248 Proceedings of the First International Weed Control Congress, Melbourne 1992

Biological control of weeds in Malaysian plantations

Peter A. C. Ooi Introduction Weed control in Malaysian plantations is International Institute of Biological Control, dominated by the use of herbicides at the Malaysian Station, P.O. Box 11872, 50760 Kuala seedling to young plant growth stage of the Lumpur, Malaysia crop. Chee (2) reported that chemical control could cost up to 24.3% of the cost to replant Summary rubber. However, in mature rubber, weed Weed control in Malaysian plantations has control costs are lower as herbicides are used for a long time depended on herbicides. This mainly to reduce interference with farm reflects the interest of weed scientists in operations (15). The preoccupation with Malaysia. For the period 1975 - 1984, 70% of chemical control in Malaysia is reflected in the the publications were on chemical control of number of publications on this topic. For weeds. However, in recent years increasing example, Teoh and Ooi (20) found that for the problems have arisen from dependence on period 1975 -1984, 70% of the publications on chemical control, for example, health effects weeds were on chemical control. However, in to operators, herbicide resistance, toxicity to recent years, there has been greater interest in non - target crops and changes in weed flora. biological control of weeds. This has been These have resulted in a greater interest in given impetus following publicity about the biological control of weeds in plantations adverse health and environmental effects of and other crops. herbicides by the local press. Problems Eighteen important weeds háve been associated with crop phytotoxicity when identified in plantation crops, of which 44% applied to immature plants and drift onto are exotic. Tropical weeds from the new non - target crops and questions about safety to world are amenable to classical biological operators have also been highlighted (Chung, control. However, studies of the ecology of personal communication 1991; 8). Herbicide native weeds are necessary to identify safe resistance and changes in the flora appear as biological control agents to help in the increasing problems in plantations which development of a sustainable weed manage- regularly use herbicides (2). ment with reduced dependence on chemical As a result, several biological control of control. A possible outcome of ecological weeds projects have been initiated in Malay- studies is the development of suitable fungi sia. This paper attempts to review the status of to augment existing biological control the projects in Malaysian plantation crops. The agents. trend reported may be similar to that reported Classical biological control is reported in neighbouring countries with similar crops. for three major plantation weeds, namely, Chromolaena odorata, Cordia curassavica Major weeds of plantation crops and Mikania micrantha. Of these, successful Weeds in Malaysian plantations are character- suppression of C. curassavica has been ized by a mixture of grasses, broadleaves and observed. For C. odorata, localized defolia- ferns. A recent review by Rosli Mohamad (15) tion was occasionally observed in Sabah. listed 18 important weed species (Table 1). Of Difficulties associated with the establish- these, six were grasses, eight broadleaves and ment of the biological control agents of M. four ferns. Forty -four percent were exotics. micrantha are discussed. The weed Cordia curassavica Indigenous enemies of native weeds, (Boraginaceae) is probably not listed in Table particularly for Melastoma malabatrichum 1 because its status has changed following. a and Dicranopteris linearis, are also re- successful biological control program (16,21). viewed. Proceedings, of the First International Weed Control Congress, Melbourne 1992 249

