Biocontrol News and Information
CABI Publishing


September 1997, Volume 18 No. 3

General News

Water Hyacinth in Africa: New Initiatives

The notorious aquatic floating weed water hyacinth, Eichhornia crassipes, variously referred to as the `water lily' or `the beautiful killer' has established a firm foothold on African inland water bodies over this century. A native of South America, it found its way across the globe and was first recorded on the continent in Egypt in the late 1880s. There are strong suspicions that the beautiful purple flower it produces when in full bloom has been a major reason for its spread across the globe as humans have moved it around and domesticated it to provide an added aesthetic to their habitats.

Water hyacinth has escaped from domestication into its natural environment, the inland water bodies, and in Africa these are interconnected and often shared by two or more countries. Outside its native range the weed is in an environment free of natural enemies that normally keep it at such low levels of ecological balance that it is not problematic. Within African water bodies, also characterized by high levels of eutrophication (as a result of high run off and pollution) and generally high temperatures, water hyacinth has proliferated, continued to spread and posed untold socio-economic and environmental problems that have warranted a need for controlling it. Several options based on physical and chemical means have been employed. Biological control is, however, the unanimously accepted long-term solution to this problem weed. Natural enemies such as the weevils Neochetina eichhorniae and N. bruchi, the moth Sameodes albiguttalis and the mite Orthogalumna terebrantis, also from the Neotropics, are currently being used extensively to combat the weed in Africa. New insect and pathogenic agents are also being sought in order to increase the ecological pressure on the weed. Efforts are also underway in Africa to make available a feasible manage-ment plan that combines the different control options to address the weed problem in both short and long terms.

Reactions by affected communities, countries and concerned organiza-tions to growing water hyacinth infestations have nearly always been after it has already got out of hand and become a crisis. Typical examples of this are the weed problems in Lakes Chivero near Harare in Zimbabwe and Victoria in East Africa. The International Development Research Centre (IDRC) of Canada, through its People, Land and Water (PLAW) Program, are currently consulting national programmes and other organizations in Africa and the Middle East to find out causes of the infestation-action time lag in the light of the availability of knowledge of known options to combat the weed. They are also seeking ways to stimulate, among affected people, prompt and effective action to control the weed and increase interaction of those working on the weed as a common problem.

IIBC, through their Kenya Station, are collaborating with the Fisheries Department in Malawi to get bio-logical control of water hyacinth in action as quickly as possible within the Shire River. Here the weed was first noticed in the late 1960s but its prominence drew attention in the early 1990s and the project commen-ced in mid-1995. A weevil rearing unit has already been set up and is yielding satisfactory numbers of agents. To date, over 10,000 weevils have been released in the river and more are yet to be released. The mite is already established and recently the moth and a mirid bug have also been released in order to knock the weed with a cocktail of biological control agents. Other issues being addressed by the project in Malawi are public awareness campaigns and com-munity participation, and two studies are being conducted to quantify the socio-economic impact of the weed on riparian communities and the impact of the weed on aquatic biodiversity and abundance. The studies are expected to offer an understanding of the ameliorating effects of water hyacinth biological control.

For further information contact: George Phiri, IIBC Kenya Station, P.O. Box 76520, Nairobi, Kenya

E-mail: G.Phiri@cgnet.com

Hungry Herbivores Feast on Purple Plague

The ecological integrity of North American wetlands is threatened by the encroachment of the beautiful but harmful purple loosestrife (Lythrum salicaria). This perennial plant was first introduced about 200 years ago from Europe in ballast water and as a contaminant in wool. Additional intentional introductions occurred because the plant was valued as a medicinal herb and for ornamental purposes. Purple loosestrife popula-tions began to explode in the 1940s, replacing valuable wetland plants with permanent monocultures that offer little food or nesting cover for wildlife such as ducks, geese, turtles, amphibians, etc.

