News 57N

General News

USA Welcomes Settlers Earlier this year it was reported that popu- Saving Dough lations of the weevils are now well- Two classical biological control pro- established, increasing, and beginning to Russian wheat aphid (Diuraphis noxia) grammes in the USA have reported disperse to other melaleuca infestations. (RWA) arrived in the USA in 1986, and progress with establishment of introduced The promising results show that the weevils since then has cost more than US$1 billion agents this year: one is for an invasive tree are highly effective at defoliating existing in insecticide costs and related losses. Its threatening an important wetland habitat, stands of melaleuca saplings, and it seems North American range now extends the other against an insect causing signifi- likely that they will be able to prevent fur- through 16 US states and two Canadian cant economic damage in key grain crops. ther spread of the invasive tree. Melaleuca provinces. It spends the winter primarily on trees shed 25-33% of their leaves each year, wheat and barley, while several native and  but O. vitiosa has a preference for new introduced grass species harbour popula- leaves, and attack these as they are pro- tions during the summer. The most important non-cultivated grass hosts of D. Florida Stripper duced. The weevils in Florida are already consuming enough new foliage that some noxia in North America are the wheat- The broad-leaved paperbark tree, Mela- trees are showing evidence of die-back. In grasses (genus Agropyron; particularly crested wheatgrass, A. cristatum) and wild- leuca quinquenervia, was introduced to time, trees may become completely defoli- Florida at the beginning of the last century. ated. Ultimately, the weevils will ryes (genus Elymus; particularly Canada wildrye, E. canadensis). Hopes of using the tree for timber were not contribute to stopping the problem at its fulfilled, although it did prove economical source, as stressed trees no longer seem to The US government is developing an to grow for ornamental production. Unfor- be producing flowers or seeds. This will arsenal of weapons against the aphid: con- tunately it proved an even bigger success as facilitate control by conventional means, as ventional breeding has produced aphid- an invasive [See: BNI 18(3), 67N ‘Mela- it overcomes the problem that has compli- resistant varieties, which are now available leuca Swamping Florida’ September cated herbicidal or mechanical control to producers; microbial agents are being 1997], and now infests some 200,000 ha of measures so far: the millions of seeds that tested [see BNI 21(1),8N-9N,‘Fungalsolu- the Everglades and is threatening native trees can shed when they die. tion for crop pests?’ March 2000]; and habitat. It thrived in Florida – growing fast, insect parasitoids have also been intro- flowering up to five times a year from 2 Additional agents from Australia are in the duced from the area of the origin of the years old, and producing copious amounts pipeline which target the mature foliage aphid. of seed. A single tree can hold over 60 mil- (Lophyrotoma zonalis, melaleuca sawfly), In 1988, USDA-ARS (US Department of lion seeds in the canopy, releasing them in saplings (Boreioglycaspis melaleucae, Agriculture – Agricultural Research times of stress (fire, frost, herbicide or melaleuca psyllid), and bud growth (Fergu- Service) began work with a consortium of death). sonina sp., melaleuca bud gall fly). Host range studies have been completed with B. federal and state scientists to release 11 spe- The trees were planted as a means of melaleucae, and a proposal for field release cies of exotic RWA parasitoids in the wheat ‘reclaiming’ the Everglades. They grow has been submitted to federal authorities. and barley growing areas of the western densely, forming impenetrable thickets, Psyllids feed on the phloem and heavy USA. They released a staggering 11.8 mil- and spread partly by adventitious roots. The nymphal feeding kills saplings. A proposal lion parasitic wasps, representing more thick mats of roots at the water surface for release of L. zonalis is still pending. than 80 geographic strains collected from cause soil accretion, and this leads to an Concern about possible vertebrate toxins 25 different Eurasian countries where the increase in the elevation of the infested might prevent eventual release of this spe- aphid originated. area. A few centimetres in elevation can cies. Australian host range studies have Key to the success of the project was the cause big differences in the composition of demonstrated the specificity of Fergu- collection of these exotic enemies by staff plant communities here, and the spread of sonina sp. This fly will be tested soon in the of the ARS European Biological Control melaleuca is threatening to transform the Florida quarantine facility with the eight Laboratory in Montpellier, France. Over 60 Everglades from a wet prairie into a closed- native species of Myrtaceae. Both leaf bud exploration trips (throughout the endemic canopy swamp. and flower bud galls are produced by the fly range of D. noxia) were