1. An initiative to develop pest-resistant maize
2. Every means has to be used in the fight against hunger
3. A textbook example of international collaboration
   
4. IRMA takes local production conditions into account
5. An open research process
6. initial tests with transgenic material
   

by Jürg Bürgi

In Kenya, voracious stem borers destroy a significant part of the maize crop every year. The amount the pests leave will soon barely be enough to feed the country's fast-growing population. By developing maize varieties capable of resisting these pests, the Insect Resistant Maize for Africa (IRMA) project hopes to help secure the future availability of the most important staple food for millions of Africans.

They have onomatopoeic, even poetic names, and they look like cute little caterpillars, so small that several of them would fit on a single fingertip. But the elegantly beige Chilo partellus, the dark-skinned Busseola fusca, and the coquettishly brown Eldana saccharina (which finds anything sweet irresistible) are all pests that are just as dangerous as Sesamia calamistis, which shows off her superiority in a costume of fine old-rose pink. Related to the infamous European corn borer that is well known in Europe and the United States, stem borers cause immense devastation in African fields, depriving small farmers of a substantial proportion of their most important foodstuff.

Every year, says maize specialist Stephen Mugo in Nairobi, the four stem borer species affect 87% of maize plantations in Kenya. Depending on the growing area, they destroy an estimated 11-26% of the crop, averaging 330,000 metric tons. As they develop, the moths larvae attack on several fronts: first they feed on the leaves on which they emerged from the egg, and then they work their way to the whorl, the center of the maize plant. For about 10 days, they regale themselves on the delicate cell material in the growth zone, and chew their way down the stem until they finally bore an exit hole for themselves under the base of a leaf. Now fat and opulent, they pupate. And once they have matured into moths, they leave the host plant through the hole they have prepared.

The destruction the voracious stem borers cause already affects the maize at an early stage of its development. The first sign of the pests is the characteristic white bite traces on the leaves. Later, when the caterpillars have worked their way inside the stem and have started tunneling, no signs of attack are visible from the outside initially. The borers are now no longer accessible to normal spraying treatment. "By protecting the pests against birds, parasites, and their other natural enemies, the plant is its own worst enemy at this stage," Stephen Mugo sums up. He is familiar with the disastrous effects from his own experience.

Having grown up on a small farm in Kirinyaza on the southern slopes of Mount Kenya, he vividly remembers his father's efforts to fight the stem borer. In accordance with what was known about the insect at that time, he tried to get rid of them using DDT powder. "For hours on end we put the white dust from the bright yellow packages into the funnel-shaped opening in each plant - with no protection, of course. Because we didn't know how dangerous the poison was."

Maize fields attacked by the stem borer are a sorry sight. The plants have died off, with many of them lying on the ground, since even the slightest breath of wind will knock them over. And often the cobs are also eaten. The small wounds in them provide an ideal breeding-ground for all sorts of disease and putrefactive bacteria, further reducing the crop yield. "We regard this as only secondary damage," Mugo says, "but to the farmers who have to suffer the crop losses that's irrelevant."

1 An initiative to develop pest-resistant maize

The widely supported project known as Insect Resistant Maize for Africa (IRMA) aims at breaking the stem borer's power. The main goal is to ensure that Kenya's population, which is growing by 2.9% per year, is provided with its most important foodstuff. The annual maize consumption is 105 kilos per person.

Reducing crop losses is the most important, but not the only, aspect that IRMA is concerned about. The project also aims to expand the information available about the farmers' economic situation, their growing methods, and the precise amounts of crop losses.

For scientists at the Kenyan Agricultural Research Institute (KARI) - entomologists, botanists, agro-engineers, plant breeders, economists, and sociologists - it is intended to provide training opportunities, including training in the handling of genetically modified organisms. Due to newly developed guidelines and regulations, politicians and officials will also have to familiarize themselves with approval and control procedures. And finally, the project is offering the Kenyan public an opportunity to conduct an open debate on the prospects and risks of modern agrobiotechnology. Those in charge of the IRMA project are involved in developing a masterpiece of development policy.

But so far they have only just made a start. In the first year, the focus was on preparatory work, including an initial stakeholder conference for all the interested parties and groups affected by the project, giving IRMA visibility as an open process. The hundred or so participants responded in a lively and positive way to the meeting. The reaction was different among a few Swiss journalists, who unfortunately based their reports only on second-hand information. The main message that reached the Kenyan public was that IRMA is not aiming to smuggle into Africa the Bt maize that has been treated as taboo in Europe, and has recently also become controversial in the United States. Instead, IRMA is concerned with finding the best method, or combination of methods, to overcome the stem borer plague by breeding more resistant varieties of maize (see "The goal is more important than the path" interview).

According to David Hoisington of the International Center for the Improvement of Maize and Wheat (CIMMYT) in Mexico, resistance would allow farmers "who are too poor to buy pesticides to harvest about 15% more maize. And better-off farmers would save the time and money they previously spent on using insecticides."