With funding provided by the US Fish and Wildlife Service and many state natural resource agencies the European Station of IIBC in Delémont, Switzerland began identifying and testing of insect herbivores in 1986. By 1992 three highly specialized herbi-vores, a root-feeding weevil (Hylobius transversovittatus) and two leaf-feeding chrysomelids (Galerucella calmariensis and G. pusilla), were released in seven states and in Canada. In 1994 these were joined by another purple loosestrife specialist, the flower feeding weevil (Nanophyes marmoratus), which was released in three states. The introduction of species that simultaneously attack roots, leaves and flowers of purple loosestrife was thought to maximize the stress exerted on the plant (a hypothesis currently under investiga-tion).

The high demand for biological control agents prompted a mass rearing that began in 1993 at Cornell University with funding provided by state natural resource agencies and the US Fish and Wildlife Service. Initially work focused on raising beetles in greenhouses, but quality control determined that field rearing was more economical and produced beetles with a higher fitness. By 1996, over one million leaf beetles were released at about 500 field sites in 28 different states and it is anticipated that this number will be doubled in 1997. The mass production techniques developed at Cornell are now used to rear leaf beetles by universities, state natural resource agencies, the Bureau of Reclamation, in National Wildlife Refuges and by the US Department of Agriculture, Animal and Plant Health Inspection Service (USDA, APHIS).

The numbers and life history of the root feeder did not allow a large-scale rearing programme. Larvae need one to two years to complete development and only some 100 adults were available to initiate a mass production. A technique was developed to manually inoculate eggs into purple loosestrife stems, and over 100,000 eggs have been distributed and field released in 28 states using this technique. No attempt was made to mass produce the flower feeders.

All four control agents are now well established in North America and their populations continue to increase. Dramatic declines in purple loose-strife performance induced by feeding of the two Galerucella species are reported from release sites across the entire continent. Within a few years of control agent release, flowering is reduced or suppressed and plants become stunted; once insect popula-tions build up entire stands are completely defoliated. Spectacular reductions in purple loosestrife (for example, biomass reduced by more than 95% over an area of 5000 square meters) and a return of native plant communities have been reported from some early release sites. At this point it appears that biological control of purple loosestrife is well on its way. It is anticipated that within 10-15 years purple loosestrife will be reduced to less than 10% of its original level over 90% of the current range.

For more information contact: Bernd Blossey, New York State College of Agriculture and Life Sciences, Department of Natural Resources, Cornell University, Ferrow Hall, Ithaca, NY 14853-3001, USA

E-mail: bb22@cornell.edu

Leafy Spurge Biocontrol Spreads...

The European perennial leafy spurge, Euphorbia esula, was introduced to North America during the 19th century, probably as a contaminant of cereal crop seed. In the USA it now infests millions of hectares of rangeland and riparian habitat. It is particularly serious in the northern Great Plains region where it displaces cattle forage and is toxic to cattle and horses who normally avoid it.

The search for suitable biological control agents in the native European distribution started in the late 1960s by the then CIBC (Commonwealth Institute of Biological Control) European Station in Delémont, Switzerland and the USDA-ARS (US Department of Agriculture - Agricult-ural Research Service) Biological Weed Control Laboratory in Rome, Italy. During the past 30 years, some 22 insect species have been investigated, and of the 17 species released in North America 11 established in Canada and 8 in the USA*.

Investigations at the IIBC European Station were sponsored by Canada Agriculture, the Provinces of Alberta, Manitoba and Saskatchewan, the Montana Noxious Weed Trust Fund, the Wyoming Biocontrol of Weeds Steering Committee, and the Ministries of Agriculture of North and South Dakota.

Successful biocontrol of leafy spurge is now being reported across North America**:

From Wyoming...

During 1996 some 3.75 million individuals of five control agents, the flea beetles Aphthona lacertosa, A. czwalinae, and A. nigriscutis, the cerambycid Oberea erythrocephala and the gall midge Spurgia esulae, were collected and redistributed to 1200 field sites throughout the state. There is now no leafy spurge site in Wyoming without Aphthona.

And North Dakota...

By 1996, North Dakota had the largest populations of A. nigriscutis, A. lacertosa, A. cyparissiae and A. flava. Interested parties from other northwestern US states and adjacent Canadian provinces are profiting from this situation and collect thousands of beetles during field days for redistribution.

All new releases resulted in establish-ment, and a reduction of 40-70% was recorded for the number of leafy spurge stems per m2 after two years.

To Alberta...

