Neem Oil Background
Neem oil is a product of the Neem tree, an evergreen tree that is native to India and other Southeast Asian countries (Schmutterer, 1990). The Neem tree possesses the ability to grow in various climates and soil types including clay, alkaline and stone soils (Atabani et al., 2013). The tree has also been adapted to higher temperatures and can withstand temperatures ranging up to 49 degrees Celsius in regions of low rainfall between 150 and 250 millimeters (Girish and Bhat, 2008). The tree reaches maximum productivity around 15 years of age and can live to be between 150 and 200 years old (Atabani et al., 2013). Oil can be obtained from both the leaves and the seeds with the leaves growing up to 30 centimeters in length (Schmutterer, 1990). The seed can provide oil through extraction from the kernel with the seed yielding between 20 and 30 percent oil in weight (Atabani et al., 2013). Furthermore, the trees can be propagated through seeds or cuttings making for easy transplantation (Atabani et al., 2013). Photo source: https://www.youtube.com/watch?v=PvHX7qCadvo |
Azadirachtin for Pest Control
Neem oil contains the secondary metabolite Azadirachtin, a chemical with a variety of insect repellent properties in the pest control of up to 350 species (Girish and Bhat, 2008). Azadirachtin has the ability to control growth and food intake, specifically by causing birth defects in larvae during metamorphosis, as well as delayed growth, mortality, and infertility (Schmutterer, 1990). This paper will focus on the effects of Azadirachtin on the rice weevil, rice brown plant hopper, and mosquito varieties as these pests are native to Nepal and will pertain to the use of the product to be introduced later.
Both the rice weevil and the rice brown plant hopper are pests that target rice crops by attacking the base of the plant and competing for plant nutrients (Kartohardjono and Heinrichs, 1984). Research has shown that when rice crops were applied with Neem oil, the rice brown plant hoppers exhibited reduced food intake and less than 50% of the population survived the spray application (Saxena et al., 1984). In Southeast Asia, mosquitoes are also of major concern for pest control as they not only cause a reduction in agricultural yields, but also pose health threats to the human population (Vatandoost and Vaziri, 2004). In mosquitoes, studies have shown that when Neem was applied to rice crops, larvae births and breeding were reduced, with an 80-100% reduction over the study period (Dua et al., 2009). In addition, the application of the oil possessed the ability to weaken the larvae’s’ immune system by making pathogen transfer more difficult, an effective strategy for disease vector control (Dua et al., 2009). Other traits that have been observed include, decreased egg hatchability and shortened life span both which could be due to the antifeedant properties possessed by Azadirachtin (Ascher, 1993)
Photo Source: https://en.wikipedia.org/wiki/Azadirachtin
Uses of Neem Oil in Industry
Aside from being used as an insecticide, other parts of the Neem tree have been used for agricultural and forestry purposes. In forestry, the bark and wood obtained from the tree have been used in afforestation and fuelwood production (Koul et al., 1990). Neem wood is commonly used as the main material in furniture production, as a source of fuel for heating, and as a material in infrastructure foundation as the bark is termite resistant (Koul et al., 1990; Girish and Bhat, 2008). Additionally, Neem cake, the solid extract in oil production, can be used in crop production as the cake can be applied to the base of a crop to act as a natural fertilizer as it adds nutrients to the soil and can increase nitrogen fixation in the roots (Girish and Bhat, 2008). Other agricultural uses include planting Neem trees to act as a shade cover for crops and in livestock production as the leaves can be fed to buffalo, sheep, and camel as feed (Girish and Bhat, 2008).
Aside from being used as an insecticide, other parts of the Neem tree have been used for agricultural and forestry purposes. In forestry, the bark and wood obtained from the tree have been used in afforestation and fuelwood production (Koul et al., 1990). Neem wood is commonly used as the main material in furniture production, as a source of fuel for heating, and as a material in infrastructure foundation as the bark is termite resistant (Koul et al., 1990; Girish and Bhat, 2008). Additionally, Neem cake, the solid extract in oil production, can be used in crop production as the cake can be applied to the base of a crop to act as a natural fertilizer as it adds nutrients to the soil and can increase nitrogen fixation in the roots (Girish and Bhat, 2008). Other agricultural uses include planting Neem trees to act as a shade cover for crops and in livestock production as the leaves can be fed to buffalo, sheep, and camel as feed (Girish and Bhat, 2008).
