A pioneering study* of the socio-economic impact of water hyacinth (Eichhornia crassipes) and its biocontrol in Benin found that control had brought about substantial benefits for the local population and thus the nation as a whole. Perhaps as importantly, it developed methodology that may be adapted for assessments of other invasive species.
Water hyacinth was first observed in West Africa in the late 1970s and within a decade it had become a serious pest. In particular it was a major threat to the highly productive coastal creek and lagoon systems from which many people derive a livelihood, particularly in Côte d'Ivoire, Ghana, Togo, Benin and Nigeria. Although a number of reports and anecdotal evidence suggest that there has been a substantial reduction in water hyacinth, the efficacy of the control and its economic benefits remain controversial.
This study focused on southern Benin, where three natural enemies (Neochetina eichhorniae, N. bruchi and Niphograpta (= Sameodes) albiguttalis) had been released between 1991 and 1994. All the agents were obtained from CSIRO (Commonwealth Scientific and Industrial Research Organisation) in Australia, quarantined by CABI Bioscience in the UK, and released by IITA (International Institute of Tropical Agriculture) together with the Benin Direction de Pêche (Ministry of Rural Development) assisted by the Project Pêche Lagunaire, which was supported by the German aid agency GTZ (Gesellschaft für Technische Zusammenarbeit).
Monitoring has been conducted since the project began and for many years impact was uncertain. More recently Neochetina eichhorniae in particular has begun to reduce water hyacinth cover and formerly abandoned fishing grounds have been reclaimed.
Wetland systems are complex and so is their economic valuation because different stakeholders may value them for different reasons and scientists place yet more values on them. This study focused specifically on the utilitarian value of the ecosystem to the communities that rely on it. Based on the results of a preliminary participatory study, a quantitative household survey was developed. The study area was defined as the flood plain between the Sô and Ouémé rivers in southern Benin and, using a two-stage random sampling design, a representative sample of 192 households from 24 villages was selected. In total, 190 men and 171 women (one wife chosen at random from each household) were interviewed concerning their perceptions of the development and importance of the water hyacinth infestation. They were asked what impact it had had on them and to rank these impacts in importance. They were asked to name their major economic activities and indicate whether water hyacinth had had an impact on these. Lastly they were asked to estimate how this translated into income before and at the peak of water hyacinth infestations, and at the time of the survey in 1999.
The study area is a complex of rivers and lagoons, interspersed with banks and elevations, and agriculture, fishing and trading are the most important activities. Its shallow waters are amongst the most productive in the world, and over time the population has developed a system of artificial breeding grounds, or 'acajas', consisting of wooden stakes sunk into the mud in the shallow water. At harvest, these are surrounded by nets and the fish inside them trapped. With few access roads to the villages, water is also the most important means of transport and is thus vital to trading.
The division of labour between men and women is quite specific in this area: men do most of the fishing and agriculture, while women are responsible for transport and trade. Agriculture was the most important activity for men (64% put it first and 10% second) followed by fishing (30% and 57%). For women trading is by far the most important activity, with food crops rated most important by 54% and fish by 23%, while 18% give agriculture as their main activity. It is not surprising, given these gender differences, that there were marked discrepancies in how men and women described the economic impact of the weed.
More men than women perceived water hyacinth to have an economic impact. However, although 70% of men said it had an impact on fishing, few reported any impact on trade and agriculture (6% altogether). On the other hand women saw the greatest impact to be on trade, especially of fish (19%) and food crops (9%). For women, the impact of water hyacinth was mostly felt in the extra effort and time that they had to put in to take their little boats to the markets, through the mats of floating water hyacinth. They commented that although their income from trade did not decrease much, it took a lot more time and effort to generate that income, and occasionally they would lose their produce when they could not get through.
Similar gender differences emerged when respondents estimated financial losses, with men mostly affected by fishing, and women by trade. Summarizing the replies, men's annual income from fishing dropped to 31% of pre-infestation levels at the peak of the infestation, but recovered to just under 60% of the pre-infestation level by 1999, largely owing to reduced water hyacinth cover which allowed fishing grounds to be exploited again. Women's income from trading fish and food crops dropped to 26% and 62%, respectively, of pre-infestation levels. By 1999, trade in food crops had largely recovered (to 92% of pre-infestation income) but fish trade was slower to re-establish, remaining at 34% of pre-infestation levels.
One unanticipated feature was a consistent skewed distribution in income from different activities in these communities. Although most people earn very small amounts a few make relatively large incomes. This led to large variation, for example with standard deviation of up to eight times the mean for women's fish trading income. The study implementers note that a larger sample size would have allowed the standard deviation to be reduced: surveying 450 households, for example, would bring standard errors below 15% of the estimated value.
Variation notwithstanding, the reduction in water hyacinth and its benefits to the local inhabitants are clear to them. The reason for the reduction is not so widely known, with only about a fifth of the respondents aware of the biocontrol programme. However, increased publicity about the biocontrol success will bring better public awareness.
Using the results from the surveys and knowledge of households gained from the survey and a recent census, the combined economic losses from water hyacinth at the peak of infestation were calculated to be US$2151 per household per year, and biocontrol had an annual impact of $783 per household. Extrapolating these figures to the entire region, the regional economic loss was calculated to be $83.9 million/year, and the increase following (and therefore the benefit of) biocontrol $30.5 million. Because of the large variation between households, the sampling error is large and this figure must be treated with caution. However, the 95% confidence interval falls between $17 million and $44 million. Extrapolating the annual benefit over 20 years, with depreciation of 10% annually, a total benefit of $260 million is reached (with a 95% confidence interval of $145-375 million). This is argued to be a good conservative estimate since the full effect of biocontrol may be to come.