The release of 500 A. nigriscutis in a south-facing railroad track at Beverly Bridge in Edmonton in 1989 resulted in the reduction of above-ground biomass from 170 g/m2 in 1989 to 2 g/m2 in 1993, while the grass biomass increased to 43 g/m2.

And Manitoba

Approximately 20,800 ha are infested by leafy spurge in Manitoba. To date, A. nigriscutis and A. cyparissiae have been the most successful insects for managing leafy spurge in this province. More recently, A. lacertosa and A. czwalinae have been successfully established for controlling leafy spurge in wet and shaded sites.

The IIBC European Station is presently screening three additional Aphthona species for release in moist and shaded habitats where leafy spurge biocontrol is still not adequate.

*See: A. Gassmann and D. Schroeder (1995) Biological Control 5, 466-477.

**Source: `Leafy Spurge News', North Dakota State University.

For further information contact: Dieter Schroeder and André Gass-mann, IIBC European Station, 1 Chemin des Grillons, CH-2800 Delémont, Switzerland

E-mail: D.Schroeder@cabi.org and A.Gassmann@cabi.org

Lantana Control in the South Pacific

Lantana (Lantana camara) has long been recognized as a serious problem in the South Pacific - it was declared a noxious weed in Fiji in the 1920s. Its range currently extends from Papua New Guinea and Kiribati, south to New Caledonia and east to French Polynesia. The weed has invaded agricultural land; it is especially problematic in coconut plantations, where access can become almost impossible, and also in cattle pasture.

A South Pacific Commission (SPC) - German Biological Control Project added biocontrol of lantana in the Cook Islands, Fiji, Niue and the Solomon Islands to its initial list of target weeds in November 1991. Since then the project has been responsible for the introduction of a number of biocontrol agents, including Teleonemia scrupulosa and Octotoma scabripennis to the Cook Islands, T. scrupulosa, O. scabripennis and Uroplata girardi to the Solomon Islands, and O. scabripennis to Fiji (other agents including T. scrupulosa, U. girardi, Hypena strigata, Ophiomyia lantanae, Salbia haemorrhoidalis and Strymon bazochii were established in Fiji before the project began). A further potential agent, Calycomyza lantanae, is currently being held in quarantine in Fiji for possible release in the region.

In Niue, a survey of natural enemies of lantana in the early 1990s had found Ophiomyia, Hypena and Salbia species established but not providing any significant impact while lantana was already infesting some 20 km2 and spreading. Under the SPC - German project, U. girardi was introduced in 1991, followed by T. scrupulosa and O. scabripennis in 1994. All three are now well established (and Niue is the only island where O. scabripennis has established). The most widespread orange variety of lantana is being controlled effectively by the combination of the introduced agents, plus the local Hypena sp., and these cause strong defoliation of the weed. Large patches have been totally defoliated leaving only the dry skeleton of the plant. A less widespread pink lantana variety is not attacked by T. scrupulosa but U. girardi is having a strong impact, and the introduction of additional agents to complement this is being considered. Currently, the spread of lantana has been halted and it is restricted to the southwest of the island. There, previously dense thickets and bushes are dried up and the weed is under good control.

For further information contact: Tony van Harten and Katarina Atalifo, SPC - German Biological Control Project, PMB, Suva, Fiji

Fax: +679 386326/370021

Rust Established on Rubber Vine in Australia

Rubber vine, Cryptostegia grandiflora, is native to Madagascar and was introduced to Australia as an orna-mental in the late 1800s where it has since become a serious weed along many rivers and adjacent rangelands in tropical Queensland. It is threatening the biodiversity of the unique riparian flora and has become a serious constraint to cattle ranching. It has been described as the single most serious threat to the National Parks of Northern Australia. A project begun 20 years ago by the Queensland Department of Lands funded by the Meat Research Corporation is starting to pay dividends.

Rubber vine rust, Maravalia cryptostegiae, collected in Madagascar and screened at IIBC (UK) was field-released in northern and central Queensland in 1994 and is now established throughout the Gulf areas, around Bowen, Rockhampton and as far south as the Calliope Shire, and to a lesser extent in the Burdekin region where conditions have been drier. It is found on all rubber vine in Gulf and Peninsula areas north of Mt Surprise, a total area of some 140,000 km2. Observations show that when weather conditions support heavy rust infection over the summer in these areas, the resulting severe repeated defoliation appears to reduce flowering and leads to an increase in grass growth near rubber vine plants.

