Plant parasitic nematodes are ever-present and incidental with plant growth and crop production, occurring on just about every crop or plant known.
Nematodes are mostly microscopic and thus unseen; and the symptoms of nematode infection are difficult to determine in the ï¬eld, as these are often nonspeciï¬c.
Yam farmers are very much aware of the physical damage that nematodes cause to the tubers, but are mostly completely unaware of what causes the damage. In the field, nematodes reduce crop vigor and performance, leading to lower yields. They cause significant damage to the tubers, resulting in deformed, unsightly tubers or tubers with cracked and flaking skin that conceals an underlying rot. Such symptoms have an immediate and direct impact on the marketability of tubers, but they also relate to reduced crop productivity. Infected tubers, when unwittingly used as planting material, due to low, unnoticeable levels of infection, affect the ability of seed to produceâ€”or even to germinate.
A wide range of nematodes are associated with yam, but only two â€˜typesâ€™ are of concern: root-knot nematodes (Meloidogyne spp.), which are evident by the disfigurement they cause to tubers (Figs. 1 and 2), and lesion nematodes (Scutellonema bradys, Pratylenchus spp.), which result in â€˜dry rotâ€™ and cracked tubers. Infected tubers can also develop erratically growing roots, referred to as â€˜crazy rootsâ€™ (Fig. 1A).
Meloidogyne spp., are an especially damaging group of pests for numerous crops, which are becoming an increasingly serious problem on yam, likely due to gradual intensification of cropping practices. For example, a recent 2013 survey by IITA in Nigeria found that approximately a quarter of all harvested tubers have some level of tuber damage by Meloidogyne spp. (Fig. 1B).
The same survey also discovered, for the first time, a particularly aggressive species, M. enterolobii, infecting yam, among a number of other Meloidogyne species, which may occur simultaneously in the same field, and on the same plant. This has implication in breeding for resistance, and requires that the screening process takes into account the variety of species affecting the crop, such as is undertaken at IITA. Once infected by Meloidogyne spp., tubers become galled and disfigured. Symptoms will vary depending on conditions, nematode species, and yam variety. Tubers normally look â€˜knobbledâ€™ due to the development of galls on the surface, the severity of which depends on the level of infection.
Farmers do not understand how this disfigurement occurs, believing it to be a supernatural occurrence in some cases. Tuber galling damage will not generally develop further once harvested. During storage, galled tubers lose weight and deteriorate much faster than healthy tubers. Galled tubers used for seed will (if they survive) result in the development of more heavily damaged (galled) tubers at harvest.
Dry rot, caused by lesion nematodes, results from their feeding action as they â€˜migrateâ€™ from cell to cell, destroying them as they pass through the yam tissue. This damage occurs first in the subsurface tissue, just below the tuber skin, moving deeper with time. A relatively healthy looking skin can also often mask the underlying damage, which may not be visible until the surface is damaged or cut back (e.g., Fig. 2A), to reveal the brown, discolored, necrotic tissue beneath. Surface cracking is also a typical symptom of lesion nematode infection, but the relation between the nematodes and cracking is less clear-cut, with cracked tubers occurring in the absence of nematodes in tubers.
The species of nematodes responsible for dry rot and cracking on yam is intriguing for several reasons. One is that S. bradys is a key species, which feeds as an endoparasite, while the remaining species in the genus are better known as ectoparasitic feeders, remaining in the soil and feeding on the outside of roots. The other is that at least two species of Pratylenchus (P. coffeae and P. sudanensis) also cause the same symptoms as S. bradys. The species distribution and occurrence is geographically related; the more research we undertake, the more we unravel the story. We have determined the center of origin for S. bradys, for example, as the central Nigeria/Benin area, although the nematode has since been distributed around the globe on infected yam tubers. At harvest, severely affected tubers may be obvious, but lower levels of infection may go unnoticed. However, during storage the nematodes continue to feed, which is a major consequence of lesion nematode infection. Heavy infections result in the complete deterioration of tubers, while less damaged tubers can, to some extent, be consumed after removing the rotted sections. Low levels of infection may not be detected, and can contribute to the disease cycle when tubers are used as seed material.
