Violet tree | |
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Scientific classification ![]() | |
Kingdom: | Plantae |
Clade: | Tracheophytes |
Clade: | Angiosperms |
Clade: | Eudicots |
Clade: | Rosids |
Order: | Fabales |
Family: | Polygalaceae |
Genus: | Securidaca |
Species: | S. longipedunculata |
Binomial name | |
Securidaca longipedunculata Fresen. | |
Securidaca longipedunculata (violet tree, Afrikaans : krinkhout, Bambara : satene, Tswana : mmaba, Venda : mpesu) [1] is a species of tree in the genus Securidaca . It is most commonly found in the tropical and subtropical areas of Africa, and it was given protected status in South Africa. [2] The generic name is derived from Latin securis, as the shape of the wing on the nut recalls a hatchet. The specific name longipedunculata hints at the long peduncle on which the flowers are borne. [3]
It is a fairly small to medium-sized tree, measuring between 6 and 12 meters tall. It has pale grey, smooth bark with leaves that grow in clusters. Its small branches are covered in very fine hair. The tree produces flowers in the early part of the austral summer, and these progress from a pink to purple colour. They are sweetly scented and grow in small bunches on a peduncle. The fruit is round and is attached to a wing that becomes up to 40 mm long. The tree carries fruit between April and August. [4]
It is found in various types of woodlands and in arid savannas, and its habit varies according to climate and altitude. It may be found on either sandy, acidic or rocky soils. [3] It is native to the North West and Limpopo provinces of South Africa, and is locally present northwards in the African subtropics and tropics. [4] In tropical savanna, it is especially found in miombo and caesalpinoid woodland. [5]
The species suffers from over-harvesting for use in local medicines. Periodic droughts and bush fires are also a hazard for the propagation of this tree. [6] It is listed on the National Forests Act of 1998 of South Africa, where it is noted as a protected tree. The Royal Botanic Gardens, Kew, has also included the species in their “Adopt a seed - save a species” campaign. The campaign enables the public to purchase a Violet tree in order to protect the species and assist local communities in Mali. The initiative forms part of the Millennium Seed Bank Partnership. [6]
The uses of the plant include a great variety. In particular there are many different medicinal uses for this tree around Africa. It can be used to treat sicknesses as small as headaches or as severe as arthritis. This tree is also commonly used as pesticide against beetles in stored grains. This technique can be very helpful for small-scale subsistence farmers in Africa who are not able to purchase synthetic pesticides.
The roots of the tree can be used for treatments to human ailments such as coughs, chest complaints, toothaches, gout, fevers, constipation, diabetes and microbial infections. It also possesses anti-inflammatory properties that help to reduce arthritic pains. [4] Uses of this tree vary across different countries. A combination of both the methanol extract and the methyl salicylate component from the roots of the plant create a poison that is used for multiple purposes. This poison is used on arrows to hunt with in West Africa. [3] In Limpopo, the VhaVenda people use the roots to prevent mental disorders and they believe that this remedy will also protect children from illnesses during breastfeeding. People in Zimbabwe use the roots to treat people who seem to be possessed by evil spirits and it is often used on snake bites. [7] Soap, fishing nets, and baskets can be made with the bark of the tree. This tree is also used to assist some subsistence farmers in maintaining stored grains. The bark and roots of this tree can be grounded up into powder and mixed in with stored grains to create a pesticide against various beetles. This alternative to synthetic pesticides is necessary for small-scale farmers in Africa who may not have the resources or money needed for synthetic pesticides.
Its roots can be ground into a fine powder which is used to protect stored grains. [5] Methyl salicylate is a well-known plant stress signal which often has insect repellent properties. Methyl salicylate constitutes up to 90% of the volatile component of its roots, which is very uncommon in other grains or legume seeds. [8] A mixture of methanol extract and methyl salicylate creates a very effective natural pesticide against weevils and other insects in stored grains. Studies done on grains such as corn and cowpea indicated that after 6 days of exposure to S. longipedunculata, the mortality rate of adult beetles was 100% in an enclosed jar. [8] In addition, when S. longipedunculata powder was applied to grains already infested with weevils, the damage done to the grains was reduced by 65%. The beetles that are most likely to infest stored grains are Sitophilus zeamais (maize weevil), Rhyzopertha dominica (lesser grain borer), and Prostephanus truncatus (larger grain borer). Studies suggest that the maize weevil is able to detect the scent of methyl salicylate and tends to avoid it. It is a repellent for insects as well as a poison, which helps to reduce the number of female eggs in the grains. As this type of pesticide use is very efficient, it allows storage of the grains for at least 9 months. [5] This discovery provides some small-scale farmers in Africa with a low cost, natural alternative to synthetic pesticides. [8] In some developing countries, it is difficult for poor farmers to access good quality and affordable synthetic pesticides. In addition these can harm the environment if they are not properly implemented. Such indigenous practices require further validation.
