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What is Chromolaena?

Biological Control

Differences between AWA and SA chromolaena



Other invasive alien plants within the Eupatorieae


Useful links

History: A detailed history of this group has recently been published (Boller et al., 2006), of which a summary is provided here. During the 1st International Workshop on Biological Control and Management of Chromolaena odorata, held in Bangkok, Thailand in 1988, a recommendation was passed to establish an International Working Group in affiliation with the International Organization for Biological Control of Noxious Animals and Plants (IOBC). This Working Group was formally established in 1993 at the 3rd International Workshop, held in Abidjan, Côte d’Ivoire. The workshops have been held in Asia (Thailand, Indonesia, India and Taiwan), Africa (Côte d’Ivoire, South Africa) and Australia.

The Chromolaena odorata Newsletter was launched during the 1st Workshop, in order to publish short articles and news on biocontrol and management of the weed. A proceedings of each of the seven workshops held thus far has been published. Each of the workshops ended with the promulgation of a set of recommendations.

Dr R. Muniappan of the University of Guam has been instrumental in organizing the workshops and forming the working group, of which he was convenor until 2006. At the 7th workshop in Taiwan Dr C. Zachariades (Agricultural Research Council, South Africa) took over as convenor for a 5-year period.

The workshops, proceedings, newsletters and working group have all proved very useful in the exchange of information and insects, in addressing regional problems such as the conflict of interest on the status of chromolaena in West Africa, and in giving direction to further research.

The workshop in Australia in 2003 was broadened to include other invasive chromolaena species, and a recommendation was made to broaden the focus of the working group to other invasive Eupatorieae. Consequently, the 2007 Taiwan workshop included both chromolaena and Mikania micrantha.

Boller, E.F., J.C. van Lenteren and V. Delucchi (eds.) 2006. International Organization for Biological Control of Noxious Animals and Plants: History of the first 50 Years (1956-2006). IOBC, Zurich, Switzerland. 275 pp.

Recommendations emanating from workshops:

  • 1st workshop. Bangkok, Thailand, 29/02-04/03/1988

1.1 The Secretariat be established and located in Guam for the present, and to produce a "Chromolaena odorata Newsletter".

1.2 An International Working Group on Biological Control of Chromolaena odorata be formally established and seek an affiliation with the International Organization for Biological Control (IOBC).

1.3 Countries and organizations active or planning to initiate biological control of C. odorata programs should inform the Secretariat or the working group to disseminate the information and to maximize cooperation and collaboration.

1.4 To encourage exchange of natural enemies of C. odorata in conformity with the local or regional regulations, the researchers must document all relevant information pertaining to identity, origin, numbers received, numbers released, locations and dates of releases together with pre-release and post-release evaluation of the natural enemies concerned.

1.5 Various donor agencies be encouraged to support activities that will strengthen biological control of C. odorata.

1.6 In the light of the benefits derived from this workshop, it will be more useful to organize another one in the next two or three years to follow up current activities and to review the progress made as well as to formulate future action plans.

  • 2nd workshop. Bogor, Indonesia, 04-08/02/1991

2.1 In view of the need for exchange of information and the coordination of research activities, a network on biological control and management of C. odorata should be established immediately with an international coordinating secretariat at the University of Guam and assisted by four regional coordinators.

2.2 Given the inefficiency and high cost of other control techniques and recognizing the success of biological control of C. odorata in Guam and neighboring islands, it is recommended that countries with a C. odorata problem should initiate biological control programmes starting with importation of P. pseudoinsulata.

2.3 Recognizing the potential of other biological control agents, further exploration and screening should be conducted in the natural range (Central and South America) of C. odorata.

2.4 In tandem with efforts on biological control of C. odorata, research on the ecology of C. odorata should be conducted to evaluate its impact in Western and Central Africa, taking cognizance of similar studies prior to the arrival of the weed into the region.

2.5 Recognizing that there are significant gaps in our knowledge of the weed and its biological control agents, there is a need to pursue basic research not only into their ecology but also into their biology and chemistry.

2.6 Appreciating the safety and sustainability of biological control, it is strongly recommended that donors support research and implementation of biological control of C. odorata in countries affected by the weed.

2.7 A third Intemational Workshop on Biological Control and Management of C. odorata should be held in 1993. In order to sensitize, focus and promote further work in Africa, it is recommended that it be organized in West Africa in collaboration with the Food and Agriculture Organization of the United Nations (FAO) Regional Office of Africa.

  • 3rd workshop. Abidjan, Côte d’Ivoire, 15-19/11/1993

3.1 The Workshop foresees the continued spread of C. odorata in sub-Saharan Africa, and recommends:
i) that this spread be monitored by the countries concerned, and
ii) that countries where C. odorata has not been reported be informed of the likely arrival of C. odorata, and be provided with balanced information on the potential ecological and socio-economic impacts of the weed.

