Hope for cabbage farmers

Cabbage damaged by diamondback moth
Cabbage damaged by diamondback moth. Photo by IITA

African cabbage farms ravaged by the Diamondback moth (DBM), Plutella xylostella, are set to recover with the help of a biopesticide (Beauveria bassiana) developed by IITA scientists to kill the pest.

Resource-poor farmers, who have tried the fungal pesticide, said the biocontrol method has proved effective in controlling the insect pest that has devastated both smallholder and large-scale cabbage farms in Africa. DBM had earlier forced thousands of farmers in West Africa to abandon cabbage production for other crops.

“We now have the hope of promising results obtained using B. bassiana,” says Raymond Ahinon, who heads the Crop Department at the Songhai Center. Songhai is a commercial farm center in Porto Novo, Republic of Bénin. “The product is effective, and has helped in eradicating DBM on our cabbage farms.”

Cabbages are among the most important vegetables in Africa in general and particularly in Bénin, especially for lower income groups. It serves as an income source among groups most affected by poverty, including small farmers, youths, and most especially women who play an important role in agricultural production.

Eaten daily, either raw in salads, steamed, boiled or fried, cabbages and their cousin, kale, serve as important cash-generating crops.

Why biological control
In recent years, chemical control of DBM is proving ineffective, according to farmer Louis, who has been cultivating the crop since 1986 in his farm in Porto Novo.

Ignace Godonou, IITA entomologist based in Cotonou, Republic of Bénin, says the pest has developed resistance to a wide range of insecticides, including Bacillus thuringiensis, a biological agent used against the pest. The situation is made worse by the high costs of inorganic or chemical pesticides.

“The most common chemical pesticides used by farmers are bifenthrin and deltamethrin,” says Godonou.

“These chemicals need to be applied about 19 times within three months of the crop’s growth prior to harvest. Also, acquiring these chemicals comes with a cost that is sometimes prohibitive.”

Diamondback moth, Plutella xylostella Lindsey, Wikimedia commons
Diamondback moth, Plutella xylostella Lindsey, Wikimedia commons

On a global scale, chemical control is estimated to cost about US$1 billion annually. The accompanying package of health and environmental risks include pollution, destruction/death of nontarget but sometimes useful insects, and the reduction of biodiversity.

But there is good news. Biological options in an integrated pest management approach could offer a solution to sustainable control of DBM, according to Godonou.

So far resource-poor farmers use botanical pesticides, mostly aqueous seed extracts of the neem tree, against DBM and a wide range of other arthropod pests. The success of this approach, however, has been limited.

B. bassiana to the rescue
In search of sustainable biological agents to control the pest, Godonou says eight isolates of the entomopathogenic fungi B. bassiana and Metarhizium anisopliae indigenous to Bénin were screened for virulence against larvae of the insect. Two isolates showed promise.

Beauveria bassiana-covered pupa of DBM
Beauveria bassiana-covered pupa of DBM. Photo by IITA

One, Bba5653, caused 94% mortality of DBM larvae, and mortality was significantly higher than that caused by any other isolate. Cabbage yield was approximately three-fold higher than the yield in plots treated with the insecticide bifenthrin or in untreated plots.

In a study published in the journal Crop Protection in 2008, Godonou and his colleagues said that fungi, such as B. bassiana and M. anisopliae, are ubiquitous in nature and are specific to target pests. They persist in the environment and are easy to mass produce.

Co-author C. Atcha-Ahowe says field trials of the B. bassiana biopesticide have sparked demand for the commodity.

“The majority of farmers who abandoned cabbage cultivation for other crops are now requesting the biopesticide so they can go back to growing the crop, but not enough of the product is available,” he says.

When compared to the production of other vegetable crops, such as carrots and lettuce, cabbage cultivation results in higher returns, say resource-poor farmers. The gap is exacerbated by the increasing demand and the dwindling supply of cabbage.

An opportunity for the private sector
Like the highly successful Green Muscle®, which was picked up by the private sector, Godonou says the B. bassiana technology is another opportunity waiting for the private sector.

He says farmers are willing to patronize the product to control the cabbage enemy and increase farm yield, but there should be enough supply to meet the demand.

“With the ability to remain active on the field for several months after initial application, B. bassiana will end the rigor of repetitions and costs associated with the application of synthetic chemical pesticides,” he adds.

Biological Control 101

Chemical pesticides have become a mainstay in pest management because of their “quick-fix” effects and their ease and convenience of use. Their use over time, however, has some negative effects on human health and the environment.

Farmer in Parakou, Benin, participates in the release of Fopius arisanus, a parasitoid of Bactrocera invadens
Farmer in Parakou, Benin, participates in the release of Fopius arisanus, a parasitoid of Bactrocera invadens

Biological control or biocontrol is an alternative to the use of chemical pesticides. It uses natural “enemies” to reduce pest populations and their damage to crops and food products. These enemies include predators, parasitoids, or pathogens.

