Although it has always been known as a wild plant that children use to paralyze fish in small streams, causing them to float for easy catch, Tephrosia vogelii, commonly known as ‘fish bean’is now being touted as a wonder plant with a huge potential for diverse and helpful agricultural purposes.
A group of researchers and environmental conservation lobbyists are now promoting commercial farming of the shrub commonly known as the “fish bean” as a raw material for manufacture of organic insecticidal compounds, pharmaceuticals and fertilizer.
Director to Manor House Agricultural Center Mr. David Mwangi said the organization is working jointly with Kenya Agricultural Livestock and Research Organization (KALRO), Participatory Ecological Land Use Management Association (PELUM) and the Ministry of Agriculture, Livestock and Fisheries to explore ways in which small scale farmers in six counties can exploit the huge economic potential of the shrub.
He said the venture had on pilot basis brought on board 500 farmers from Nakuru, Trans Nzoia, West Pokot, Bungoma, Kakamega and Busia counties who were being trained on home based extraction and blending of compounds to produce environmentally friendly acaricides and insecticides that will eliminate pests such as fleas and ticks on animals and aphids and moths on plants.
Mwangi said the initiative was also encouraging farmers whose farms have been infested by moles, rodents or root rats among other similar pests, to grow Tephrosia vogelii as a remedy for destructive mammals.
“The plant’s roots emit chemicals that repel moles from the farm. Apart from controlling moles, it is a good source of pollen and nectar for the honey bee,” said the Director.
Mwangi stated that a team of entomologists and agricultural experts in the program had extracted compounds from the shrub from specimen collected in the pilot counties laboratory analysis, which proved that the shrub could be the key to countering the issue of tick resistance to acaricides, which is as a result of continuous use of a single type of chemical.
“The herb contains compounds that interrupt ticks’ reproductive cycle, by destroying those that are not fully grown and which have soft skins. It can also be used to keep at bay poultry pests such as lice, fleas and mites.
Biological control of pests is always better than chemical control as it enhances environmental conservation,” reiterated the Director to Manor House Agricultural Center.
He said the shrub was widely available in most parts of the country and that Manor House Agricultural Center had embarked on helping farmers across Kenya to establish Tephrosia vogelii seed banks.
Advocacy officer at Participatory Ecological Land Use Management Association (PELUM) Ms Beth Omae said scientific studies had established that the shrub increases various nutrients in the soil when used in inter cropping.
“Studies have shown a 30 percent increase in soil nutrients, and as a result, a 23 percent to 26 percent greater crop yield. Tephrosia vogelii treatments increase organic carbon and mineral nitrogen in the soil.
And by using it, farmers can maximize the amount of crop yield by increasing soil fertility and removing insects and other pests. If this shrub is developed further, it might be able to provide an even greater synergistic effect and crop yield in arid and semi-arid environments” stated Ms Omae.
She observed that water and soil quality in Kenya are decreasing and there is an increase in chronic health effects due to use of inorganic farm inputs such as fertilizer, pesticides and herbicides.
“PELUM is also working with eighteen member organizations, schools and non-governmental organizations to promote adoption of the many uses of Tephrosia vogelii. Since it is a nitrogen-fixing plant, it can be intercropped with other plants and used as a source of green manure. Food produced using organic farm inputs is healthy for humans and animals,” she observed.
A researcher attached to the programme, Patrick Shiundu called on agrochemical and pharmaceutical companies to shift their attention to the shrub as various studies had confirmed that it also had fungicidal properties.
He explained that the shrub’s leaves contain high amounts of nutrients, including nitrogen, which is important for good plant development.
He said when Tephrosia vogelii shrubs are cut down, the leaves are worked into the soil and the nutrients can then be used by the plants that are grown in the field thereafter.
“Leaf extracts of Tephrosia vogelii can be used as chemical pesticides. Crops that have had this extract applied show significant decreases in insect and other pest activity. Therefore, crops can grow in areas that they could not before, if they are grown alongside Tephrosia vogelii.
In fact, studies have shown a 46.2-52.2% decrease in grain damage. Grain damage was measured by the amount of kernels that were destroyed and also by the net weight loss of the crop. This number varies based on method of storage, type of insect measured, and type of stored grain” stated Shiundu.
He indicated that in one particular study, the extract killed 40% of the attacking insects after a 21-day period. The decrease, he said, was about what would be expected from most chemical pesticides.
Shiundu explained that in making a low cost acaricides from the shrub, first the leaves are ground up and a juice is extracted which is then used on the animal.
The green liquid from the plant is mixed with water and is then applied to the animal’s skin with a piece of cloth or a sponge.
“A little bit of soap can be added to the liquid to make it stick to the skin. Usually it is left on the animal for a week. It is very effective against ticks that still have soft skin and are immature. This is a rewarding practice for farmers that do not have access to veterinary services,” said the researcher.
By Anne Mwale/Dennis Rasto