made between and its symbiotic nematode, Fergusobia sp. 1988 and 1994. Seventeen different coun- A USDA-ARS (US Department of Agri- This will further help stem flower produc- tries were visited by more than 40 federal culture – Agricultural Research Service) tion and enhance traditional control and state scientists and technicians, and that project based at its Australian Biological measures. resulted in the collection (mostly from D. Control Laboratory identified some 400 noxia-infested wheat and barley fields) of species attacking this and other related Contact: Ted Center, at least 29 species of natural enemies for Melaleuca species in its native range in Invasive Plant Research Laboratory, release in North America to combat the Australia. It identified, amongst others, a USDA, Agricultural Research Service, pest. leaf-feeding weevil, Oxyops vitiosa,asa 3205 College Ave., promising potential biocontrol agent. The Fort Lauderdale, FL 33314, USA From 1991 to 1993, ARS scientists at the weevils were first released in Florida in Email: [email protected] Plant Sciences and Water Conservation March 1997, and between then and June Fax: +1 954 476 9169 Research Laboratory in Stillwater, Okla- 1998, some 1500 adults and 6700 larvae homa released seven parasitoid species in were released at 13 sites in six counties.  wheatfields in eastern Colorado, with the

Are we on your mailing list? BiocontrolNews and Information is always pleased to receive news of research, conferences, new products or patents, changes in personnel, collaborative agreements or any other information of interest to other readers. If your organization sends out press releases or newsletters, please let us have a copy. In addition, the editors welcome proposals for review topics. 58N BiocontrolNews and Information 2000 Vol. 21 No. 3 aim of establishing natural enemies in the The weevils and the mite were reared in a an increase was observed, and no additional grain-growing areas there. Seven years glasshouse under quarantine conditions. releases were necessary. later, John Burd (ARS) reports that four of Detailed host-specificity tests, involving 76 the species have become established species of plants belonging to 42 families Studies in Bangalore indicated that N. eich- throughout a six-state area: Colorado, for the weevils and 88 species of plants horniae and N. bruchi could be successful Kansas, Montana, Nebraska, Oklahoma belonging to 42 families for the mite, con- even in tanks that dry during the summer. and Wyoming. Three of the species were firmed their safety to cultivated plants in In the laboratory they survived without also found parasitizing related greenbugs India. Limited field trials were then con- food for as long as 48 and 28 days, respec- (Schizaphis graminum) on sorghum, and ducted with permits issued by the Plant tively, in 95% humidity, and much longer two species successfully parasitized RWA Protection Adviser to the Government of inthepresenceoffreewater.Theycan on summer wild grass hosts. India (PPA). Based on the results obtained probably survive periods of drought by during these studies the PPA gave permis- remaining below plant debris or within Contact: John D. Burd, USDA, sion for open field releases throughout the crevices in the soil and water may be avail- ARS, PSWCRL, 1301 N. Western Road, country. able to them in the form of dew. Stillwater, OK 74075, USA Email: [email protected] Neochetina eichhorniae and N. bruchi More than 150,000 weevils were released at Fax: +1 405 624 4142 established readily under field conditions in different locations in 15 states elsewhere in  India after large-scale releases were initi- India. Spectacular biological control of ated in 1983. Field studies indicated that water hyacinth was achieved in the 286 km² release of a breeding population of about Loktak Lake in Manipur, 75% of which was Biological Control of 1000-5000 adults, depending on the area of covered by the weed. Control was achieved Water Hyacinth: the Indian weed coverage, invariably resulted in within 3 years of release of some 18,500 Experience establishment, irrespective of whether the adult weevils during 1987-88. Besides the initial releases were made at one spot or lake’s importance to the local community Water hyacinth (Eichhornia crassipes), over a wide area. During the first year the for fishing, a hydroelectric power project set which entered the country as an orna- insects were observed to multiply and up at Loktak Lake in 1983 has an installed mental, is the most serious aquatic weed in spread throughout the weed mat on which capacity to generate 105 MW of power and India, creating a large number of problems they had been released. Thereafter, an irrigate 23,000 ha of land. Control of water in the management and utilization of fresh- increase was seen in the number of adults hyacinth by release of weevils has brought water resources. Attempts made from 1969 per plant, which in turn caused a reduction about a permanent solution to the weed by the Indian Station of the Commonwealth in the number of leaves and petiole lengths. problem, which in turn