Thirteenth Australian Weeds Conference

Biological control of tropical weeds with Central and South American origin: current activities by CSIRO Entomology

Mic Julien CSIRO Entomology, 120 Meiers Road, Indooroopilly, Queensland 4068, Australia

Summary CSIRO Entomology Tropical Weeds of Mexico at Acapulco, where the climate was simi- Project carries out research on the following weeds: lar to Darwin, Northern Territory (NT), and surveys mimosa (), parkinsonia (Parkinsonia continued on mimosa and hyptis, and were initiated aculeata), mesquite (Prosopis spp.), alligator weed on spinyhead sida (Sida acuta Burhman f.), sida retusa (Alternanthera philoxeroides), bellyache bush (Ja- (S. rhombifolia L.), and fl annel weed (S. cordifolia L.). tropha gossypiifolia), hyptis (Hyptis suaveolens), For improved convenience, the station was relocated and Mexican poppy (Argemone mexicana and A. to the east coast at Veracruz, Mexico, in December ochroleuca). 1986, where it remains today. From Veracruz additional The native range of these weeds is Neotropical plants surveyed include: bellyache bush (Jatropha Americas except for alligator weed that is from temper- gossypiifolia L.), lantana, Mexican poppy (Argemone ate South America. Studies on mesquite are centred in mexicana L. and A. ochroleuca), and parkinsonia (Par- Australia, evaluating the impact of a biological con- kinsonia aculeata L.). Surveys in the native ranges, and trol agent and developing integrated management. activities based from the Central and South American Studies of each of the other weeds involves one or fi eld stations, are the foundations of our research to a combination of the following activities; surveys develop biological control in Australia. in their native ranges, biological control agent biol- In addition, potential control agents have been in- ogy, host specifi city studies in Mexico and Brisbane, troduced from other sources, and studied and released plant ecology, post-release monitoring and evaluation on mesquite (Prosopis spp.), and water hyacinth (Eich- of agent populations, agent impact assessment, non- hornia crassipes (Martius) Solms-Laubach). target impact assessment and integrated management Current projects on temperate South American that includes biological control. Activities involve a grass weeds, serrated tussock (Nassella trichotoma national perspective on weed management and where (Nees) Hack. ex Arechav.), Chilean needlegrass (Nas- possible collaboration and cooperation with state de- sella neesiana (Trin. & Rupr.) Barkworth), and blue partments. A number of these projects are included in heliotrope (Heliotropium amplexicaule J.Vahl), are the CRC for Australian Weed Management. under study in the CSIRO Entomology Temperate Keywords Biological control, weeds, integrated Weeds Project and are not discussed here. weed management, native range, Central America, A precis of research activities and collaborations is South America. presented for each of these weeds. Potential for future research is also considered. INTRODUCTION Many weeds in northern Australia have their origins in CURRENT TARGET WEEDS the tropical Central and South Americas. The CSIRO Mimosa Exploration for biological control of Entomology Tropical Weeds research group based mimosa commenced in 1979. The fi rst agents, seed in Brisbane and Darwin, concentrates much of its feeding beetles, were released in the NT in 1983. research effort towards weeds of this origin. To assist To date 37 species (35 and two fungi) have this effort,a fi eld station is maintained in Mexico from been studied and 12 (10 insects and two fungi) have which survey work is conducted in the region. Initially, been released. Four of these, the seed feeding beetle, in the late 1960s and early 1970s, under Dr. Ken Harley, Acanthoscelides puniceus Johnson, the fl ower feed- a fi eld station was set up in Curitiba, Brazil, to survey ing weevil, Coelocephalapion pigrae Kissinger, the for potential agents on lantana (Lantana camara L.) tip boring , Neurostrota gunniella (Busck) and and later on mimosa (Mimosa pigra L.), hyptis (Hyp- the stem boring moth, mimosa Eichlin & tis suaveolens (L.) Poit.), salvinia (Salvinia molesta Passoa, are widespread, abundant and damaging. Re- D.S.Mitchell), and water lettuce (Pistia stratiotes L.). cent studies have shown that where these agents have Field collections of a known agent were also made on been present for a number of years, seed production alligator weed (Alternanthera philoxeroides (Martius) and seed soil bank have been reduced by one to two Grisebach). The station was closed in February 1982. orders of magnitude and are approaching the levels In March 1984 a station was opened on the west coast found in mimosa’s native range (Paynter and Flanagan