A particular characteristic of yam is that the nematode problem is perpetuated through the use of infected planting material. Heavily damaged tubers are obvious, and are not generally used as seed, and usually consumed at home. Less visibly damaged tubers may be sold in the market or stored, for sale or consumption later or for use as a planting material in the next season. The use of poor quality planting material thus serves to maintain the disease cycle, by returning inoculum from the store back to the field. This adversely affects crop establishment, yield, and storability of harvested tubers, ensuring a continued and negative impact on quality, especially of highly susceptible cultivars. It is likely even, that nematode damage, in particular, has been a major contributing factor to the loss of some traditional (susceptible) varieties.
To overcome nematode problems on yam, a key area of focus is to target the seed system, and farmer awareness and understanding of the problem. This has become an increasingly important focus for IITA and its partners in recent years. It also forms the central pillar for a large IITA-led yam project. By generating and maintaining sustainable healthy seed systems, farmers will have greater access to seed material that will result in more productivity that will be less likely disfigured at harvest. In-field infection will occur, especially by root-knot nematodes, but damage will be less severe and yields higher.
Irmgard Hoeschle-Zeledon*, email@example.com or firstname.lastname@example.org *Coordinator of the CGIAR Systemwide Program on Integrated Pest Management (SP-IPM) convened by IITA
The discussion on the impact of climate change (CC) on agriculture has often focused on how changes in temperature, rainfall, and CO2 concentrations will affect the suitability of temperate regions for crop production and how crops will react in terms of yields. The effects of climate change on biotic factors in the tropics, such as weeds, pests, and pathogens (hereafter referred to as pests), have not received much attention.
Empirical data exist, however, to show that these biotic factors have major effects in determining productivity in the tropics. For instance, during the 1997 El NiÃ±o phenomenon, the mean temperature on the Peruvian coast increased by about 5 Â°C above the annual average, causing a decrease in potato infestation by the leafminer fly Liriomyza hydobrensis, which otherwise was a major pest. However, the abundance and infestation severity of all other pests increased in all crops, including potato (Kroschel et al. 2010). The complex consequences of CC particularly on pests and pathogens are still only imperfectly understood (Gregory et al. 2009).
CGIARâ€™s work on climate change
What are IITA and the other centers of the Consultative Group on International Agricultural Research (CGIAR) doing to mitigate the impacts and adapt to the effects of CC on pests? Historically, CGIAR centers have a broad R4D focus; centers have been developing knowledge (e.g., pest profiles), products (e.g., new crop varieties, biocontrol agents against invasive pests), and technologies (e.g., predictive models, diagnostic tools) that are suitable for diverse agroecologies including the tropics, wet, humid, semiarid, and dry, and to some extent the temperate zones as well. The broad knowledge and experience of centers provide an unprecedented advantage to assess the products and technologies in different agroecologies and weather settings and to determine their resilience and ability to cope in altered climatic situations.
Several programs directly focus on managing pests. For instance, the breeding of crop varieties for resistance to pests and pathogens has always been a focus of the CGIAR. With the uncertainties of CC, this work has become more relevant. Breeding for resistance to drought and waterlogging, although not the primary objectives, also aim at making varieties better able to tolerate biotic threats, since drought and excess water in the soil both increase the plantsâ€™ vulnerability to these factors.
A good example is the effort to develop drought-resistant maize cultivars by CIMMYT and IITA. These will not only allow the expansion of maize production into areas with less reliable rainfalls but also ensure the continued production in regions that are prone to future water scarcity. Drought- tolerant cultivars also reduce the risk of aflatoxin contamination in the field. Additional characters are incorporated into the drought-tolerant maize, such as resistance to maize streak disease which is endemic in Africa. Similar programs are ongoing to develop drought-resilient cassava and cowpea, and yam with tolerance for major pests.
The CGIAR centers are also working towards the development of cropping systems with greater intra- and interspecific diversity to increase resilience to CC-induced threats from biotic factors. For example, IITA is promoting maizeâ€“cowpea intercropping to reduce the pest pressure on cowpea.
Bioversity International is exploring how intra-specific crop genetic diversity on-farm not only reduces current crop losses to pests and pathogens, but also decreases the risk of genetic vulnerability and the potential of future crop damage, thus enhancing the impact of other IPM strategies and providing farmers with increased adaptive capacity to buffer against climatic changes.
