Do It Yourself Pest Control - Some people find it satisfying to make up their own pest control products. Gardeners interested in creating their own pest control remedies are not necessarily looking for cheap or easy options, but merely searching for low toxic alternatives to chemical sprays. There is also something rewardingly macabre about watching caterpillars that have been decimating your cabbages, wriggling around in agony when covered in chilli spray you have made yourself.

Tree Pastes
Tree pastes are used as an aid to tree vigour and for pest and disease control. Biodynamic gardeners routinely use tree pastes during winter. The original formula proposed by biodynamics founder, Rudolf Steiner, was composed of:
4 parts cow manure (naturally aged, not processed products)
2 parts diatomaceous earth* or silica sand
3 parts fine clay* or bentonite*

My own experiments centre on insecticide grade diatomaceous earth as the primary ingredient. I use pastes to prevent borer attack and control scale infestation on roses and citrus. It should be noted that insecticide grade diatomaceous earth is not the same as the heat treated and highly dangerous diatomaceous earth used in swimming pool filters.

I include diatomaceous earth (2 parts), clay (1 part), powdered or liquid seaweed (1 part), sheep manure (1 part) and molasses (0.25 parts) in my mixture, but know of gardeners who add blood and bone. Including clay and manure helps the paste stick and gives it an earthy colour. Pastes are diluted with water until they reach the consistency of thick paint and work best when applied to thin barked trees and shrubs during winter.

*Insecticide grade diatomaceous earth is available in domestic quantities from Green Harvest www.greenharvest.com.au. Bentonite can be purchased from most produce stores, but is usually only available in large bags. Potter’s clay is available in small quantities from discount stores and craft suppliers.

Black Spot Spray/Bicarb Soda Spray
1 tablespoon of bicarbonate soda
4.5 litres of water
1 tablespoon of homemade Oil Spray concentrate (see below) or commercial oil spray (vegetable oil based)
Spray weekly as a preventative treatment to minimise black spot and mildew.  Improve air circulation around plants.  Avoid wetting the foliage and thin out overcrowded growth. Remove any leaves affected by black spot as soon as they are sighted.

Casuarina Tea
Casuarina trees contain high levels of silica. Biodynamic gardeners make a spray made from casuarina foliage for use against fungal diseases like anthracnose and other mildews.
Simmer 60gm dried Casuarina needles in one litre of water for 20 minutes using a stainless steel container.
Strain and dilute 1 part concentrate to 40 parts water.
Spray in the air around trees early in the morning.
For further information go to www.biodynamics.net.au

Garlic Spray
Three large cloves of crushed garlic
1 tablespoon of vegetable oil
One teaspoon of liquid soap
One litre of water
Combine the garlic and vegetable oil and leave to soak overnight. Strain and add to the litre of water along with the liquid soap. Spray regularly. Garlic in known for its antifungal and antibacterial properties, but it is its insect repellent qualities that most gardeners admire.

Powdery Mildew Spray/Milk Spray
Powdery mildew appears as grey or white powdery spots on the new foliage.  It causes puckering of the foliage and in severe infestations, a burnt appearance and leaf fall.   This disease occurs most frequently when night temperatures drop and relative humidity remains high.  Avoid the over-use of high nitrogen fertilisers as these can tend to make leave growth that is soft and more susceptible to disease.
1 part of milk
9 parts of water
Spray regularly over the leaves, paying particular attention to soft new growth

Homemade Oil Spray
Mix 500ml of vegetable oil
½ cup of Sunlight dishwashing liquid or other pure liquid soap
Blend thoroughly and seal in a clean, clearly labelled jar. Store in a cool area for later use.
Dilute one tablespoon of the concentrate into one litre of water before spraying.

Oil based mixtures can be used to suffocate mites, scale and other soft bodied insects. They help to repel leaf miner moths and some gardeners even find them effective against grasshoppers. Avoid using on plants with hairy leaves and during very hot weather.

Molasses Spray
Dissolve one tablespoon of molasses into a litre of warm water.
Add one teaspoon of Sunlight dish washing liquid or other pure liquid soap

Spray regularly over the leaves of all plants attacked by caterpillars and other chewing pests. Caterpillars would rather starve than eat leaves sprayed with this mixture. It has also been used with success by some gardeners as a possum repellent and for the treatment of soil affected by root knot nematodes by doubling the concentration of molasses.

Chilli Spray
Small hot chillies (40-50)
2 litres of water
5 grams of pure soap flakes dissolved in hot water or a few drops of liquid soap
Puree the chillies and one litre of water together in a blender. Strain the mixture through a fine sieve and add the soap and the other litre of water. Spray this mixture undiluted on to plants.

This spray is a favourite with warm climate gardeners who have chillies in abundance almost year round. If you do not have a chilli bush you can substitute chilli powder or paste. Chilli spray is particularly effective against ants, aphids and other soft-bodied insects.

Warning - This mixture can look attractive to children, so be sure to label correctly and store out of their reach. Wear gloves when spraying and ensure that the mixture does not come in contact with your skin or eyes.

(This text contains an edited extract from my book, 'Organic Vegetable Gardening', published by ABC Books). See [What's New]