How Can Pests be Controlled Organically?
Organic vegetable growers do not use chemicals to control pest or disease problems, but they may use "natural sprays" that are approved and accepted by the organic industry where they operate.
There are safe, organically sound sprays which can be used in the garden. They may not have a "bulldozer effect" like some of the potent chemicals, but they are safe to both you and the environment, and if used properly will keep most of your problems well under control.
There are two types of organic sprays:
- Sprays Made by the Grower. These can be effective if prepared and used as recommended, however things can go wrong when you don't know exactly what you are doing, both with making, and using a spray.
- Pre Packaged or Professionally Manufactured Sprays -There are a lot of companies today which specialize in organically sound garden products. The range of sprays available seem to be continually on the increase. Be sure they are 100% organic though.
SPRAYS YOU MIGHT TRY MAKING
Despite their low toxicity, it pays to always follow some basic rules with any spray, even organic ones:
- Don't use containers (eg: saucepans) for making sprays for cooking or anything other than making sprays.
- Label everything you make clearly and keep out of reach of children.
- Protect your skin when spraying and avoid breathing the spray in.
- Don't spray on hot or windy days.
- Only spray what needs to be sprayed.
Diatomaceous Earth Spray
This is fossilized algae (ie. Diatoms) which, when ground into a fine powder, produces microscopic razor sharp needles which will cut small animals such as insects or snails without being any serious threat to larger animals or humans. It can be applied as a dust or made into a solution and sprayed on. Avoid breathing it in. It can be purchased from swimming pool shops.
- Mix: 0.3 of a kilogram of diatomaceous earth
- 1 teaspoon of liquid detergent (eg: dishwashing detergent)
- 1.2 litres of warm water
Spray directly onto insects or plant parts which they will eat. It is effective against snails, slugs, aphis, thrip, mites, caterpillars, maggots and most soft bodied insect larvae.
Soapy water when sprayed over some insects will kill them. It is important to understand that it kills by putting a film of soap over their bodies which suffocates them. As such, it must contact and cover the insect when it is sprayed to work.
- Mix: 16gm of pure soap powder (be careful that it doesn't have any chemical additives).
- 2 litres of water
This is particularly effective on caterpillars, aphis, mealy bug and scale.
Quassia is sometimes available as chips of wood from stems of the plant "Picrasma quassioides".
- Boil 45gm of Quassia chips in water for half an hour.
- Strain off while still warm and mix with 40gm of soap flakes
- Mix 1 part of this solution with 2 parts of cold water and spray.
This may kill soft bodied insects such as aphids, caterpillars and even leafhoppers, but does not kill insects with a hard shell such as ladybirds or beetles.
- Mix 120gms of chopped garlic, 2 tablespoons of paraffin oil, 20gms soap powder and half a litre of water.
- Leave to stand for 2 days, strain, bottle and store in a dark, cool place.
- Add one part of this solution to 50 parts of water when ready to spray.
This has an effect that helps control both insects and fungal disease.
Particularly appropriate to control sucking insects such as mealy bug or aphis, or on fungal problems usually treated with sulphur sprays.
This is made from the flower heads of either "Chrysanthemum cinerariaefolium" or "Chrysanthemum roseum".
- Add 1 tablespoon of flower heads to 1 litre of hot water,
- Allow to stand for 1hr,
- Strain off the flower heads and add a pinch or two of soap powder.
- Mix and spray.
Effective against most insects.
- Boil 1kg of rhubarb leaves (not stems) in 2 litres of water for half an hour.
- Strain off leaves
- Add the solution to 9 litres of water
- Use within 24hrs
Spray on aphis
Do not eat any plants that have been sprayed within 2 days of spraying.
- Grind mustard seed into a fine powder.
- Put into a jar with some nail holes punched in the lid.
Shake over plants to control powdery mildew.
Stinging Nettle Spray
- Place chopped stinging nettle plants in a bucket of water,
- Cover and allow to stand for three weeks, or until the foliage has rotted down.
- Strain off the remaining plant material to obtain the nettle liquid.
It is rich in iron and can be sprayed as a nutrient fertilizer
The spray is reported to help control pests & diseases, and promote
better growth in a range of plants.
Can be used as an insecticide spray, similar to pyrethrum. Also deters mosquitoes and flies when leaves are bruised.
White Cedar (Melia azaderach)
A spray made from the leaves steeped in boiling water (which is cooled before application) repels grasshoppers.
Spray made from crushed eucalyptus leaves repels earwigs, slaters, ants and cockroaches. Applications should be done with care, as beneficial earthworms may also be adversely affected.
Organic vegetables can often command a higher price than other vegetables; but they can also cost more to grow, and in some respects, require a higher level of skill to be grown.
A big part of being able to avoid crop damage or losses is to identify and control problems before they get out of hand. Growers who use toxic chemicals can apply chemicals so freely that the problems are unlikely to ever appear; and if they do, the grower can use an "over kill" approach to attack and eliminate the problem quickly. The downside for that approach is that the produce is likely to contain chemical residues; and customers are increasingly aware of that fact., This is when and why organic produce can command a higher price.
You may use this course to help you convert your existing practices toward more "organic" growing; or you may use it to learn the basics before setting out to establish your own farm, small or large.