CIP developed a temperature-driven phenology model for the potato tuber moth, Phthorimaea operculella that provides good predictions for the population in areas where the pest exists at present (Kroschel et al. 2010). Linked with geographic information systems (GIS) and atmospheric temperature, the model allows the simulation of risk indices on a worldwide scale to predict future changes in the distribution of the species due to increasing temperatures. The approach can also be used for other insect species. Hence, CIP created the Insect Life Cycle Modeling software (ILCYM) to facilitate the development of other insect phenology models. With its support, the phenology model can be implemented and allows for spatial simulation of insect activities.
Many centers support the collection and conservation of plant genetic diversity that can be built into new cultivars to enhance their resistance to biotic stresses. Diagnostics capacity is continuously augmented for the accurate and timely recognition of endemic pests, new variants, and invasive pests. Crop biodiversityâ€”landraces and wild relatives that are the reservoirs of genes for abiotic and biotic factorsâ€”is conserved ex situ to protect the species from erosion by CC-induced changes.
In a collaborative effort, CIP, IITA, icipe, and partners in Germany and Africa are implementing a project to understand the effects of rising temperatures on the distribution and severity of major insect pests on main food crops. ILCYM will be further improved and adapted to cover a wide range of insect species. The results will contribute to filling the knowledge gap about CC effects on economically important insect herbivores and their natural enemies.
IITA is planning to research the effect of changes in temperature on the invasion potential of major biotic threats in the Great Lakes region of East Africa and elsewhere: Banana bunchy top virus (BBTV), Banana Xanthomonas Wilt (BXW), and Panama Diseaseâ€“Tropical Race 4, cassava brown streak virus disease, cassava mosaic disease, maize streak, soybean rust, and pod borer pests, among others.
As whiteflies and aphids are considered to become more problematic with increased temperatures, IITA is also preparing research on the biocontrol of different whitefly and aphid species in vegetables and staple crops.
A project has been proposed on the bio-enhancement of seeds and seedlings of cereals and vegetables for East Africa to stimulate the plantsâ€™ defense mechanisms against pests and pathogens expected to increase in number, frequency, and severity. This project also addresses the registration of biopesticides and the availability of endophytes to the tissue culture industry.
CGIAR research programs
Under the new CGIAR Research Programs (CRPs), centers are addressing CC-induced crop health issues in various ways. Breeding for resistance to predicted biotic stresses continues to be a major focus in CRP3 (roots, tubers, banana) and its subcomponents. This component, coordinated by CIP, specifically recognizes CC and agricultural intensification as drivers for higher pressure from pests. Hence, this program aims at developing management strategies for priority biotic threats to these crops. These include the development of improved detection and monitoring tools, and surveillance methods for detecting and mapping existing, emerging, and resurgent molecular pests and pathogens. It will look into increasing general plant and root health through the enhancement of the natural disease suppressing potential of soils, and the antagonistic pest and disease potential of the aboveground agroecosystems.
The CRP on Integrated Systems for the Humid Tropics, led by IITA, will have a substantial focus on CC, its impact on pests, and plans for mitigation. For example, research will establish the relationship between CC and key cassava pests to develop integrated pest management (IPM) strategies including those for whitefly, African root and tuber scale, termite, green mite, aphid, and mealybug.
Phenology models for insect and mite pests and their antagonists on several crops will be developed and validated and their potential for changes in warming will be determined.
In collaboration with CABI, community surveillance for pests and diseases will take place through the expansion of the mobile plant clinic network.
Knowledge and decision support tools for the management of potato and sweetpotato pests (diseases and insects) will be developed and assessed in relation to the expected intensification of the agroecosystems in the humid and subhumid tropics.
Sustainable management of cassava virus disease in the cassava-based system will also be studied, and the vulnerabilities of these systems to CC- induced pest and disease problems will be determined.
The CIAT-coordinated CRP on CC, Agriculture, and Food Security began operations this year. It will continue the activities initiated by the CGIAR Challenge Program on CC. This CRP aims at mainstreaming strategies that address the management of CC- induced pest and disease threats among international and national agencies. It will identify and test innovations that enable communities to better manage and adapt to climate-related risks from biotic factors.
A lot of surprise shifts in ecosystems could come. It is therefore important that research capacity and knowledge bases are maintained to understand and rapidly react to mitigate any debilitating impacts (Shaw and Osborne 2011).
