|Environmentally Sound Technologies for Women in Agriculture (IIRR, 1996, 213 p.)|
|Pests and pesticides|
Use of synthetic pesticides for controlling pests and diseases in field crops and stored grain is hazardous. It is also-often unnecessary since a number of common plants can be fumed into effective pesticides. Neem is one such tree.
Neem is a large evergreen shade tree grown in all parts of India. It bears flowers in February-April and its fruit matures after 4 months. Important parts are the fruit, leaves, twigs, and bark. About 40 percent of the seed weight consists of the kernel which contains 25-35 percent oil and 65-75 percent neem cake. One neem tree gives 15-30 kg of seeds per year.
For centuries, neem has been used as a pesticide. Dried leaves protect clothes and books against termites and other household pests. Dried neem leaves also help to keep stored grain free of pests. Neem cake mixed in soap helps control soil-borne pests in field crops. Neem seed chemical repels insects, deterring them from landing, feeding, and laying eggs on crops. Neem seed chemical reduces the growth and development of some insects, or causes them to be infertile or eventually die.
Neem products kill insects more slowly than synthetic pesticides, but neem has many advantages:
- Neem products are nonpoisonous. They do not affect people, birds, fish, and wildlife.
- Crushed neem seed kernel extracts are less costly than synthetic insecticides.
- Neem products do not pollute the air, water, or soil.
- Farmers can grow their own pesticides.
- Neem products can be made easily and cheaply at home.
Collecting and preparing seed
1 Collect ripe fruit fallen on the ground, or shake the tree branches and collect the fallen fruit.
2 Depulp immediately by hand or with a mechanical depulper.
3 Wash the seeds and dry them in the sun. Spread the seeds evenly on the ground and turn them regularly to ensure even drying. Make sure the seeds are thoroughly dry to avoid mould. (Mould affects both the amount of oil that can be extracted and the efficacy of the product.)
4 Store dried seeds in airy containers, such as baskets, jute or cloth bags, in a cool, dry place. Seeds can be stored up to one year, but not longer. Never store seeds in plastic bags.
Preparation of neem seed kernel extract
1 Collect fruit.
2 Remove seed coats.
Ready-made commercial neem products cost less than synthetic pesticides.
3 Crush 2 handfuls of kernels.
4 Add to 10 litres of water.
Add to 10 litres of water.
5 Stir for 20 minutes with a stick. Leave for 6-16 hours.
6 Add about a teaspoon of soap powder andteaspon of soap thoroughly.
7 Filter the contents through a muslin cloth.
Neem seed kernel extract
8 Spray on crop. Depending on the size of the crop, you will
need 2. 5-4 barrels of liquid (500
750 litres) to spray 0.4 ha (1 acre) of crop.
9 Repeat the spray after 5-6 days.
Preparation of neem oil emulsion
1 Put 500 ml of neem oil in a 10-litre bucket.
2 Add 50 g (10 teaspoons) of soap powder or Teepol. Stir well.
3 Add water to fill the bucket and stir until a white creamy liquid is formed.
4 If the oil forms on the surface as a separate layer, add more soap powder and stir again.
5 Spray the emulsion on a few plants before large-scale spraying. Wait for two days and check whether the spray has damaged the plants. If the plants are damaged, add more water to the liquid to reduce its concentration.
6 Spray 500-750 litres per acre, depending on the type and size of the crop. Spray until moisture runs off the plants. The crop should be completely covered (completely wet) with spray.
Contributors: Dr. R.P. Singh and Dr. Jagdish Singh