Homemade Pest Control Remedies
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.

Bicarbonate of Soda Spray - Black spot; mildew
• 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)
Combine the ingredients and spray weekly to minimise black spot and mildew diseases. This spray works by changing the pH of the leaf surface. Take steps to also improve air circulation around plants; avoid wetting the foliage and thin out overcrowded growth. Remove and dispose of any diseased leaves as soon as they are sighted.

Casuarina Tea - Bacterial and mildew diseases; grasshoppers
• 60gm dried Casuarina needles
• 1 litre of water
Simmer the dried needles for 20 minutes using a stainless steel container. Cool, strain and dilute 1 part concentrate to 40 parts water. Spray directly on to the foliage of plants. For further information go to biodynamics.net.au

Casuarina trees contain high levels of silica. Foliage that contains high levels of silica is tougher and more difficult for disease organisms to penetrate and is less attractive to chewing pests. Biodynamic gardeners use this spray against fungal diseases like anthracnose and other mildews. The sprayed silica is absorbed by plant leaves and roots.

ChilliChilli Spray - Caterpillars; ants; soft bodied insects
• 20+ small hot chillies
• 2 litres of water
• 1 teaspoon liquid soap or 5 grams of pure soap flakes dissolved in hot water
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, paste or a little tobacco sauce. Chilli spray is particularly effective against ants, aphids and other soft-bodied insects like caterpillars. Label and store out of reach of children. Wear gloves when mixing and spraying. Avoid contact with your skin or eyes. Chilli powder sprinkled directly on the tops of potted plants also acts as an ant deterrent.

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.

Garlic Spray - Caterpillars; soft-bodied insects
• 3 large cloves freshly crushed garlic
• 1 tablespoon of vegetable oil
• 1 teaspoon of liquid soap
• 1 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. Garlic and chilli sprays can be combined for an extra potency.

Fruit Fly Bait – Queensland fruit fly (courtesy A & H Gugger - Mary Valley Orchards)
• 20lt of water
• 3kg sugar
• 50ml vanilla essence
• 400ml cloudy ammonia
Add this mix to recycled 2lt bottles with entry four holes ½-3/4 the way up the bottle. Fill the mix up to Ό (25%) full and hang multiple traps around the boundaries of your property. Proportionally reduce quantities for smaller properties.

Change bait regularly. Combine baits with the following strategies: Mulch thickly around trees; pick up fallen fruit and place in buckets of boiling water before composting; free-range your poultry to eat fallen fruit; net trees or bag fruit. Avoid growing guavas, feijoas and Brazilian cherries as these fruit attract and encourage fruit fly to breed in your garden.

Milk Spray - Powdery mildew
• 1 part full cream milk
• 9 parts of water
Spray regularly over the leaves, paying particular attention to soft new growth
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 they tend to make leaf growth soft and more susceptible to disease.

Molasses Spray – Caterpillars; soft-bodied insects; nematodes; cut worms; possums
• 1 tablespoon black strap molasses
• 1 litre warm water
• 1 teaspoon liquid soap or 5 grams of pure soap flakes dissolved in hot water
Combine and spray regularly over the leaves of all plants attacked by caterpillars and other chewing pests. Caterpillars cease eating sprayed foliage. The molasses then works by osmosis to force water into the body of the caterpillar causing it to die a day or two after application. Black strap molasses is the most concentrated, nutrient dense form of molasses as it is the residue of the third and final stage of the sugar extraction process. It is available at produce stores. Stronger solutions (x 2 molasses) may be used as a soil drench to guard against root knot nematodes and cut worms (apply in the evening when cut worms move to the soil surface). Regular spraying helps to repels possums. For an alternative possum spray see Oil of Cloves.

Oil of Cloves - Possum repellent
• 6 drops Oil of Cloves
• 1 litre water
Combine in a spray bottle and shake contents. Spray on plants or around the area that you want to protect from the possums. Repeat every week. Whole cloves can also be sprinkled around the perimeter of gardens you wish to protect and combined with the oil of cloves spray for ongoing possum issues.

Oil Spray - Mites; scale; aphids; soft-bodied insects; citrus leaf miner
• 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 suffocate mites, scale and other soft bodied insects. They help to repel leaf miner moths and some gardeners even find them effective against small grasshoppers. Avoid using on plants with hairy leaves and during very hot weather.

Soap Spray - Mites; aphids; soft-bodied insects
• Pure bar soap (Preserve or Velvet soap) or Lux Soap Flake
• Warm water
Grate bar soap (if using) or combine soap flakes with water to make a soapy mix to the strength you might use to wash cloves. Spray directly on to insects. Repeat sprays are necessary. Soap sprays break down the waxy external skeleton of insects.

Tree Paste – Borers (moths and beetles larvae); scale
Original formula proposed by biodynamics founder, Rudolf Steiner.
(Parts refer to volume eg: cups, buckets or handfulls)

• 4 parts cow manure (naturally aged, not processed products)
• 2 parts insecticide grade diatomaceous earth* or silica sand
• 3 parts fine clay* or bentonite*
• Water or seaweed extract (diluted to manufacturer’s instructions)

Wear a mask to avoid inhaling dry ingredients. Sieve the cow manure and clay (if using). Combine all ingredients with the liquid until it reaches the consistency of thick paint. Remove loose bark and paint all trunk and branches you can reach. Fill cracks and crevices with paint. Avoid coating leaves. The paste persists on trunks for around 6 months. Pastes can also be further diluted and strained to allow spraying on tree trunks and branches where large numbers of trees need to be treated. Do not store as it will ferment. Tree pastes work best when applied to thin barked trees and shrubs.

Painting the stems of trees and shrubs to aid to tree vigour and for pest and disease control is a traditional gardening practice. White paints are lime-based; others are clay-based. Biodynamic gardeners routinely use tree pastes during winter. The clay and manure help the paste stick; give it an earthy colour and provide nutrients to the tree. The diatomaceous earth acts as a barrier to pests. Traditionally these pastes are used during winter, but can be used successfully at any time of year. Use to prevent borer attack. Borers (moths and beetles) lay eggs that must tunnel through the bark. Diatomaceous earth acts as an abrasive barrier. Use it to control persistent scale infestation on roses, citrus and other trees and shrubs. Remove as much of the attached scale as possible, then apply a thick layer of paste to smother any remaining pests.

*Insecticide grade diatomaceous earth is not the same as the heat treated and highly dangerous diatomaceous earth used in swimming pool filters. Domestic quantities are available from City Chicks [https://citychicks.com.au/products/1311/]. Bentonite is available from produce stores (large bags only). Potter’s clay is available in small quantities from discount stores and craft suppliers.

Wood Ash – Caterpillars; soft-bodied insects; mites; small grasshoppers
If you have cold, waste ash from a wood fire you can recycle it on the garden to control pests. It is highly alkaline and irritates insect bodies. It is quite effective at controlling some mite infestations. Wear a mask to avoid inhalation and use gloves. Dust on plants or place on the palms of your hands and press on the upper and lower leaf surfaces of affected plants. Excess wood as can also be used as an alternative to garden lime. Apply at one-third the rate of lime.

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

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