Biocontrol approaches build on the natural control already existing within an ecosystem by strengthening a naturally occurring enemy or by importing and introducing a natural enemy into that ecosystem.

Predator and pest mites
Predator and pest mites

IPM toolbox
Biocontrol is just one of the many components in the integrated pest management (IPM) toolbox that includes, among others, the use of cultural practices, planting of resistant or tolerant crop varieties, and the application of inorganic (or chemical) pesticides.

Biological alternatives involve the use of biological control, biological pesticides, botanicals, semiochemicals, and transgenic organisms.

Biocontrol
Biocontrol is the use of natural enemies, also called biological control agents, such as predators or parasitoids that attack the pest to reduce pest damage. In an undisturbed ecosystem, insects, mites, or microorganisms, and other species that prey on or parasitize different species are part of the natural control or balancing mechanisms.

Biocontrol approaches include conservation biocontrol, augmentation biocontrol, and classical biocontrol.

10Maize cob being co-inoculated with toxigenic and atoxigenic strains to identify competitive atoxigenic strains in the field
10Maize cob being co-inoculated with toxigenic and atoxigenic strains to identify competitive atoxigenic strains in the field

Conservation biocontrol enhances the effectiveness of natural enemies already present in the ecosystem through, for example, the application of cultural practices. Examples include planting food sources for natural enemy pests or reducing the amount of chemicals in the system to allow natural enemy numbers to increase.

Augmentation biocontrol means the addition of a predator or parasitoid to an ecosystem to increase numbers or begin a new population when the natural enemy has disappeared. Inoculation is adding small numbers of the species, which increase naturally over time, whereas inundation means adding large numbers of the natural enemy for a rapid effect on the pests.

Classical biological control involves importing natural enemies to a location where they have not been present before, especially, when a pest has been accidentally introduced. Classical biocontrol has been applied successfully to control hundreds of pests in horticultural and field crops and in forestry. Despite the initial high investment, it is the most economical form of pest control.

Biopesticides

Diseased cassava leaf
Diseased cassava leaf

Biopesticides involve the use of pathogens—microorganisms that cause disease—to kill pests. Also called microbial pesticides, they contain pathogenic microorganisms as their active ingredient, e.g., bacterium, virus, fungus, nematode, or protozoa. They are applied in a manner similar to chemical pesticides, but their “live” ingredient gives them a potentially greater advantage over chemicals since this is able to reproduce and provide continuing pest control.

Some popular examples include the use of Bacillus thuringiensis (Bt), which naturally occurs in the soil and in plants, or mycopesticides (insect-killing fungi) such as Beauveria bassiana and Metarhizium anisopliae, which attack a relatively wide range of insects. IITA has been using these fungi for its biocontrol work.

Botanicals

<em/>Bactrocera invadens ovipositing on a mango fruit” title=”11Bactrocera invadens” width=”250″ height=”188″ class=”size-full wp-image-1149″ /><figcaption class=Bactrocera invadens ovipositing on a mango fruit

Also called botanical pesticides, these contain plant extracts that have biocidal properties. The best example is the use of the extracts from the popular neem tree (Azadiracta indica) (active ingredient: azadirachtin), which can be used to disrupt molting in a wide range of insect pests. Such botanicals can be grown alongside agricultural crops.

Semiochemicals
These are chemicals produced by insects and other species that stimulate behavior or interactions, and are used to manipulate behavior to control pests. Well-known examples are pheromones, which stimulate behavior between individuals of the same species, and allelochemicals, which mediate interaction between different species.

Transgenic crops
Transgenics contain protectants produced by the plants themselves, following the introduction of genetic material coding for that substance, as in Bt transgenic plants, e.g., Bt maize, potato, and cotton. The gene coding for the Bt toxin is inserted into the chromosome of the crop plant so that the plants themselves become toxic to the pest.

Source: SP-IPM. 2006. Biological alternatives to harmful chemical pesticides. IPM Research Brief no. 4. SP-IPM Secretariat, IITA.

Developing genomic resources for banana

Jim Lorenzen, j.lorenzen@cgiar.org

jim_lorenzen-looking-at-banana-flower
Jim Lorenzen checking a banana flower. Photo by IITA

Banana and plantain (Musa sp.) are a very important staple food and cash crop in Africa. Although the principles of banana breeding and genetics were established decades ago, it is still a time-, land-, and resource-intensive process. A crew of several persons collects male flowers and pollinates female flowers while perched on ladders. When successful, seeds must be surface-sterilized and embryos removed for germination in test tubes (or else most won’t germinate), multiplied, and carefully “weaned” for field planting.

Large-sized plants require much field space, and new hybrids must be evaluated through two or three production cycles (about 3 years) before being selected for further testing, such as for disease resistance. Some essential attributes, such as resistance to disease or nematodes may also take several years to assess properly. It would be a huge advantage if early selection could be done, based on some associated marker or rapid test, to eliminate susceptible individuals without wasting resources on them. For other complex traits, it would be useful to have markers based on component genes to be able to select ideal “genotypes”.