Prior tó the. programit was a very important was initiated (19). This led to the, introduction weed in cóconutplantations, particularly in of Liothrips mikaniae (Priesner) Selangor and Johor. (Thysanoptera: Phlaeothripidae) from Trini- Weeds in plantations are economically dad. This project continues, despite initial important in the establishment stage. For problems with rearing the : This was example, Mikania micrantha is known to solved, but the insect is proving difficult to depress early rubber tree growth (23), probably establish in the field because of the presence as a result of an allelopathic compound of many general predators (9). Indeed, in the produced by the weed (24). laboratory, predatory thrips,.ants and spiders occasionally reduce the breeding populations. Biological control attempts Despite the interest in exotic biological The prospects for classical biological control control agents to control weeds, there have of exotic weeds in Malaysia was discussed by been comparatively fewer studies about Ung and Ooi (22). They pointed out that the natural enemies of native weeds. This can be pest status of the major exotic weeds was due seen in Table 3 compiled from the list pre- to the lack of effective biological control pared by Ahmad and Ho (1). Impressive agents. It was suggested that proven agents be defoliation of Mélastoma malabathricum by. introduced. This strategy worked following the Altica cyanea (Coleoptera: Chrysomelidae) program to control C. curassavica with two was observed by Karnal and Aziz (5) and d Ooi agents, Metrogaleruca obscura DeGeer (12). This conspicuous weed has other natural (Coleoptera: Galerucidae) and Eurytoma attiva enemies, as two species of were intro- Burks (Hymenoptera: Eurytomidae). They duced into Hawaii from Malaysia (4). There is proved most effective in reducing large a need to carefully study the natural enemies populations of the weed throughout the of M. malabathricum to understand why this Malaysian peninsular (10,16,21). weed is still a nuisance in its native range. A Some of the weeds targeted for biological possible outcome is the discovery of fungal control.by Ung and Ooi (22) are listed in Table pathogens. 1. An example is Chromolaena odorata, a Recently it was reported that the fern plant present both in plantations and vacant Dicranopteris linearis was severely defoliated land. Both Pareuchaetes pseudoinsulata Rego. by Schlenklingia ssp. (Coleoptera: Barros (: Arctiidae) and Apion Chrysomelidae) (7), but little is known about brunneonigrum Beguin - Billecoq (Coleoptera: the biology of this, insect. Apionidae) were introduced into Sabah Based on our experiences, strategies for the between 1970 -73 (18). Only the former biological control of weeds in plantations are established, but did not provide control (14). suggested. It is hoped that they will prove Also, Acalitus ádoratus fortuitously arrived in valuable to those projects in a similar

Malaysia and neighbouring countries, but has environment. . not caused much damage to the weed (see Table 2). Strategies for biological control of Biological control of camará has plantation weeds been the subject of many projects (Table 2), The successful biological control of C. but still remains a challenge. However, some curassavica was an important milestone for of the agents released in one country have Malaysia, for it showed that it was possible, travelled to others in the region. Two such economically viable, sustainable and safe. This agents are Calycomyza lantanae Frick and stimulated support for more projects by the Ophiomyia lantanae (Froggatt) (Diptera: National Biological Control Coordinating.

Agromyzidae) (11). Damage by the former Committee currently based at the Malaysian . causes severe localized defoliation, but Agricultural Research and Development insufficient to control the weed effectively. Institute (MARDI): Currently, there are four The role of pathogens should receive more projects on weeds. Therefore, it is necessary to attention now. begin with a proven biological control agent to Following the success of the control of C. convince 'negative' administrators of the value curassavica and encouraging results from of biological control of weeds. Cock (3), a program to control M. micrantha 250 Proceedings of the First International Weed Control Congress, Melbourne 1992