To accomplish this, it is necessary to establish good baseline data on current pest status in agroecosystems. This knowledge base will serve as a reference point to measure the fluctuations and the effectiveness of interventions.
It is important to determine the key weather variables that could change as a consequence of CC and their influence on agroecosystems and pests, and establish preemptive coping strategies. Available CC models could be handy for predicting CC factors.
A diverse scientific base including specialists in pathology, entomology, ecology, taxonomy, and epidemiology is required. They should work together to ensure that the outcomes of their research are linked to existing knowledge, economic forces, and common understanding (Shaw and Osborne 2011).
As it generally takes more than 10 years to breed a new resistant cultivar of a crop, breeding programs must start well in advance of the serious risk of a biotic threat Breeders need to be informed on the problems which might become important in the future (Chakraborty et al. 1998 in Juroszek and Tiedemann 2011).
Crops being bred for abiotic threats such as drought, waterlogging, and salinity should be prepared for the pests that could flourish under these conditions and select varieties that can tolerate pests as well.
Changes in occurrence, prevalence, and severity of infections and infestations will also affect crop health management (CHM) practices. There is a need to effectively disseminate and use those techniques that are currently underused (Juroszek and Tiedemann 2011).
Significant contributions could be made in improved field monitoring of pests and diseases, and better delivery systems for pest control products (Strand 2000 in Juroszek and Tiedemann 2011). Preventive crop protection measures may become more relevant under CC to reduce the risks (Juroszek and Tiedemann 2011).
CC is a global problem that affects all countries. Hence, global cooperation is required. However, given the nature of plant pests and pathogens, more local or regional strategies need to be put in place that define potential risks and measures to tackle expected threats. Investments in early detection systems, including border controls to monitor the migration of pests through plants, plant products, and other goods, will be the key to avoid the spread of invasive pests and reduce high management and eradication costs (FAO).
New farming practices, different crops, and IPM technologies must be developed to control the established pests and prevent the spread of new ones (FAO).
Governments should consider developing country-specific strategies to cope with CC-induced changes and put in place favorable policies for the introduction and promotion of new technologies for CHM.
It is also crucial to create and augment awareness about the effects of CC among policymakers and other officials involved in developing agricultural strategies.
Chakraborty S and Newton AC. 2011. Plant Pathology 60: 2-14.
Climate change (CC) is a long-term change in the statistical distribution of global weather patterns over periods of time that range from decades to millions of years. Several factors, known as climate forcers, usually natural events such as volcanic eruptions, earthquakes, solar radiation, and ocean currents shape climate change.
However, the climate forcer of the 21st century CCâ€”carbon dioxide (CO2)â€”is mainly human-induced and attributed to the burning of fossil fuels and tropical deforestation. The property of CO2 to trap heat within the earthâ€™s atmosphere is contributing to global warming. Thus, a rise in CO2 levels increases the warming effect. Trapped heat in the atmosphere warms oceans, melts ice caps, raises sea levels, and increases average surface temperature, all of which are affecting normal weather patterns.
Some of the abnormal changes experienced over the last two decades include severe and prolonged droughts, extreme storms and prolonged rainfall pattern, high temperatures, and heat waves. These sudden and extreme variations in weather patterns due to â€˜global warmingâ€™ have profound effects on living organisms on earth. The altered conditions create risks as well as opportunities favoring certain living beings over others and contribute to shifts in niches. In addition, it could lead to long-term variations in climate (e.g., permanent increase in average temperature) that might irreversibly affect biodiversity in a given region.
In the context of agriculture, sudden and abnormal changes in weather could change the suitability of a given environment for cultivation of crops. This could be due to abiotic factors such as drought, heat (cold), or excessive water directly linked to weather or simply due to increased pests and diseases that would severely impede performance of the crops. Since crops, diseases (pathogens), and pests (including vectors) are intimately associated and influenced by the environment, any shift in these factors will alter the balance, and could have a positive impact (e.g., decreased pest pressure) or negative impact (e.g., increased pest pressure) on overall crop performance.
Using simulation models, attempts the world over are being made to determine the impact of CC on agroecosystems to establish appropriate coping strategies, particularly for the negative impacts. Although this appears simple, it is the most complex issue confronting researchers, policymakers, governments, and entrepreneurs worldwide.