3.2 The Workshop recognizes that, of the major land systems in the humid and sub-humid tropics of Africa:
i) the arid savanna zone is not susceptible to invasion by C. odorata;
ii) dense evergreen forests in the humid tropical zone are not susceptible to invasion when intact, but become very susceptible whenever disturbed;
iii) the moist savanna zone is very vulnerable to invasion;
iv) the native flora in the vulnerable ecologies is likely to be dominated and eventually suppressed by C. odorata, affecting the entire biodiversity.
The Workshop also encourages the collection and synthesis of research in the management of C. odorata within these vulnerable ecologies.

3.3 The Workshop strongly recommends that where biological control of C. odorata is found necessary in Africa and elsewhere, it should be conducted according to the FAO Code for the Importation and Release of Biocontrol Agents. In particular, Article 3 which stipulates that importation can be made only with governmental consent from the importing country, that other countries in the region concerned be consulted, and that introductions should only be made when it is in the best interest of the public. Article 4 which stipulates that the host range of any potential agents must be adequately investigated before release should also be followed.
Since conflicts of interest are likely to occur, the Workshop also recommends that the different viewpoints and arguments expressed in the Proceedings of this Workshop be considered before any permits to import are issued.

3.4 The Workshop encourages African countries as well as international research agencies to initiate comprehensive research on the status of C. odorata, on its importance in the various agro-ecosystems, and on its impacts on native flora and fauna. The Workshop also encourages African countries to organize national meetings to document available information on the status of C. odorata, and its economic importance in the agro-ecosystems of each country.

  • 4th workshop. Bangalore, India, 14-18/10/1996

4.1 So far, only Pareuchaetes pseudoinsulata has been used for biological control of C. odorata in many countries. Importation of other effective natural enemies such as Procecidochares connexa, Mescinia parvula, Melanagromyza eupatoriella, Actinote anteas, etc., should be considered.

4.2 Countries wherein Pareuchaetes pseudoinsulata has been introduced should consider introduction and establishment of Procecidochares connexa from IOPRI in Indonesia. Host specificity testing of this natural enemy has been carried out in Indonesia and the information on host plants tested is available.

4.3 The Workshop highlights the importance of the complex of alien invasive weeds, including Chromolaena odorata, in the Western Ghats, and other ecologically important regions in the humid tropics which are threatening biodiversity of these regions; this should be brought to the attention of the Indian and other governments and international donors in order to seek support and funding for multi-disciplinary programmes of management of these weeds.

4.4 National governments should promote collaborative programmes nationally and internationally on management of Chromolaena odorata, Parthenium hysterophorus, Mikania micrantha, Lantana camara, Ageratina adenophora and other alien invasive weeds.

4.5 National governments through their agricultural research agencies should include use of pathogens in biological and integrated control programmes against noxious weeds.

4.6 For immediate suppression of C. odorata in certain conditions, where alternative technology is not available, research on herbicide and other methods should be encouraged.

4.7 Alternative uses of Chromolaena, such as use as a green manure crop, in certain agro-ecological systems should be explored.

4.8 It is recommended that a national network should be formulated to co-ordinate the research programmes on Chromolaena odorata in India.

4.9 Training programmes on biological control of exotic weeds at national, regional and international levels should be encouraged.

4.10 In view of the serious problems caused by C. odorata in developing countries in Asia and Africa to the livelihood of small- and medium-scale farmers, and the threat to biodiversity in natural ecosystems, countries of origin of the plant (tropical Americas from Argentina to the USA) are requested to assist researchers from affected countries and their agencies by allowing exploration for, and collection and export of promising candidate organisms for biological control of the weed, without imposing administrative and other barriers to the export of live materials.

  • 5th workshop. Durban, South Africa, 23-25/10/2000

5.1 To change the name of the future workshops to ‘International Workshop on Biological Control and Management of Chromolaena’.

5.2 To adopt as the common name ‘chromolaena’ in future literature for Chromolaena odorata.

5.3 That other specialist tephritid taxonomists be approached to sort out the generic placement of (Pro) Cecidochares connexa Macquart and its relationship to Procecidochares alani and P. utilis.

5.4 Cooperative international work should be encouraged especially in the aspects of foreign exploration and preliminary screening of candidates.

5.5 As a follow-up to the 1993 recommendations of the Chromolaena odorata workshop held in Abidjan, West and Central African stakeholders should hold a regional meeting in 2001 to assess the expansion of the biological control effort across the region. The recommendations of this meeting will be tabled to the regional governments.

5.6 That an integrated weed management strategy including eradication where applicable (countries where the weed has only been found), slashing, burning, cultural, chemical and biological control be developed for the management of C. odorata.

  • 6th workshop. Cairns, Australia, 06-09/05/2003

6.1 Governments of West and Central Africa should introduce Cecidochares connexa.

6.2 Regional organizations e.g. SPC to produce public awareness material on chromolaena for identification and containment and control measures.