The costs of biocontrol are easier to estimate. Rearing the weevils uses little space and simple equipment, thus most of the costs were for labour. Between 1991 and 1998, IITA, GTZ and local organizations' labour costs were some $2.09 million (calculated with depreciation). Comparing this to the estimated benefit of $260 million, the benefit cost ratio is 124:1 (or, taking the 95% confidence interval into account, between 69:1 and 180:1).
The benefit-cost analysis compares the financial benefits to the people of southern Benin with the cost of the international research and implementation programme. The study does not attempt to quantify other benefits such as health and water quality. Furthermore, like many classical biocontrol programmes in Africa, the knowledge and technology generated has been `exported' along with weevils and adapted for other countries at little additional cost.
This study has implications beyond the boundaries of biocontrol. The economics of invasive species, of which water hyacinth is a well-known example, are poorly understood, but with international agreements such as the Convention on Biodiversity now in place governments are faced with responsibilities for managing them. They need to be able to carry out impact assessments and estimate the effects of various strategies, yet there is very little guidance available on how to do this. This study of the costs of water hyacinth and benefits of biocontrol in southern Benin is the first impact assessment of biocontrol that uses participatory methods and gender-specific data from household surveys. It is therefore significant and timely, providing novel ideas and useful methodology. Thus, in answer to the question in the title to this article, many people in Benin and beyond gained, and will continue to gain, from the biocontrol programme against water hyacinth led by IITA.
Contact: Hugo De Groote
How important is an exotic (i.e. a non-native) ornamental tree in people's backyards? The answer is "very important if it is a large feature tree in your garden." However, what importance should it be given by governments (state or federal) when making decisions regarding the importation of organisms for biological control of weeds?
This question has arisen in Queensland, Australia, because the lantana treehopper, Aconophora compressa , has started attacking fiddlewood trees (Citharexylum spinosum) in southeast Queensland and some regional areas of eastern Australia. Fiddlewoods are West Indian trees that were widely planted as shade and screen trees in Brisbane and elsewhere in Australia in the 1970s and 1980s. They are no longer popular because they are untidy and history has shown that the roots damage pipes and underground cables. They have, in fact, been placed on the 'undesirable species' list by the Brisbane City Council and other local councils, as well as by several state authorities. The tree has also become an invasive weed in Hawaii and the environmentally sensitive Galapagos Islands.
Lantana is a major invasive plant from Central and South America. It already affects over 4 million hectares of coastal and subcoastal Queensland and New South Wales, and is still spreading. It is toxic to stock and displaces useful pasture species. Lantana is spread by birds into native woodland, where its dense thickets smother native vegetation and prevent rainforest regeneration. There has been an active biocontrol programme against lantana in Australia since 19141. Aconophora compressa was introduced from Mexico as a biocontrol agent against lantana by the Queensland Government in 1995. Releases of this agent ceased in December 2001.
When this membracid was host-tested in 1993-4, fiddlewood, which is in the same family (Verbenaceae) as lantana, was not included on the official or approved test list. Under the Australian system, the test list was approved by all states and territories as well as by the federal authorities, none of whom suggested the addition of the genus Citharexylum. The plant was overlooked possibly because it was no longer being sold by most nurseries, the extent of its ornamental use was not known or documented, and because it did not appear in regional floras as it had not naturalized. Several other genera in the family Verbenaceae were tested, but only Duranta, another ornamental genus from Mexico, and which is also often weedy, supported development to adulthood, albeit in very low numbers. The one or two herbaceous species in the family Verbenaceae possibly native to Australia were tested and not fed upon. The bug was therefore approved under the national system as safe to release in 19952. Females lay a batch of eggs, containing between 30 and 50 eggs, but stay with the developing nymphs until maturity before moving off to oviposit again. Nymphs take about 7 weeks to complete development and adults live for up to 6 months.
After release, the bug established slowly on lantana in the Brisbane area, but large and damaging populations began to build up in spring in 2001 and 2002. Unfortunately, hot weather (daily maxima above 37ºC) in both summers killed the bugs, and A. compressa was thought to be a failure in the Brisbane region. However, the 2002/03 summer was mild and the populations have steadily increased since on lantana. Whilst this gave encouragement in regard to its value as a biocontrol agent for lantana in the Brisbane area, there was a significant escalation of earlier observations (1999, 2001 and 2002) that fiddlewood trees also appeared to be an attractive host plant. In many areas, much larger and more damaging populations of the bug are occurring in 2003 on fiddlewoods than on lantana. It seems that fiddlewood is less affected by dry conditions, probably because it is a tree, with better sap-flow than lantana.
Fiddlewood trees planted 20 or 30 years earlier are now prized features in some gardens, and the damage to the trees is causing a great deal of community concern and media interest. The large bug populations are causing problems other than the damage to the fiddlewoods: the abundant honeydew is killing lawns, damaging plants beneath the tree and staining laundry (apparently, bugs are attracted to white clothes), and there have been reports that the bugs are even taking sample bites from people if they land on them. They are also leaving the fiddlewood trees as branches die back and are moving onto adjacent garden shrubs, especially Duranta varieties. However, this spillover of the bug onto other garden plants should only be temporary. The bugs are not able to maintain populations on these other plants, and should disappear once the nearby dense populations on fiddlewood or lantana have stabilized at lower levels. This kind of spill-over damage happened when the cactoblastis moth (Cactoblastis cactorum) was first released back in 1930. Very large numbers of cactoblastis larvae developed in the prickly pear (Opuntia spp.) and in several places there was damage to tomatoes, melons and pumpkins. Once the cactoblastis populations fell, there has been no more damage to tomatoes or other crops in the 70 years since.