Following the successful C. curassavica predators in West Malaysia (1920 - 1978). project, it was possible to embark on a new Bulletin No. 153, Ministry of Agriculture, program using an untested agent for M. Kuala Lumpur, Malaysia . micrantha. This augurs well for a country 2. Chee, Y.K. (1990). Recent weed manage- where 75% of the total pesticides used are ment development in rubber. In 'Proceed- herbicides (15). ings of the symposium on weed manage- An important consequence of running new ment', eds B. A. Auld, et al., pp. 189 -197, biological control projects, such as for M... Biotrop Special Publication, No. 38, Bogor, micrantha, is that expectations are high. As the Indonesia biological control agent L. mikaniae had not 3. Cock, M.J.W. (1982). Potential biological been introduced elsewhere, it was difficult to control agents for Mikania micraantha HBK predict its success. Initially, the thrips were not from the neotropical region. Tropical Pest easy to rear under laboratory conditions. Management 28 (3), 242 -54 General predators provided problems in field 4. Julien, M.H. (1987). `Biological control of establishment. As studies of rice pests showed weeds. A catalogue of agents and their that general predators are important in keeping target weeds', 2nd ed CAB International homopteran pests in check (6,13), it should not Institute of Biological Control, Ascot, U.K. come as a surprise that general predators 150 pp. would prevent L. mikaniae from establishing. 5. Kamal, A.K. and Aziz, A.S. (1978). The Even in the case of the biological control of potential of Altica cyanea Weber Clidemia hirta using Liothrips urichi Karny (Coleoptera: Chrysomelidae) as a biological (Thysànoptera: Phlaeothripidae) in Fiji, it took control agent for Melastoma malabathricum thousands of thrips and about two years before Linn. MARDI Research Bulletin 6, 15 -24. establishment was reported (17). 6. Kenmore, P.E., Carino, F.O., Perez, C.A., The rather poor establishment of P. Dyck, V.A. and Gutierrrez, A.P. (1984). pseudoinsulata in Sabah was also attributed to Population regulation of the brown general predators. As this has not been proven, planthopper (Nilaparvata lugens Stal) attempts.should be made to discover the within rice fields in the Philippines. Journal factors which prevented it from exerting its of Plant. Protection in the Tropics 1, 19 -37. potential. Studies of natural enemies of weeds 7. Khoo, K.C. and Chung, G.F. (1990). should not only be confined to exotic weeds. Schlenklingia sp. - a prospective biological Indeed, a knowledge of natural enemies of control agent against bracken. MAPPS native weeds may result in more appropriate Newsletter 14 (4), 53. systems to keep the weeds in check. It is 8. Lee, S.A. and Chung, G.F. (1985). Safety suggested that weed scientists should record aspects of LV, VLV, ULV and CDA all natural enemies found, as this may result in application. In `Recent Developments in the discovery of weed pathogens. Weed Pesticide Application Technology', ed C.H. pathology is neglected and efforts should be Teoh, pp. 46 -66, Malaysian Plant Protection made to understand its role in native weed Society, Kuala Lumpur, Malaysia.. populations. The development of 9. Liau, S.S., Ooi, P.A.C., Mohd. Ridzuan mycoherbicides is an important growth area Ismail, Tay, B.L., Lee, S.A., Chung, G.F. for biological control. and Ho, C.T. (1991). Mikania micrantha: Increased interest in biological control of early experiences on biological control in weeds has also resulted in the need for more Malaysia. Presented at the International efficient quarantine procedures. As a result, Conference on Biological Control in Malaysia has constructed a new biological Tropical Agriculture, Pahang, Malaysia control quarantine facility. This is encouraging 10. Ooi, P.A.C. (1981). Eurytoma attiva Burks to biological control specialists working in (Hym., Eurytomidae) attacking Cordia Malaysia as it shows the commitment of the curassavica (Jacq.) R. & S. in Kedah and, country to biological control. Perlis, Malaysia II. Incidence of E. attiva. Malaysian Agricultural Journal 53,1 -8. References 11. Ooi, P.A.C. (1987). A fortuitous biological 1. Ahmad, Y. and Ho, T.H. (1980). List of control of Lantana in Malaysia. Tropical economic pests, host plants, parasites and Pest Management 33, 233-6. Proceedings of the First International Weed Control Congress, Melbourne 1992 251

12. Ooi, P.A.C. (1987). A Melastoma feeding Mohammed (1985). Prospects for biological chrysomelid beetle, Altica cyanea. Malayan control of Mikania micrantha HBK'.in Nature Journal 41, 379 -82. Malaysia. Planter Kuala Lumpur 61, 13. Ooi, P.A.C. (1988). Ecology and surveil- 515 -30. lance of Nilaparvata lugens (Stal) - implica- 20. Teoh, C.H. and Ooi, P.A.C. (1986). To- tions for its management in Malaysia. PhD. wards more effective plant protection in the thesis, University of Malaya, Kuala tropics. Journal of Plant Protection in the