6.3 All information produced by countries and organizations on chromolaena be linked to the chromolaena website at UQ.

6.4 Expand the focus of the workshop to include other invasive Eupatorieae (e.g. Ageratina, Ageratum, Austroeupatorium, Campuloclinium, Mikania, Praxelis).

6.5 Research to assess additional natural enemies, including fungi, should be encouraged in countries having problems with invasive Eupatorieae.

6.6 Eradication of chromolaena, wherever possible, should be the preferred strategy, and continuation with eradication efforts in Australia and the Marshall Islands must be given the highest priority.

6.7 An e-mail list for invasive Eupatorieae should be set up and maintained by Wayne Parasram.

  • 7th workshop. Pingtung, Taiwan, 12-15/09/2006

7.1 Governments of all countries affected by chromolaena are encouraged to consider the introduction of Cecidochares connexa.

7.2 Governments of all countries affected by chromolaena and mikania are encouraged to send representatives to the next workshop.

7.3 Regional organizations e.g. SPC and countries affected to produce public awareness material on chromolaena for identification and containment and control measures.

7.4 Countries should increase awareness of, and promote, biological control of weeds and its benefits.


Future vision for the IOBC Working Group on Chromolaena

 The IOBC Working Group will for now remain officially a working group only on Chromolaena odorata, but will involve itself in biocontrol and management of other invasive alien Eupatorieae as considered desirable and necessary. The Chromolaena odorata Newsletter will remain as is for now. However, workshops will continue to accommodate other tropical and subtropical Eupatorieae as the need arises, and this website provides links and some information on these weeds.

Prospects for the biocontrol of chromolaena have improved dramatically since the 1990s. Pareuchaetes species have been established in several more countries, and although the performance of these moths has not always been adequate, they have had a positive impact. Actinote thalia pyrrha has been established in Indonesia, and attacks not only C. odorata but also the invasive Eupatorieae M. micrantha and A. inulifolium. C. eupatorivora has established in South Africa and may be having an impact. Undoubtedly the most successful agent, however, has been C. connexa, which has had a real and consistent impact in most of the areas where it has been released for long enough to build up in population. Several other very promising agents will become available from the SA program within the coming years. The Working Group will therefore continue to work to increase awareness of the threat of chromolaena and biocontrol solutions to it, to facilitate the exchange of information, to make available suitable insect and pathogen agents for release (particularly at this stage, C. connexa), and to identify areas of need for further research and implementation.

With regards to M. micrantha, the rust fungus Puccinia spegazzini has been released in India, China and PNG. In India it initially spread from the release sites but may not have persisted; in China it spread but further assessments are not available; in PNG it is spreading (C. Ellison, unpubl. data). Releases are planned in Fiji. The Working Group will thus also promote the use of this agent where appropriate.

Workshop Proceedings

Proceedings of the First International Workshop on Biological Control of Chromolaena odorata, 29 February – 4 March 1988, Bangkok, Thailand. Muniappan, R. (ed). Agricultural Experiment Station, University of Guam, Mangilao, Guam, 1988.

Proceedings of the Second International Workshop on Biological Control of Chromolaena odorata, 4-8 February 1991, Bogor, Indonesia. Muniappan, R. and Ferrar, P. (eds). ORSTOM & SEAMEO BIOTROP, Bogor, BIOTROP Special Publication No. 44, 1991.

Proceedings of the Third International Workshop on Biological Control and Management of Chromolaena odorata, 15-19 November 1993. Prasad, U.K., Muniappan, R., Ferrar, P., Aeschliman, J.P. and de Foresta, H. (eds). Agricultural Experiment Station, University of Guam, Mangilao, Guam, Publication No. 202, 1996.

Proceedings of the Fourth International Workshop on Biological Control and Management of Chromolaena odorata, 14-18 October 1996, Bangalore, India. Ferrar, P., Muniappan, R. and Jayanth, K.P. (eds). Agricultural Experiment Station, University of Guam, Mangilao, Guam, Publication No. 216, 1998.

Proceedings of the Fifth International Workshop on Biological Control and Management of Chromolaena odorata, 23-25 October 2000, Durban, South Africa. Zachariades, C., Muniappan, R. and Strathie, L.W. (eds). ARC-PPRI, Pretoria, South Africa, 2002.  [ProcFifthIntWorkshop.pdf]

Proceedings of the Sixth International Workshop on Biological Control and Management of Chromolaena, 6-9 May 2003, Cairns, Australia. Day, M.D. and McFadyen, R.E.C. (eds). ACIAR, Canberra, Australia, ACIAR Technical Reports 55, 2004.  [Proceedingsofthe6thWorkshopAustralia2003.pdf]

Proceedings of the Seventh International Workshop on Biological Control and Management of Chromolaena odorata and Mikania micrantha, September 12 - 15 2006, Pingtung, Taiwan. Lai, P-Y., Reddy, G.V.P. and Muniappan, R. (eds). National Pingtung University of Science and Technology, Pingtung, Taiwan, 2007.