has benefited the Institute of Biological Control (CIBC) to Once the population of adults exceeded five economy of the entire region. import exotic natural enemies were unsuc- individuals per plant, the leaves of the weed cessful owing to an ongoing debate on the Results with O. terebrantis are so far more turned brown, starting from the tip, and ulti- potential of this weed as a resource. With equivocal. Although it established under mately the whole plant collapsed and sank the inception of the All India Coordinated field conditions after releases were initiated to the bottom of the water body. Research Project on Biological Control of in 1986, the mite does not appear to be Crop Pests and Weeds in 1976, renewed Successful biological control ranging from capable of suppressing water hyacinth on efforts were made by the Indian Council of 90-98% was achieved in six tanks, with a its own. Heavy population build up was Agricultural Research to import host-spe- combined total surface area of over 1000 observed in all the tanks where releases had cific natural enemies. Water hyacinth ha, in Bangalore within 3-4 years of the been carried out, leading to browning of creates special problems in India, because release of a total of about 25,000 weevils. leaf laminae, but promising results are yet drought and associated problems are The tanks are manmade lakes created some to be achieved. chronic features. Water hyacinth reduces four centuries ago by damming natural The results of the studies carried out to date the volume of available fresh water by rainwater channels to provide water for use clearly show that N. eichhorniae and N. increasing losses through evapotranspira- during the summer months, mainly for irri- bruchi are effective biological control tion (up to 9.84% reduction reported). It gation but also as a source of drinking agents, capable of bringing about a perma- impedes the flow of water in irrigation sys- water. The proliferation of water hyacinth nent solution to the problems posed by this tems (40-90% reduction reported) and in them is a symptom of the pollution weed in India. Hence, there is an urgent need impairs the quality of water, making it unfit afflicting these once pristine water bodies. to spread them to regions where releases are for human consumption. After taking into Some have been breached, but sewage has yet to be made. This objective can easily be consideration these and other major disad- polluted others as the city has grown. Both achieved by releases of field-collected nat- vantages of the weed, it was finally agreed N. eichhorniae and N. bruchi, separately ural enemies into selected weed-infested by the Indian authorities in July 1981 that andincombination,werefoundtobeeffec- water bodies in different parts of the country some biocontrol agents should be obtained tive in suppressing water hyacinth. and redistribution from these spots after for trials. However, the rate of weed suppression was establishment and population build up. found to be very slow in a partially sedi- With the assistance of CIBC (now part of mented tank, where the water hyacinth CABI Bioscience) a shipment consisting of By: K. P. Jayanth, Bio-Control Research plants were anchored. This was probably the two weevil species, Neochetina eichhor- Laboratories, A division of Pest Control due to silt coverage of root hairs of the niae and N. bruchi, and the mite (India) Limited, P. O. Box 3228, weed, on which the insects pupated. Orthogalumna terebrantis was received R. T. Nagar, Bangalore 560 032, India from the US Department of Agriculture, Fort Interestingly, there were fluctuations in Email: [email protected] Lauderdale, Florida. Neochetina eichhor- weed cover, ranging from 5-30%, in all the Fax: +91 80 3334316 niae was also imported from Long Pocket tanks in which the weevils had been This article also appears in Water Hyacinth Laboratories, CSIRO, Indooroopilly, released for 3-5 years after the initial col- News No. 2 (October 2000) with agreement Queensland, Australia (although this culture lapse. However, residual weevil of the author and the publishers. was subsequently discarded owing to micro- populations were found to be capable of sporidian infection). reducing weed populations every time such  News 59N

IPM Systems

This section covers integrated pest man- To add to the problems, and plan- ties developed by breeding programmes agement (IPM) including biological tains are perennial crops, in which new have only become available for distribution control, and techniques that are compatible plants emerge as suckers from a shared rhi- in the last few years. INIBAP is playing a with the use of biological control or have zome. (The rhizome and bananas/plantains number of different roles in helping to little negative impact on natural enemies. attached to it are collectively called a mat.) ensure the continual availability of Pest and disease problems tend to get worse improved varieties for use in IPM pro- Flavouring with successive ratoon crops. grammes worldwide. The articles in this section have a common Two wild species ( acuminata and M. Support to