Lumpur. 275 pp. Tropics 3, 51 -72. . 14. Ooi, P.A.C., Sim, C.H. and Tay, E.B. 21. Ung, S.H., Ahmad, Y. and Chin, W.H. (1988). Status of the arctiid introduced (1979). Biological control of Cordia to control Siam weed in Sabah, Malaysia. curassavica (Jacq.) R. & S. in Malaysia by Planter Kuala Lumpur 64, 298 -304. Schematiza cordiae Barb. (Coleop: 15. Rosli Mohamad (1990). Country report: Galerucidae). Malaysian Agricultural Malaysia Weeds and weed management in Journal 52, 154 -65. Malaysian agriculture. In `Proceedings of 22. Ung, S.H. and Ooi, P.A.C. (1979). Biologi- the symposium on weed management', eds cal control of exotic weeds in Malaysia. B. A. Auld et al., pp. 41 -52, Biotrop Special Proceedings Plant Protection Seminar 1979 Publication, No. 38, Bogor, Indonesia. - Strategies in Plant Protection. eds T.K. 16. Simmonds, F.J. (1980). Biological control Lim et al. pp. 49 -63. of Cordia curassavica (Boraginaceae) in 23. Watson, G.A., Wong, P.W. and Narayanan, Malaysia. Entomophagá 25, 363-4. R. (1964). Effects of cover plants on soil 17. Simmond, H.W. (1933). The biological status and on growth of Hevea IV. control of the weed Clidemia hirta, D. Don., Leguminous creepers compared with in Fiji. Bulletin of Entomological Research grasses, Mikania cordata and mixed 24, 345 -8. indigenous covers on four soil types. 18. Syed, R.A. (1979). An attempt on biological Journal of the Rubber Research Institute of control of Eupatorium odoratum L. f. in Malaya 18, 123 -45. Sabah, Malaysia. Proceedings 6th 24. Wong, P.W. (1964). Evidence for the Asian- Pacific Weed Science Society presence of growth inhibitory substance in Conference, Vol. II, pp. 459 -66. Mikania cordata (Burm. f.) B. L. Robinson. 19. Teoh, C.H., Chung, C.F., Liau, S.S., Ghani Journal of the Rubber Research Institute of Ibrahim, Tan, A.M., Lee, S.A. and Mariati Malaya 18, 231 -42.

Table 1 Common weeds in plantation crops (adapted from (15)).

Name Family Origin

Axonopus compressus Poaceae' new world tropics Asystasia coromandeliana Acanthaceae pan- tropical Asystasia intrusa Acanthaceae pan- tropical Chromolaena odorata Asteraceae new world tropics Clidemia hirta Melastomaceae new world tropics Cynodon dactylon Poaceae pan- tropical Dicranopteris linearis Gleicheniaceae pan- tropical Imperata cylindrica Poaceae pan- tropical Lantana camara Verbenaceae new world tropics Lygodium flexuosum Schizaeaceae pan- tropical Melastoma malabathricum Melastomaceae S. China/Malaysia Mikania micrantha Asteraceae new world tropics Mimosa pudica Leguminosae new world tropics Nephrolepis biserrata Nephrolepidaceae pan- tropical Ottochloa nodosa Poaceae pan- tropical Paspalum commersonii Poaceae Africa Paspalum conjugatum Poaceae new world tropics Stenochlaena palustris Blechnaceae pan- tropical 252 Proceedings of the First International.Weed:Control Congress, Melbourne. 1992

Table 2 Review of worldwide attempts at classical biological còntrol of major plantation weeds in Malaysia (after (4)):

Weeds Agents Countries and degree of control:

C. odorata Apionbrunneonigrum Not established in, Beguin- Billecoq Ghana, India, Malaysia, ( Coleoptera: Apionidae) Nigeria and Sri Lanka. Pareuchaetes pseudo - Successful suppression in Gúam. insulata Rego Barros Established in India, (Lepidoptera: Arctiidae) Malaysia and Sri Lanka. Not established in Ghana and Nigeria. Arrived fortuitously in Brunei and Philippines. Acalitus adoratus Arrived fortuitously in Keifer China (Hainan), Indonesia, (Acari: Eriophyidae) Malaysia, Philippines and Thailand.