Another biocontrol agent from Madagascar, the caterpillar Euclasta whalleyi, which had been introduced much earlier has also now become widespread and is complementing the damage caused to the rubber vine by the rust.

Because of the vast area over which it grows, biological control would seem to be the only economic method of controlling rubber vine in remote areas.

For further information contact: Allan Tomley, Alan Fletcher Research Station, 27 Magazine Street, Sherwood, Qld. 4075, Australia

E-mail: TomleyAJ@exchange.lands.qld.gov.au

Italian Beetles for a Botanical Porcupine

A flea beetle from Italy, Psylliodes chalcomera, is the latest biocontrol agent to be released in the USA against musk thistle, Carduus thoermeri (a member of the C. nutans complex). The adults feed on young rosette leaves, while larvae attack the leaf and flower buds, and the results of larval feeding, in particular, are reported to be devastating.

Musk thistle, a plant of European origin, was first recorded in the USA in the 1850s and since then has become a serious weed of rangeland, pasture, recreational areas and other natural grasslands. It is now found in 35 states from Maryland to California and is especially common in the eastern and midwestern areas. It is a strong-growing dense biennial which chokes out other plants, and each plant can produce up to 2000 seeds annually. New plants emerge in autumn and form a rosette; this sends up a branched, leafy stalk up to 2 m tall in spring which later bears large purple flowers. The plant is covered in sharp spines - on branches, leaves and flowerheads - turning the plant, according to Jim DeQuattro, into a botanical porcupine.

Natural enemy introductions are not new for this weed and a number of species have been released to try and control it in various parts of the USA. In 1978 Paul Boldt and Gaetano Campobasso published the results of a three-year survey of southern Europe for potential biological control agents of the musk thistle complex. The surveys were coordinated from the Rome Substation of the US Department of Agriculture - Agricul-tural Research Service (USDA-ARS) European Biological Control Lab-oratory. They had surveyed the plant in its native range with the aim of identifying a diverse complex of insects to attack different parts of the plant at different times of the year, and to cope with the climatic variations of its range in the USA. Of all the phytophagous species found, about 50% were polyphagous, 25% fed on members of the Compositae, 21% fed on plants in the tribe Cardueae and only 10% (eight species) appeared sufficiently host specific to begin testing as potential biological control agents.

Two of the European species have been introduced widely in the USA and Canada. Larvae of the flowerhead weevil Rhinocyllus conicus feed on developing seeds and pupate in the flowers; adults emerge in midsummer and overwinter in the soil or plant debris. Trichosirocalus horridus larvae feed on the rosette and pupate in the soil; adults feed after emergence and overwinter in the rosette. Two different strains of T. horridus which emerge in autumn and spring have been introduced from southern
and central Europe, respectively. Establishment of both agents occurred first in Montana and Virginia, and they are now found in several states reducing musk thistle populations. Trichosirocalus horridus has reduced musk thistle populations in Virginia, Maryland, Missouri and Tennessee; Paul Boldt says that although slow to expand it is proving to be a useful agent.

Approval of the USDA environmental assessment in March 1997 cleared the way for introducing P. chalcomera, which was supplied by Gaetano Campobasso (USDA-ARS, Rome) to Paul Boldt at the ARS quarantine facility in Temple, Texas. First releases were made in Texas this spring and further releases of the flea beetle are planned for Kansas and Maryland, and for some 20 other states in 1998. Also released with P. chalcomera in Texas was the syrphid Cheilosia corydon from southern Italy which feeds on the rosettes and large flower-bearing stems. The syrphid releases are being coordinated by James Nechols, Kansas State University; it was first released in 1994 in several states including Montana and Mary-land, and in 1995 in Texas where the climate more closely resembles that of southern Italy; larvae were recovered in Texas in spring 1996, and further recoveries this year could indicate its establishment.

