Author: Nabin Pandey
BSc. Ag. 5th Semester
Agriculture and Forestry University
10th November 2019,
(Azadirachta indica,) commonly known as neem is a tree in the family meliaceae. It is typically grown in tropical and semi tropical region of Nepal. Plant diseases and insect occurrence are the major factors of crop yield loss in Nepal. Insects and disease loss account more than 35% in crops. According to latest estimate, the annual import of pesticides in Nepal is about 211 t a.i/ha with 29.19% insecticides, 61.38% fungicides, 7.43% herbicides and 2% others. Farmers in Bara, Chitwan, Dhading and Kavre district spray pesticides five to six times a year. 85% of annually imported pesticides are used in vegetable farming.
According to UN an average of about 200,000 people die from the toxic exposure of pesticides per year across the world. In this havoc situation, it will be a little justice if we talk about neem plant. As we know, neem plant is bitter in taste. But there is profound sweetness for agriculture in the bitterness of this plant. Neem contains a large number of chemically diverse and structurally complex bioactive commonly referred to as limonoids and azadirachtin. Scientists estimate that the chemical compounds from neem can combat more than 300 species of insects, including cabbage loopers, gypsy moth, cockroaches, fleas, aphid and mosquitoes. Indeed, as foreseen by some scientists, this tree may usher in a new era in pest control. Neem acts in various ways against different insects as repellent, feeding inhibitor, egg laying deterrent, growth retardant, sterilizer, and toxin.
The importance of neem as bio- pesticide was realized by the modern scientific community, as early as 1959, when a German scientist in Sudan found that neem was the only tree that remained green during a desert locust plague. Martin Jacobson, a chemist with federal Department of Agriculture, has isolated several substances from neem trees that protect commercial crops from a wide variety of agricultural pest. One of the extracts, called azadirachtin, is so potent that it prevents insects from even touching the plant. Neemix, which was just registered with the Environmental Protection Agency in March for use on vegetables, claims to incapacitate everything from Colorado potato bugs to cabbageworms, without harming beneficial insects. Its active ingredient, azadirachtin, which is derived from the neem seed, appears to control insects and fail metamorphosis of insect larvae by disrupting the activity of ecdysone.
Neem oil can also suffocate mites, whiteflies, aphids, and other types of soft bodied insects on contact. Multiple modes of action make it unlikely that insects and plant pathogen can develop resistance to neem. Also, certain pest such as floral thrips, diamond back moth and several leaf miners which develop resistance to the inorganic pesticides or that are inherently difficult to control with conventional pesticides are effectively controlled or managed with neem. Furthermore, it is natural product, absolutely non- toxic to other natural predators, 100% biodegradable and eco- friendly. Even some of the most cautions researchers are saying that neem deserves to be called a wonder plant’. Each and every part of neem plant are beneficial in agriculture.
- Neem cake: Neem cake has been found to have inhibitory effect on the growth of phytopathogenic fungi causing powdery mildew, wilt, leaf blight, leaf spot, blight and stem rot.
- Leaf: Leaves can be used as a cattle feed supplement which possess carminative properties and help in food digestion. They are also useful as mulch and manure. They are particularly useful in alleviating the copper deficiency of most straws and dry fodders.
- Fruit: The fruit pulp is useful as a tonic, antiperiodic, purgative, emollient and as anthelmintic.
- Seeds: Insects will not feed the grains treated with seeds of neem. The oil extract from the seed of neem helps to reduce the pest not by allowing the female to deposits eggs. This property is known as ovipositional deterrence.
- Neem seed Cake: Neem seed cake is a major byproduct of the neem oil industry. It contains more Sulphur than other cake. The nitrogen content varies from 2 to 3% nitrogen, 0.5% phosphorus and 0.5% potassium. Being totally, botanical product 100% natural NPK content and other essential micro products. The cake is also used as manure. Neem cake has 6.5% digestible crude protein with 19 amino acids. Urea coated neem cake has been found to regulate the rate of nitrification and increase yield of grains and straws.
An angel tree, Neem can be an alien in chemical haunted agriculture of Nepal. The bitterness of this plant can be converted into sweetness which will help in bio friendly and sustainable agriculture. Really, global problems solving tree, neem needs to be accounted on time by government. Nepalese farmers want to get ride from the multitude of pests with a multitude of pesticidal ingredients. The best option will be, neem. Tomato is one of the major vegetable crops of Nepal. It is one of the major sources of income for small farmers. However, it is attacked (Helicoverpa armigera) insect. Neem based products can help in Helicoverpa management.
Likewise, Rice is an important agronomic crop in Nepal. But due to occurrences of pest and several diseases its production is limited. The spray of neem seed kernel extract can control brown plant hopper (BPH), leaf folder, leaf thrips, and silver shoot in rice crop. These are just a sample. Nepalese farmer faced many multifaceted problems in agriculture due to disease and pest. For the effective of IPM and for the solution of pest and disease in agriculture, government should create awareness about the multiuse of neem plant. Government should bring the holistic package that promotes the plantation of neem. To dwindle indiscriminate use of noxious chemical pesticide and to reduce its hurdle, slogan, “one farmer, one neem plant” should be nationally celebrated.