361 Thirteenth Australian Weeds Conference

2002). In addition, sustained attack by C. mimosa over Table 1. that either failed preliminary host several years has lead to plant death. Another recently range tests in Mexico or Brisbane or failed to survive released agent, the leaf-feeding beetle Malacorhinus on Australian hyptis. irregularis Jacoby, is increasing in the fi eld and may Potential agent Plant part Status have developed sustainable populations. attacked In 1997 the program broadened to include the Coleoptera: Chrysomelidae development of integrated management of mimosa. Metriona sp. Leaf feeder Ex Brazil. Failed The aim was to determine cost-effective management specifi city tests in tools and integrate them with biological control. This Brisbane in 2001 work is nearing completion, has provided exciting and Neocharida bifi da Leaf feeder Ex Brazil. Failed applicable results and is subject of a presentation at specifi city test in this conference (Paynter and Flanagan 2002). Brisbane in 1980s There are about fi ve potential biological control Coleoptera: Apionidae agents that remain to be assessed. Any one of these Coelocephalapion Leaf feeder Ex Mexico and may contribute to future control. The management of sp. Venezuela. Failed fi re and grazing to prevent reinvasion of cleared areas specifi city tests in Brisbane in 2000. by mimosa also requires investigation, as does the ma- nipulation of thickets to increase edges and so encour- Coleoptera: Bruchinae Meibomeus sp. Flower feeder Ex Venezuela. age population increase and damage by the important Failed to survive on agent C. mimosa. This project has been supported by Australian hyptis in the Federal and NT Governments, CSIRO Entomology 2001. and The Australian Centre for International Agricul- Diptera: tural Research (ACIAR). Calcomyza hyptidis Leaf miner Ex Mexico. Failed Spencer preliminary tests in Hyptis Exploration for potential agents began in Bra- Mexico in 1980s. zil with two major surveys conducted between 1979 : Pyralidae and 1982 and several preliminary surveys in Venezuela Pyrausta panopealis Leaf and stem Ex Mexico. Failed and Mexico in 1981. When the fi eld station was moved (Walker) feeder preliminary tests in to Acapulco, surveys on hyptis in Mexico were carried Mexico in 1980s. out in conjunction with surveys on other weed spe- Nematoda cies until 1986 when work ceased. Variation in hyptis Unknown species ? Ex Mexico. Not plants was noted and very few natural enemies (12) specifi c. Studied in were found. It was considered that the chemistry of Mexico in c. 1990 this aromatic plant provided protection from herbivory. Several insect species were studied either in Mexico or Brisbane but none proved to be specifi c to hyptis Several species were imported into quarantine in (Table 1) (J.D. Gillett and K.L.S. Harley, unpublished Brisbane where they either failed to survive on Aus- results). A rust fungus, Puccinia hyptidis, also recorded tralian hyptis or they attacked a wide range of plant from hyptis has not yet been studied. species and so were eliminated (Table 1). During 2000, support increased and in the Surveys are planned in new areas of Central 2000–2001 and 2001–2002 growing seasons surveys America in Guatemala, Nicaragua and Costa Rica in were conducted in Venezuela and Mexico. The plant conjunction with surveys on other weeds. Depending is highly variable morphologically and there appears on fi eld availability and likely impact one or more of to be differences in the suite of insects encountered the unstudied insects will be collected and attempts on different forms. Molecular taxonomy is being used to rear and assess host ranges will be made either in to check plant population differences. Mexico or Brisbane. This work is supported by NT The insects collected recently include the follow- DBIRD and CSIRO Entomology. ing: fl ower feeding beetles, including Meibomeus sp., the chrysomelid leaf feeder Omorphoita sp., several Bellyache bush A project supported by NT DBIRD leaf and stem feeding weevils, including Coelocepha- began in 1997. Eight Caribbean and Central and South lapion sp., a stem galling weevil, and , includ- American countries have been surveyed to date and 61 ing a stem boring Sesiid, a Geometrid looper, and the insect and pathogen natural enemies recorded (Heard Pyralid moths Pyrausta that are now considered to be and Chan 2002). In the last four years QDNRM have fi ve or six different species. supported host range testing of agents in quarantine.