Communities are working together to bridge the gaps and establish global coordination networks to mitigate the impact of CC. IITA and other CGIAR centers, together with national and international organizations, are contributing to these endeavors with a primary focus on conserving biodiversity and improving the resilience of smallholder agriculture in the developing countries in Africa, Asia, and Latin America.
Jean-Gerard Mezui Mâ€™ella is the Director of the Inter-African Phytosanitary Council (IAPSC), the African Plant Protection Organization with headquarters in Nlongkak, Yaounde, Cameroon. IAPSC is an intergovernmental organization with 53 members under the umbrella of the African Union. It coordinates plant protection procedures in Africa.
The IAPSC Director coordinates the activities of its four sections (Phytopathology; Entomology; Documentation, Information and Communication; Administration and Finance). He represents the African region in the Commission for Phytosanitary Measures of the International Plant Protection Convention (IPPC/FAO), promotes compliance with International Standards for Phytosanitary Measures (ISPMs), and represents the African Union Commission on diplomatic matters in Central Africa. In this interview, he talks about the important work of IAPSC.
Why is IAPSC important?
IAPSC is a technical office of the African Union/Directorate of Rural Economy and Agriculture. It is one of the 10 Regional Plant Protection Organizations of the IPPC. As the regional organization for Africa, it works in collaboration with the national plant protection organizations of the 53 countries of the AU.
IAPSC mostly implements its activities through the eight African Regional Economic Communities (RECs) and sub-RECs. It addresses phytosanitary issues in Africa including the following:
– The vulnerability of African crop production systems to the impact of diseases, insect pests, and noxious weeds;
– Economic losses incurred through spoilage;
– Noncompliance with ISPMs, trade regulations, and equivalents;
– Dearth of phytosanitary data (Pests Risk Analysis, diagnostics, surveillance, etc.)
AU-IAPSC safeguards agriculture and natural resources from the risks associated with the entry and establishment or spread of pests of plants and plant products to ensure food safety and quality supply to intra-African and international markets.
How would you assess the state of plant protection in Africa?
Africa still has a lot of problems with plant protection. In fact, most African countries inherited an administration put in place before independence, which to a certain extent, has safeguarded the plant health of the different countries. There were departments of Agriculture and Divisions such as plant pathology, entomology, agricultural chemistry, and also plant quarantine. After independence, with the coming into force of the IPPC, adopted by the FAO Conference of 1951, the global approach and harmonization of phytosanitary measures started to take shape. For example, a common format for phytosanitary certificates was set up, common action was secured to prevent the spread of pests of plants and plant products, guidelines were provided regarding phytosanitary matters and the relevant actions to be taken by national governments in the implementation of plant quarantine.
IAPSC promotes cooperation among countries to prevent the movement of serious pests. It provides a forum for African countries to promote their views on plant health. In addition, quarantine structures in Africa differ from one region to another. In fact, some countries have operational quarantine stations but others do not. We at IAPSC encourage the creation of regional and subregional quarantine stations, although even those in existence find it difficult to comply with IPPC standards. It is our hope to have quarantine stations in each country.
Harmonizing phytosanitary regulations and policies in Africa must be quite challenging. How are you doing this?
Nontariff barriers such as SPS measures are often used as a disguised way to restrict trade. It is becoming essential, following the World Trade Organizationâ€˜s agreement on SPSMs for member countries of the WTO to ensure that the SPS measures they apply are in line with this agreement. To do so, the technical and organizational capacity of the various organizations at national, regional, or international levels have to be given the necessary tools to deal with the new challenges.
The 1995 WTO agreement was set up to remove unnecessary, unjustified, and arbitrary pressure on international trade in plants and plant products. This was a new situation for the various stakeholders, e.g., new themes such as transparency, scientific justification, notifications, inquiry points, risk analysis, and standards are now the guiding principles.
It is thus of the utmost importance for African countries, where phytosanitary capacity deficits are most severe, to begin a process of developing a strategy for capacity building to meet their obligations under the WTO rules.
In 2003, the RECs became the implementation arm of IAPSC whose technical programs are assessed by the RECs during the annual meetings of the Steering Committee and General Assembly.
IAPSC, much like AU, encourages regional common markets.
What are your major challenges?
Besides funding, the major challenges IAPSC faces on a daily basis include the entry of new pests on the African continent that annihilate the efforts of member countries; the proliferation of invasive pests; climate change that brings about new plant heath challenges; and a lack of scientists specialized in plant protection.