Attempts are being made in Maryland and Montana to establish another species supplied by Gaetano Campobasso. Larvae of the fly Urophora solstitialis from Italy feed and develop in musk thistle flower heads. Releases are being made by Philip Tipping of Maryland Depart-ment of Agriculture, Annapolis and Norman Rees, USDA-ARS, Bozeman, Montana.

Further work is being conducted on pathogens of musk thistle at the USDA-ARS Foreign Disease-Weed Science Research Laboratory in Maryland, and promising results have been obtained with a rust from Turkey, Puccinia carduorum.

Main source: Jim DeQuattro, Two Italian imports tackle musk thistle. USDA-ARS Agricultural Research, March 1997.

For further information contact: Paul Boldt, Grassland, Soil and Water Laboratory, ARS, USDA, Temple, TX 76502, USA

E-mail: boldt@brcsun0.tamu.edu
or Gaetano Campobasso, European Biological Control Laboratory, USDA-ARS Rome Substation, Via Colle Trugli N. 9, 00132 Rome, Italy
Fax: +39 6 207 90 86

E-mail: EBCL.RomeSubstation@agora.stm.it

Melaleuca Swamping Florida

Melaleuca quinquenervia, the paper-bark tree, is an evergreen tree with a slender crown which grows up to 29 m tall. It has white many-layered papery bark and white flowers in brush-like spikes. It is native to Australia and Papua New Guinea and was introduced to Florida at the beginning of the 20th century to provide a useful crop that would grow in an area subject to drought, flooding and periodic fires where little else was productive. Although hopes of using Melaleuca for timber were not fulfilled, it did prove economical to produce as an ornamental.

But it was an unfortunate choice for an introduction. It grows phenomen-ally fast in Florida (18-month-old trees can be 6-7 m tall) and it flowers up to five times a year. Its wind- and water-dispersed seeds are produced from trees as young as two years old, and are retained on the tree to be released in times of stress - fire, frost and herbicide all cause seed capsules to open. Mature tree can hold up to 20 million seeds; on the tree they can remain viable for up to 10 years, but viability is lost quickly once the seeds are in the soil. Melaleuca grows densely, forming inpenetrable thickets, and also spreads by adventitious roots which cause soil accretion to occur owing to thick mats of roots at the water surface, and this leads to an increase in the elevation of the infested area. Small increases in elevation of a few centimetres make huge differences in the composition of Everglades plant communities, so Melaleuca is converting wetland to upland in this manner. It is adapted to subtropical climates with a prefer-ence for seasonally wet sites and flourishes in standing water. In the last 30-40 years it has spread rapidly and now infests close to half a million acres (some 200,000 ha) in south Florida, causing extensive environ-mental and economic damage part-icularly in the Everglades where it threatens the native habitat. It was declared a federal noxious weed in 1992 and a Florida prohibited aquatic plant at about the same time.

A US Department of Agriculture - Agricultural Research Service (USDA-ARS) biocontrol project based at their Australian Biological Control Lab-oratory in Queensland found an extensive complex of over 400 insect natural enemy species which attacked M. quinquenervia and related Melaleuca species in their native range, and some of these were assessed as potential biocontrol agents. In particular, they looked at seed and seedling feeders which might be able to prevent or reduce further spread of the tree. Initially they identified a foliage-feeding weevil, Oxyops vitiosa, which attacks the growing tips of seedlings, saplings and large trees, and a defoliating sawfly, Lophyrotoma zonalis, which attacks mature foliage only. These two species were exported to quarantine in Florida. The O. vitiosa larvae, especially, are voracious feeders and have a preference for young foliage: each fourth-instar larva can destroy most leaves on several shoots of M. quinquenervia, and high populations inflict severe damage which persists for more than a year even on mature trees, so that the tree has less foliage and fewer flowers.

Following five years of quarantine and screening studies by USDA-ARS, a USDA Animal and Plant Health Inspection Service (APHIS) environ-mental assessment cleared O. vitiosa for release in Florida and permits were issued by APHIS in March 1997. Initial releases were made in the same month followed by more widespread releases in April. At the end of June, larvae and new adults of O. vitiosa were found at the initial release site, and by late July about 1000 weevils had been released at some 10 sites and evidence of reproduction has been seen at many of them.