One way to do early selection is to use molecular markers that are linked to the target traits (molecular-assisted breeding). This method is becoming common in cereal breeding, yet should be even more cost-effective for a large perennial crop such as banana that requires so much time and space to evaluate. The tools of DNA fingerprinting are applied, and by knowing which DNA markers lie near genes of interest, selecting for the markers will be equivalent to selecting for the trait a year or more later.

The problem is that we lack enough information on the banana genome to have molecular tools to map traits. One of our activities has been to map and characterize new molecular markers for use in banana breeding and genetics. PhD student Gaby Mbanjo from the University of Yaoundé, Cameroon, has been working in Uganda and Kenya to characterize and map a large new set of simple sequence repeat (SSR) markers, often called microsatellite markers. She is a scholar of the Biosciences for Eastern and Central Africa (BecA) program, with funding provided by the Canadian International Development Agency (CIDA).

Gaby is also working to develop other types of molecular markers based on small genetic differences (single nucleotide polymorphisms = SNPs) between alleles of genes involved in controlling plant defensive reactions. These will be used to try to map the genetic loci responsible for resistance to the burrowing nematode (Radopholus similis) and banana weevil (Cosmopolites sordidus) in the population she is studying. Markers of both types can be converted to semi-automated assays for hundreds or thousands of assays. This effort is expected to result in a DNA fingerprinting assay in which we can select the associated DNA markers and thus also select the target resistance without spending as many resources on susceptible plants.

The molecular markers will have other practical uses. Unfortunately, sometimes varieties get distributed with wrong names, or a batch of plants supposedly of a single variety may actually contain a mixture of varieties. Molecular markers can be used to “fingerprint” mother plants used to produce new planting material to ensure that they are of the proper variety. They can also be used to select diverse parents for maximizing the heterozygosity of offspring. Some of the markers are being transferred to a national research program for assessing varietal purity in their advanced selections.

Molecular markers are a way in which biotechnology and the rapidly expanding knowledge of DNA sequences in plant genomes can be used to make classical breeding more efficient. This should be especially helpful for large perennial crops such as banana and plantain.

Ensuring biosafety

Christian Fatokun, c.fatokun@cgiar.org

For thousands of years, developing improved crop varieties has depended on conventional plant breeding methods.

With developments in scientific research and technologies, it is now possible to ”design” crops with improved characteristics within a shorter time and with more precision using biotechnology. Through transformation, genetic information (genes) can be transferred between distantly related species, which would not happen in nature (transgenes). This allows novel and unique characteristics to be incorporated into crop varieties. Through this technology it is possible to develop new crop varieties (genetically modified organisms, GMOs) with higher yield, adaptation to variable environments, resistance to pests and diseases, enhanced storage time, and improved nutritional values, among others.

Cowpea plants in the IITA screenhouse. Photo by O. Adebayo
Cowpea plants in the IITA screenhouse. Photo by IITA

Concerns have been expressed about the impact on human and animal health of these transgenes. Concerns also revolve on their possible movement from the bioengineered crop to other cross-compatible crops, and in particular, to wild relatives growing in regions where the crop has its origin or center of diversity, and on the impact of products of transgenes with pesticidal activities on nontarget organisms The concern is that transgenes could confer “fitness” on the crop’s wild relatives, thus making such plants develop into “super weeds,” especially when they become resistant to herbicides. There are also concerns that the protein in the transgenes could be allergenic to people. Outcrossing is a common occurrence between compatible plants and the degree of outcrossing depends on the crop species.

To regulate the release of GMOs to the environment in any country, a set of biosafety regulations are put in place. The International Biosafety Protocol (Cartagena Protocol) places emphasis on the transboundary movements of GMOs and offers a set of guidelines on their safe handling and use. It has been adopted by several countries, including 38 in Africa.

Biosafety is generally defined as “policies and procedures adopted to ensure the environmentally safe applications of modern biotechnology in medicine, agriculture, and the environment, so as to avoid endangering public health or environmental safety.”

IITA’s research on genetic engineering is in consonance with the CGIAR’s guiding principles on the application of modern biotechnology in the improvement of any of its mandate crops. We do not have a separate set of biosafety guidelines. The Institute has worked very closely with agencies of the Federal Government of Nigeria to establish biosafety guidelines for the country. The Federal Ministry of Environment is responsible for regulating the release of bioengineered products, and reports that a Biosafety Bill has been prepared. The document will soon be presented to the National Assembly for deliberation prior to being passed into law. With the existing biosafety guidelines that became operational in 2001, it is possible to carry out research on genetic engineering and test products of the technology under confinement in Nigeria.