Since host specificity testing aims to test species closely related to the target weed, if the scientists had realized in 1993 that there were considerable numbers of fiddlewood trees in Brisbane, the tree would have been included in the test list. The host tests would have shown that the bug can develop and breed on fiddlewood, and this might have prevented the release of the agent. But would this have been right? Biocontrol is by far the safest and most cost-effective tool we have to manage serious environmental weeds such as lantana. Biocontrol programmes have led to the control of groundsel bush (Baccharis halimifolia), rubber vine (Cryptostegia grandiflora), and the serious aquatic weeds water hyacinth (Eichhornia crassipes) and salvinia (Salvinia molesta) in Queensland, among many other successes in the last 30 years. Any cost-benefit study would probably have concluded that the damage to fiddlewoods, and the cost of treating highly valued trees by stem injection or other methods or replacing the trees by other more desirable shade trees, would be far outweighed by the benefits from improved control of lantana. However, the identification of the fiddlewood tree as a host at that time may have triggered specific research on stem injection or other treatment measures before the release of the agent was made.
In 1995-dollar terms, weeds cost Australia approximately A$3.3 billion per year and biocontrol is by far the most cost-effective weapon. It is also probably the only method for environmental weeds such as lantana, since use of chemical or mechanical control is simply not feasible, economically or environmentally, over the huge areas already invaded. Should damage to an exotic ornamental such as fiddlewood (brought in to the country, sold and widely planted without any controls on the process) be allowed to prevent possible successful control of lantana?
The question is difficult and depends on the perspective. We cannot ignore community concerns - the political backlash has the potential to threaten future use of biocontrol. However, we need to learn from the Aconophora incident, and be better prepared to respond to similar issues in the future. When an insect likely to damage ornamentals is approved for release, an appropriate communication plan and recommendations for control should be developed before any release is made.
2Palmer, W.A.; Willson, B.W.; Pullen, K.R. (1996) The host range of Aconophora compressa Walker (Homoptera: Membracidae): a potential biological control agent for Lantana camara L. (Verbenaceae). Proceedings of the Entomological Society of Washington 98 , 617-624.
*Chief Executive Officer,
of Natural Resources & Mines,
European blackberry (Rubus fruticosus agg.) occupies nearly 9 million hectares of Australia following multiple introductions since the 1800s. This `Weed of National Significance' consumes land used for pasture, forestry, recreation and conservation and is difficult to control. The European leaf rust fungus, Phragmidium violaceum, was first reported in Australia in 1984 following an unauthorized release of unknown origin. In 1991 and 1992, strain F15 of P. violaceum, collected from central France, was released specifically for biological control. The impact of the rust fungus has been spectacular in some locations, but even when the weather is favourable for rust epidemics some blackberry biotypes escape severe disease.
In Europe the R. fruticosus aggregate comprises numerous apomictic species (i.e. they reproduce without fertilization) that are closely related. Phenotypic plasticity may be high and morphological variants can arise by hybridization between species. A consensus in the taxonomic treatment of Rubus in Europe, let alone in Australia, has not been reached. The increasing availability of DNA tools was a prime reason for a revival of the biocontrol programme of weedy blackberry in 1996 by the Cooperative Research Centre for Australian Weed Management (Weeds CRC). A primary objective was the selection of additional rust strains in Europe to match the range of blackberry biotypes in Australia, a task that depended on adequate characterization of the weed host and rust pathogen.
Weeds CRC researcher Kathy Evans and her colleagues made at least 200 collections of the R. fruticosus agg. across Australia and identified 49 DNA phenotypes using an M13 RFLP (restriction fragment length polymorphism) technique. A form of genotyping or DNA fingerprinting, the M13 probe detects length variants in minisatellite DNA sequences when the probe is hybridized to genomic DNA digested with a restriction enzyme. The term DNA phenotype, rather than genotype, is used to reflect that only a proportion of the genome is detected by the DNA probe. Two plants that have different DNA phenotypes are genetically different, but may still belong to the same taxonomic species. However, RFLP analyses revealed that two blackberry plants sharing the same DNA phenotype were very likely to be the same species.
With the help of taxonomist D. E. Symon of the State Herbarium of South Australia, and specialist European Rubus taxonomists H. E. Weber of the University of Vechta, Germany and A. Newton of Exmouth in the UK, 33 of the 49 DNA phenotypes identified were correlated positively to 14 taxa or 'species' of the R. fruticosus aggregate. The 16 undetermined DNA phenotypes were either new biotypes that have evolved in Australia, biotypes that have not yet been recognized or characterized in Europe, or biotypes that no longer exist in Europe. The outcome of the taxonomic revision, based primarily on morphology but confirmed using DNA technology, is that ten names can now be applied for the first time to exotic Rubus material collected in Australia.
A significant outcome of this taxonomic revision of Rubus was the determination that the most common and widespread weedy blackberry in Australia was R. anglocandicans . The DNA phenotype of five collections of R. anglocandicans in England matched exactly the DNA type of 97% of samples ( n = 76) of R. anglocandicans collected across Australia. This weedy taxon in Australia can now be distinguished from R. armeniacus , the common weedy European blackberry in the Pacific-Northwestern region of the USA and some parts of New Zealand.
Another important application of the DNA typing tool has been the identification of Rubus clones in pathogenicity studies with strains of the rust fungus. The DNA 'fingerprint' of each Rubus clone is analogous to bar coding consumer goods in the retail sector. Regardless of their taxonomic status, this technology enabled the identification of plant propagation material with certainty. The M13 DNA typing tool was also applied to strains of P. violaceum , to confirm that genetically different rust strains were being assayed and for preliminary studies of the genetic diversity of the rust population in Australia. A major outcome of the research was the development of a differential set of Rubus clones for characterizing the virulence phenotype of each strain of P. violaceum, thus streamlining the selection process for additional rust strains. An unexpected outcome of population-genetic studies was evidence to suggest that strain F15 is not well established in Australia today.