362 Thirteenth Australian Weeds Conference

Four insects have been studied in Brisbane, three at all release sites across rangeland Australia. It is were rejected through lack of acceptable specifi city, most abundant in the Pilbara Region, WA, where and one, the seed feeding bug Agonosoma trilineatum high levels of prolonged defoliation are likely to be Fabricius, appears to be specifi c to bellyache bush. having a signifi cant impact on reproduction, growth An application for its release will be submitted soon. and survival (van Klinken et al. 2002, van Klinken Several other insects have been imported but due to et al. in press). Impact, and possible implications for diffi culties with rearing the colonies failed or host integrated management, is currently being monitored range testing has stalled. The fungus, Phakopsora in the Pilbara. jatrophicola (Artt.) Cumm., was sent to CABI Bio- With NWP funding, an integrated management sciences, UK, to determine if growing it on bellyache strategy will be developed over the next few years bush was feasible. This was successful and funds are based on the large infestation in the Pilbara Region. required to proceed with further biological and host The outcomes may be applicable to mesquite manage- range assessments. A number of other agents await ment elsewhere and for other woody weeds. importation and testing and permits are or have been obtained (Heard and Chan 2002). Mexican poppy Studies in the native range of Mexi- can poppy commenced in the summer (dry season) of Parkinsonia Ecological studies in Australia on par- 1998–1999 in Mexico and continued over the follow- kinsonia began in 2000 in collaboration with QDNRM, ing two summers. The plant appears to have a relatively NT DBIRD, CSIRO Sustainable Ecosystems and the depauperate fauna. WA Department of Agriculture. The aim being to quan- Two weevil species have potential as biological tify reproduction, growth, seed banks, germination and control agents. One breeds and feeds on the fl owers, population dynamics over a range of landscapes to seeds and fruits, and the other breeds on the roots and assist selection of potential biological control agents the adults eat all plant parts. Preliminary host range and development of sustainable management strate- studies are limited in Mexico due to the very few gies. In addition, the impact of the widely established species of Papaveraceae growing there. A small fi eld seed feeding bruchid, Penthobruchus germaini (Pic), study indicated that adult feeding may be restricted which was released by QDNRM in 1995 (Julien and to Mexican poppy. There are no native Papaveraceae Griffi ths 1998), is being assessed. in Australia and this improves the chances of fi nding Surveys had previously been conducted in south- suitable biological control agents. ern USA and northern Mexico with a single short This research has been supported by NT DBIRD survey into Costa Rica in 1984 (Woods 1988). As a and CSIRO. result three insects were released and are established in Australia (Donnelly 1998, 2000). Two are not causing Alligator weed Successful biological control of al- useful damage and the impact of the third, P. germaini, ligator weed growing as fl oating mats in central coastal is being studied. Recent information suggests that the NSW was achieved in 1979 following the release of centre of origin of parkinsonia is likely to be southern the fl ea beetle Agasicles hygrophila Selman & Vogt Mexico to Costa Rica (C.E. Hughes unpublished re- (Julien 1979, 1995). However this aquatic insect was port 1989), including areas not previously surveyed. unable to control growth on banks, in swamps, and in With funding through the National Weed Program, terrestrial areas and is not suited to cooler climates surveys for new potential agents began February (Julien et al. 1995). 2002 in southern Mexico, Guatemala, Costa Rica Recent spread of the weed and the limited options and Nicaragua. for effective management have lead to a renewed effort in biological control. The original surveys, conducted Mesquite While studies on seed feeding bruchids in the 1960s by Vogt (1973), identifi ed three agents that were underway in the 1990s by QDNRM, we devel- have been used for biological control in USA. Two of oped a project focusing on agents that attacked other these were released and are established in Australia; A. parts of this weed. Between 1996 and 1998, four in- hygrophila and the moth Arcola malloi (Pastrana). An- sects were selected from known lists of natural enemies other, the fl ea beetle Disonycha argentinensis Jacoby, of mesquite and tested in quarantine. As a result two was later studied and released in Australia and New were released, the moth Evippe sp., a leaf tier, and the Zealand but did not establish. Other species were also sap sucking psyllid, Prosopidopsylla fl ava Burckhardt, collected by Vogt but were not considered further, and and two were rejected. many were not identifi ed. Vogt et al. (1979) estimated The psyllid is tenuously established at a few that 39% of the native range of the weed had yet to locations. However, the moth is well established be surveyed.

