FOCUS ON AFRICA
See quotes at end from Director General of Kenya's International Centre of Insect Physiology and Ecology, amongst others.
See also the incisive article from the Kenyan press, 'Don't Embrace GM, Go for Homegrown Solutions'
And nice to see Rothamstead's Prof John Pickett FRS doing something constructive - for more on Pickett's less constructive side:
Non-GM alternatives in Kenya
1.Icipe Researchers Find a Way to Stop the Stemborer
2.Tapping into Nature's Arsenal to Fight Farmers' Enemies
1.Icipe Researchers Find a Way to Stop the Stemborer
The Nation, 9 August 2004
The push-pull programme aims at controlling the stemborer, which causes an estimated loss of 15 per cent of Kenya's maize and other cereals, writes 'Nation' Science Editor NAFTALI MUNGAI
On June 18, the fraternity of the International Centre of Insect Physiology and Ecology (Icipe) honoured its founder director, the late Prof Thomas Risley Odhiambo, by renaming the Mbita Point field station after "TR", as he was fondly known by his friends.
But besides renaming the station after one of Africa's most illustrious scientists and visionaries, Icipe also showcased one of its most interesting works in sustainable agriculture that is having a far-reaching impact and changing lives in several districts of western Kenya.
When Prof Thomas Odhiambo founded the International Centre for Insect Physiology and Ecology (Icipe) in a car garage at the Chiromo campus of the University of Nairobi in 1970, some sceptics criticised such a development as premature, arguing that Africa was not yet ripe for science-led development.
But to Prof Odhiambo, the mission of Icipe was clear. One of its aims was "to transform the discoveries and innovations from advanced research and development work into first class ecologically-friendly, sustainable strategies for managing insect pest and vector populations so that they are rendered harmless both socially and economically."
Thus, when on June 18, the Icipe fraternity honoured Prof Odhiambo by renaming the Mbita Point field station after him, it was recognising one of Africa's most illustrious scientists and visionaries.
However, besides renaming the station after Prof Odhiambo, Icipe also showcased one of its most interesting works in sustainable agriculture that is having a far-reaching impact and changing the lives people in several districts of western Kenya.
One year after his death, resource-poor rural communities in Nyanza Province, where he was born, are reliving his dream by the thousand through the "push-pull" programme. This is a habitat management method that controls the stemborer which causes an estimated loss of 15 per cent of Kenya's maize and other cereals, worth an estimated Ksh6 billion ($76.9 million) by using fodder plants. The programme also increases milk production.
Push-pull is a repellent and attraction diversionary strategy that uses different plants for the management of cereal stemborers. The stemborers are repelled from the main plant (maize or sorghum) and are simultaneously attracted to a trap plant, usually napier or Sudan grass, where they go and lay their eggs.
But push-pull is not only about controlling stemborers only. It is also controlling Striga hermonthica one of the most noxious weeds known in the world, aptly called the African witchweed, and kayongo in Dholuo.
The striga weed, which has strikingly beautiful pink flowers, is the bane of maize farmers wherever it is found. It attaches its roots to those of maize, literally sucking the maize plant dry by imbibing nutrients that the maize would otherwise use for its growth, and will only germinate in the presence of maize or other cereals such as sorghum.
Says the head of the Habitat Management Programme at Icipe, Dr Zeyaur Khan: "During attempts to control stemborer damage to maize by intercropping with repellent plants, the fodder legume silverleaf, Desmodium uncinatum, was accidentally found to reduce the incidence of infestation by the African witchweed, Striga hermonthica. This reduction was found to be significantly greater than that observed with other legumes such as sun hemp, soybean and cowpea."
In Africa, the intercropping of maize and legumes has been practised for a long time and the most common system is the intercropping of maize and beans.
The push-pull system relies on a carefully selected combination of companion crops to be planted around and among the maize or sorghum plants for the manipulation of pests and their natural enemies. Dr Khan says that both domestic and wild grasses, often ploughed under in modern single cropping practice, can help protect the cereals by attracting the stemborers.
The grasses are planted in a border round the maize or sorghum fields, where invading adult moths become attracted to chemicals emitted by the grasses themselves.