The next challenge is to monitor the fate of additional strains of P. violaceum to be released in Australia soon. This requires that weed managers identify which species of blackberry they are dealing with. DNA identikits for field use are still a dream, so Kathy Evans has teamed up with Bill and Robyn Barker from the State Herbarium of South Australia to develop a computer-driven, user-friendly tool to distinguish between cultivated, native and invasive blackberry species. Funded by the National Heritage Trust, this web-based, interactive tool is expected to be available in 2004, following trials with land managers and community groups across southern Australia.
The battle against blackberry in Australia is far from over, but better understanding of the taxonomy of Rubus and the identification of the pathogenic rust strains, underpinned by DNA typing, is helping to close the net on this thorny invader.
Contact: Dr Kathy Evans,
Tasmanian Institute of Agricultural Research, University of
Tasmania, 13 St Johns Avenue, New Town, TAS 7008, Australia
Mikania micrantha (mikania or mile-a-minute weed) has earned the epithet 'green tidal wave' for the speed with which it can envelop Asian hillsides of tea and forest. An inception workshop in New Delhi in June 2003 signalled the start of the implementation phase of a biological control project against this invasive alien weed in India. The project is developing a biological control component to fit into an IPM strategy being developed against mikania. It is the first time that a plant pathogen has been approved for importation into India as a prospective weed biocontrol agent, and as such the workshop was a landmark event. However, the project has some way to go before an application for field release can be considered.
The weed first emerged as a problem in tea in Assam in the 1940s, but in recent decades its importance has escalated owing to large-scale degradation of natural forests, from which stronghold it can invade tea gardens, which has led to the escalation in herbicide use. More recently, mikania arrived in the Western Ghats range in southwestern India where it poses an immediate threat to natural and agricultural ecosystems, and may spread further.
Current control measures focus on slashing and herbicides but these are expensive, ineffective and unsustainable, and can be environmentally damaging. The initial phase of this DFID (UK Department for International Development) funded collaborative project (1996-2000) involved three institutions in India, Kerala Forest Research Institute (KFRI), Project Directorate of Biological Control, Bangalore (PDBC) and Assam Agricultural University, and CABI Bioscience , UK. Their investigation into the potential for an IPM approach to mikania control in the Western Ghats included mapping the distribution and monitoring the spread of the weed, assessing its socio-economic impact on subsistence agriculture, and evaluating fungal pathogens as biological control agents (as mycoherbicides and for classical introductions).
Surveys in India found no indigenous natural enemies with potential as control agents for mikania. However mikania is rarely a weed in its native range in the Americas and natural enemies are seen to exert a significant pressure on the occurrence and abundance of the species, so the weed was considered to be an ideal candidate for classical biological control (CBC) using co-evolved natural enemies from their common area of origin. Characterization of worldwide populations of mikania using AFLP (amplified fragment length polymorphism) analysis indicated that the weed has a relatively narrow genetic base in tropical Asia but is highly variable in its native range. This supports the evidence in the literature of a small number of deliberate introductions of the plant (perhaps four in India) as a cover crop and as airfield camouflage during World War II. As well as confirming the history of its introduction to India, the results suggest that there is a good chance of successful CBC throughout the exotic range, using a single or limited number of natural enemies. Fungal pathotypes are highly specific within species and different pathotypes may be needed to control each genetic type in the introduced range. However, if the invasive population comes from a limited number of introductions it will contain a restricted number of genetic types, which may be controlled by a few pathotypes.
Puccinia spegazzinii was identified as the prime candidate for introduction into southern India as a classical biocontrol agent. It is a common and damaging pathogen on mikania in the Neotropics, but is not found in the exotic range of the weed. Eleven isolates of the rust from five countries (Brazil, Costa Rica, Argentina, Trinidad & Tobago and Ecuador) were evaluated. The pathogen demonstrated intra-species specificity, each isolate only infecting a selected number of genotypes of its host. However, one pathotype from Trinidad (W1761) proved to be virulent against a wide range of Indian isolates of the weed, infecting all those tested from the Western Ghats, and hence was selected for intensive screening. This pathotype was shown to be totally specific to M. micrantha (55 non-target species have been tested, including many important crop species in India), as well as highly damaging (leaf, petiole and stem infections leading to cankering and whole -plant death). In addition, the rust has a broad environmental tolerance (able to infect after less than 10 h dew at temperatures of 15-25ºC). It is an obligate biotroph, surviving only on living plant material: if infected plant material is dried, the rust is rendered non-viable. However, although the Trinidadian isolate of P. spegazzinii infected almost all collections of M. micrantha from the Old World, and the ten target populations in the Western Ghats tested were fully susceptible, some collections from Assam proved to be not fully susceptible to this strain. Since then, newly discovered Peruvian and Ecuadorian strains of P. spegazzinii have excited interest, as all the northeastern Indian biotypes so far tested are fully susceptible to them, and they are currently being considered as additional agents.
Two Dietelia species, D. portoricensis from Costa Rica and Dietelia sp. nov. from Mexico, are also being maintained in CABI Bioscience quarantine as `reserve' candidates. Preliminary studies found them to be as damaging to their host as P. spegazzinii , and they have also only been recorded from M. micrantha . Importantly, the Dietelia species fully infected some of the mikania strains from northeast India that are only semi-susceptible to the Trinidadian isolate of P. spegazzinii and they could thus be considered as alternative agents for mikania in this part of India also.
The first phase of the project culminated in a workshop held at KFRI in November 1999 attended by local and regional scientists involved in the control of invasive weeds [see BNI 23(2), 53N (June 2002), Indian invasive forest weeds] which recommended inter alia the development of an implementation phase including an application for the introduction of P. spegazzinii . A dossier was subsequently produced by CABI Bioscience , for the Indian collaborators, containing detailed data on the information summarized above concerning P. spegazzinii , as required by the Code of Conduct for the Import and Release of Exotic Biological Control Agents, 1996 (International Standards for Phytosanitary Measures (ISPM) No. 3). This was submitted to the relevant quarantine authorities in India, and permission for PDBC to import the rust into quarantine in India was approved in October 2002, opening the way for the implementation phase to commence.
