Safeguarding against locust invasion

Nomadacris septemfasciata hopper band
Nomadacris septemfasciata hopper band. Photo from Wikimedia Commons

Fourteen years after the introduction of the fungal biopesticide—Green Muscle®—developed by IITA’s scientists with their partners, the product is gaining more prominence as a control option against invasive locusts that threaten African farmlands.

Recently, the biopesticide, which had been picked up by a South African firm for commercialization, averted the devastation of farmlands from an invasion of red locusts in Tanzania.

The rapid intervention by the Food and Agriculture Organization (FAO) using the biopesticide drastically reduced locust infestations in Tanzania and prevented a full-blown invasion that could have affected the food crops of around 15 million people in the region.

Ignace Godonou, entomologist based in IITA-Bénin, was part of the team that developed the biopesticide more than a decade ago. He said that, if left uncontrolled, a full-blown invasion would have caused a major setback to food security in the region.

“We are happy that Green Muscle® has proved effective in controlling locusts and is now widely used.”

Green Muscle® is a fungal biopesticide that was developed in response to a locust plague in the 1980s. It is effective against most locust and grasshopper species; it is safe, does not affect other species, and can be sprayed in the same way as chemical pesticides. A fungus, Metarhizium anisopliae, which is common in the tropics and subtropics, is used to kill the pests.

Top: Healthy hopper; Bottom: Hopper infested with Metarhizium
Top: Healthy hopper; Bottom: Hopper infested with Metarhizium. Photo by IITA

If not restrained, large swarms of red locusts will fly over vast areas of farmland, traveling daily more than 20 or 30 km and feeding on cereals, sugarcane, citrus and other fruit trees, cotton, legumes, and vegetables cultivated by poor farmers. A red locust adult consumes roughly its own weight in fresh food, about 2 g, in 24 hours. A very small part of an average swarm (about 1 t of locusts) eats the same amount of food in one day as around 2,500 people.

The biopesticide was developed by an IITA technical team under the LUBILOSA project (LUtte BIologique contre les LOcustes et les SAuteriaux – Biological Control of Locusts and Grasshoppers). It has proved effective in controlling locusts in the Sahelian region, including the Republic of Niger and Mauritania.

Godonou said that initial field trials of the product were conducted in the Republic of Bénin under the close watch of IITA scientists, based in Cotonou. The subsequent large-scale field trials were held in Niger and Mauritania.

“Mass production of the fungus for small- to large-scale field trials also started at IITA-Bénin,” he added.

“Moreover, it can persist in the ground for several weeks or for up to a year after spraying, continuing to attack and kill healthy locusts and grasshoppers. The fungus is very safe and has a narrow range of hosts,” said Godonou.

This environment-friendly alternative to synthetic chemical pesticides weakens and kills the locusts in 10 to 14 days, continuing to attack and kill the grasshoppers. It remains effective under prolonged dry conditions and is therefore more effective as a control agent. The fungal spores are suspended in an oil solution, giving the product its green color.

Apart from IITA, other leading institutions in the LUBILOSA project were the Commonwealth Agricultural Bureau International in the UK, and the Département de Formation en Protection des Végétaux in Niger, with many partners drawn from donors, several research institutes, national agricultural research and extension systems, nongovernmental organizations, FAO, private sector companies, and farmers.

Increasing capacity for plant healthcare

Plants, like people, need healthcare. But in Africa, where agriculture is dominated by smallholders, farmers do not have access to reliable plant health advice and management services.

Many farmers rely on extension workers and researchers from national and international organizations for such needs. And such help is not always readily or quickly available.

Bunchy top virus-affected banana in Rusizi Valley, DRC, Rwanda, and Burundi. Photo by IITA
Bunchy top virus-affected banana in Rusizi Valley, DRC, Rwanda, and Burundi. Photo by IITA

This is why IITA and its partners are developing the capacity of national agricultural research and extension systems (NARES) in research, disease surveillance, diagnostics, and deployment of control options. A good example is in banana: when national partners at the L’Institut des Sciences Agronomiques du Burundi (ISABU) in Central Africa needed help in diagnosing and culturing the pathogen that was attacking banana, they turned to IITA for assistance. ISABU wanted to develop local capacity to independently make diagnoses, culture Banana Xanthomonas Wilt (BXW) from diseased banana plant samples, and provide treatment advice.

At that time, IITA was already working on BXW in Burundi under the Crop Crisis Control Project (C3P), managed by the Catholic Relief Services (CRS). IITA and CRS liaised closely to develop a regional training course, for national partners from Burundi, Rwanda, and Democratic Republic of Congo (DRC) to learn new techniques, while encouraging greater collaboration among scientists.