The practice of using S. longipedunculata as a common pesticide for stored grains is not a widespread solution. Although it is very efficient to use this species as a tool to store grains for longer periods of time, there are constraints to wider adoption rates. A very significant problem is scarcity in natural resources. [9] S. longipedunculata is used for various different purposes, and they often involve the roots of the plant. If the root of the plant is always being cut, it is difficult for the plant to be harvested constantly. [3] There is little incentive to invest in a project like this because there is no assurance that the starting material can be reproduced in sufficient quantities. In addition, studies have shown that a specific concentration of the active ingredient, methyl salicylate, is needed for the powder to effectively work as a pesticide. [8] Improved technologies are needed in order to fully cover all the seeds with the powder in order for the repellent to work. Turning over the crops and mixing it by hand can be very labor-intensive for the farmer and it doesn’t always assure full coverage of the seeds. [5] One solution could be to create an extract by mixing the powder with water. An extract would be useful for maize seeds because the glassy surface of maize prevents the powder from adhering to its surface. This will allow the pesticide to be evenly spread out, although more tests and studies need to be done to improve this technique. [5]
Insecticides are substances used to kill insects. They include ovicides and larvicides used against insect eggs and larvae, respectively. Insecticides are used in agriculture, medicine, industry and by consumers. Insecticides are claimed to be a major factor behind the increase in the 20th-century's agricultural productivity. Nearly all insecticides have the potential to significantly alter ecosystems; many are toxic to humans and/or animals; some become concentrated as they spread along the food chain.
Pyrethrum was a genus of several Old World plants now classified as Chrysanthemum or Tanacetum which are cultivated as ornamentals for their showy flower heads. Pyrethrum continues to be used as a common name for plants formerly included in the genus Pyrethrum. Pyrethrum is also the name of a natural insecticide made from the dried flower heads of Chrysanthemum cinerariifolium and Chrysanthemum coccineum. Its active ingredient are pyrethrins.
An essential oil is a concentrated hydrophobic liquid containing volatile chemical compounds from plants. Essential oils are also known as volatile oils, ethereal oils, aetheroleum, or simply as the oil of the plant from which they were extracted, such as oil of clove. An essential oil is "essential" in the sense that it contains the "essence of" the plant's fragrance—the characteristic fragrance of the plant from which it is derived. The term "essential" used here does not mean indispensable or usable by the human body, as with the terms essential amino acid or essential fatty acid, which are so called because they are nutritionally required by a given living organism.
The pyrethrins are a class of organic compounds normally derived from Chrysanthemum cinerariifolium that have potent insecticidal activity by targeting the nervous systems of insects. Pyrethrin naturally occurs in chrysanthemum flowers and is often considered an organic insecticide when it is not combined with piperonyl butoxide or other synthetic adjuvants. Their insecticidal and insect-repellent properties have been known and used for thousands of years.
Pest control is the regulation or management of a species defined as a pest, a member of the animal kingdom that impacts adversely on human activities. The human response depends on the importance of the damage done and will range from tolerance, through deterrence and management, to attempts to completely eradicate the pest. Pest control measures may be performed as part of an integrated pest management strategy.
Sitophilus is a genus of weevils in the tribe Litosomini. Some species are familiar as pests of stored grain, nut, or seed. Notable pest species include the rice weevil, wheat weevil, and maize weevil.
Ricinodendron is a plant genus in the family Euphorbiaceae first described as a genus in 1864. It includes only one known species, Ricinodendron heudelotii, native to tropical Africa from Senegal + Liberia east to Sudan and Tanzania and south to Mozambique and Angola. It produces an economically important oilseed. The tree is known as munguella (Angola), njangsa (Cameroon), bofeko (Zaire), wama (Ghana), okhuen (Nigeria), kishongo (Uganda), akpi, djansang, essang, ezezang and njasang. Two varieties of the tree species are recognized R. heudelotii var. heudelotii in Ghana and R. heudelotii var. africanum in Nigeria and westwards.