"Instead of landing on the maize plants, the insects head for what appears to be a tastier meal. The grasses thus provide the "pull." They also provide a haven for the borer's natural enemies, where they are devoured as they seek refuge," says Dr Khan. According to him, good trap crops include napier grass (Pennisetum purpureum) and Sudan grass (Sorghum vulgare sudanese), a type of wild sorghum.
The "push," which is the repellent effect, was initially provided by molassses grass (Melinis minutiflora). But now, it is provided by a nitrogen-fixing leguminous plant that also provides fodder for cattle, the desmodium (Desmodium uncinatum), which is native to Latin America. "It came to Africa about 50 years ago after seeds were imported from Australia," said Prof Lester Wadhams, the head of the Biological Chemistry Division at Rothamstead Research Station in the UK.
Dr Khan says that as they were working with "push-pull" to control stemborers, they noticed that where desmodium was planted, the maize fields had less striga germinating.
Striga, which is native to Africa, causes maize losses of between 50 and 80 per cent. In the US, it is controlled by exposing it to ethylene continuously so that it keeps germinating, burning itself out in the process. But Dr Khan says that, "This is a very expensive method that only very rich countries like the US can afford."
In the fields, desmodium is planted in between the rows of maize. Because it is a low growing plant, it does not interfere with maize growth and has the advantage of maintaining soil stability and improving soil fertility through its nitrogen-fixing action. It is also easy to harvest and serves as a highly nutritious animal feed.
Dr Khan says that a ground cover of desmodium, interplanted among the maize, reduces striga growth by a factor of 40. The desmodium ground cover also reduces soil erosion, conserves water by acting as a mulch and provides fodder for cattle.
According to Dr Khan, more than 2,000 small-scale farmers covered by the Icipe programme have significantly increased their maize yields and milk production. "Fodder produced by the 'push-pull' farmers contributes to production of one million litres of milk annually," he says.
He adds that 300 farmers are now producing desmodium seed for income generation and are linkedto the Western Seed Company. "Extra income from push-pull has helped more than 300 farmers to send at least one child to secondary school," adds Dr Khan.
It is estimated that by the end of 2006, at least 10,000 farmers will benefit from the "push-pull" strategy. But by the way the technology is spreading, Dr Khan's estimate could be modest, to say the least. It is also projected that by 2006, at least three tonnes of desmodium seed will be produced annually by 1,000 small-scale farmers.
Joseph Odek, a small-scale farmer in Sigulu Village of Lambwe Division, said before the Icipe programme was introduced, the most he could harvest from his three-hectare maize plot was eight bags. But this had risen to 35 bags in the past three years.
"When my son joined secondary school at the beginning of this year," said Mr Odek, "I took two bags of maize to the school as part of the school fees."
The push-pull research was funded by the Gatsby Trust of the UK, which provided Icipe with $3.6 million. Dr Khan collaborates with Prof John Picket and Prof Lester Wadhams. Prof Picket is the head of the Chemical Ecology Group at Rothamstead Research Station in the UK.
Push-pull was conceived by Prof Jim Miller, who was working at the Michigan State University with onions. "We at Rothamstead later took it up and after screening 400 grass species, our trials showed that napier and Sudan grasses were good trap plants for stemborers. Napier grass is particularly effective because when the stemborers attack it, it emits a sticky substance that traps the borers, which are in turn attacked by their natural predators," said Prof Picket.
Dr Khan said that the initial trials were conducted in Mbita and Kitale and now more than 2,000 farmers in Kenya, Uganda and Tanzania have taken it up
The current director-general of Icipe, Dr Hans Herren, a firm believer in Prof Odhiambo's philosophy of ecologically-friendly farming systems, said: "Prof Odhiambo's main objective was that Icipe would provide a link between the world's leading scientists and the problems facing small-scale farmers in Africa. Today, Icipe's goals are greater food security, environmental integrity and sustainable livelihoods for Africa's people."
The push-pull programme, the flagship of the Habitat Management Programme at Icipe, is Prof Odhiambo's dream come true, nurtured by those, like Dr Herren, who kept it alive against many odds in a world where genetically modified crops, especially maize, are being relentlessly promoted by agri-business companies as the panacea to Africa's perennial food shortages.
2.Tapping into Nature's Arsenal to Fight Farmers' Enemies
The East African, 9 August 2004
Icipe and Rothamstead, who have been collaborating in unravelling the chemical basis of "push-pull," have come up with findings that reveal how plants defend themselves from insect damage.