Breeding Research ingredient in this issue: bananas and plan- balbisiana)gaverisetomoderncommer- tains. This is not a comprehensive cial bananas and plantains. These diploid The absence, until very recently, of summary, but indicates the sheer effort species have produced diploid, triploid and improved, pest and disease resistant varie- going into overcoming the very serious tetraploid offspring. The conventional way ties has been attributed to the difficulties of constraints to production of this key crop of indicating the (probable) parentage of breeding bananas at the genetic and prac- around the world. Bananas and plantains current clones is by using ‘A’ and ‘B’ for tical levels (most important varieties are can be divided into those which are sweet acuminata and balbisiana, respectively highly sterile and can only be used in con- and eaten as a dessert fruit and those that (e.g. Cavendish AAA). However, the ventional breeding programmes with are starchy and only eaten after cooking. In narrow genetic base of modern export, des- difficulty), together with the very low many parts of the world cooking bananas sert bananas makes them susceptible to pest levels of investment in banana breeding. In and plantains are staple foods, and 90% of and disease attack, and a key element in an effort to accelerate the development and the total world production (some 85 million banana and plantain IPM programmes is release of new varieties, INIBAP works in tonnes) is grown for domestic consump- improving host plant resistance. a number of ways: tion. On the other hand, in the developed  • Providing direct support to research on world dessert bananas are a favourite fruit, Musa improvement, with a focus on the and this makes them the fourth most valu- IPM and INIBAP use of biotechnology and molecular able food crop and the most important fruit, approaches to increase breeding worth US$2.5 billion annually in export INIBAP (the International Network for the efficiency. trade. Improvement of Banana and Plantain) was established in 1985 as an international One of the most serious pests of bananas is • Providing the secretariat and co- organization with a mission to sustainably a boring weevil, and the many promising ordination for PROMUSA, the Global increase the productivity of banana and avenues being explored for controlling it Programme for Musa Improvement. plantain grown on small-holdings for are described. There is also an array of PROMUSA brings together all the domestic consumption and for local and nematode pests that infest the crop in dif- major players in Musa improvement export markets. INIBAP is a programme of ferent regions and climatic conditions, and worldwide, allowing researchers to the International Plant Genetic Resources progress against these is also reported. develop collaborative projects and forge Institute (IPGRI). It has a small headquar- Above all, though, bananas are threatened partnerships, thus creating synergies ters staff in Montpellier, France and by diseases. There are a host of these, and and avoiding unnecessary duplication regional offices in the four major banana- new ones are still emerging. The most of research. growing areas of the world. serious of them, black Sigatoka was first seen (in Fiji) in 1963 but has now found its IPM is a very important area of work for • Organizing a worldwide, multi-site way to all the banana-growing regions, INIBAP, and a number of different activi- evaluation programme (International although some countries are still free of the ties are ongoing. These include supporting Musa Testing Programme) which disease. Research on management of this and carrying out research on various com- allows breeders to test their materials disease is in the early stages, and we hope ponent parts of IPM (host plant resistance, over a wide range of environments and to report on it in a later issue. Here we biological control, disease management, disease pressures, while at the same report on initiatives and progress against etc.), organizing meetings and workshops, time providing national programmes other diseases, both ‘old’ (such as yellow and distributing relevant information. This early access to improved varieties. Sigatoka) and ‘new’ (such as report provides an overview of INIBAP’s streak disease in ). Lastly, we look different IPM-related activities. It should Distribution of Germplasm at control of post-harvest diseases, which be noted that INIBAP is a networking INIBAP maintains the world’s largest col- are particularly important in export bananas organization. It does not conduct research lection of Musa germplasm. This material because they affect quality and storage. in-house. Instead it works through out- is held in trust for the global community sourcing, thus making use of and Although wild species are seed-bearing, and is freely available for distribution to strengthening existing facilities and exper- modern cultivars are sterile. Propagation is bona fide users. The collection contains tise. INIBAP also plays an important role by vegetative means, and this has implica- wild species of the genus