Technician examines banana cultures, IITA genebank. Photo by O. Adebayo
Technician examines banana cultures, IITA genebank. Photo by IITA

Uganda and Tanzania are two countries where IITA is undertaking transformation research. In Uganda, work on transforming banana resistant to banana Xanthomonas wilt (R4D Review Edition 1) and nematodes is ongoing. In Tanzania, transformation research on incorporating resistance to cassava brown streak disease is being undertaken with partners. Both Uganda and Tanzania are signatories to the Cartagena Protocol, which requires signatory countries to develop a regulatory framework and the capacity (in terms of people, expertise, and technology) to undertake risk assessments in developing and using GMOs.

The Government of Uganda recognizes biotechnology as a tool that can be used to help stimulate economic development and meet national goals for improving the standard of living for the poor. Biotechnology is specifically included in the Poverty Eradication Action Plan as a component in the Program for the Modernization of Agriculture.

Recently Uganda’s cabinet has approved its first National Biotechnology and Biosafety Policy after 8 years of deliberation. The policy provides objectives and guidelines for promoting and regulating biotechnology use in the country, and contains the guidelines on the legal, institutional, and regulatory framework. The guidelines cover tissue and cell culture, medical diagnostics, industrial microbiology, and biochemical engineering.

For the policy to be implemented, there must be a law. At the moment, a draft bill has been presented to Parliament. The commercialization of GM crops in any country requires this law.
Tanzania released its National Biosafety Framework in 2005. An Institutional Biosafety Committee addresses biosafety activities within any institution conducting genetic modification. The Division of Environment is currently the National Biosafety Focal Point, which is responsible for overseeing the review and approval of applications, and implementation of biosafety issues.

In vitro yam seedlings. Photo by O. Adebayo
In vitro yam seedlings. Photo by IITA

An interim biosafety regulatory process exists for permitting small-scale confined research/field trials of plant and plant products. Applications are reviewed by the Agricultural Biosafety Scientific Advisory Committee and the National Biotechnology Advisory Committee. The Tropical Pesticides Research Institute and the Plant Biosafety Office require risk management measures to ensure that the field trial does not adversely affect the environment or human health.

The first application using the interim measures was for the MARI-IITA project on cassava genetic transformation for virus resistance in Tanzania.

With contributions from Leena Tripathi, IITA–Uganda, and Caroline Herron, IITA–Tanzania.

Guiding Principles
1. In keeping with its mission, IITA will continue to engage in research designed to produce international public goods appropriate for use by resource-poor farmers. In doing so, it will typically use a range of technologies, including in some cases modern biotechnological methods, to produce breeding and planting materials containing traits important to and useful for resource-poor farmers. It follows that IITA believes that genetically modified organisms (GMOs) that contain traits beneficial to small farmers and have been fashioned carefully, with due regard to the range for social, economic, biosafety, and environmental concerns, are a legitimate subject for its research and development.

2. For sound scientific and practical reasons, IITA will continue to work with the gene pools of cultivated species and their wild or weedy relatives as the first and often most effective means of bringing benefits to resource-poor farmers. The formulation of these Guiding Principles is therefore not intended to be, nor should it be interpreted as signaling a shift in emphasis or priorities in IITA research programs: conventional breeding techniques will continue to be used widely in all crop improvement programs. Indeed, they are likely to remain the dominant approach for some time to come.

3. IITA will continue to monitor, research, and assess the possible social and environmental implications of the use of genetically transformed plant varieties in the ecological regions in which they might be used and, especially, in the centers of origin or of diversity of the species that may be genetically transformed. As in other subject areas, these activities will routinely be carried out in cooperation with national agricultural research systems, farmers, and other partners.

In all its genetic engineering-related research, IITA will observe the highest scientifically accepted standards of safety in the conduct of laboratory and field experiments.

Yam cultures in IITA genebank. Photo by O. Adebayo
Yam cultures in IITA genebank. Photo by IITA

4. IITA will comply with relevant national or regional biosafety, food, environmental and policy regulations for the deployment of genetically engineered organisms. IITA will not deploy genetically engineered organisms in any country lacking such regulations. In certain circumstances, IITA may voluntarily adhere to higher or more stringent standards than the minimums imposed by national legislation and regulation. IITA will not make GMOs or other such products available in a country without that country’s prior informed knowledge, consent, and support.

5. IITA will work with national partners, using the best expertise available, to address potential risks and ensure confidence in the product. If a recipient country lacks the expertise to conduct its own risk assessment,

6. IITA will work with national partners to help develop this capacity, and to develop appropriate strategies and methodologies.

7. Currently, IITA adds a modest number of plant genetic resource accessions each year to those it already conserves under long-term, ex-situ conditions. Under proper management, geneflow between accessions is essentially nonexistent, and thus the presence of GMOs within IITA’s collection is not considered to undermine or pose a significant danger to the goal of its long-term conservation of genetic diversity. When circumstances so indicate, however, IITA will screen incoming (and/or already-held) accessions for the presence of promoters or other indications of the presence of GMOs. IITA will make the resulting data available to anyone requesting samples of these accessions, and IITA will take sufficient measures to ensure the appropriate and safe management and use of such materials.

Is genetically modified cowpea safe?