According to Prof Ahmed Hassanali of Icipe, insect antennae have been used to identify an array of compounds that form a complex interplay in the plant defence mechanism. "We isolate the volatile compounds using a method known as gas chromatography and pass these through the insect antennae, which react to any active chemical. This is recorded as an electric pulse, a process known as electroantennography," says Prof Hassanali, an expert in insect communication.
Through the process, a chemical called naphthalene has been identified as one of the volatile compounds emitted by molasses grass, and acts as a repellent for stemborers.
Naphthalene is the strong smelling compound that is the major ingredient in moth-balls the white balls used to keep moths away from clothes drawers, or in men's urinals to neutralise the pungent ammonia fumes from concentrated urine.
Another compound known as (E) Ocimene has also been identified. But why do the compounds repel moths? "In nature, plants that are damaged by insects produce these compounds to repel insects and thus prevent further damage," says Prof Hassanali. "What essentially happens is that the molasses grass or desmodium that is damaged by an insect attack produces these insect-repellent compounds in sufficient quantities, such that some of them rub off on the maize, making it repellent as well. This phenomenon is known as allellopathy and is one of the defence mechanisms that plants use to protect themselves against insect attack," adds Prof John Picket, head of the Chemical Ecology Group at Rothamstead Research Station in the UK.
However, he says, the stemborer larvae are also parasitised by a small wasp known as Cotesia sesami. By using the chemicals produced by the damaged molasses grass or desmodium as a cue, they can easily locate stemborer caterpillars on which they lay their eggs, which later hatch and kill the caterpillars," says the chemical ecologist. Both maize and desmodium readily stimulate the germination of striga seeds, he adds.
"However, the desmodium acts as a double-edged sword by stimulating the germination while at the same time its root exudate contains compounds that inhibit the growth of the roots of striga and this prevents the striga from attaching to the roots of the maize plant and sucking its nutrients, resulting in a suicidal germination," says Prof Hassanali.
However, the scientists add that the work on this interplay of nature is still going on at both Rothamstead and Icipe. "While some of the active compounds have been identified, the key compounds are yet to be identified," they say. Prof Picket says that some of the compounds so far identified fall in the class of isoflavanones compounds commonly found in legumes. "Some of them are said to have some health benefits such as reducing bone thinning, or osteoporosis, a common affliction of old people." The story of "push-pull" indicates that nature, in all its simplicity and complexity, has the entire arsenal that man so desperately seeks to control some of the most daunting problems.
In nature, plants that are damaged by insects produce compounds to ward off these insects and prevent further damage
"...farmers are likely to be weaned from pesticides to be force fed biotech seeds, in other words, taken off one treadmill and set on a new one!"
"The trend towards a quasi-monopolization of funding in agricultural development into a narrow set of technologies is dangerous and irresponsible. Also, too many hopes and expectations are being entrusted in these technologies, to the detriment of more conventional and proven technologies and approaches that have been very successful and which potential lies mostly unused in the developing countries.
It is only too obvious to concerned scientists, farmers and citizens alike that we are about to repeat, step by step, the mistakes of the insecticide era, even before it is behind us. I would even argue that these new miracle technologies are mostly not necessary, let alone desirable, to solve the world's food security problem."
Hans R.Herren, Director General, The International Centre of Insect Physiology and Ecology Nairobi, Kenya and winner of the 1995 World Food Prize
"I don't think any of us would disagree that, if an alternative exists to a GE solution, it's to be preferred"
Mr Hodson QC, acting on behalf of the Life Sciences Network at the New Zealand Royal Commission on Genetic Modification, 8th Feb 2001
"The poor and hungry need low-cost, readily available technologies and practices to increase food production."
Professor Jules Pretty, Director of the Centre for Environment and Society, University of Essex
"Low-tech 'sustainable agriculture,' shunning chemicals in favour of natural pest control and fertiliser, is pushing up crop yields on poor farms across the world, often by 70 per cent or more... The findings will make sobering reading for people convinced that only genetically modified crops can feed the planet's hungry in the 21st century... A new science-based revolution is gaining strength built on real research into what works best on the small farms where a billion or more of theworld's hungry live and work... It is time for the major agricultural research centres and their funding agencies to join the revolution."
New Scientist editorial, February 3 2001
Better solutions than GM in Kenya
FOCUS ON AFRICA