Musa,aswellas co-ordinating and catalysing research car- tions for the incidence of pests and diseases a wide diversity of cultivated varieties and ried out by its partners worldwide. and how they may be managed. Vegetative improved varieties from breeding pro- propagation means that both have been Host plant resistance is one of the most grammes. All material is introduced and passed on in planting material between and important components of any IPM pro- distributed under the terms and conditions within countries, and the provision of clean gramme. In the case of bananas, despite the of Material Transfer Agreements, to ensure planting material has been an area of fact that breeding started as long ago as the that the germplasm and information related intense research that is yielding dividends. 1920s, new pest and disease resistant varie- to it remain in the public domain. 60N BiocontrolNews and Information 2000 Vol. 21 No. 3

In the case of improved varieties, INIBAP region. In recent years severe outbreaks of • Biologically-enhanced planting material: has introduced a specific Germplasm this disease have also been seen on the endophytes, arbuscular mycorrhizal Acquisition Agreement and a Material southern tip of Sumatra, in the region of fungi, etc. The screening and testing of Transfer Agreement. These agreements Lampung, where it is now seriously threat- organisms and formulations is required. provide a framework within which ening the smallholder banana crop. improved germplasm can be distributed by INIBAP’s Regional Office for Asia and the • Biological pesticides: the efficiency of INIBAP, while at the same time providing Pacific is working with the Research Insti- neem needs to be tested under farmers’ breeders the opportunity to benefit from the tute for Fruits in Indonesia, to conduct conditions. commercial use of their material. Through demonstration trials on the management of this innovative approach, INIBAP has been this disease. Disease management technol- • Enhanced trapping technologies for able to acquire improved varieties from all ogies, effective in combating a similar weevils should be further investigated. the major banana-breeding programmes disease known locally as ‘tibaglon’ or • Use of semio-chemicals (kairomones and is working to ensure that such varieties ‘Bugtok’, have been developed in the Phil- and pheromones): improved efficiency will continue to be available free-of-charge ippines. A study previously carried out in to those who need them most – small-scale Negros Oriental (Philippines) showed that and delivery mechanisms are required. farmers in developing countries. an integrated disease management pro- • Resistance breeding (including genetic gramme including sanitation, early All material is virus indexed by INIBAP engineering): new hybrids must be debudding, disinfection of tools and fruit before distribution. Only accessions in evaluated across years and environ- bagging can reduce disease incidence by up which no viruses have been identified are ments. Decentralized breeding strat- to 100% over a 12-month period. It was dis- available for dissemination. As plants are egies and the use of varietal mixtures covered however that farmers found distributed in the form of in vitro plantlets, could also be investigated. bagging impractical because of the height a clean source of planting material is of the local varieties of cooking bananas ensured for the end users. • Various aspects of cultural management being cultivated. Nevertheless, the practice (soil fertility, water management, Improved pest and disease resistant varie- of sanitation and early debudding alone was mulches, intercrops, etc.) and their ties have been distributed to over 50 shown to reduce infection from an initial effects on pathogen levels need further countries by INIBAP, and in several coun- incidence of 88% to 6% after 12 months. study. tries, most notably in Cuba, Nicaragua and These methods were considered practical , smallholder banana producers and have been well accepted by farmers. On-Farm Testing of IPM Strategies in are gaining significant benefits from the use The disease management strategies devel- East of these varieties. oped for Bugtok in the Philippines are being tested for their effectiveness against Pest and diseases have been identified as Clean Planting Material against Viruses Blood disease. It is hoped that the simple the major constraint to banana production A number of viruses affect bananas and techniques, either alone or in combination throughout the East African region [see these include Banana Bunchy Top Virus with other techniques, such as the use of below]. However, options for IPM are (BBTV), Cucumber Mosaic Virus (CMV), clean planting material, will help to solve known to be available and following the Banana Mosaic Virus (BBrMV) and the Blood disease problem in Indonesia. recommendations of the IPM workshop Banana Streak Virus (BSV). Banana organized in South Africa in 1998, these Mobilizing IPM for Sustainable viruses, especially BBTV and BBrMV (this should now be tested on-farm. A project Production in Africa one was