How do you ensure that regulations or policies are strictly implemented?
We endeavor to strengthen the capacities of countries so that they can prevent and control the introduction of plant pests in Africa. We encourage the setting up of Centers of Phytosanitary Excellence, the creation of phytosanitary networks, and the regular updating of pest lists in Africa.
What are you doing to improve the links and working relationships among NPPOs and networks in Africa?
We organize workshops and seminars on plant matters; we publish a quarterly phytosanitary news bulletin; and we enrich on a regular basis the phytosanitary information in the International Plant Protection Portal of FAO.
IAPSC provides information on quarantine pests on plants as well as for the protection of plant products for the AU member countries through both the paper and electronic media. Paper-based information systems include a scientific analysis, a phytosanitary situation in Africa, reports of service activities, and a collection of phytosanitary regulations and standards. Electronic information on compact discs covers a database of the meetings and phytosanitary regulations of member States. The Phytosanitary News bulletin of IAPSC is issued four times a year. It welcomes contributions and articles from National Plant Protection Organizations.
There is a web site for the worldwide dissemination of information (http://www.au-iapsc.org), and a library that hosts scientific books.
Our workshops and seminars aim at sharing information on the phytosanitary situation and on the findings in crop protection research.
We frequently conduct monitoring and evaluation exercises (country visits, exchange and information sharing among countries). All these activities help in networking among the partners in Africa.
What support do you need from the member countries? From partners? From clients?
To improve the prevailing situation concerning quarantine standards, regional cooperation and compliance with international regulations, the following priorities have been identified:
1. Ensuring that all African countries are parties to the IPPC;
2. Ensuring the harmonization of plant protection policies across RECs through capacity building;
3. Regularly updating pest lists and quarantine pests;
4. Harmonizing phytosanitary inspection systems; surveillance, emergency responses, risk analysis: procedures to analyze and reduce the risk of new pests entering a country;
5. Setting up a harmonized pesticide management system.
Describe your collaboration with IITA.
IAPSC-IITA cooperation is in the following key areas: Cassava pestsâ€™ diagnostics and control technique methods, Cassava germplasm and planting material exchange, Banana pestsâ€™ diagnostics and control technique methods, Banana germplasm and planting material exchange, and Harmonization of African countriesâ€™ phytosanitary systems.
What could international bodies such as IITA do to ensure that Africaâ€™s agriculture is safeguarded?
IITA, like other bodies, should work with country structures through IAPSC, and collaborate with recognized subregional and regional structures of the public and private sectors in plant protection.
Olufunke Awosusi is a Senior Plant Quarantine Officer with the Nigeria Agricultural Quarantine Service (NAQS) in the Federal Ministry of Agriculture and Rural Development. NAQS is charged with the responsibility of protecting the Nigerian agricultural economy from the attacks of pests, especially “foreign” pests, and also enhancing agricultural trade through export inspection and certification. Below are excerpts from an interview with Godwin Atser on the role of the NAQS and the collaboration with IITA.
What is the role of NAQS?
The NAQS evolved from the former Plant Quarantine Service. It was established in recognition of the fact that agricultural quarantine is the control of the introduction and spread of pests and diseases by means of legislation and as a result of the countryâ€™s problems within a decade before independence with the introduction of cocoa and maize pests. The cocoa industry almost collapsed; plantations were destroyed; and disease-resistant cocoa varieties were handed to farmers for replanting. This cost the Government a colossal amount. For maize, it took the concerted efforts of several West African nations coming together to revive production in the region.
NAQS was created to harmonize the quarantine of plant, veterinary, and aquatic (fisheries) resources in Nigeria to promote and regulate sanitary (animal and fisheries health) and phytosanitary (plant health) measures in connection with the import and export of agricultural products with a view to minimizing the risk to the agricultural economy, food safety, and the environment.
The main objective of NAQS is to prevent the introduction, establishment, and spread of animal and zoonotic diseases and pests of plants and fisheries including their products. NAQS also undertakes emergency protocol to control or manage new pest incursion or diseases outbreak in collaboration with key stakeholders.
What is the situation with NAQS today?
The standards have improved drastically. Today NAQS has improved personnel who are more skillful and trained in pest diagnosis stationed in the entry and exit points in the country. We have had improvements in diagnostic facilities and this is perhaps one of the reasons why some of the exotic pests have been kept outside our borders.