Genetically modified cowpea resistant to the cowpea pod borer (Maruca vitrata) will soon become a reality. This transgenic cowpea contains the gene from the soil microbe Bacillus thuringiensis (Bt) that is toxic to the pests. But before that happens, IITA is making sure that it addresses some of the potential risks associated with using such genetically modified organisms (GMO).

Typical damage by pod borer caterpillar. Photo by M. Tamo
Typical damage by pod borer caterpillar. Photo by M. Tamo, IITA

IITA started preliminary studies to assess concerns, including the development of resistance by the target insect pest to the insecticidal protein expressed in the plant, negative effects of the insecticidal protein on nontarget organisms present in the same agroecosystem, such as natural enemies or pollinators, the accidental introduction of the gene expressing the toxic protein into wild relatives of cowpea (referred to as “gene flow”), and negative effects on human and animal health.

In the meantime, a team of scientists headed by Dr T.J. Higgins of the Commonwealth Scientific and Industrial Research Organisation (CSIRO), Australia, was able to transform cowpea successfully with the Bt toxin-expressing gene. The transgenic plant has been tested in Puerto Rico and is not yet available for testing in Africa.

Parasitic wasp, Phanerotoma leucobasis, laying egg into egg of pod borer. Photo by M. Tamo
Parasitic wasp, Phanerotoma leucobasis, laying egg into egg of pod borer. Photo by M. Tamo, IITA

IITA started evaluating some of the unintended effects of the purified Bt-toxin on nontarget organisms, focusing on natural enemies of the target insect pest, the caterpillar of the pod borer (M. vitrata).

In our first case study, we used a locally available natural enemy, a small parasitic wasp called Phanerotoma leucobasis, which develops by destroying caterpillars of the cowpea pod borer. This wasp has a curious biology because it can insert its small egg into the bigger egg of the pod borer, but its immature stages develop inside the caterpillar only when it starts feeding on the cowpea plant. It destroys the pod borer’s internal organs from the inside, ultimately killing it.

Following standard protocols in collaboration with Purdue University, USA, we first determined the lethal dosage of the Bt-toxin that could kill 50% and 95% of the young caterpillars. Subsequently, we let the wasp parasitize the eggs of the pod borer, and transferred the hatching caterpillars onto an artificial rearing diet contaminated with different doses of the toxin to let them feed on it.

Exotic parasitic wasp Apanteles taragamae. Photo by G. Georgen
Exotic parasitic wasp Apanteles taragamae. Photo by G. Georgen, IITA

The level of wasp mortality recorded in this experiment favorably compares with results obtained in other studies, and is primarily due to the death of the host caterpillar while feeding on the contaminated diet. Similar experiments are ongoing, using another natural enemy of the pod borer, the exotic parasitic wasp Apanteles taragamae introduced into our laboratories from the World Vegetable Center (Asian Vegetable Research and Development Center) in Taiwan.

What would then be the likely impact of Bt cowpea on these natural enemies in the field?

For now, we know from previous studies (Romeis et al. 2006) that the negative, unintended effects of Bt-transformed crops such as corn and cotton on natural enemies and biodiversity at large are far less than those caused by repeated applications of synthetic pesticides to control the same pests under conventional crop protection schemes. For the cowpea pod borer, several alternative host plants exist in the wild where the pest is exposed to the attacks of natural enemies throughout the year, hence providing natural refugia and thus avoiding being negatively impacted by the Bt-toxin present in the transformed cowpea.

Reference
Romeis, J., M. Meissle, and F. Bigler. 2006. Transgenic crops expressing Bacillus thuringiensis toxins and biological control. Nature Biotechnology. 24:1. p 63-71. January. www.nature.com/naturebiotechnology

Training farmers using video

IITA, together with partners, is using an innovative approach to strengthen knowledge of cocoa farmers in Ghana on integrated crop and pest management techniques and practices.

Video viewing club in Ghana. Photo by S. David
Video viewing club in Ghana. Photo by S. David, IITA

Drama is a popular learning tool in rural Ghana and video viewing booths are found everywhere. Taking a cue from this, IITA’s Sustainable Tree Crops Program (STCP) assisted the development of video viewing clubs (VVCs) to train farmers in increasing cocoa production and improving safety and labor efficiency. A VVC consists of 20 to 25 farmers meet weekly to learn new production practices, using videos, illustrated guidebooks, guided discussions, and field demonstrations.

Using video as a training tool engages the participants, enables new techniques and practices to be shown in a short period, and standardizes the technical information disseminated to farmers.

The VVC is a pilot project assisted by STCP’s funding partners including the Chocolate Manufacturers’ Association, Nestlé, Sunspire, Mars Incorporated, USAID, and the World Cocoa Foundation. Project activities are focused on integrated crop and pest management (ICPM) practices in cocoa. Local farmers, cocoa researchers, communication specialists, media specialists, and other partners such as ANS Media, CABI Bioscience, and Stratcomm Africa collaborated in producing the videos. So far, five have been developed, dealing with cultural methods to control black pod disease, chemical control of mirids and black pod disease, pruning, harvesting, pod breaking, fermentation, and drying.