Thus, IITA and partners that include CABI UK, Central Science Laboratory (CSL), CRS, and the Consortium for Improving Agriculture-based Livelihoods in Central Africa (CIALCA) conducted a Training Course on Surveillance and Vigilance for Plant Diseases in Burundi early this year. It is a pilot effort to kick-start a series of capacity building initiatives in the banana-growing countries in the region.

The training was attended by participants from extension and research, universities, and a regional organization. Trainers came from IITA, CABI and Global Plant Clinic (GPC, see box), and Central Science Laboratory (CSL).

Training covered new methods for surveillance and vigilance of all banana diseases. Feedback from the participants highlighted the need for sustained training and the importance of introducing a system of mobile plant clinics to effectively link farmers and transfer knowledge.

The mobile plant clinics initiative was developed by CABI UK as part of GPC, led by Eric Boa and has been tried and tested across the world. Under the umbrella of Mobile Plant Clinics and GPC, IITA had collaborated on initiating clinics in Rwanda, Cameroon, Sierra Leone, and Benin and providing training in diagnostics and surveillance in Uganda, DRC, and Burundi.

“Training, however, is just the tip of the iceberg. It is important to consolidate capacity building in diagnostic techniques and to ensure that people adopt new methods with confidence and then use them regularly,” said Fen Beed, IITA’s plant pathologist based in Uganda. “Isolating and identifying plant bacteria require practice as does the conduct of participatory disease surveys. When such methods are reliably deployed, the national programs could significantly improve the reliable detection of BXW and other disease outbreaks.”

Training participants look at Banana Xanthomonas Wilt chart. Photo by IITA

Knowing where a disease occurs allows extension staff to target particular areas and plan control programs. This requires careful organization and marshalling of resources. Although IITA already has effective recommendations for managing BXW, it lacks mechanisms for presenting them to farmers and monitoring their uptake. Further effort is needed to implement training that emphasizes direct action to help farmers.

In their after-training report, Beed and colleagues said that “Effective extension depends on sound intelligence about disease distribution and the damage it causes. National governments need to understand the risks posed to new areas and the actions required to control disease through sound research planning and identification of best management strategies.”

Beed and colleagues forwarded this blueprint for managing risk and reducing banana disease losses to ensure success of a plant healthcare service managed by national programs.

Surveillance
It is important to undertake systematic and comprehensive surveys of banana growing areas to get an update on the distribution of BXW and control strategies being used by growers. The surveys provide the opportunity to determine spread and identify reasons why control strategies may not have been adopted. Where control methods have been deployed their socioeconomic impact can be quantified.

The extensive surveys will assess incidence and severity of BXW and other banana pests and diseases.
Systematic and quantitative surveillance of banana-growing areas begin with participatory surveys, a promising technique for assessing large numbers of growers quickly. Survey results can identify sites where permanent sample plots (PSP) would be established for more intensive assessments. PSP sites should be regularly monitored for disease incidence, severity, and efficacy of control methods. Data produced can determine disease spread and help to evaluate socioeconomic impact and deployment of control options.

The C3P project made huge strides towards developing databases on the spread of BXW and the influence of farmers’ practices to control this disease. These databases can be further updated with information from the surveys and with data generated from pilot sites.

The databases could be linked to regional databases of climate, growing conditions, topography, farmer demographics, and agricultural practices (e.g., produced by the CIALCA project and many others). This allows use of the databases for predicting spread and risk due to disease at various geographic scales.

Vigilance
The next step is to establish and operate an extensive system of mobile plant clinics in targeted areas. Training courses for plant doctors are available and both DR Congo and Rwanda already have some experience in running clinics. The clinics concentrate on giving advice and gathering “intelligence” about banana problems, providing information on disease control, and offering services for other crops and diseases. This is important since farmers rarely grow bananas in isolation of other crops.

Once clinics are established and their benefits realized they can be self-sustaining and can provide a routine service to farmers and extension officers.

Upgrading facilities
There is a need to ensure that participating laboratories can isolate and confirm the presence of pathogens that cause BXW and other diseases of banana. Field staff should learn how to collect diseased plant samples for sending to diagnostic centers. Diagnostic centers will be established in the region and linkages developed with advanced research institutes (ARI) to provide technical backstopping for disease diagnostics using, for example, molecular techniques.

Banana field trials in Rwanda. Photo by IITA
Banana field trials in Rwanda. Photo by IITA

In addition, for BXW, rapid diagnostic field-based kits will be fully tested for accuracy to confirm the presence of the disease. Standard operating procedures for laboratory methods should be introduced to ensure consistent results and interpretation of results. The responsibilities of staff from national, regional, and ARI laboratories should be identified and links among them strengthened to create and nurture a network of expertise available to all.

Awareness raising
Data produced from the three activities can be used to publish new disease reports and develop pest risk analysis (PRA) documents for each banana disease in the region. PRA documents are crucial as they summarize all current information and increase awareness of disease recognition, distribution, control and risks. They must be routinely updated with new information and shared across the region to alert stakeholders of potential risks. This can lead to the deployment of preemptive disease control strategies before a disease epidemic breaks out.