2 Every means has to be used in the fight against hunger

With regard to the use of genetically modified organisms, over which there is controversy in Europe and the United States, the criteria are clear. When it is a matter of feeding a fast-growing population that is threatened by hunger, every means available has to be used. "Modern biotechnology is certainly not a patent remedy for hunger," says Per Pinstrup Anderson, Director-General of the International Food Policy Research Institute and recent laureate of the World Food Prize. "But in combination with traditional agricultural methods, it can provide an effective weapon in the fight against undernutrition, and it should be made available to poor farmers and consumers."

The IRMA project, which has set its sights on using a combination of all the available methods of pest control, is taking exactly this approach, David Hoisington notes. CIMMYT is providing the scientists at KARI with support in the form of its expertise and training courses, and is managing the socioeconomic surveys and laboratory work involved in developing transgenic plants. The approach CIMMYT has taken so far with regard to biotechnology is also found in Kenya: CIMMYT is opposed to the so-called terminator technology, which makes it impossible to use the harvest to obtain seed for the next growth season. CIMMYT also rejects the use of antibiotic markers: "No transgenic plant we produce that might at some time grow in a Kenyan field will ever feature an antibiotic-resist-ant gene," Hoisington promised.

The KARI and CIMMYT researchers are being particularly careful in their approach to the controversial issue of creating resistance. Because if every plant were to be protected against stem borers, there would be a danger of insects developing that would be immune to the genetically implanted toxins. In industrial countries, farmers who cultivate Bt maize use traditional seed on 20% of their land. The idea is that the pests living there will cross-breed with strains immune to the Bt toxins, thereby slowing down the development of resistance. In a developing country like Kenya, CIMMYT entomologist David Bergvinson explains, it would be impossible to explain that type of strategy. The farmers would refuse to create that sort of refuge for pests, regarding it as a waste of valuable land. Margaret Mulaa, an insect researcher at KARI, has therefore tested some 30 economically useful plants as alternative refuges that would be suitable for the pests to use for egg-laying, and that would also produce crops for the farmers. Initial tests have shown that in fairly arid growing areas, sorghum would be a possibility, while areas with more rain could use Napier grass, which is useful as cattle fodder. Sufficient test areas will be available in 2002 to investigate the whole range of potential alternatives.

Another method of slowing down the development of resistance involves "pyramiding" toxins and the plant's natural defenses. Under the direction of the project coordinator, Stephen Mugo, the testing station at Kibuku is trying out 500 breeding lines from Mexico. The ones best suited to Kenya will be exposed to artificial pest infestation at the end of 2001, and further selection will then follow. Kenyan farmers use the same non-hybrid seed for 3 or more years, and preventing the development of resistance is therefore decisively important.

There is no doubt that this problem requires particularly intensive research, in which even those who criticized the development of Bt maize for Africa can take part.

3 A textbook example of international collaboration

The Syngenta Foundation for Sustainable Agriculture is limiting its involvement to providing IRMA with the financial resources necessary, as Interim Executive Director Klaus M. Leisinger affirmed at the first meeting of the stakeholders: "There is neither any business interest on the part of our sponsor Syngenta, nor any secret political goal behind our involvement. CIMMYT, the International Maize and Wheat Institute in Mexico, which has scientific responsibility for IRMA, requested our support. We are glad to be able to work with a partner whose research efforts on behalf of poor farmers in the Third World have earned it an outstanding reputation."

The international expertise that is concentrated in IRMA makes the project a textbook example of international cooperation. The CIMMYT experts involved have American, Indian, Italian, and Belgian passports; the management committee also includes a German and a Swiss. All of them are working alongside Kenyan scientists, some of whom have acquired their academic degrees overseas, while others have them from African universities.

How well they work together was evident at the beginning of December at the IRMA researchers' annual meeting. In intensive plenary and group meetings, they discussed what had been achieved so far and their plans for the coming year. At the start of work on the project, the main concern was improving mutual information. It emerged that staff at KARI's 30 research units had been under pressure from impatient farmers for months. They had heard of IRMA on the radio and were besieging the scientists and extension officers with demands for the new seed. KARI representatives reported it was very difficult to explain to them that it would still be years before the farmers would actually be able to sow insect-resistant maize.

Collecting data on crop losses and cultivation methods Of those involved, another novelty was finding out how unreliable the available data about growing methods and crop losses were. Hugo De Groote from the CIMMYT outreach office in Nairobi is busy filling the gap. With the support of five local specialists, the Belgian director of the accompanying socio-economic research has started collecting meaningful data.

A satellite navigation system is helping him locate the control farms, which are scattered throughout the country and are often difficult to reach at any time - even without precise maps.