only identified for the first time in proposal was therefore developed by 1989), have had a significant effect on the INIBAP in collaboration with the national An Africa-wide workshop on banana IPM agricultural research services of Uganda, production of non-export, traditional des- was organized by INIBAP, together with sert bananas in several Asian countries, Kenya and Tanzania. The project was the International Institute of Tropical Agri- accepted for funding by DFID (the Depart- including the Philippines, Sri Lanka, Bang- culture (IITA) and the Institute of Tropical ladesh, Vietnam and Pakistan. Control ment for International Development, UK) and Subtropical Crops, South Africa and commenced in May 2000. measures for these viruses are based on (ITSC) in the framework of the Banana quarantine, sanitation (use of clean planting Research Network for Eastern and The project will allow combinations of material) and roguing. INIBAP’s regional Southern Africa (BARNESA) in South IPM options to be tested on-farm in a range office for Asia and the Pacific has been Africa in November 1998. This attracted of settings in benchmark sites in Kenya, active in helping to develop virus control IPM researchers from across Africa and Tanzania and Uganda. Such settings programmes in several countries in Asia. beyond. The proceedings of this meeting include agro-ecological variation in terms Workshops and training courses on virus werepublishedbyINIBAPin1999and of varieties grown, disease/pest pressure, control, virus indexing and the use of clean provide state-of-the-art information on soil fertility levels, climatic factors, etc., in planting material have been held in the banana IPM. The meeting identified tech- combination with the differing socio-eco- Philippines (for the region) and Sri Lanka. nologies ready for testing in farmers’ fields. nomic situations of the participating As a result of these workshops, national Such technologies are: the use of clean farmers. One of the most important aspects banana rehabilitation programmes based on planting material, host plant resistance and of the IPM project will be the testing of new IPM, with clean planting material as the a range of cultural management practices. varieties. key component, have been put in place in The meeting called for greater efforts in on- both the Philippines and Sri Lanka. farm testing of banana IPM strategies. The One other INIBAP initiative is described later in this news section. An INIBAP Controlling Bacterial Diseases in main research gaps were identified as: Associate Expert, located at the Centre de Indonesia • Biological control: Beauveria bassiana Recherches Régionales sur Bananiers et ‘Blood disease’, a destructive banana bac- holds promise for the control of weevil Plantains (CRBP) in Cameroon, is working terial disease, is serious in the Sulawesi borer (Cosmopolites sordidus), but on the development of an IPM strategy area of Indonesia and has devastated the other predators and pathogens should against the banana weevil borer, C. Kepok (Saba) in this also be investigated. sordidus. News 61N

By: Suzanne Sharrock, INIBAP, reason to change to short duration crops is activity was a rapid rural appraisal at 25 Parc Scientifique Agropolis 2, thus compelling. banana-producing villages across southern 34397 Montpellier Cedex 5, France Uganda. Pests and soil fertility decline Email: [email protected] As if these problems are not great enough were ranked as key constraints in nearly all Fax:+33467610334 the arrival of alien diseases and pests like sites. Farmers ranked the banana weevil as black Sigatoka (Mycosphaerella fijiensis),  the leading pest/disease problem at 18 sites. yellow Sigatoka (M. musicola)andthebur- Within the central region, many farmers rowing nematode (Radopholus similis)has were replacing cooking banana in favour of Pearls of Banana Research accentuated the decline. The most signifi- exotic brewing bananas such as Pisang cant pest recognized by farmers is the Uganda is the world’s largest banana pro- awak (ABB) and Ney poovan (AB) which weevil Cosmopolites sordidus.Whenthis are resistant to the weevil and require less ducer, with a 15% share of total global pest was introduced is unknown but it is yield; in 1996, it produced about 9 million management attention. In many areas, likely to have arrived with the newer farmers have lost confidence in a crop that tonnes of the fruit. Highland cooking ‘exotic’ cultivars in the late 19th or early had long been their mainstay. banana is the most important staple in the 20th century. The first cited record for Great Lakes region. Uganda is also a sec- Uganda is 1918. The combined effects of Later in this section, progress made by this ondary centre of banana diversity and there nematodes and weevils include destruction programme in developing strategies to are many locally evolved cultivars; an of the root system, reducing anchorage and manage the constraints to banana produc- average of 12 different cultivars were found water and nutrient uptake, which leads to tion and to ensure that Uganda retains its growing on farms surveyed by