Farmer field school participants. Photo by S. David
Farmer field school participants. Photo by S. David, IITA

Farmers participated in filming, editing, pretesting, and the final production of the videos, supported by media specialists. Production involved farmers earlier trained in ICPM through STCP-supported farmer field schools (FFS), and specialists. A second group of farmers and communication specialists developed the illustrated guidebooks by identifying technical messages, depicting these, reviewing drafts, and pretesting the materials.

In recognition of this innovative effort in training farmers, Dr Soniia David, IITA regional participatory extension specialist, and her team at STCP received the 2008 CGIAR Science Awards – Outstanding Communications Category.

Red-podded cocoa, Cameroon. Photo by S. David
Red-podded cocoa, Cameroon. Photo by S. David, IITA

If farmers adopt the major ICPM practices promoted by VVC, they can increase yield, on average, by 20-40%, and decrease pesticide use by 10-20%. Production training with marketing interventions can also increase household income by 23-55%. STCP expects that at least 60% of VVC-trained farmers will adopt four or more improved practices.

To date, STCP has assisted in training 450 farmers through pilot VVCs in Ghana’s central region. It will support partners in training 11,000 farmers in three other West African countries on ICPM over the next five years.

Previously, STCP supported the training of 125,000 farmers in West Africa on ICPM through farmer field schools, a participatory training and research method, to increase production and improve safety and labor efficiency.

Video is becoming increasingly popular as a training tool. The videos developed by STCP can be used for the training of trainers and promoting more effective farmer-to-farmer knowledge and technology diffusion.

STCP will continue to strengthen the capacity of national partners using VVCs and other innovative communication tools to educate farmers.

Science meets industry

In Uganda, the local word for food is matooke, which is what the Ugandans call the green banana, their staple food. Nowhere is banana eaten in such a scale as in this East African nation of 31 million.

Ugandans reportedly eat, on average, more than a quarter of a kilogram of banana in a day, or in some areas, 450 kilograms per year! That’s a lot of bananas.

Bananas are as important to the Great Lakes region as rice is to East or Southeast Asia. They are a valuable source of vitamins, minerals, and carbohydrates or calories; they are the primary source of income for 16 million smallholder farmers in Uganda; and they play a central role in the sociocultural fabric of the country.

About one-third of the total global banana production comes from sub-Saharan Africa where millions of subsistence farmers and consumers depend on the crop as a staple food. Bananas are easy to grow especially in the Great Lakes region where growing conditions for the crop are ideal.

Enhancing small tissue culture plants with endophytes. Photo by IITA

But banana production in the region is being threatened by a complex of pest and disease problems, including Fusarium wilt (Fusarium oxysporum f.sp cubense), black leaf streak or sigatoka (Mycosphaerella fijiensis), viruses, banana weevils (Cosmopolites sordidus), and nematodes (e.g., Radopholus similis). The most serious threat at the moment is banana Xanthomonas wilt (BXW, Xanthomonas vasicola pv. musacearum), which could devastate the banana industry in East Africa. These pests and diseases damage the banana plants, cause yield loss, and eventually food insecurity and loss of livelihoods.

With the food security and livelihood of millions of farmers at stake, science and industry meet to save the crop and develop technologies to make production more sustainable. One technology involves the rapid, mass propagation of more robust bananas using endophyte-enhanced tissue culture,” said Thomas Dubois, biocontrol specialist and nematologist based in Uganda, who leads the team of IITA scientists that helped develop the technology.

“Old” technology
Tissue culture is not a new technology. Tissue-cultured banana is the norm in the rest of the world. Commercial tissue culture laboratories are beginning to emerge across East Africa to satisfy the rapidly rising demand for healthy planting material.

Tissue culture banana plants made in specialized private-sector laboratories are healthy and can grow faster than traditional plants. They are also ideal for establishing large plantations, which are then uniform, enabling better planning for harvests and marketing.

Tissue culture banana plantlets. Photo by IITA

Tissue culture produces clean plantlets without disease but also without a natural defense system. They are quite sensitive to the relatively harsh conditions in the East African fields, including attack by pests and diseases, and low soil fertility. The smallholder fields are burdened with biotic pest pressures and abiotic constraints, and the small-scale farmers do not practice essential high-input field maintenance. Thus, tissue culture adoption in Africa faces a “barrier”.

This is where IITA came to the rescue. “Endophytes” is a general term for naturally occurring microorganisms inside the plant that protect it from pests and diseases, and that enhance plant growth. Every single individual plant species, including banana, contains endophytes. They can be used as a natural form of control. Introducing endophytes in plants during propagation is like immunizing them. Plants inoculated or “vaccinated” with endophytes become resistant to pests or diseases.

Army against pests and diseases
The endophytes become part of the planting material before the young tissue culture plants are sold to farmers. Once inside, the endophytes go to work, boosting the plant’s immune system—so long as they get there first, before the pathogen.