Oil Components and Environmental Impact
In comparison to other oilseeds, Neem trees yield about 2,670 kg of oil per hectare whereas other oilseeds such as the rubber tree and the castor tree yield 50 kg of oil per hectare and 1,188 kg of oil per hectare respectively (Atabani et al., 2013). The seed kernel yields approximately 45% oil which in weight is 2.5 kg (Koul et al., 1990).When considering the environmental impact of the growth and production of Neem oil, one benefit that has been scientifically proven is that Neem is completely non-toxic to humans; therefore any applications on crops for human consumption would have no negative health impacts (Isman, 1997). The growth of the Neem tree is environmentally friendly as the tree has an increased capacity to release high quantities of oxygen (Raval et al., 2003). Additionally, the seeds, leaves, bark and seed cake from Neem are biodegradable and can act as natural pesticides, supplying additional nutrients to any crops applied with the oil (Isman, 1997). The application of Neem does not impact the survival of native pollinators and as well can maintain the ecosystem balance as Neem favours natural predators, therefore, it will not introduce new pests into the environment (Isman, 1997).
In comparison to other oilseeds, Neem trees yield about 2,670 kg of oil per hectare whereas other oilseeds such as the rubber tree and the castor tree yield 50 kg of oil per hectare and 1,188 kg of oil per hectare respectively (Atabani et al., 2013). The seed kernel yields approximately 45% oil which in weight is 2.5 kg (Koul et al., 1990).When considering the environmental impact of the growth and production of Neem oil, one benefit that has been scientifically proven is that Neem is completely non-toxic to humans; therefore any applications on crops for human consumption would have no negative health impacts (Isman, 1997). The growth of the Neem tree is environmentally friendly as the tree has an increased capacity to release high quantities of oxygen (Raval et al., 2003). Additionally, the seeds, leaves, bark and seed cake from Neem are biodegradable and can act as natural pesticides, supplying additional nutrients to any crops applied with the oil (Isman, 1997). The application of Neem does not impact the survival of native pollinators and as well can maintain the ecosystem balance as Neem favours natural predators, therefore, it will not introduce new pests into the environment (Isman, 1997).
Health Benefits
In addition to pest control, Neem is also effective in the prevention and control of diseases such as HIV, and certain cancers (Roy and Saraf, 2006). Neem also contains many antimicrobial and anti-inflammatory compounds to combat diseases such as malaria, and bronchitis (Girish and Bhat, 2008). In chemotherapy, Neem has been used as it contains limonoids, which are naturally occurring chemicals that inhibit the growth of breast cancer cells and can also stop the production of neuroblastoma cells (Roy and Saraf, 2006). As previously mentioned, Neem is also effective in controlling pest populations of mosquitoes, a benefit to the control of malaria, a disease that is affecting millions worldwide (Roy and Saraf, 2006). Neem has also been used in inhibiting the replication of HIV-1, the gene that transmits HIV (Roy and Saraf, 2006). Certain soaps and shampoos also contain Neem as the oil contains a high quantity of fat, which is ideal for production purposes (Ahmed and Grainge, 1986).
In addition to pest control, Neem is also effective in the prevention and control of diseases such as HIV, and certain cancers (Roy and Saraf, 2006). Neem also contains many antimicrobial and anti-inflammatory compounds to combat diseases such as malaria, and bronchitis (Girish and Bhat, 2008). In chemotherapy, Neem has been used as it contains limonoids, which are naturally occurring chemicals that inhibit the growth of breast cancer cells and can also stop the production of neuroblastoma cells (Roy and Saraf, 2006). As previously mentioned, Neem is also effective in controlling pest populations of mosquitoes, a benefit to the control of malaria, a disease that is affecting millions worldwide (Roy and Saraf, 2006). Neem has also been used in inhibiting the replication of HIV-1, the gene that transmits HIV (Roy and Saraf, 2006). Certain soaps and shampoos also contain Neem as the oil contains a high quantity of fat, which is ideal for production purposes (Ahmed and Grainge, 1986).
Table 1: Breakdown of Neem Components based on Medicinal and Biological Properties (Girish and Bhat, 2008
Table 1 provides data with respect to specific components of Neem and the variety of medicinal properties including anti-inflammatory, antibacterial, spermicidal and immunomodulatory properties (Girish and Bhat, 2008).
Photo Source: https://ezgrogarden.com/all-about-plants/the-neem-tree-a-miracle-plant/