A quarantine facility at PDBC is under construction, scheduled for completion later this year. In the meantime, PDBC and KFRI will begin studies on the rust at the NBPGR (National Bureau of Plant Genetic Resources) quarantine facilities in New Delhi, by agreement with the Director, using material supplied by CABI Bioscience .
The workplan for this phase of the project will begin by ensuring that material is pure and hyperparasite-free and by conducting further host specificity testing to confirm that the rust is safe for India, after which an application for a permit to release can be made. This will include public consultation, in conjunction with the Indian Directorate of Plant Quarantine and Storage (DPQ&S), to ensure that local people are reassured that indigenous plants, e.g. medicinals and tree crops, are not under threat from the pathogen. Methods and facilities for mass producing will be developed, together with a system for transporting the material to Assam and Kerala where further bulking up will be carried out.
In the long term it may prove unnecessary to continue with the inundative releases since, if the rust is successful, the weed population should substantially decline throughout its exotic range to an extent that it would no longer be considered invasive. A significant bonus in Assam, both economically and environmentally, should be a reduction of herbicide use in tea gardens.
A crucial part of this project will be a farmer and forest department information campaign. As the project to fund the first pathogen to be intentionally released in India against a weed, it is seen as essential to engage with local stakeholders, to ensure they are fully aware of what is happening, and understand the principles and implications of the release of the rust. Socio-economic studies undertaken in Phase I showed that many farmers are aware of biological control and are supportive of the use of fungal pathogens, but the campaign aims to expand on the understanding within farming communities and will promote the release of the rust fungus, analogous to the community-based approach of countries with long experience of weed biocontrol, such as Australia. Wide dissemination is seen as essential to promote the broadest possible uptake of the outputs of this project, and lay the foundations to aid implementation of other biological control programmes in the future.
The project will establish monitoring plots in Kerala and Assam for impact assessment. Biocontrol scientists tend to be reluctant to forecast success for individual introductions; history contains too many disappointments. However, in this case they are optimistic from both field observations within mikania's native range and glasshouse investigations that P. spegazzinii could indeed prove to be a rare 'silver bullet'. They predict that, if released in the moist forest region of the Western Ghats, the rust would establish and spread rapidly under the prevailing environmental conditions, and should unilaterally exert a significant effect on the abundance and spread of mikania populations within a few growing seasons. In the long term (5-10 years or more), they predict that the growth and fecundity of mikania would be severely reduced over a significant part of its range. The weed, thus, should no longer pose a threat to the agricultural economy of the infested regions, and the agent would therefore contribute to alleviation of poverty in subsistence farmers, by increasing crop yields and/or reducing time spent on weeding. Equally important, the rust would perform a significant role in the conservation of biodiversity of natural forest ecosystems by reducing the impact of mikania in these habitats.
While work in India has been in progress for some years, alarm about the `green tide' has also been emerging in other Asian countries. Growing recognition of the threat this invasive weed poses in China led to an initiative between CABI Bioscience , Guangdong Agricultural Institute and the Institute of Biological Control, Chinese Academy of Agricultural Sciences. Funding has been secured under the Darwin Initiative of DEFRA (UK Department for Environment, Farming and Rural Affairs), and work will begin in Guangdong Province, China in October this year.
Dr R.J. Rabindra,
Dr Ding Jianqing,
A UK£0.5 million partnership project to investigate the potential for biological control of Japanese knotweed (Fallopia japonica) may be a turning point for biological control in the UK, and even Europe. The 4-year initiative, which is being funded by Cornwall County Council, the South West of England Regional Development Agency, the Welsh Development Agency, British Waterways, the Environment Agency, Network Rail and DEFRA (UK Department for Environment, Farming and Rural Affairs), is the first project with the specific aim of developing biological control for an invasive weed in Europe and the first in the world to research the potential for the biological control of Japanese knotweed.
The story behind Japanese knotweed's emergence as an invasive weed will strike chords with weed biocontrol scientists around the world. It was first introduced to Britain in the 19th century as an ornamental plant, and was actually awarded a gold medal at a European flower show as best newcomer. These plaudits were in short supply within a few years once botanists realized exactly what an unwelcome guest it was, and this year the plant won a gold at the UK's premier flower show when used by the Cornwall Knotweed Forum to highlight its dangers.
Japanese knotweed is now a major problem in Cornwall (England's most southwesterly county) and Wales, with sand dunes, forests, riverbanks, canals, waterways, road verges, railway embankments, sites of high heritage value and potential development sites in many areas choked by the weed. Capable of growing from tiny fragments, the plants form large stands, smothering habitats and threatening wildlife. The weed also creates a major problem on `brown field' (re-development) sites where it can add 10% or more to a developer's cost. Its extensive below-ground root system can cause structural damage, capable of breaking up concrete and tarmac, and soil has to be excavated to a depth of 4.5 m to ensure no fragments remain before building can begin.
The new initiative came about because local authorities had recognized that conventional (chemical and mechanical) control methods for Japanese knotweed were unsustainable and ineffective. It is easy to chop back the plant at the stem, but the weed is equally active beneath the surface. It has an underground rhizome that can spread up to 7 m from the original stem and to a depth of 4.5 m. Even if the land is ploughed up, a new plant can grow from fragments. Pesticides will kill the plant, but this can take years of repeated applications and there are concerns about the toll heavy herbicide use will have on other plants and animals.
A recent DEFRA review of non-native species policy in the UK gave a conservative estimate for knotweed control across the whole of the UK using existing approaches of £1.56 billion, if it were to be attempted.
Alternative technologies were needed. Discussions with scientists from CABI Bioscience , which has global experience of biological control spanning 70 years, convinced them that biological control may hold the best long-term prospects for containing the weed.