Thus, farmers are provided with a weapon to fight the banana weevils and nematodes, which abound in the soil and which are transferred by farmer-to-farmer contact through exchange of infected planting material.

IITA, through its station in Kampala, Uganda, developed the endophyte technology to produce robust pest- and disease-free banana planting material, in collaboration with various national and international partners. Research on this technology started in 1997 with funding from the German Federal Ministry for Economic Cooperation and Development (BMZ).

IITA isolated nonpathogenic strains of endophytes belonging to the Fusarium family from healthy plants growing under high levels of pest and disease pressure. Institute scientists developed a rapid, easy, and low-cost laboratory screening protocol for testing the numerous endophyte strains obtained against the banana weevil and the burrowing nematode. They also devised a more efficient technique to mass produce the best strains, and introduce them into the tissue-cultured plantlets. The endophyte-enhanced plants are then grown in screenhouses and in farmers’ fields to assess their performance against target pests.

Genetically modified endophyte strains with genes for fluorescent colors. Photos by IITA
Genetically modified endophyte strains with genes for fluorescent colors. Photos by IITA

Using endophytes as biological control agents offers several advantages. When endophytes enter the plants first, they get a head start over the other microorganisms, and once they are established, other microorganisms would offer less competition. Because the endophytes are already in the plantlets when they are transplanted, control can be targeted using low levels or doses, and performance is consistent. Using endophytes also makes it easier to control cryptic pests such as the banana weevil and the burrowing nematode, which are embedded within plant tissues.

As an off-shoot of work on endophytes, IITA-Uganda scientists realized that endophytes circumvent many of the barriers associated with conventional biopesticides. This has spurred novel research in using conventional biopesticides, such as Beauveria bassiana, as artifical endophytes in seed systems. B. bassiana worldwide is the most researched and commercialized fungal biopesticide against a variety of insect pests.

Laboratory and screenhouse studies have revealed the great potential of this entomopathogenic fungus for use against the banana weevil. However, impractical field delivery methods and high costs associated with its application prevent its use and commercialization in banana fields.

IITA’s research also showed that B. bassiana can “colonize” the internal banana tissues for at least four months and that B. bassiana-enhanced plants reduced larval damage by more than 50%. It kills the damaging insect stages inside the plant; it is protected from adverse biotic and abiotic factors; little inoculum is required, greatly reducing cost. Farmers do not need to apply the biological control organism themselves, as the technology is easily transferable to a commercial tissue culture producer.

But IITA’s research-for-development work does not end there. How does IITA make endophyte-treated plantlets available to farmers, the ultimate users of the technology, as a ready-to-plant product at low cost?

Confluence of science and industry
The Institute has established strategic alliances with several private and public sector entities to develop international public goods. It leads the research effort on endophyte-enhanced tissue culture technology, and a commercial tissue culture entity and a private biocontrol company handle the formulation, distribution, application, and storage of the plantlets. In the process, IITA and its partners are helping commercialize the banana industry in East Africa.

Endophyte-enhanced banana tissue culture research is undertaken with research partners that include the University of Bonn, Germany; the National Agricultural Research Organization (NARO), Uganda; the University of Pretoria, South Africa; Makerere University, Uganda; Wageningen University, the Netherlands; the Catholic University of Leuven, Belgium; and the Biologische Bundesanstalt fur Land-und Forstwirtschaft, Germany.
The work though is not confined to banana production in Africa. Bioversity International, in collaboration with IITA’s German partners, is testing endophyte-enhanced tissue culture with large-scale banana producers in Costa Rica, using Latin American endophyte strains.

Since IITA does not have the in-house capability to undertake large-scale endophyte-based research in its facilities, the Institute partnered with several private and public organizations involved in tissue culture: Agro-Genetic Technologies (AGT), a commercial tissue culture laboratory in Uganda; Jomo Kenyatta University of Agriculture and Technology (JKUAT) and RealIPM, a biopesticide company in Kenya.

An exploratory and collaborative effort to produce more robust tissue culture plantlets as research material has developed into a synergistic partnership that bridged upstream research and downstream application. On the other hand, linking up with large-scale tissue culture producers in Uganda and Kenya have helped refine and move the technology from the lab to the farmers themselves.

Researcher inspecting banana plantlets in greenhouse, DRC. Photo by IITA
Researcher inspecting banana plantlets in greenhouse, DRC. Photo by IITA

Through collaboration, endophyte-enhanced technology is now being tested in farmers’ fields in East and Central Africa. The technology enables the farmers to switch from subsistence to income generation, and more importantly to reach and create markets.

Following the research-for-development model, IITA and its partners realized that engaging and mobilizing the community of farmers is essential for the technology to succeed and gain wider adoption.

IITA saw the value of harmonizing public-private sector collaboration at the early stages of the project. It has adopted this approach in its R4D work in Africa, and is promoting its application in technology transfer work in other areas of research, mandate crops, and commodities.