During the year, De Groote's team collected all the available data on maize cultivation in Kenya. They examined the few detailed studies available, and carried out their own inquiries in the six agricultural zones. They counted the planting density in the fields, had farmers estimate their crop losses, and arranged field experiments. Over the next few years, five farmers each in selected villages will protect only half of one maize field with an insecticide against stem borers, so that the losses can be precisely measured.

At the same time, KARI entomologist Josephine Songa, with intensive support from farmers, is investigating insect populations in the maize fields. Each week, traps are emptied and pests and beneficial insects are identified and counted. Most of the farmers taking part are finding out for the first time how many different species exist in their fields. In Kilifi, in the moist coastal lowlands, insects from 65 different families have so far been identified, while the figure was 45 in Kakamega in the hilly western region.

In the laboratory to begin with, and later in greenhouses, the beneficial species will be exposed to various Bt toxins. The results will then be compared with field studies in which traditional insecticides and Bt sprays are used. "This type of comprehensive testing of insect ecology," David Bergvinson observes, "has never been done before, either in the United States or any other country with Bt cultures."

4 IRMA takes local production conditions into account

Hugo De Groote also investigated the effectiveness of the various methods of pest control - a complex project, it turned out. Because, as he explains, in addition to the costs, you also have to take into account the effectiveness and acceptability of a procedure. For example, it is quite possible that farmers in individual regions might not regard the introduction of Bt maize as being particularly attractive.

In arid regions at an altitude of 700-1400 meters, for instance, the farmers estimate that their losses due to stem borers are relatively low, and in addition two-thirds of them state that they do not plant any modern varieties. "In these regions," De Groote concludes, "biological control might prove to be the cheapest method, although it is less effective than planting transgenic varieties." In the lowlands, by contrast, where pest losses amount to US$90 per hectare, maize is only grown on 33,000 hectares and only 40% of the farmers plant modern varieties. In comparison with the relatively slight benefits, it is liable to be expensive to produce specialized seed for this region.

In the transitional zones and in the tropical highlands, however, farmers prefer modern varieties, and the value of pest losses is US$82-100 per hectare. De Groote and his team therefore consider that the acceptability of pest-resistant seed and its foreseeable advantages would be high here. However, a negative aspect is that stem borers only appear in these regions sporadically.

5 An open research process

These considerations show how openly those responsible at IRMA see their work. Hugo De Groote presented his ideas initially at a meeting of the International Center for Insect Physiology and Ecology (ICIPE). Its Director-General, Hans R. Herren, takes a very critical view of the IRMA project. At the same time, however, the scientists at CIMMYT, KARI, and the ICIPE work together closely in many areas.

For example, William Overholt, Director of the ICIPE's stem borer program, would like at some time to use IRMA test plantings to investigate the effects of Bt maize on parasitoids, which have proved their value for biological control of Chilo partellus. He is also very interested in the effects of transgenic maize varieties on the so-called "push-pull method," which the ICIPE is propagating as a natural and inexpensive version of pest control, as Overholt assured his CIMMYT colleague David Bergvinson (see "Biotechnology can be useful," a discussion with Hans R. Herren on the introduction of biotechnology research into Africa, p. 51).

Bergvinson also learned from his ICIPE colleague that the domestic stem borer Busseola fusca is now being joined out by the more aggressive species Chilo partellus. The species introduced from India and Pakistan breeds faster, attacks the maize earlier, and develops more quickly. In contrast to Busseola fusca, it also does not avoid plants that are already infested when it lays its eggs.

6 Initial tests with transgenic material

In a secure laboratory established in a former office building at KARI's headquarters in Nairobi, work on transgenic material started in spring 2001. Leaves from Bt maize from Mexico were fed to domestic stem borer larvae to test the effectiveness of the genetically incorporated toxins. Four of the Bt genes proved to be effective against Chilo partellus and Chilo oricalcocliellus, and two were effective against Sesamia calamistis and Eldana saccharina. However, the toxins proved to be only 50-60% effective against Busseola fusca. The CIMMYT scientists in Mexico are now looking for other genes against this pest species.

At its annual meeting in December 2000, the IRMA management committee explicitly praised the tremendous commitment shown by all those involved, and particularly emphasized the fruitful collaboration between experts from various countries and institutions. In addition to the intensive scientific work, communications work will now be enhanced, and dialog with all of the groups affected by the project will be intensified through another stakeholder conference. Preparatory work will also be carried out in case the transgenic maize varieties bred by KARI during the IRMA studies may prove to be patentable. Klaus M. Leisinger emphasized to the committee that neither Novartis nor its agribusiness successor Syngenta have any commercial interest in IRMA, and that they would waive any licensing fees.

Whether the small farmer Philip Gichuki Wahome in the green highlands near Nyeri will ever want to plant pest-resistant maize in his little field remains to be seen. If he does decide to do so, he will still have a few years to wait (see case study). As he can't buy any pesticide granules, he will probably go on just looking away and ignoring the traces the stem borer has left on his maize leaves.

Jürg Bürgi is freelance journalist from Basle.