Further potential agents are being screened in Australia and Florida, with interest in a psyllid (Boreioglycaspis melaleucae), a leaf-blotching mirid bug (Eucerocoris suspectus), a gall fly (Fergusonina sp.) and a moth (Poliopaschia lithochlora). The psyllid and the mirid have been imported into Florida quarantine.

For further information contact: Dr Gary R. Buckingham, USDA/ARS, Biocontrol of Weeds, c/o Florida Biocontrol Laboratory, P.O. Box 147100, Gainesville, FL 32614 7100, USA

Fax: +352 955 2301

E-mail: grbuck@nervm.nerdc.ufl.edu

Combating the Increasing Menace of Alien Weeds in India

Some of the World's worst weeds have been present in India for over a century. Familiar names from `Rogues Gallery' include lantana (Lantana camara var. aculeata) and Siam weed (Chromolaena odorata). Lantana was introduced in 1809 into the Calcutta Botanical Garden because of its beautiful aromatic flowers. However, the weed soon became naturalized and the seriousness of lantana `outbreaks' was well recognized early this century when the first searches for insect biocontrol agents by Government entomologists were begun. Siam weed probably entered via the same route in the late 1800s. Later but equally devastating arrivals from the Gallery include mikania (Mikania micrantha), introduced into Asia as a cover crop during the Second World War and parthenium (Parthenium hysterophorus), accidentally introduced in the 1950s. All of these invaders from the Neotropics are rapid colonizers, with high reproduc-tive capacities and dispersal rates. All favour disturbed habitats without dense shade and between them they significantly reduce yields from subsistence and cash crops, prevent forest regeneration and interfere with wildlife management programmes. In total, these alien invaders pose a major threat to the conservation of biodiversity. In addition, Siam weed and parthenium are toxic to livestock and both cause allergenic responses in susceptible humans.

The geography of invasion into India by particular species has, however, largely been determined by climate. Lantana is well adapted to tropical humid and semiarid regions; the weed is now distributed from the Himalayan foothills to Cape Comorin and within this range increasing amounts of forest are being colonized. Parthenium has spread particularly fast and has a similar distribution to lantana. Siam weed and mikania are more adapted to tropical and sub-tropical humid conditions. The former is well distributed in wetter parts of the subcontinent, and on the windward side of the Western Ghats this weed has now largely replaced lantana. Mikania which also invaded the Western Ghats in the southern part of the range about 10 years ago now appears to be moving northwards.

Various control measures have been researched and/or recommended for the control of these alien weeds including weeding, herbicides and classical biological control with insect agents. Unfortunately, none of these has resulted in any substantial impact on either the distribution or abund-ance of the weeds. This is largely because of the regional nature of the problems; weeding and herbicides are difficult to implement on a large scale and broad applications of herbicides are also undesirable because of possible effects on local communities and native flora and fauna. Most research efforts to date on classical biological control using insect agents have been directed at lantana although some insect agent releases have been made against parthenium and Siam weed. A number of agents have been established in India but, at best, impact has been only local in nature. Also, little effort has been put towards identifying complementary herbivores that hit critical stages of the life cycles of the weeds. Likewise little effort has been made to examine the possibilities of exploiting indigenous or exotic host specific pathogens even though recent studies in the Neotropics have indicated that for the latter potential agents exist.

This situation is now rapidly chang-ing and for some of India's notorious weeds their `years' may be numbered. Two projects sponsored by Britain's Department for International Development (DFID, formerly ODA) have recently started to examine the possibilities of using indigenous and exotic pathogens for the control of parthenium and mikania in India. These projects, which form part of broader integrated pest management (IPM) projects for the weeds, are a collaborative effort between a number of national organizations and IIBC. For the parthenium project national collaborators include Tamil Nadu Agricultural University, Project Directorate of Biological Control, National Centre for Weed Science and Kurukshetra University, and for the mikania project the collaborator is the Kerala Forest Research Institute. Furthermore, the Indian Council of Forestry Research and Education and IIBC are currently developing an IPM initiative which will also include an assessment of exotic pathogens and insects.