363 Thirteenth Australian Weeds Conference

In October 2002 surveys began in the north and the fi eld. In biological control we are good at predict- central sections of eastern Argentina, south-eastern ing which agents are safe for release, but we cannot Paraguay and southern Uruguay. A range of interesting predict which agents will provide successful control. insect and fungi natural enemies have been collected Therefore we need to consider all potential species and submitted for identifi cation but little or nothing with equivalent weighting. History suggests that at is known of their biology or host ranges. least one of those remaining species will contribute Morphological variation of alligator weed has to control of mimosa. been noted in the native range of the weed (Pedersen We are utilising the mimosa experience to assist in 1999) and insect diversity, particularly among chry- more effi cient management of other weeds. Through somelid leaf feeders, appears to differ on the various the CRC AWM the past and present selection of agents plant forms. This is consistent with plant biotype for a number of projects will be assessed and tested differences and variation in attack by A. hygrophila to determine how we might improve our ability to between two biotypes of the weed observed in USA pick winners. (Kay and Haller 1982). Survey work will continue on hyptis, bellyache In addition, viable seeds and seedlings have been bush, parkinsonia and alligator weed to ensure that found for the fi rst time, and only in southern popula- we know the fauna with potential as control agents. tions in Argentina (Sosa, Julien and Cordo unpublished Selected species will then be studied and hopefully information). Morphological and molecular taxonomy released. Ecological work on bellyache bush and par- is underway to determine variation within native popu- kinsonia will allow assessment of impact of control lations and compare these with Australian populations. agents, and assist the development of integrated strate- This may assist our interpretation of native range sur- gies. We anticipate that current ecological studies of vey data, help direct future surveys and alert Australian parkinsonia in Australia will contribute to the selection quarantine authorities to the presence of a fertile taxon of suitable agents once the range of potential natural of alligator weed that should not enter Australia. enemies is known. Ecological work is needed for hyptis and alligator weed. HOW SUCCESSFUL HAVE WE BEEN? Preliminary host range studies will be conducted CSIRO Entomology Tropical Weed Project with its in Mexico on several potential agents for Mexican collaborators have researched biological control for poppy. Detailed studies will have to wait until the rela- 13 weeds species of Central or South American origin tive importance of this weed increases in Australia or since the late 1960s when the group was developed. eastern Africa. There is potential here for international Agents have been released on eight species: no ap- coinvestment. preciable control was achieved for one, lantana; the Community and government interests are such that prognosis for control of mesquite in the Pilbara and for surveys for natural enemies of cabomba (Cabomba mimosa is very good but not yet achieved; good control caroliniana A.Gray), are likely to begin within the next of water hyacinth and alligator weed has been achieved year or so. This will be a challenging activity working in some situations or habitats, and sida, salvinia and with a weed that grows in tussock form, rooted over pistia have been successfully controlled. two metres below the surface of South American water Of the remaining fi ve species, agents have not been bodies. Compared to other habitats, the diversity of released against fl annel weed and Mexican poppy, due fauna is likely to be limited, but the degree of speciali- to lack of funds to undertake detailed studies. However, sation may be greater: interesting questions to deal we believe that there are host specifi c species avail- with during the pursuit of applied ecology. able. Suitably host specifi c agents have not yet been identifi ed for hyptis. The release of the fi rst insect ACKNOWLEDGMENTS for bellyache bush is expected this year. Surveys for I acknowledge Tim Heard, Quentin Paynter, Rieks van parkinsonia have just begun. Klinken and Ricardo Segura and support staff of the CSIRO Entomology Tropical Weeds Project for studies THE FUTURE that contributed to this paper. The investment in developing suitable controls for mi- mosa appears to be paying off. This is undoubtedly due REFERENCES to adequate levels of long-term support and excellent Donnelly, G. (1998). Levels of attack and destruction collaboration. It is important that this project be taken of Parkinsonia aculeata seed by bruchid biological to its logical conclusion, i.e. the known small suite of control agents in Queensland. Sixth Australasian remaining potential agents should be processed and Applied Entomological Research Conference, the suitable ones released and established widely in p. 310.

