Neem: Uses in Plant Protection

E. Lireni Kikon
SMS Plant Protection, KVK Dimapur

 

NEEM: It is commonly known as Neem or Margosa tree
Scientific name: Azadirachta indica

Family: Meliaceae

Plant part use: Leaves and seeds

Mode of action: Repellent, Insecticidal, Antibacterial, Antifungal, Antifeedant, Oviposition and growth inhibiting and crop and grain protectant.

Different formulations of Neem

 

1) Neem leaf extract:

 Take 1-2 kg of fresh Neem leaves and keep in a pot
 Pound Neem leaves gently with mortar and pestle
 Add 2-4 liters of water to it
 Cover the mouth of the pot securely with a used cotton cloth and leave it as such for 3 days
 Strain it to get clear extract
 Dilute 1 liter of Neem leaf extract with 9 liters of water and add 100 ml of soap
 Stir well and spray on the infested plants

 

Target pests: The solution can be used against Aphids, Colorado beetles, Grasshoppers, Grubs, Japanese beetles, Leafhoppers, Locusts, Plant hoppers, Scales, Snails, Thrips, Weevils and Whiteflies. ##10-12 kg of Neem leaves are needed for 0.4 ha

 

2) Neem seed extract:

 Take 3-5 kg of Neem seeds, remove the shells and place in a pot and pound seeds gently with mortar and pestle
 Add 10 liters of water to it
 Cover the mouth of the pot securely with the cloth and leave it as such for 3 days.
 Strain to get clear extract with used cotton cloth
 Dilute 1 liter of this extract with 9 liters of water and add 100 ml of soap and stir well.

 

Target pests: Spray on the infested plants against Aphids, Beetles, Bugs, Grasshoppers, Grubs Flies, Leafhoppers, Locusts, Moths, Nematodes, Plant hoppers, Scales, Snails, Thrips, Weevils and Whiteflies

 

3) Neem seed oil suspension in water:

 Put the 5 kg of finely ground seeds into a basin. Add half liter of hot water little by little until it is possible to knead the mixture
 Knead and press the mixture to get the oil

Approximately 650-750 ml oil is extracted from this mixture. (Refer to table 2)

Take desired amount of Neem oil and mix with soap before adding water. Stir thoroughly to prevent oil separation. Fill in the knapsack sprayer.

 

Target pests: Spray thoroughly on infested plants against Aphids, Brown plant hopper, Flea beetle, Leaf hopper, Potato tuber moth, Psyllid, Scale insect, Whitefly and Whorl maggot

 

Neem as a prophylactic:

1. Pound Neem leaves or seeds or Neem cake. Put it in a clay pot. Add twice the volume of water, and then cover securely the opening of the pot. Let it stand for 3 nights.
2. To use, divide the filtrate into 4 (or more) and put these separately in opened containers. Place containers in strategic areas in the field at night time to repel nocturnal pests. The smell repels the insects from coming into the field.
3. Fill in jute sacks with Neem cake. Place the sacks along the water canals. The dissolved Neem cake carried into field prevents the attack of pests and diseases affecting the roots and tillers.

 

Important points:

1. Neem seed extract should be white in colour and not brownish. If pounded with the seed coat on, 1 half times the amount of seeds are required.
2. It is very important to add the soap with the oil before adding water. It should be used immediately otherwise oil droplets will start floating. A knapsack sprayer is better for Neem oil spraying because it has a tendency to mix the extract while in the process of spraying.
3. The 3 extract formulations can also be used for fungal disease control including those that are soil borne. Neem cake can be used as soil manure to improve the soil condition and to control various species of nematodes.

Precaution: Oil maybe phytotoxic at a ratio of 10ml/litre of water on sensitive plants. Wait for 2 days for the effects (symptoms) to appear before going into a large scale application.

 

Standard procedure for the preparation and application of the plant extracts:

1. Select plant parts that are free from diseases
2. When storing the plant parts for future usage, make sure that they are properly dried and are stored in an airy container (never use plastic container), away from direct sunlight and moisture. Make sure that they are free from moulds before using them
3. Use utensil for the extract preparation that are not use for your food preparation and for drinking and cooking water containers. Clean properly all the utensils every time after using them
4. Do not have a direct contact with the crude extract while in the process of the preparation and during the application
5. Make sure that you place the plant extract out of reach of children and house pets while leaving it overnight
6. Harvest all the mature and ripe fruits before extract application
7. Always test the plant extract formulation on a few plants first before going into large scale spraying. When adding soap as an emulsifier, use a potash based one
8. Wear protective clothing while applying the extract
9. Wash your hands after handling the plant extract

 

Effects on humans:

None/Nil: the proper use of Neem has not been associated with any side effects on humans.

 

Effect on non-target organisms:

Azadirachtin which is one of the active ingredients of Neem is relatively harmless to butterflies, bees, ladybugs and wasps since these beneficial feed on nectar and pollen. Azadirachtin must be ingested to be effective so that pests which feed on plants are affected by its content. However, constant spraying of flowering plants with highly concentrated Neem products affect bees since they carry contaminated pollen and nectar to the hives.

 

Azadirachtin has no side effects on birds and other animals. There is no toxic residue left to contaminate the environment and also insects do not develop resistance to Neem.