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Bio-pesticides: Copper, Sulfur
Copper can be used against the following pests/diseases:
Alternaria fruit spot / Anthracnose / Armillaria root rot / Bacterial black spot / Bacterial blight of coffee / Bacterial spot / Brown spot / Coffea leaf rust / Common blight / Downy mildew / Early blight / Leaf blight / Late blight / Phaeoramularia fruit and leaf spot / Phytophthora blight
Sulfur can be used against following pests/diseases:
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Some Pesticides Permitted in Organic Gardening
Organic gardeners can use certain pesticides -- chemicals that are derived from botanical and mineral-bearing sources. These chemicals may be highly toxic, but they break down more rapidly than common chemicals, such as the Sevins, Malathions and 2,4,Ds.
The use of botanical and mineral-bearing pesticides, even though some are toxic, also can be incorporated into an Integrated Pest Management (IPM) approach to growing crops. IPM relies on a variety of pest control means rather than on one product or method. The pesticides discussed below are appropriate to include in IPM programs.
Just as the more common chemicals are given toxicity ratings -- CAUTION, WARNING or DANGER -- so are chemicals from botanical and mineral-bearing sources. "CAUTION" means low toxicity or completely free from danger; "WARNING" means moderately toxic and "DANGER" means highly toxic. The toxicity rating for each pesticide is provided in the paragraphs below.
General information on copper
Copper fungicides were formerly accepted in organic farming provided that the number of applications was strictly followed and a proper soil amendment is observed to prevent copper accumulation in the soil, and can still be accepted with permission from the certifying authority. (Other fungicides such as Sulphur (Thiovit) are being tested by CIP).
In wet weather fungicide sprays should be applied as soon as the disease is observed or as soon as local experience suggests that weather conditions are favourable for disease development.
Crop scouting should be used as a guide in making a decision on whether to apply a fungicide. And when applying fungicides, safety procedures in application must be complied with, particularly, in use of protective clothing. Observe right dosage and prescribed pre-harvest intervals. Ask your local agricultural extentionist on locally registered fungicides.
Bordeaux mixture is primarily a fungicide that controls bacterial leaf spots, blights, anthracoses, downy mildews and cankers. It also repels many insects. The compound is labeled for use on many vegetables, tree fruits and nut crops.
Bordeaux, as with sulfur and lime sulfur, can be phytotoxic to plants. If applied in cool, wet weather, it may burn leaves or cause russeting of fruit.
Bordeaux mix spray
Materials needed to make a gallon mixture
- 3 ½ tbsp of copper sulphate
- 10 tbsp of hydrated lime
- 1 gallon of water (4 liters of water)
- Wooden stick
- Plastic bucket
How to prepare?
1. Add copper sulphate and hydrated lime in water. Make sure to use plastic container
2. Stir well using a wooden sick or ladle
3. Protect self from direct contact with the solution
How to use?
1. Spray plants thoroughly preferably early in the morning, in a dry and sunny day. In this way, the plants have the time to dry and the solution can not penetrate into the leaves' tissues
2. Constantly shake the sprayer while in the process of application to prevent the solution from clogging
Pest controlled
1. Flea beetles on tomatoes and potatoes
2. Anthracnose
3. Bacterial blight
4. Bacterial wilt
5. Black spot
6. Downy mildew
7. Late blight on solanaceous crops
8. Powdery mildew
9. Rust
10. and many other disease causing pathogens
General information on sulphur
Sulfur can be used as a dust, wettable powder, paste or liquid. Its primary use is to control powdery mildews, certain rusts, leaf blights and fruit rots. Spider mites, psyllids and thrips also are susceptible to sulfur. Most pesticidal sulfur is labeled for vegetables such as beans, potatoes, tomatoes, peas and fruit crops such as grapes, apples, pears, cherries, peaches, plums and prunes.
Sulphur has the potential to cause plant injury in dry hot weather (above 32°C). It's also incompatible with other pesticides. Don't use sulfur on plants within 20-30 days of applying spray oils. Sulphur reacts with the oil to create phytotoxicity.
While copper fungicides were formerly accepted in organic farming in many countries provided that the number of applications was strictly followed and a proper soil amendment is observed to prevent copper accumulation in the soil, and can still be accepted with permission from the certifying authority. Other fungicides such as Sulphur (Thiovit) are currently being tested by CIP.
Sulfur is non-toxic to mammals, but it may irritate eyes and skin. It has been given a CAUTION rating.
Lime Sulfur
Lime sulfur is made by boiling lime and sulfur together. The mixture is used as a dormant spray on fruit trees to control diseases such as blight anthracnose, powdery mildew and some insects including scales, thrips and eriophyid mites. Its drawbacks include its rotten-egg smell, its potential to burn exposed skin and eyes and to injure plants if applied when temperatures exceed 26°C. Lime sulfur has been assigned a DANGER rating.
Standard procedures for the preparation and application of homemade copper extracts
2. Read and follow the label instructions carefully, particularly, dosage, pre-harvest intervals and safety measures. Ask for assistance from your local extension agriculture office, if unsure.
3. Spray in the early morning or late afternoon.
4. Wear protective clothing when handling pesticides and during application. Wash your hands after handling of pesticides and application. Do not eat, drink or smoke when handling and during application of synthetic pesticides including copper.
5. Do not have a direct contact with the crude extract while in the process of the preparation and during the application.
6. Make sure that you place the extract out of reach of children and house pets while leaving it overnight.
7. Harvest all the mature and ripe fruits before extract application.
8. Always test the extract formulation on a few infected plants first before going into large scale spraying. When adding soap as an emulsifier, use a potash-based one. Gun soap (Kenya) is recommended.
Information Source Links
- OISAT: Online Information Service for Non-Chemical Pest Management in the Tropics. www.oisat.org
