Organic pesticides are pesticides made from naturally occurring organic mixtures.
Introduction
Organic pesticides can allow farmers to control pest and diseases in plants without resorting to conventional pesticides. This does not necessarily mean that they are safer to use. Organic presticides can be as damaging to the environment as conventional ones. (For further discussion see http://www.bna.com/webwatch/organicpesticide.htm)
This page focuses on providing recipes to help make organic pesticides from locally available materials. This can be of great benefit to farmers in the developing world, where it is often probitively expensive to buy commercial pesticides
Know your problem!
The key to organic pest control using pesticides is to know exactly what the problem in that is causing problems. If pests or fungii can be indentified this can help choose the best pesticide to use.
Here are some resources that can help you identify the problem:
- Texas Plant disease Handbook- This excellent resource has a list of common crops in Texas and commonly associated pests and diseases. Pictures included
- A guide to Natural Enemies in North America - List of predators with pictures. Useful guide but some latin may be required!!
- Household and Structural Pest Identification - Follow the key to identify common pests.
Organic Pesticide List
Note: Where a plant is named as an potential pesticide, this plant can often be intercropped to have the same pesticidal effect
Organic Pesticide | Pests & Diseases to use against | Notes | Recipe links | Academic articles |
---|---|---|---|---|
Alcohol | Mealy bugs | [1] | - | |
Animal Urine | Aphids, cattepillars | Has dual use as it acts both a fertiliser and a pesticide | recipes | |
Ash | Common insects | recipes | ||
Baking soda, sodium bicarbonate, potassium bicarbonate | fungus', powdery mildew, rose black spot, anthracnose, downy mildew, brown patch | [2] [3] [4] [5] [6] | [7] | |
Black Jack seeds | Aphids, cattepillars | recipes | ||
Cornmeal, Cornmeal solutions | yellow leaves on photinia, brown patch, algae in seedlings, leaf spots on roses | [8] | ||
Dead bug spray | Any insects | [9] | - | |
Detergent, detergent solutions | Aphids | [10] | ||
Garlic, garlic solutions | Aphids, mosquitoes, onion flies, rabbits (on potatoes), other chewing and sucking insects | Garlic can also be intercropped to repel similar insects | [11] [12] [13] [14] [15] | - |
Melia Leaves | Aphids, cattepillars | recipes | ||
Milk, milk solutions | Mildew, blight | [16] recipes | [17] (abstract) [18] - Crop Science (Vol. 18, 1999, pp. 489-92) | |
Neem Leaves | Aphids, Bull worm, cattepillars | Neem can have multiple functions such as for medicinal use. See Neem article | recipes | |
Pepper, Hot pepper, Chillis | cats, dogs, insects, bugs, snails and snails (on leaves) | often used in combination with spearmint to improve effectiveness | [19] [20] | - |
Soap, soapsuds, soap solutions | Slugs, aphids | Solutions can be sprayed on any plant leaves or used near affected plants | [22] [23] | - |
Spearmint | insects, bugs, chewing insects | often used in combination with hot pepper to improve effectiveness | [24] [25] | - |
Tobacco, Nicotine, Nicotine Solutions | Caterpillars, aphids, many types of worms, fungus gnats, symphylids, centipedes, root lice, other underground pests | Solutions can be sprayed on any plant leaves or used near affected plants | [26] [27] | - |
Tomato leaves | Insect repellent, blight | [28] recipes | ||
'Traditional' appropriate pesticides | Common insects | These include battery acid, cigarette butts in water, soapy water |
To be added to list:
- Neem oil
- BT
- Confusion Lures
- Copper Sulfate
- Jojoba Oil
- Citric Acid
- Potassium Bicarbonate
- Sulfur
- Insecticidal Soap
- Paraffinic Oil
- Diatomaceous Earth
- Garlic Oil
- Spinosad
- Pyrethrum
- Kaolin Clay
- Bordeaux mixture
- silicic acid
Plant extracts
For this, plants are steeped in cold or warm water for a certain period. The liquid is then sifted trough a linen cloth and then sprayed on the crop or on the nearby soil. Most extracts contain trace elements and/or plant hormones that strengthen the cell walls and reinforce the plant's defenses. A number of them also contain substances that kill off or slow down the targeted pest organism. Treatment should thus be often repeated from the start of the cultivation.
- Wormwood: the poisonous tannins that the plant contains make the crop unpalatable for insects. Effective against aphids and mites. Extract: 200-300 g of dried wormwood is mixed with boiling water. After 1 day, water is added so that 10 liter is obtained. Sift and and spray on the crop.
- Tansy: animals find the odor and taste of this plant unpleasant and will not eat from it. Usable against various insects. Extract: 300g fresh plant parts per 10 liters of water. Cook briefly first and then allow to rest for 24 hours. Sift and spray.
- Stinging nettle: the active substance is formic acid. It is the most known, softest cure for aphids, not usable against other insects. Extract: steep 1kg fresh nettles per 10 liter of cold water. Then sift after 24 hours and spray undiluted. Stinging nettle manure: the same mixture is left to stand for about 5 days. Stir regularly and add rock meal. Dilute 10 times and then pour on the soil. The slurry is used as a strengthening fertilizer.
- Equisetum arvense: This herb contains much silica which strengthens the cell walls. An extract of horsetail has a good efficiency against fungal diseases. Extract: 1 kg of fresh or 150 g of dried horsetail is boiled for 15 minutes in 10 liter water. Let rest for a few hours, sift, and dilute 5 to 10 times before spraying.
Seaweed extract: extracts of brown and blue-green algae contain a high content of trace elements, magnesium and potassium. Their growth-promoting value it attributed to the vitamins, plant hormones and enzymes. It increases resistance to disease and promotes growth.
Derris and kwassia: harmless to humans but it is less effective as an insecticide.
Rock meal: Seaweed calcium, basalt and lava meal have a crop protective function. They increase the acidity which impairs development of bacteria and fungi. The fine rock meals act dehydrating and damage the wax layer of many insects. By dusting or spraying, the plants are covered with a thin layer of dust. Treatment is done in the evening and it should not rain for 12 hours (maximally done for up to 2 times per month). Dosage= 250g/are.
Commercial preparations: Soap: a hot water solution with 1 to 3% (10-30g/liter) soft soap (green or brown) has a moderate working against aphids and some other insects. The insects must be properly hit with the soap solution.
Ethanol-soap mixture: ditto above but add 50 ml of ethanol per liter of water
Sulfur: one sprays pure sulfur against several fungi (mildew and scab). Is harmless to humans and animals.
Bordeaux mixture: is a mixture of copper sulphate and slaked lime. It works preventively to fungal attacks. It is a very old mixture. The copper ions on the leaf prevent the germination of the fungal spores and the calcium also increases the pH.
Pyrethrum: this plant-based insecticide is a strong neurotoxin to all cold-blooded creatures. It is virtually harmless to warm-blooded creatures however. Pyrethrum breaks down within 48 hours. Other plant-based insecticides are Koppert Rotenon and Koppert Plantschoon.