The power of small

People tend to overlook the “small” and “insignificant”, focusing more on the “big” and “obvious”. In economic development, micro-businesses often receive less attention and access to growth-enhancing support facilities. Their contribution is also often undervalued.

Until recently in Nigeria, when people discussed economic development, they mainly talked about the oil and natural gas industries. These industries account for nearly 100% of earnings and more than 80% of government revenues1 and they receive all the inputs and attention. Small-scale agriculture and agriculture-based enterprises are hardly ever talked about, as if they contribute very little to economic development. And yet agriculture still provides more than 60% of employment.

During the last 3-5 years, cassava has joined oil in the headlines. Because it is a highly important element in the Nigerian diet, growing cassava is embedded in the daily routine in many rural areas and city suburbs. For many years, it was considered a woman’s subsistence crop. Things changed when the Presidential Initiative on Cassava was introduced early in 2002 by then President, Chief Olusegun Obasanjo. A directive of the Federal government followed instructing bakers to include 10% cassava flour in the production of bread and confectionery. Two years later, the directive urged flour millers to buy high quality cassava flour from local processors. This has encouraged both farmers and processors to produce large volumes of this good quality cassava flour.

In line with the Cassava Presidential Initiative, IITA implemented the Integrated Cassava Project (ICP). Through its two subprograms, the Preemptive Management of Cassava Mosaic Disease Project (CMDP) and the Cassava Enterprise Development Project (CEDP), ICP aims to reduce the impact of cassava mosaic disease (CMD) and increase productivity in 11 states in the south-south and southeast of Nigeria. The project benefits farmers, many of them smallholders, and small and medium cassava-processing enterprises (SMEs).

Through strong partnerships with the government, private sector, and farmers, the project deployed and tested 40 new cassava varieties to counter the threat of CMD and increase yield. Usually it takes 6-8 years to release a new variety in Nigeria, but in agreement with various partners, ICP adopted a participatory approach that led to the official release of 10 new varieties in just 2 years.

This had dramatic results. A disease monitoring field survey in 2006 found no severe forms of CMD, and 10-30% of fields were completely free. A similar survey in 2007 showed that disease incidence in fields with mixed virus infections on the same plants had dropped by 20%. The two variants of CMD can recombine to form the virulent Ugandan mosaic virus.2

The Project continues to distribute planting materials of these varieties. Recorded yields were impressive, averaging 25.6 t/ha, a significant increase over the 12 t/ha from traditional varieties. Some beneficiaries got even higher yields at 30-50 t/ha.

CEDP was implemented in 2004 to increase economic opportunities through sustainable and competitive cassava production, processing, marketing, and enterprise development. It links farmers to processors and facilitates processors’ access to basic technologies and markets. It provides training on production and business development services, such as planning, record keeping, pricing, developing market linkages, sanitation and hygiene, and machine maintenance.

On the production side, nearly 250,000 farmers have benefited so far. They were trained on proper farm management and rapid multiplication techniques. Farmers succeeded in rapidly multiplying the planting materials and are gaining from increased income from greater production and sales and by selling cassava stems as well. In support and to provide a means of employment and income, a group of young people has been trained on proper weed control techniques to provide service whenever needed.

Other beneficiaries are the processors, including the mobile graters, microprocessing centers (MPCs), and the SMEs, which serve as market outlets to farmers.

Cassava is bulky and heavy. With the mobile grating service, women were able to save time and labor for other productive activities. The project created employment and income for the beneficiaries, mostly youths.

The MPCs, which are equipped with more facilities, can produce 1 t/day with basic equipment such as a grater, press, sieve (manual or motorized), and fryers. Owned mostly by cooperatives and women’s associations, the MPCs produce value-added cassava products for sale, and provide service—grating, pressing, or frying—to the public.

SMEs produce value-added cassava products. They have processing equipment similar to that in the MPCs but usually of higher capacity or more sophistication, such as flash and rotary driers. CEDP provided only a few of the machines for the MPCs and SMEs. The beneficiaries acquired most of them from more than 20 machine fabricators who had been trained by IITA and are now manufacturing machines of better quality and efficiency.

In collaboration with partners, especially the Agricultural Development Program in each beneficiary-state, CEDP provided intensive training for MPCs and SMEs on producing improved and high-quality flour, odorless fufu, garri, starch, chips, and their uses for industry as well as human consumption. A recipe book was also published.

Overall, the project introduced 22 technologies for beneficiaries, generating a total gross income of US$50 million, and creating 6,000 jobs. They gained knowledge and skills in farming and business development. The cooperatives and women’s associations became stronger.

Through continuous collaboration with IITA, some of the SMEs have scaled up their farm production. Now Nigeria has factories producing glucose syrup, ethanol, adhesives, and starch, all using cassava raw material and assisted by ICP.

These enterprises may be small, but with assistance and opportunity, the small could become powerful instruments of economic development.

1 Economy of Nigeria. 2008. www.wikipedia.org.
2 IITA Integrated Cassava Project. 2007.