The active ingredients of neem oil include a group of seven constituents similar to, and including the compound, azadirachtin. This compound has been shown to be a systemic feeding deterrent for insects. Azadirachtin does not kill pests but it breaks the life cycles and deters feeding, hatching, ecdysis (moulting) or any combination of these processes. Neem is effective in the control of fruit fly, aphids, mealy bug, cabbage worm, nematodes, Japanese beetle, leaf eating insects. Neem oil also controls powdery mildew, black spot, rust, leaf spot to name just a few. It can be used as a household pesticide for ants, cockroaches, house flies, sand flies, snails, termites and mosquitoes, both as a repellent and larvicide. However, neem oil is non-toxic to humans, birds, fish, bees, earthworms, mammals and predatory insects.

Neem oil has a garlic-like odour and an extremely bitter taste. The bitter flavour can make many insects stop feeding on the host plant. Neem oil can also suffocate mites, whiteflies, aphids and other types of soft bodied insects on contact. These multiple modes of action make it unlikely that insects and plant pathogens can develop resistance to neem compounds. 

Neem can be effectively used in hydroponics, aeroponics, greenhouses, shadehouses, ornamentals, interiorscapes, horticulture, landscapes, nurseries, turf farms, shrubs, flowering shrubs, fruit and nut trees. Great for the organic gardener! To date, neem is not registered in Australia and therefore should not be used by commercial growers of food crops.

As a fungicide, neem oil is mainly used as a preventative and when disease is just starting to show. It coats the leaf surface which in turn prevents the germination of the fungal spores. Neem oil is effective against rots, mildews, rusts, scab, leafspot and blights.

Like most vegetable oils, neem oil is also non-soluble in water and has to be made soluble with the use of a suitable emulsifier before spraying. Some commonly available emulsifiers that can be used include hand washing or dish washing liquid soaps, soap oil, eco-friendly detergents, soap nut powder, or Natra soap.

APPLICATION

A general-purpose application rate is to use neem oil at a 1% ratio to water with an emulsifying agent. 

To make 1 litre 

1. Take 100ml of water in a container.
2. Add 5ml of liquid soap, detergent or suitable emulsifier (eg Natrasoap) to this 100ml of water and agitate well until the soap/emulsifier is completely dissolved in the water.
3. To this solution, add 10ml of neem oil and agitate well until a pale yellowish-white emulsion is formed.
4. Add this prepared emulsion to 900ml of water in a spray bottle and agitate.

You now have 1 litre of eco-friendly, powerful, bio-pesticide ready for use.

The following recipe makes 10 litres: 

1. Take 1 litre of water in a container.
2. Add 50ml of liquid soap, detergent or suitable emulsifier (eg Natrasoap) to this 1 litre of water and agitate well until the soap/emulsifier is completely dissolved in the water.
3. To this solution, add up to 100ml of PURE NEEM 100% neem oil and agitate well until a pale yellowish-white emulsion is formed.
4. Add this prepared emulsion to 9 litres of water in a bucket and stir thoroughly.

You now have 10 litres of eco-friendly, powerful, bio-pesticide ready for use.

Spraying should be done within 8 hours of mixing, using a knapsack sprayer or any suitable sprayer. This can be used as a foliar spray on plants and also can be drenched near crop roots. As neem is biodegradable, it is recommended to repeat the spraying at internals of 7 to 10 days. Spraying should be undertaken in the morning or late in the evening. During hot conditions the frequency of spraying should be more. In winter, spraying once every 10 days is sufficient.

For the organic gardener, try our garden spray concentrate which has been pre-mixed with Natrasoap as an emulsifier and is ready for use in your own spray bottle using 5ml – 10ml to 1 litre of water.