Non-pesticidal Management (NPM) describes various pest-control techniques which do not rely on pesticides. It is used in organic production of foodstuff, as well as in other situations in which the introduction of toxins is undesirable. Instead of the use of synthetic toxins, pest control is achieved by biological means.
Push–pull technology is an intercropping strategy for controlling agricultural pests by using repellent "push" plants and trap "pull" plants. For example, cereal crops like maize or sorghum are often infested by stem borers. Grasses planted around the perimeter of the crop attract and trap the pests, whereas other plants, like Desmodium, planted between the rows of maize, repel the pests and control the parasitic plant Striga. Push–pull technology was developed at the International Centre of Insect Physiology and Ecology (ICIPE) in Kenya in collaboration with Rothamsted Research, UK. and national partners. This technology has been taught to smallholder farmers through collaborations with universities, NGOs and national research organizations.
Intensive crop farming is a modern form of farming that refers to the industrialized production of crops. Intensive crop farming's methods include innovation in agricultural machinery, farming methods, genetic engineering technology, techniques for achieving economies of scale in production, the creation of new markets for consumption, patent protection of genetic information, and global trade. These methods are widespread in developed nations.
Fish toxins or fish stupefying plants have historically been used by many hunter gatherer cultures to stun fish, so they become easy to collect by hand. Some of these toxins paralyse fish, which can then be easily collected. The process of documenting many fish toxins and their use is ongoing, with interest in potential uses from medicine, agriculture, and industry.
Lonchocarpus laxiflorus is a species of legume in the family Fabaceae. The tree grows to 4–8 meters in height, has grey or yellowish bark and compound leaves. New leaves are accompanied by purple flowers on multi-branched panicles. The fruit is a glabrous papery pod, usually containing one seed. L. laxiflorus is widely distributed in West Africa, Central Africa, the African Great Lakes, and Northeast Africa. It is found in savanna woodlands and dry forested areas, particularly fringing forest near water courses.
Phlobaphenes are reddish, alcohol-soluble and water-insoluble phenolic substances. They can be extracted from plants, or be the result from treatment of tannin extracts with mineral acids. The name phlobaphen come from the Greek roots φλoιὀς (phloios) meaning bark and βαφή (baphe) meaning dye.
Bobgunnia madagascariensis, also called the snake bean plant, is a species of legume in the family Fabaceae.
The maize weevil, known in the United States as the greater rice weevil, is a species of beetle in the family Curculionidae. It can be found in numerous tropical areas around the world, and in the United States, and is a major pest of maize. This species attacks both standing crops and stored cereal products, including wheat, rice, sorghum, oats, barley, rye, buckwheat, peas, and cottonseed. The maize weevil also infests other types of stored, processed cereal products such as pasta, cassava, and various coarse, milled grains. It has even been known to attack fruit while in storage, such as apples.
Tephrosia vogelii, the Vogel's tephrosia, fish-poison-bean or Vogel tephrosia (English), tefrósia (Portuguese) or barbasco guineano (Spanish), is a flowering plant species in the genus Tephrosia.
Strophanthus kombe, the kombe arrow poison, is a vine that grows in the tropical regions of Eastern Africa, and is part of the genus Strophanthus, which contains approximately 38 species. S. kombe contains a cardiac glycoside which directly affects the heart. Historically, both the seeds and roots of the plant were used in the preparation of poison arrowheads used for hunting. Today, the seeds are used pharmaceutically for patients with certain heart conditions that affect blood circulation. The seeds are traded primarily with Europe, but have also been exported to the United States and Japan.
Prostephanus truncatus is commonly referred to as larger grain borer (LGB) with reference to the related Rhyzopertha dominica, which is relatively smaller in length, hence is referred to as the lesser grain borer. P. truncatus is about 6 mm (0.24 in) long as compared to 3 mm (0.12 in) long in Rh. dominica. At optimum conditions of 80% relative humidity and 32 °C (90 °F), and available food, P. truncatus completes its lifecycle within 27 days. It is a serious pest of dried grains, especially maize and dried cassava in West Africa. This beetle is believed to have been introduced into West Africa through food aid from America. It reached Africa through Tanzania in the early 1970s.
Culcasia scandens is an African climbing plant, often epiphytic, with slender, wiry stems, up to 5 m long clinging to tree trunks by means of clasping roots, and growing on forest and stream margins and in savanna. It is native to countries of western tropical Africa from Senegal east and south to Angola.
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