Monitoring and evaluation
Detailed assessment of the progress and linkages should be undertaken. The increased capacity in laboratory and field techniques should be shared by project members through training. The support of IITA and the GPC in diagnostics, surveillance, and vigilance techniques encourages national and regional cooperation and use of new methodologies. Empowering scientists and extension staff and making them accountable for their actions is a powerful way to encourage sustainable development and to promote trade.

Linkages
The benefit of creating a knowledge network for banana diseases in the region is clear. This network can be expanded through linkages with scientists and the private sector and key extension, research, and government staff from Burundi, DRC, Rwanda, and regional organizations.

The International Plant Diagnostic Network (IPDN) was set up in response to NARES’ surveys that highlighted the lack of diagnostic capacity in much of Africa and in recognition that this directly hindered the adoption of appropriate and effective integrated pest management programs and therefore international trade. IPDN has been established in collaboration with IITA in East and West Africa to increase communication and data sharing. Software for digital imaging and diagnosis, information management, and access to disease management recommendations provides a platform for enhanced diagnosis and communication between laboratory staff and experts across the world. Improved diagnostics tools and protocols have been developed and tested. This has been combined with training programs to enhance technical capacity and increase networking among diagnosticians in East and West Africa.

Initiatives such as IPDN can benefit by collaboration with similar internet-based initiatives in Africa such as the East Africa Phytosanitary Information Committee (EAPIC). EAPIC is linked to FAO’s International Plant Portal to provide posting of plant pests for each respective country, which now includes Kenya, Tanzania, Uganda, and Zambia. The plant pest list helps in developing harmonized border inspection protocols, which support capacity building efforts in plant pest survey, identification, and communication systems, such as IPDN.

A follow-on project with these components that combines good science, effective surveillance, and proven advisory services could strengthen the contribution of extension and research to increase food security, income generation, and improved trade in Africa. It also highlights support required from national and regional organizations, governments, and donors. These include local training for diagnostic techniques and expansion of participatory disease surveys and strengthening of disease vigilance through the establishment of mobile plant clinics.

Figure 1. Disease management scenario (fire fighting vs. preemptive control)
Figure 1. Disease management scenario (fire fighting vs. preemptive control)

”Addressing all these considerations will contribute significantly towards providing a service to support farmers and trade that would move away from the current scenario of ‘fire-fighting’ diseases to providing preemptive control (see Figure 1),” concluded Beed.

Global Plant Clinics

The CABI Bioscience Global Plant Clinic (GPC) provides a comprehensive diagnostic and advisory service for disease problems on all tropical crops. The Service is unique in its global operation and the range of plant diseases it handles. CABI Bioscience has been identifying plant diseases for over 90 years and other key partners in GPC include Rothamstead Research and Central Science Laboratories. The Global Plant Clinic gives expert advice on the interpretation and application of diagnostic results drawing on extensive international experience in a wide range of crops and information from CAB International’s award-winning Crop Protection Compendium.

Mobile plant clinic in Butembo, DR Congo. Photo by IITA

The GPC has initiated a series of mobile plant health clinics that offer regular and reliable advice on all plant health problems affecting any crop. These clinics are run by plant “doctors”, many of whom are agronomists or extension workers, who work for existing, grassroots organizations.

The clinics are not a technology but an advisory service. They link diagnostic labs with extension workers (plant doctors) and provide regulatory bodies in plant health with up-to-date information on current priorities by clinic ‘area of influence’. Such clinics have little direct expense. In the long term they need public investment and private support (from farmers or input suppliers such as those responsible for improved varieties or even fertilizer).

According to GPC head Dr Eric Boa, “Farmers benefit from advice at clinics: they preempt new problems and avert losses by quick action; reduce pesticide use; and reduce losses and save money by giving good or better recommendations for managing a problem. On vigilance/surveillance, clinics identify current problems affecting priority problems in an area.”

In banana, the most recent disease outbreak due to banana Xanthomonas wilt (BXW) was first reported to move from Ethiopia to Uganda by regional scientists and was subsequently confirmed by the GPC in Uganda in 2001. As the disease spread within Uganda and relentlessly across the region research programs led by CRS, IITA, and other national scientists tracked its movement into Burundi, DRC, Rwanda, Tanzania, Kenya, and the causal agent was confirmed by GPC.

BXW is one of several damaging diseases in East Africa and the demand for better surveillance and vigilance through mobile plant clinics has been widely expressed. The deployment of control options through clinics was based upon methods used to control a similar disease of banana caused by another bacterium. These primarily consist of the use of disease-free planting material and farmers tools and the removal of male flower buds to prevent infection from insect vectors.

http://194.203.77.76/globalplantclinic/