C. hirta Blepharomastix Established in Hawaii but ebulealis Guenee ineffective. (Lepidoptera: Pyralidae) Liothrips urichi Established in Fiji and Karny good control. (Thysanoptera: Established in Hawaii Phlaeothripidae) with partial success. Not established in Solomon-Islands Present in Samoa but status unknown.

L. camara Aerenicopsis championi Not established in Hawaii. Bates (Coleoptera: Cerambycidae) Alagoasa parana Not established in Samuelson and South Africa. (Coleoptera: Chrysomelidae) Apion spp. Not established in (Coleoptera: Apionidae) Hawaii. Autoplusia illustrata Not established in Guenee Australia. (Lepidoptera: ) Calycomyza lantanae Established in Australia Frick with no control. (Diptera: Agromyzidaé) Established in South Africa. Arrived fortuitously in Indonesia, Malaysia, Papua New Guinea, Philippines, Singapore and Thailand. Cremastobombycia Established with partial lantanella Busch control in Hawaii. (Lepidoptera: Gracillariidae) Diastema tigris Not established in Guenee Australia, India, Fiji, (Lepidoptera: Ghana, Hawaii, Mauritius, Noctuidae) Tanzania, Uganda and Zambia. Epinotia lantana Established and provide some control (Busck) in Australia, Caroline Islands (Lepidoptera: Tortricidäe) and Hawaii. Arrived fortuitously in N orfolk Island and India. Proceedings of the First International Weed Control Congress, Melbourne 1992 253.

Eutretaxanthochaeta Established in Hawaii but Aldrich of minor importance. (Diptera: Tephritidae) Not established in Australia and S. Africa. Hepialussp. Not established in Hawaii. (Lepidoptera: Hepialidae) Hypena strigata(F.) Established in Australia, (Lepidoptera: Fiji, Hawaii and . Noctuidae) Not established in Guam. Apparently indigenous to S. Africa. Arrived fortuitously in Mauritius. Lantanaphaga Established inHawaii. pusillidactyla Not established on (Walker) Caroline Islands and (Lepidoptera: probably S. Africa.

Pterophoridae) . Arrived fortuitously in . Australia, Hong Kong and India. Leptobyrsadecora Established in Australia, Drake Hawaii & Norfolk Island. (Hemiptera: Tingidae) Not established in Fiji, Ghana, Guam and Zambia. Unconfirmed establishment in Cook Islands and South Africa. Arrived fortuitously in Tonga Islands. Neogalea esula(Druce) Established in Australia (Lepidoptera: and Hawaii. Noctuidae) Not established in South Africa. Octotoma championi Ineffective in Australia. Baly Establishment unconfirmed (Coleoptera: in South Africa. Chrysomelidae) Octotoma plicatula (F.) Not established in (Coleoptera: Hawaii. Chrysomelidae) Octotoma scabripennis Established in Australia, Guerin- Meneville Ghana, Hawaii, India, New (Coeloptera: Caledonia, Norfolk Island Chrysomelidae) and South Africa. Not established in Cook Islands, Fiji and Guam. Ophiomyia lantanae Established in Australia, (Froggatt) Cook Islands, Fiji, Guam, (Diptera: Agromyzidae) Hawaii, Hong Kong, New Caledonia, Norfolk Island and South Africa. Not established in Caroline Islands. Arrived fortuitously in Argentina, Burma, Ghana, India, Kenya, Malaysia, Madagascar, Papua New Guinea, Philippines, Singapore, Sri Lanka, Uganda, Vanuatu, Zanzibar and Zimbabwe.