364 Thirteenth Australian Weeds Conference

Donnelly, G.P. (2000). Biology and host specifi city of Paynter, Q. and Flanagan, G.J. (2002). Integrated man- Rhinacloa callicrates Herring (Hemiptera: Miri- agement of Mimosa pigra. Proceedings of the 13th dae) and its introduction and establishment as a Australian Weeds Conference, Perth. biological control agent of Parkinsonia aculeata L. Pedersen, T.M. (1999). Amaranthaceae, In ‘Flora De (Caesalpiniaceae) in Australia. Australian Journal San Juan’, Vol. 1. pp. 123-124. of Entomology 39, 89-94. van Klinken, R.D., Fichera, G., McCormick, E., Heard, T.A. and Chan, R.R. (2002). Prospects for the Cobon, R., March, N. and McMahon, J. (2002). biological control of bellyache bush, Jatropha Challenges facing the successful management of gossypiifolia. Proceedings of the 13th Australian widely distributed weeds: biological control of Weeds Conference, Perth. mesquite (Prosopis species). Proceedings of the Julien, M.H. (1979). The current status of biological 13th Australian Weeds Conference, Perth. control of Alternanthera philoxeroides in Aus- van Klinken, R.D., Fichera, G. and Cordo, H. (in press). tralia. Proceedings of the 7th Asian-Pacifi c Weed Targeting biological control agents across diverse Science Society Conference, pp. 231-233. landscapes: the release, establishment and early Julien, M.H. (1995). Alternanthera philoxeroides success of two mesquite (Prosopis spp.) insects in (Mart.) Griseb. In ‘The Biology of Australian Australian rangelands. Biological Control. Weeds,’ eds R.H. Groves, R.C.H. Shepherd and Vogt, G.B. (1973). Exploration for natural enemies of R.G. Richardson, pp. 1-12. alligatorweed and related plants in South America. Julien, M.H. and Griffi ths, M.W. (1998). Biological Aquatic Plant Control Program Biological Control control of weeds. A world catalogue of agents and of Alligatorweed, Technical Report 3, B3-B66. their target weeds. Fourth edition, 223 p. (CABI Vogt, G.B., McGuire, J.U. and Cushman, A.D. (1979). International, Wallingford, UK). Probable evolution and morphological variation in Julien, M.H., Skarratt, B. and Maywald, G.F. (1995). South American Disonychine fl ea beetles (Cole- Potential geographical distribution of alliga- optera: Chrysomelidae) and their Amaranthaceous tor weed (Alternanthera philoxeroides) and its hosts. USDA Technical Bulletin 1593. biological control by the fl ea beetle Agasicles Woods, W. (1988). The potential for biological control hygrophila. Journal of Aquatic Plant Manage- of Parkinsonia aculeata L.: phytophagous insects ment 33, 55-60. collected from the USA, Mexico and Costa Rica Kay, S.H. and Haller, W.T. (1982). Evidence for the ex- and the effect of insect damage on the growth istence of distinct alligatorweed biotypes. Journal and survival of the plant. MSc. (Agric.) Thesis, of Aquatic Plant Management 20, 329-30. University of Western Australia, Perth.

365