Biological control has never been used against a weed in Europe. Historically, the continent has been more a source of invasive weeds than a victim of their effects. It has been a rich source for biological control programmes against weeds exported (albeit inadvertently) to the southern hemisphere and North America, with over 380 releases of biocontrol agents sourced from European Union member states. But although Europe is home to a wide range of biocontrol expertise, efforts to interest European governments in biological control have only recently begun to succeed. Invasive weeds, largely escaped ornamentals, have begun to emerge as an intractable problem in Europe for a variety of reasons [see BNI 22(3), 54N-56N (September 2001) Europe acts on invasive alien weeds]. At the same time, the obligations placed on signatories to the CBD (Convention on Biological Diversity) mean that governments must act to control invasive alien species that threaten biodiversity. Taken together these have given invasive weeds an unprecedented high political profile in Europe.
In the UK Japanese knotweed is particularly resilient, which makes it all the harder to control. This resilience can be attributed in part to an absence of its natural enemies, and thus classical biological control is an obvious option to pursue. An added bonus in this context is that Japanese knotweed in the UK is essentially just one female plant as every individual is effectively a cutting of the original import. This is good news for biological control as it means the target population has extremely limited genetic diversity, while the absence of sexual reproduction means that currently it has limited chances of evolving defences against a specific natural enemy.
The results of a preliminary phase of the Japanese knotweed project, jointly funded by the USDA Forest Service and the Welsh Development Agency, were encouraging. Field assessments in Japan to assess the natural enemies in the plant's area of origin indicated that many species of insects and fungi attack it in its native habitat, including various beetles and rust fungi that appear to specialize on knotweed. The next phase will involve more detailed survey work with Japanese collaborators and a full technical research assessment of promising species to ensure that they are specific to knotweed and pose no danger to crops or native biodiversity.
The partnership project is led by Cornwall County Council's Natural Environment Team, part of the Environment and Heritage Service. Cornwall led the way in looking at new methods of controlling the plant through the Cornwall Knotweed Forum, which was set up in 1997 to provide guidance and information on policy and control methods, now an internationally recognized example of Best Practice in the control of invasive, non-native species. Project partners do not expect biological control to be a silver bullet, but are hoping that it will stop its spread and allow native species to compete more effectively.
If the Japanese knotweed project is successful there may be calls for more. The mild southwest of the UK that has borne the brunt of the Japanese knotweed invasions is under attack from others. For example, Cornwall's land managers, farmers and gardeners are also battling giant hogweed (Heracleum mantegazzianum) and Himalayan balsam (Impatiens glandulifera) while native vegetation in its picturesque hedgerows is being smothered by winter heliotrope (Petasites fragrans) and yellow archangel (Lamium galeobdolon ssp. montanum).
Under the terms of the Code of Conduct for the Import and Release of Biological Control Agents (International Standards for Phytosanitary Measures (ISPM) No. 3), the government of a country implementing classical biological control "should designate the competent authority empowered (normally the National Plant Protection Organization) to regulate or otherwise control and, where appropriate, issue permits for the importation and release of biological control agents. The authority may exercise its powers by using an internationally accepted standard (such as this Code) for guidance or by applying national legislation (which should be aligned with this Code. Importations of biological control agents should only be carried out with the consent of the authority."
Thus the final decision on whether biological control agents of Japanese knotweed can be released in the UK will lie with DEFRA. Looking at the furore surrounding attempts to introduced `GM' crops to the UK, the process of informing the public about biological control needs to be taken as seriously as the search for an effective biocontrol agent. In this context, countries such as Australia, New Zealand, South Africa, Canada and the USA, with a successful history of community involvement in biocontrol, may provide some useful models.
Contact: Dick Shaw, CABI
The platygasterid parasitoid Amitus fuscipennis has been evaluated as a biocontrol agent of Trialeurodes vaporariorum on bean crops in Colombia in a PhD project by Maria Manzano (supervized by Joop van Lenteren, Wageningen University, Netherlands and co-directed by Cesar Cardona, CIAT (International Centre for Tropical Agriculture), Colombia). The parasitoid has proved easy to mass rear with a sex ratio strongly biased towards females. Populations of the parasitoid grew faster than those of the whitefly in tropical high and mid altitude zones. In addition, it exhibits area-restricted searching, which is an appropriate searching strategy for a whitefly host such as T. vaporariorum which tends to have a clumped distribution. Field releases are planned to find out whether these promising attributes translate into field efficacy.
Coenosia attenuata `tiger flies' are from the same family as, and are similar in appearance to the house fly Musca domestica , but females have three black horizontal stripes on their abdomens. Adult flies kill not only adult whiteflies but also adult leafminers, while its larvae prey on soil-dwelling pests such as fungus gnat larvae. These flies, which have been recorded in Spain, Italy and Germany and thrive in the glasshouse crop environment, are generating great interest as prospective biocontrol agents in protected crops. Studies in all three countries have shown them to be able to reduce whitefly, leafminer and fungus gnat populations, and artificial breeding methods are under development.
Contact: [A. fuscipennis] Maria Manzano, Dept. Biology, Universidad del
attenuata] M. D. Rodriguez & A. M. Aguilera
This article is based, with kind permission, on tributes given at Professor Odhiambo's funeral by Professor David Wasawo and Dr Hans Herren. The Editors also gratefully acknowledge the help of BNI Editorial Advisory Board member Dr Brigitte Nyambo .
Professor Thomas Risley Odhiambo, the founding director of the International Centre for Insect Physiology and Ecology (ICIPE) in Kenya, who died on 27 May 2003, was described by ICIPE's Governing Council and staff as "a great scientist and visionary who founded an institution of which all Africans could be proud." In an appreciation of his life, Professor David Wasawo (Chairman, University of Nairobi Council) described him as "a distinguished son of this nation of Kenya; and an incomparable and valued member of the world's scientific community." Hans Herren (ICIPE's current Director General) praised Odhiambo's "dedication to educate and train young developing country scientists."