IITA. How- reduced bunch weight or plant toppling. place at the top of the world’s banana pro- ever, the many different clones of the East Diseases reduce photosynthetic capacity ducers is reported. African highland bananas are all Musa and therefore fruit production and often From: Cliff Gold and Simon Gowen. (AAA) and have therefore evolved (by quality, or even cause the death of the plant. somatic mutations) from a relatively Contact: Wilberforce Tushemereirwe, Devastating banana weevil and nematode narrow genetic base. The ancestral cultivars UNBRP, Kawanda Agricultural Research outbreaks in the mid 1980s led to wide- that would have been introduced are Institute, Box 7065, , spread crop failure in Masaka and Rakai unknown. There is little difference in the Uganda districts. Although these outbreaks per- susceptibility of these cultivars to the more Email: [email protected] important pests and diseases that have been sisted for only a few years, early stages of introduced in recent times. The Uganda yield decline are already in evidence in cer-  highland banana cultivars have recently tain areas in the southwestern region. This been taxonomically characterized by Deb- has caused apprehension about the future of A Cosmopolitan Weevil orah Karamura at the National Agricultural the crop in Uganda. Moreover, commercial Research Station (NARO). banana production has been shifting further The banana weevil, Cosmopolites sordidus, and further away from Kampala. Currently, was first recorded in connection with Since the 1970s, banana has undergone a much of the banana serving Kampala bananas in Guadeloupe in 1889, but has decline in the traditional growing areas in comes from Mbarara and Bushenyi districts been distributed throughout the tropics on central Uganda. During the same period, it (240-300 km from the capital). As a result, banana planting material. It has no other has expanded into the southwest. The revitalization of banana production in the host and all types of banana are susceptible increasing importance of banana in this central zone and stabilizing production in to varying degrees. In some of the banana- region has been related to (a) improved the southwest became high priorities within growing regions it has serious impact (for food security and (b) increasing urban the Uganda Ministry of Agriculture and example, in East Africa) but elsewhere its market demand following rapid population NARO. Banana weevil is considered a pri- importance is not as great. The reasons for growth in Kampala and Jinja. Cooking ority concern. It is an important pest of this are not clear but environmental factors banana is the preferred urban staple, in con- highland cooking banana in East Africa, and differences in crop growth and man- trast to many urban areas of the world and has been implicated in the decline and agement could be influential. There is yet whichrelyongrains.Itremains,also,the disappearance of cooking banana from its no evidence to suggest that the weevil pop- preferred rural staple food throughout traditional growing areas in central Uganda ulations vary in aggressiveness. southern Uganda. and western Tanzania. Since the 1960s, The first attempt at biological control of Partly associated with this geographical accelerated yield decline in this region has this pest was in Fiji by Frank Jepson, the shift, there has been a major decline in pro- led to the replacement of cooking banana Government Entomologist. In 1913 he duction in the last 25 years. Yields have with exotic beer bananas (types AB and made collections of the histerid beetle Plae- fallen to as low as 6 tonnes/ha and the lon- ABB) and annual crops. sius javanus and other natural enemies in gevity of banana plantations has fallen from However, Uganda is also home to exciting Java. Subsequently, this predator was about 50 years to only 5-10 years in some and innovative research into banana pest released in several countries, including areas. The decline in productivity and plan- and disease control. There is an active Uganda by C. C. Gowdey in 1918-20, but it tation longevity is attributed to social, national programme, and they have never became established. economic and biological factors. The (often involved many international organizations, quoted) decline in soil fertility can be traced so the prospects for bananas are becoming Biological control was forgotten during the to labour costs and availability associated rosier. early insecticide era. Aldrin was recom- with the traditional system of culture with mended for weevil control in Uganda during organic manures and regular mulching. In 1990, the International Institute of Trop- the 1950s until resistance developed. Post- These practices are now less common. ical Agriculture (IITA) and the newly colonial funding from the UK Government Land ownership is an issue as farms are formed Uganda National Banana Research was for chemical control of the banana divided by inheritance. Replanting bananas Programme (UNBRP) developed a collab- weevil which was done by Graham Mitchell will be less acceptable on the smaller farms orative programme