Methods of Using Neem Seed

There are 4 methods of using neem seed :

Aqueous extracts

Neem oil

Neem kermel powder

Neem press cake

Aqueous neem seed extract

                   Fallen fruits are collected from underneath the trees. The flesh is removed from the seeds and any remaining shreds washed away. The seed is then carefully dried to avoid fungus forming and stored in airy conditions.

                   When requirred the seeds are shelled, finely grated and stepped overnight in a cloth suspended in a barrel of water at the rate of 25 – 50 gm / litre. This solution has proved to be very effective against vegetable pests such as cabbage caterpillars, melon beetles and grasshoppers.

                   KUMAR gives the following method for a water extract of neem :

5 kg of dried pulverised seed       are suspended overnight in a cloth in a bucket of water. After about 12 hours the clotth is taken out and squeezed. About 10 mg of soap are separatlely dissolved in a little water and added to the bucket. The whole is well stirred and made up to 100 litre with water. This preparation was used against Corn earworm (Heliothis armigera) infesting peas, at the rate of 500 litre per hectare. The infestation by the caterpillars of H. armigera which had bored into the pods was reduced to 1.1 %. An untreated sample showed an infestation rate of 7.45 %.

                   According to experience in Togo grasshoppers stopped eating immediately after application of aqueous neem extract. For caterpillars it usually takes 2 – 3 days to die. However, because the solution becomes less effective with time it is recommended that a second application be given in severe cases.

                   Experience has also shown that neem extract can be used preventely. However, this should not be allowed to develop into a regular practise since it may also affect natural ennemies of the pests.

                   JACOBSON recommends an aqueaous extract as repellant with 500 gm neem seed dissolved in 400 litres of water which is sufficient for 0.4 hectares. This application will protect the crop for about 2 weeks if it is not washed away by heavy rain.

2 kg whole neem fruit and 15 litres of water.

The fruit is shredded in an electric mixer with a little water,(precaution should be taken not to overload the mixer). Part of the water is added to the pulp and allowed to stand overnight before stewing and making up the full 15 litres. Sprayed weekly this prearation inhibits feeding by the flea beetle (Podagrica uniforma) and inhibits the development of larvae of Epilachna chrysomelina and Papilio demodocus.

If it is kept in the dark this neem prearation will remain effective for 3- 4 days.

Neem oil

                   To produce neem oil by hand, use the dried kernels. These firstly have to be decorticated.In a mortar they are lightly cracked, so that the outer husks are freed from the inner seed. The husks are then removed by winnowing. The decorticated seeds are returned to the mortar where they are pounded until they form a brown, slightly sticky mass. A little water is added so as to form a workable paste which forms an almost solid ball. This ball is kneaded for several minutes over a bowl until oil collects on the surface, then press it firmly. Oil will come ou in drop. Alternate kneading and squeezing will separate the oil. With this method 100 – 150 ml of oil can be extracted from onr kg of neem kernels. This is about half of the oil content.

If machine are available these can be used for oil extraction. Heating of oil is said to not affect the insecticidal properties.

                   To protect beans in store from infestation by bruchids, each kg of beans should be mixed with 2 – 3 ml of neem oil. Thus a 50 kg sack of beans need 150 ml of oil at the most. It is important to ensure that the oil is well mixed so that each  bean is completely coated. This treatment protects the beans for six months.

                   To remove the bitter taste of oil from the beans before eating they should be covered with hot water for a few minutes and drained after.

Neem kernel powder

                   The Indian Research Institut (IARI) in New Dehli has tested the effectivness of the neem seed powder in storage protection against rice weevils, lesser grain borers and khapra beetles. Neem seed powder was mixed with wheat at the rate of 0.5 % , 1 % and 2 .0 %  by volume. The results showed that the 1.0 % and 2.0 % admixture protected the seed against rice weevils, lesser grains borers and kharpa beetles for 269, 321 and 379 days respectively. This method should be of interest to village farmers storing grain in smaller quantities.

                   In another test the IARI examined the effect of neem powder against the kharpa beetleand the lesser grain borer when mixed with wheat at the rate of 0.5 % , 1.0 % , 2.0 % and 4.0 % . This showed that the kharpa beetles were more vulnerable to neem. After 240 days 24 % of the wheat was found to have suffered kharpa damage when treated with 0.5 % of neem, but only 8 % in the case of the 4.0 % admixture. On the other hand , neem powder had no effect on the lesser grain borers, for even with the 4.0 % treatment., 92 % of the wheat suffered insect damage. This result contradicts the foregoing one obtaine by the same research institut.

Other methods of use

                   Accoring to RADWANSKY neem is effective against nematodes. Barley seed can be stepped for 2 hour in a 1 % water solution of ground neem seed. After sowing a 50 % reduction in infestation by nematodes of the genus Pratylenchus was noted.

                   Indian farmers in the Pune district plough in 1/2 t/ha of pressed neem cake. This protects eggplants from borers and tomatoes from nematodes and leaf spot disease.

                   Some farmers spray aqueous solutions of neem press cake onto citrus trees to protect them  from miners.

Fungicidal effects

In india trial have carried out with different neem preparations in efforts to control fungi affecting chickpeas, particulary Fusarium oxysporum, Rhizictonia solani , Scerotium rolfsii and Sclerotinia sclerotiorum.

The following prearations were tested :

                   Neem oil, fruit pulp , aqueous leaf-and bark extracts.

The seed of the chickpeas were treated before being sowed in fungi-effected earth.

Neem oil protected the seed most effectively against fungus attack in the following order : Rhizoctonia solani > Sclerotium rolfsii > Fusarium oxysporum > Sclerotinia sclerotiorum.

The pulp of the neem completely prevents the development of resting form of R. solani. This was important discovery since it is these which are responsible for the longevity of the fungus. However, in the case of S. clerotiorum development of the resting forms was not impaired because they have such strong bodies.

Little is known about the effectiveness of neem against fungus diesases. The initial observations constitute the ground for further research. Possibly pressed neem cake can be similarly used to control fungus growths in the ground. Other line of investigation may offer themselves.