Herren outlined how a lifelong interest in insects led a small boy who conducted experiments on wasps and their nests to become, via the prestigious Makerere University College in Uganda, Cambridge University in the UK, the University of Nairobi and then ICIPE, Africa's leading biological scientist of his generation. Wasawo described how this began 50 years ago when "the late professor Leonard Beadle who was then the professor of Zoology at Makerere recognised the academic promise of Tom. After his BSc qualification, Professor Beadle arranged for his placement at the Tea Research Institute for East Africa at Kericho as a Research Assistant; and later found him a job as a curator at the Insect Collections at Kawanda Research Station in Uganda. Tom's love for insect science thus started early in his life. In those days every effort was being made at Makerere, to identify brilliant students and enable them to be trained abroad so that on qualification they could return to Makerere as members of staff." Professor Beadle arranged for Odhiambo to be admitted to his own alma mater, Cambridge University, from where he emerged with an excellent PhD.
At Cambridge, where he studied under the legendary Professor Sir Vincent B. Wigglesworth, he is remembered as an organized student already capable of excellent research when he arrived. Peter Lawrence (MRC Laboratory of Molecular Biology, Cambridge), who shared a room in the Department of Zoology with him, says, "Tom was very well organised... the central table was divided up between us with a precise boundary in the middle, Tom's pens and pencils lined up like soldiers on his side, a mess on my side. He was always indulgent, putting up with my chaotic attempts to discover how to do research, something he knew all about from the beginning. He used to give me advice... He was so patient with me, and always even tempered and kind. He had a wonderful laugh, and we had a good deal of fun together." Simon Maddrell, still in the Department, describes him as, "a quiet, well organized student who did some excellent electron microscopy under the supervision of Sir Vincent Wigglesworth." Later, in the mid 1980s, when Maddrell was sent by the Royal Society to attend a presentation of science carried out at ICIPE, he found Odhiambo "by then also an excellent politician and manager as he must have been to have been so important in the setting up and maintenance of the centre as a dynamic place with such uncertain lines of financial support."
Professor Wasawo described how Odhiambo's dual talents as scientist and teacher have created their own legacy: "It has often been remarked that good science practice depends upon the quality of questions one poses but a good scientist only comes about as a result of the breadth of knowledge one has acquired in the relevant subject area, and the God-given ability to ferret out the interrelatedness of those bits of knowledge. Tom had all these qualities in abundance, to the extent that he was already publishing refereed scientific papers even before his PhD was out. What is more, he had the uncanny ability as a university teacher to rub off some of these qualities of his onto his own students. It was thus not surprising to see him rise rapidly from being a lecturer in University of Nairobi's Department of Zoology to a full Foundation Professorship in the newly created Department of Entomology in the Faculty of Agriculture in a matter of 6 years. A few months later, he became the first Dean of the Faculty. I have been privileged to meet some of his academic children and grandchildren. They all speak very highly of their mentor. Tom had the satisfaction of interacting with these, his children and grandchildren. One academic child is now the Dean of that very faculty of which he was the first Dean."
Odhiambo combined the qualities of outstanding scientist and teacher with those of a visionary. Herren described how: "His love and fascination for insects was only equalled by his love and dedication to the next generation of scientists and their successful undertakings to see Africa and other developing countries move forward in science-led sustainable development. This was his vision long before these words became common language." Odhiambo himself said of his university years, "One of the key issues we were always thinking about was excellence. How does one build that into African endeavours?" His answer was ICIPE.
Wasawo recalled the disquiet felt after World War II by "some of the greatest scientists and philosophers of the day, at the disastrous effects of the atomic bomb and the directions scientific research were taking. This led to Albert Einstein, the great philosopher Lord Bertrand Russell, the Nobel Prize winner Joseph Rotblat and others, to found the Pugwash Conferences on Science and World Affairs. In 1965 they decided to hold one of their meetings in Africa at the headquarters of the Organization of Africa Unity. They were anxious to address themselves to the increasing poverty on the African continent, which could be a threat to world peace. One of the ideas that was mooted at that conference was the need to set up first-rate scientific research institutions that would address the needs of the African continent. This took another 4 years before it could happen."
Herren described the history of ICIPE's founding as "somewhat of a legend." While still a young staff member at the then University College, Nairobi of the University of East Africa, in Odhiambo's own words, "a `serendipitous opportunity' presented itself in 1967 when I took the challenge from the Editor of... Science to write a major review of the status of science in Africa. In it, I made a strong plea for establishing a few large centres of excellence... I gave, as an example, the pivotal areas of the management of insect populations in a sustainable, ecologically-friendly way, [using technologies] that would be within the means of the resource-poor rural communities. Strong encouragement to actually launch such a centre cascaded from an over-arching positive response..."
Herren summed up: "This article proved to be a rallying call for attention to be paid to Africa and its development issues. The centre would provide a mechanism and focal point for linking the world's leading scientists with the problems facing the small-scale farmers of the developing world." Wasawo pointed out that Odhiambo's proposal "...because of his international track record in research, could be seriously listened to and looked at [thus] Tom was able to win backers like Professors Carl Djerassi and Eugene Rabinovitch of Pugwash. He obtained support from the various scientific organisations, from foundations, from governments and from multilateral agencies. The International Centre for Insect Physiology and Ecology was born... with Tom as its first Director." In 1977, ICIPE was granted full international status by the Government of Kenya and in 1986 it was converted into an intergovernmental organization by the signing of a charter in a ceremony chaired by the UN Development Program.