What is your assessment of quarantine in Africa?
Africa has witnessed improvement in the quarantine system. The Inter-Africa Phytosanitary Council (IAPSC) has been playing a tremendous role in harmonizing phytosanitary regulations within the continent, training phytosanitary inspectors, and coming up with pest lists to guide nations, revision of phytosanitary legislation and regulation, and implementation of phytosanitary standards, among others.
Any challenges in carrying out your task?
The problem faced by NAQS is the lack of political will concerning the quarantine system itself. Again, the role of the quarantine service is not very much appreciated, especially in food security. A lot of attention has been focused on how to improve production. The attention placed on plant protection is not as much as that given to plant improvement. But, however successful the improvement program, once you allow pests to come in, they would destroy the crops/gains. This understanding hasnâ€™t been appreciated and it is partly why the sector is given low funding.
Also, the public is not properly being informed about what plant quarantine stands for. Therefore, having voluntary compliance with the regulations is a bit difficult. Another problem is the lack of emergency funds and preparedness to contain the immediate outbreak of pests.
In recent times, what are some of the pests you find challenging?
Recently, we have noticed the introduction of fruitflies that are fast devastating fruits in our country. But we need a regional approach to tackle this problem, because the insect involved is a strong flier. We are also faced with the threats of more pests. On cassava, we have Cassava mosaic virus (Ugandan strain) which is ravaging crops in East Africa. Another is the Cassava brown streak virus, which affects cassava leaves and roots. We also have threats of banana bunchy top and banana bacterial wilt. We need to inform people so that they donâ€™t bring planting materials into the country from East Africa. There is the need to put preemptive action in place so that new diseases donâ€™t get to Nigeria and West Africa.
What measures are being put in place to contain the spread of these pests?
For fruitflies, we held a sensitization workshop in 2009 where different stakeholders participated. The FAO is coming up with a regional control measure for the West African bloc to harmonize and adopt. Again, scientists are looking for ways to control these pests. For cassava brown streak disease or CBSD, we have stepped up quarantine efforts aimed at curtailing/scrutinizing the entrance of planting materials from those endemic regions. In the future, we are thinking of training our officers on new tools that aid the inspection of imported planting materials.
Why is the response to crop pests especially slow when compared with the response to animal pests?
When new crop pests come in, the impact for the first few years is not so obvious. This is not the case with the invasion of animal pests when you see the deaths of animals. Perhaps this is the reason why crop pests donâ€™t catch the attention of the Government immediately. We could be talking about fruitflies but people are saying, â€œMangoes and oranges are still on the streets.â€ When the devastation arising from pest establishment, spread, and destruction becomes much serious and farmers start crying, that is the time we get an official response, especially in terms of funding for control measures.
What kind of support would you ask for specifically?
Capacity building to enhance pest interception and diagnosis is very important for us. If you donâ€™t have knowledge about the biology of the pests, you may have problems. The quarantine inspectors/officers need to be trained and the training needs to be continuous. Secondly, a country like Nigeria has a very diverse culture and the climatic conditions to grow crops all year round, so there is a need for us to conduct pest surveillance so that we know the pest status in the country.
There is an ongoing pest survey and this is being done on a crop by crop basis. Scientists from universities, national agricultural research institutes, and international organizations are involved and we hope it will be on a continuous basis with support from the government and stakeholders.
How good an option is biocontrol?
Biocontrol is a good strategy. Everybody wants to deemphasize the use of pesticides because of the effect of chemical residues and there is a lot of emphasis now on food safety. Also there is concern about preserving biodiversity. Now the emphasis is on integrated pest management. The more often you can eliminate the use of pesticides, the better.
How is the collaboration with IITA?
We have a very good and strong relationship with IITA. IITA is our major stakeholder when it comes to germplasm exchange.
IITA has been assisting us in the training of our officersâ€”upgrading their skillsâ€”especially in the area of pest diagnosis.
Sometimes when we are handicapped by inadequate facilities IITA steps in. Also IITA is good in the area of information dissemination which had been beneficial to us.
The collaboration with IITA is quite strong and mutually beneficial. Sometimes IITA assists us to attend international workshops and seminars that are relevant for job improvement.
The institute has contributed to our effectiveness in the country.