For further information contact: Sean Murphy and Harry Evans, IIBC UK Station, Silwood Park, Buckhurst Road, Ascot, SL5 7TA, UK

E-mail: s.murphy@cabi.org and h.evans@cabi.org

Cooperation in Europe for Biological Control of Russian Knapweed in North America

During a meeting in Worland, Wyom-ing on 29 January 1997, organized by the Wyoming Biological Control Steering Committee, chaired by Lars Baker, and attended by representatives of USDA-ARS, USDA-APHIS, USDI-BLM (respectively, the US Department of Agriculture, Agricultural Research Service and Animal and Plant Health Inspection Service, and the US Department of the Interior, Bureau of Land Management), Montana Department of Agriculture, Montana State University, the University of Wyoming, numerous Wyoming Weed & Pest Supervisors, and Dieter Schroeder representing IIBC, it was decided to initiate a new project for the biological control of Russian knapweed (Acroptilon repens) in the northwestern United States. A con-sortium was formed by five Wyoming County Weed & Pest Control Districts, the USDI Bureau of Indian Affairs and USDA-APHIS to fund research by the European Station of IIBC for the period 1997-1999.

At the Wyoming meeting, Dr Rick Bennett, Director of International Operations for USDA-ARS, pointed out that research for potential biological control agents of Russian knapweed had been started by the ARS European Biological Control Laboratory (EBCL) at Montpellier, France in 1996. He therefore proposed that EBCL and IIBC should join forces in a truly cooperative effort.

Following detailed discussions in Braunschweig, Germany between EBCL and IIBC, a Letter of Under-standing on Cooperative Work on Russian Knapweed by EBCL and IIBC has been drafted. Particular attention has been paid to avoid duplication of work, to coordinate surveys for potential control agents and their study and screening, to exchange information on progress made at regular intervals, and to evaluate results jointly at the end of each year and develop work plans for the following year. The results of the research will be published jointly where appropriate.

During 1997, EBCL scientists will concentrate their field surveys in Georgia, Central Asia and China, whilst IIBC will survey two regions in Turkey. Of the potential control agents already known, EBCL scientists, supported by Dr Jeff Littlefield of Montana State University, will study three species in genus Urophora, two Aceria mites and two as yet unidentified species, whilst IIBC will concentrate on Aulacidea acroptilonica, Napomyza lateralis, an anthomyiid stem miner, and any new potential agent species found in Turkey.

There is a paucity of information of fungal pathogens on Russian knap-weed, probably because no organized collections have been made on this plant within its native range and, of the material that may have been collected, none has been deposited in easily accessible mycological herbaria. However, Turkey would appear to be a promising area for surveys since the rust, Puccinia calcitrapae, has already been recorded on this host. Signifi-cantly, most records have been of opportunistic necrotrophic pathogens (e.g. Phomopsis) in North America, reflecting the abundance of collectors in its weedy range rather than the richness of the mycoflora.

Apart from reinforcing cooperation between ARS-EBCL and IIBC, the aim of this cooperative project is to provide suitable and effective bio-logical control agents for Russian knapweed within the shortest pos-sible period of time to address one of the noxious invasive weeds in the northwestern United States.

For further information contact: Dr Lloyd Knutson, EBCL

E-mail: ebcl@cirad.fr

or Dr Urs Schaffner, IIBC European Station, 1 Chemin des Grillons,
CH-2800 Delémont, Switzerland

E-mail: u.schaffner@CABI.org

Hibiscus Mealybug* in the Caribbean

Since its arrival in the Caribbean in Grenada in 1994, the hibiscus mealy-bug (Maconellicoccus hirsutus; HMB) has been spreading at an alarming rate. Its current reported distribution in the Caribbean includes Trinidad & Tobago, Grenada, St Vincent, St Lucia, St Kitts-Nevis, St Maartin, Virgin Gorda in the British Virgin Islands, St Eustatius, St Thomas and St John in the US Virgin Islands and Puerto Rico. It was first reported from mainland South America, in Guyana, this April and is threatening Central and North America. It has been intercepted several times this year at airports in the USA, and in some cases on produce imported from other countries in the region where HMB has yet to be found in the field.

