likely to resist infestation, so basic care is important. A dry atmosphere and dried-out compost are particularly likely to encourage pests.

Inspect plants regularly, especially in areas prone to attack - the undersides of leaves, tips, buds leaf joints and crevices. Crush any insect you find between finger and thumb or nails, trying to avoid damaging the plant. Checking the first sign of infestation promptly can save you from serious problems later on.

If you have not been doing this and discover a major infestation, move a badly affected plant away from healthy stock. If possible, put the plant outside (obviously, not in cold weather). The pests will probably dislike the outside environment more than the plants and birds or ladybugs may give a helping hand. If the plant is heading for its doom anyway unless treated, this is likely to be a risk worth taking. If the plant is strong enough, another approach is to use a hose with a nozzle to blast the creatures from the leaves. Don't use ice cold water and don't set out to wreck the plant with too much pressure!

Where the infestation is not out of control, consider the use of commercial sprays. Garden centres stock a range of organic and non-organic sprays and powders targeted at specific pests. These can be effective although the claims on the packaging can be somewhat optimistic. Finally, specialist suppliers can provide biological controls - predators that attack specific pests.

Outdoor pests

Dealing with Slugs and Snails
If you have a garden, you are guaranteed to have slugs and snails.

American Horticultural Society Pests and Diseases: The Complete Guide to Preventing, Identifying and Treating Plant Problems