Palmers Guide to Pest and Disease Control

Plants suffering from moisture stress (either too little or too much) are more susceptible to pests and diseases.

Combining Natural & Chemical Methods

The decision to use chemicals depends on the nature of the problem. If there is a high risk of damage, it is often the only solution. However, some planning and regular attention can be very effective in discouraging pests and preventing disease. Here are some examples.

Garden Hygiene

Keep your garden clear of long grass and weeds - they often harbour pests.
Diseased plants, fallen leaves and fruit and pruning wood should be removed and burnt.

Plants suffering from moisture stress (either too little or too much) are more susceptible to pests and diseases.

Choose disease resistant varieties of plants. Choose plants suited to your local soil and climatic conditions.

Companion planting is a natural form of pest control. Include herbs that deter garden pests (e.g. chives and garlic planted under roses deter aphids; marigolds combat whitefly) and shrubs which attract insect-eating birds.

Mechanical control

Here’s how you can get 15 minutes exercise a week! Weed your garden regularly and remove pests, diseased fruit and leaves by hand.

Lay insect traps. Yellow cards spread with glue will attract and trap whitefly.

Lay dishes of beer to attract slugs and snails. (They will drown themselves in it.)

Biological control - Natural predators

Introduce natural enemies to pests. Birds feed on insects, while lacewings feed on aphids and whitefly. Ladybirds, frogs, lizards, spiders and wasps all feed on insects. Welcome and conserve as many of these creatures as possible in your garden. A single frog can eat as many as 10,000 insects in a three month period.

Chemical control

Fungicides and pesticides are the quickest and most effective method of preventing and controlling pests and diseases. It is important to remember that all chemicals are dangerous and require careful, responsible use. For further information on safe usage of chemicals read our Palmers Guide To Spraying.

Common pests and diseases

Vegetables such as Courgette, Sweetcorn, Cucumber, Beans, Cabbage, Broccoli & Tomatoes

Symptom:
Holes in leaves or fruit
Cause:
Caterpillars
Control:
Target, Mavrik, Orthene.

Symptom:
Clusters of insects on growing tips
Cause:
Aphids
Control:
Target, Mavrik, Orthene.

Symptom:
Tiny white insects on the undersides of leaves - fly when disturbed
Cause:
Whitefly
Control:
Target, Mavrik, Orthene.

Symptom:
Mottled or yellow leaves becoming dehydrated
Cause:
Mites
Control:
Mite Killer or Mavrik

Symptom:
White powdery mould on leaves
Cause:
Powdery Mildew
Control:
Saprol, Fungus & Mildew spray

Symptom:
Small black spots with yellow margins on the tomatoes
Cause:
Bacterial spot
Control:
Remove bad leaves. Spray with Copper

Symptom:
Black rot on the bottom of tomatoes
Cause:
Blossom End Rot
Control:
Regular watering

Common pests and diseases

Fruit trees & ornamentals such as Peaches, Feijoa, Tamarillo, Passionfruit, Citrus, Apples, Grapes, Azalea, Camellia, Fuchsia, Bottlebrush, Manuka & Pittosporum

Symptom:
Yellow leaves distorted and tightly rolled
Cause:
Leaf Curling Midge
Control:
Target or Orthene

Symptom:
Leaves webbed together, sometimes rolled, many small holes especially on new growth
Cause:
Leaf Roller Caterpillar
Control:
Target or Othene

Symptom:
Tunnels in apples
Cause:
Codling Moth
Control: 
Target or Mavrik

Symptom:
Black spots on leaves or fruit
Cause:
Black Spot
Control:
Saprol, Fungus & Mildew Spray

Symptom:
Powdery Mould
Cause:
Powdery Mildew
Control:
Saprol, Fungus & Mildew Spray

Symptom:
Leaves silver & dry, with brown specks on the underside
Cause:
Thrips
Control:
Target or Orthene

As mentioned before, if you are unable to identify the problem in your garden take a sample to your local Palmers Gardenworld and we will identify it for you.

Natural Methods

Natural methods can help control pests and diseases, but a suitable spraying programme is the only sure way of preventing them from becoming established in the garden.

Pests and diseases will always be present in your garden to some degree. To treat the problem effectively, you must first identify the pest or disease you are dealing with. If you are unable to do so, bring us a sample of your affected plant and we will be happy to advise you on how to deal with the problem.