As a newly introduced outbreak pest, the mealybug attacks an enormous variety of horticultural, agricultural and tree crops and ornamentals and has inflicted serious damage. Classi-cal biological control offers the best prospect for its sustainable manage-ment, and regional governments are aggressively tackling this problem with assistance from regional and international agencies such as CARDI (the Caribbean Agricultural Research and Development Institute), CSC (the Commonwealth Science Council), FAO (the Food and Agriculture Organization of the United Nations), IIBC (the International Institute of Biological Control), USDA (the US Department of Agriculture) and the Inter-American Institute for Co-operation in Agriculture (IICA).

A Chinese strain of the parasitic wasp Anagyrus kamali was obtained from Guangdong Entomological Institute, People's Republic of China, quaran-tined by IIBC in the UK and, since 1995, distributed for release in Grenada, the island of Trinidad and St Lucia, and to a USDA-supported programme in St Kitts. There is already evidence that in countries where the natural enemy has been released significant control is being achieved. Reports from Grenada and Trinidad suggest visible effects from the mealybug are less than a few months ago and biocontrol practi-tioners are optimistic, while on St Kitts an 80-90% reduction in mealybug population density has been reported at release sites.

Under a separate intiative, CARDI and the Trinidad & Tobago Ministry of Agriculture, Land and Marine Resources imported the coccinellids Cryptolaemus montrouzieri and Scymnus coccivora from India. The former was released in Trinidad in February 1996 and subsequently in Grenada and St Kitts. The latter has been released in Trinidad and St Kitts. Several national national programmes have also introduced C. montrouzieri from a commercial insectary in California. Meanwhile USDA have supplied Gyranusoidea indica, a mealybug parasite originating from Egypt, to St Kitts and this was recently released in the field.

A Regional Technical Cooperation Programme (TCP) sponsored by FAO was approved in April and will be implemented by CARDI and IIBC. This project aims to support regional activities towards long-term, sus-tainable management of HMB in the Caribbean and Latin America. Activit-ies will include the preparation of updated dossiers on selected natural enemies, including A. kamali, a second Anagyrus species (A. dactylopii), C. montrouzieri and S. coccivora in observance of the FAO Code of Conduct for the Import and Release of Exotic Biological Control Agents. These dossiers will assist countries with making informed decisions about natural enemy introductions.

The impact of natural enemies will be assessed, initially in Grenada but eventually extending to HMB-affect-ed countries in the wider Caribbean, and used to analyse the spread of the pest and its natural enemies and evaluate the efficacy of the biological control agents in sustainable suppres-sion of the pest. Technical support and natural enemies will also be provided to national programmes. Training will be provided through a formal training course organized by CARDI and IIBC as well as consultancies and work-shops.

There is no doubt that HMB is in the region to stay and will continue to spread to unaffected countries. However, experiences of affected countries underscore the need for vigilance and early implementation of biological control programmes.

*We have previously referred to M. hirsutus as pink mealybug. However, we will in future use the common name hibiscus mealybug as recom-mended in: Williams, D. J. (1996) A brief account of the hibiscus mealybug Maconellicoccus hirsutus (Hemiptera: Pseudococcidae), a pest of agriculture and horticulture with descriptions of two related species from southern Asia. Bulletin of Entomological Research 86, 617-628.

For further information contact: Moses Kairo, IIBC Caribbean Regional Office, Gordon Street, Curepe, Trinidad & Tobago

E-mail: CABI-IIBC-CLAS@cabi.org

TWNSO Prize

Since 1990, the Third World Network of Scientific Organizations (TWNSO), based in Trieste, Italy, has awarded prizes each year in agriculture and technology to individuals or institu-tions whose scientific and technical innovations have provided significant and sustainable solutions to economic and social problems in the Third World. One of the recipients of the 1996 prize for agriculture, to be presented in Rio de Janeiro this September, is a leading Brazilian biological control specialist, Dr Flávo Moscardi. Dr Moscardi has been awarded the prize for his outstanding contributions to plant protection and environmental conservation in agri-cultural systems, including the development of a programme for large-scale use of a biological insecticide based on a nuclear polyhedrosis virus against the soyabean caterpillar, Anticarsia gemmatalis, in South America.

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