Orthezia insignis . Arrived fortuitously in Browne Hawaii and India but (Hemiptera: Ortheziidae) ineffective. 254 Proceedings of the First International Weed Control Congress, Melbourne 1992

Parevander xanthomelas Not established in (Guerin- Meneville) Hawaii (Coleoptera: Cerambycidae) Plagiohammus Limited establishment in spinipennis (Thomson) Australia, Hawaii and (Coleoptera: South Africa. Cerambycidae) Not established in Guam. Pseudopyrausta Not established in acutangulalis (Snellen) Fiji and Hawaii ( Lepidoptera: Pyralidae) Salbia haemorrhoidalis Established in Australia, Guenee Fiji, Hawaii, Mauritius; (Lepidoptera: South Africa and Uganda: Pyralidae) Not established in India, Kenya, Tanzania and Zambia.

Teleonemia elata Drake Not established in (Hemiptera: Tingidae) Australia, Cook Islands, South Africa, Uganda and Zambia.

Teleonemia harleyi Established in Australia. Froeschner (Hemiptera: Tingidae)

Teleonemia prolixa Stal Not established in Australia. (Hemiptera: Tingidae)

Teleonemia scrupulosa Established in Australia,

Stal. Caroline Islands, Fiji, (Hemiptera: Tingidae) Ghana, Guam, Hawaii, India, Indonesia, Kenya, Madagascar, New Caledonia, Papua New Guinea, South. Africa, Tanzania, Tonga, Uganda, Vanuatu, Western Samoa, Zambia and Zanzibar. Not established in Zimbabwe. Arrived fortuitously in Malaysia (Sabah), Mauritius and Philippines. Thecla bazochii Established in Fiji and (Godart) Hawaii. (Lepidoptera: Not established in Lycaenidae) Australia. Thecla sp. Established in Hawaii. (Lepidoptera: Lycaenidae) Uroplata girardi Established in Australia, Pic Cook Island, Fiji, Ghana, (Coleoptera: Guam, Hawaii, India, Chrysomelidae) Mauritius, New Caledonia, Papua New Guinea, Philippines, South Africa, Tonga, Trinidad, Uganda, Vanuatu, Western Samoa and Zambia. Uroplata lantanae Not established in Buzzi & Winder Australia. (Coleoptera: Establishment not Chrysomelidae) confirmed in S. Africa. Proceedings of the First International Weed Control Congress, Melbourne 1992- 255

Uroplata sp. nr. Established in Australia. bilineata Chapuis Not established in South (Coleoptera: Chrysomelidae) Africa.

M.` málabathricum Bocchoris adipalis 'Established in Hawaii. (Zeller) (Lepidoptera: Pyralidae) Bocchoris fatualis Established in Hawaii... (Lederer) (Lepidoptera: Pyralidae) Selca brunella Hampson Established in Hawaii.:' (Lepidoptera: Arctiidae)

Table 3 Number of species of recorded on major weeds of plantations in Malaysia (after (1))

Weed No. of species recorded in each Order Coleo Dipte Hemip Isopt Lepid Ortho

A. coromandeliana 0 0 1 0 0. 0"

A. compressus 0 0 . 2 1 5 0. C. hirta 2 0 0 0 0 0 C. dactylon 1 5 0 1 3 0

D.linearis . 2 0 1 0 1 0 I. cylindrica 0 0 13 0 4 3

L. camara 1 . 0 2 0 1 0

M. malabathricum . 6 0 4 0 5 0- M. micrantha 1 0 1 0 2 0 N. biserrata 1 0 0 0 1 0 P. conjugatum . 0 0 2 0 0 0 Coleo Coleoptera Dipte Diptera Hemip Hemiptera Isopt Isoptera Lepid Lepidoptera Ortho Orthoptera