From its humble in a small garage, ICIPE moved to purpose-built premises on the University of Nairobi, Chiromo Campus before relocating in 1990 to its present-day headquarters, Duduville, at Kasarani north of Nairobi. A major field station at Mbita Point in Western Kenya was inaugurated in 1986, and other field sites were established in Kenya and neighbouring countries. ICIPE developed and still possesses some of the best facilities for scientific research and development (R&D) on the continent.
Herren described how the R&D programmes Odhiambo established on important pests of field crops such as stemborers, termites and the desert locust; on disease vectors (yellow fever and malaria mosquitoes and sandflies) and on livestock pests (tsetse and ticks), together with the development of technologies such as NGU tsetse traps and biological control of stemborers, provided a firm foundation on which ICIPE can still build. Wasawo recognized the importance of Odhiambo's clear thinking and leadership, saying, "...it is one thing to found an institution and have a vision for it, but quite another to develop it along the right pathways in order to achieve its goals. Here, Tom's knack for asking the right kind of scientific questions based on his immense knowledge of the subject of entomology came in handy. He formulated research programmes that correctly addressed the problems of pests in their relation to agricultural productivity in Africa. In this he had the instinctive support of his Governing Council, because of the respect he had earned." Herren described how Odhiambo had been strongly influenced by Rachel Carson's book, The Silent Spring, which sounded the alarm about pesticide misuse and its implications for ecosystems, declaring how he "understood very early on the problems that the use of synthetic pesticides were (and still are) creating, both for the environment and the farmers, as he recognised that pesticides soon lead into a treadmill from which farmers would eventually beg to be taken off. He therefore based the research programmes at ICIPE on the biological and integrated control track. This was far ahead of many scientists in the developed world at the time. He has been proven right many times over, and today ICIPE is continuing with this philosophy, for the benefit of the farmers and the environment." Wasawo pointed out that, "The research results emanating from ICIPE have helped not only in solving some of the problems addressed; but have also formed the basis for further research, carried out not only at ICIPE but also at universities and research institutions in Africa and elsewhere. ICIPE has thus helped in stimulating the quality of university education in this continent of ours as well as elsewhere in the developing world."
However, both Wasawo and Herren highlighted human and institutional capacity building as perhaps the most enduring of Odhiambo's many achievements. Herren outlined how a highly successful programme for training PhD scientists was launched by ICIPE in 1983. Called the African Regional Postgraduate Programme in Insect Science (or ARPPIS), some 230 students have been enrolled and over a hundred have received degrees. Herren points out that in this way Odhiambo's "legacy in building the human capital to solve Africa's problems lives on, and the ARPPIS and other graduates are now filling prominent positions in universities, government departments and R&D institutions, private companies, and international organisations throughout the continent." Wasawo said, "Professor Odhiambo conceived of and executed the postgraduate as well as postdoctoral programmes in collaboration with universities and research institutions in Africa and elsewhere. He thus made a tangible contribution in the development of high-level manpower and brainpower for various institutions on our continent." Herren noted that ICIPE is proud that most have not succumbed to the temptation to join part of the `brain drain', and are still working in Africa.
Odhiambo believed that scientific publication and access to literature, and for African scientists to be heard and exchange information with colleagues abroad was an integral part of scientific research, and capacity building. From his years at ICIPE, two important outputs emerged: The first was the international journal co-hosted by ICIPE and the African Association of Insect Scientists, Insect Science and its Application, which he served as the first Editor and is now in its 23rd year. In 1987, Odhiambo spearheaded the establishment of a new imprint, ICIPE Science Press, and publication of the journal was moved from the UK to Nairobi. ISP continues to be an active, scientific scholarly publisher. Wasawo noted: "The role of academies in stimulating academic excellence has been well appreciated since the days of Plato and Aristotle; through the foundation of the Royal Society in England up to the present day. Professor Odhiambo acutely felt the need for such academies for the Third World and for Africa. With the Nobel Laureate Professor Abdul Salaam they founded the Third World Academy of Sciences, of which Tom became the first Vice-president. Tom was also the Founding President of the Africa Academy of Science. Who else but Professor Odhiambo could have the capacity and the professional clout to persuade our African presidents of the need for science-based development in Africa; and then set up a forum for them to deliberate on such matters? Thus the Research and Development Forum for Science-led Development in Africa (RANDFORUM) came into being with Tom as its first director." And, always mindful of the importance of the next generation, Odhiambo has also been chairman for the Foundation for the Promotion of Children Science Publications in Africa.
In terms of his own scholarly output, Odhiambo was the author of over 160 peer-reviewed publications and he was awarded numerous international prizes: the Albert Einstein Gold Medal (1991), the Gold Mercury International Award (1982), the Gold Medal Award from the International Congress of Plant Protection (1983), the African Prize for Leadership for the Sustainable End of Hunger (shared with President Albert Diouf of Senegal in 1987), the ISCTRC Silver Jubilee Award of the African Union (2000), and others. He was also awarded honorary doctorate degrees from some of the world's leading institutions. Under his tenure, ICIPE itself was awarded as an organization the St Francis Prize for the Environment (1992), awarded by the Franciscan Centre of Environmental Studies in Assisi, and the Alan Shawn Feinstein World Hunger Award of Brown University (1986).
Herren referred to the "many and varied initiatives of Professor Thomas Odhiambo" and Wasawo described how Odhiambo's broad interests had continued to provide fresh ideas: "Recently he has been developing ideas on community-based university institutions as well as the role of faith and spirituality in human society."
Herren declared that "[Odhiambo's] vision when he created ICIPE with a few friends and colleagues way back in the late 1960s became reality, thanks to his perseverance and dedication. He created an absolutely unique institution, that has become known around the globe for scientific excellence in biological and integrated pest and vector management." Herren said that ICIPE is meeting the challenge of how to pay a long-lasting tribute to Odhiambo by helping "spearhead the formation of a trust in his honour that will help sponsor promising young African academics in their research, among other activities. This will help his legacy live on through the next generations of scientists and leaders."