to address the problems of the Centre for Overseas Pest Research because there is a 12-15 month wait for of banana weevil, nematodes, diseases and (COPR) in the Caribbean in 1974-78 when bananas to come into production, the other production constraints. The first alternatives to the organochlorine insecti- 62N BiocontrolNews and Information 2000 Vol. 21 No. 3 cides were being sought. At this time much unimportant above 1600 m above sea level. tures. However, the immature stages are research was done on damage assessment, Weevil pest status varied considerably hidden within the banana plant and largely population estimation and chemical control across sites and among farms within sites. immune to many control strategies. throughout the commercial export-pro- For example, weevil population estimates ducing countries. (based on mark and recapture studies) Cultural Control within one watershed in Ntungamo district The opportunities for developing biological found density to range from 1600 to Dispersal of the banana weevil is primarily control have been revived over the last 10 149,000 weevils/ha. These studies found through infested planting material, so clean years and the most promising biological only a weak relationship between adult planting material could protect new stands control agent, Beauveria bassiana,has density and damage. from banana weevils for at least several been isolated from weevils in many coun- crop cycles, if this is planted some distance tries.Thisfungushasbeenusedinbanana Salient features of the weevil’s biology from other infested stands. However, plantations in Brazil. In Uganda, isolates of include a cryptic life style, long life span, replanting previously infested fields will B bassiana have been collected by Caroline limited mobility, low fecundity and slow only be possible after an interval of many Nankinga (National Agricultural Research population build-up. The adult weevil com- months to allow the existing population to Organization, NARO) and significant monly lives more than one year, while die out. Otherwise, these weevils will reductions in weevil populations have been some adults have been reported to live readily attack suckers (that have been achieved with formulations of this fungus more than 4 years. The weevil is very sen- detached from mother plants and have an under field conditions. Another promising sitive to desiccation but can live for several exposed cut rhizome surface). In one field line of attack is with entomopathogenic months without feeding. These factors trial, more than 40% of planted suckers nematodes (epns). These nematodes (Stein- mean that weevils are often favoured by were killed by weevils, as were an addi- ernema spp. and Heterorhabditis spp.) mulches (which contribute to soil moisture tional 40% of the replants. have also been tested successfully under retention during dry periods) and that field conditions in Australia and Brazil. extensive plant loss may occur when The use of clean planting material, disin- Recently, epns have been recovered from banana is planted in a previously infested fected of weevils through paring and/or hot bananas in Kenya by Charles Waturu field without an adequate break between water treatment, has been recommended as a (Kenya Agricultural Research Institute, the crops. cultural control strategy to reduce initial KARI) and there is a survey planned for infestation levels and retard pest build-up. The adults are most often found in the leaf Ugandalaterthisyearaspartofaweevil Paring of the rhizome surface exposes dam- sheaths, in the soil around the base of the management project. aged suckers, which can then be rejected. mat or associated with cut residues. They Paring also removes most eggs and many The chemical nature of the male-produced are nocturnally active and not casually first instar larvae. Hot-water treatment of aggregation pheromones has been identi- observed. Adults are often sedentary for suckers has also been recommended for both fied and both lures and traps have been extended periods and most do not move weevil and nematode control. However, hot developed commercially in Costa Rica more than a few metres at a time. They water regimes commonly used for nematode from where there have been reports of suc- rarely fly. The weevils are attracted by control (i.e. 54ºC for 20 minutes) killed only cessful reductions in weevil damage in plant volatiles (especially those emanating 32% of weevil larvae. Therefore, paring commercial Cavendish plantations. from cut rhizomes) and also produce a male alone is probably adequate for reducing ini- aggregation pheromone. Under field condi- By: Simon Gowen tial weevil infestations. [The IITA/UNBRP tions, mean oviposition may be 0.5-2 eggs programme initiatives against nematodes are  per week. The eggs are inserted singly into described below.] the leaf sheaths or rhizome. The larvae feed Many Hands Tackle Weevil within the rhizome cortex, central cylinder In field studies, weevil populations were Problem and, occasionally, the (pseudo)stem. The lower in cleaned planting material plots insect passes from egg to adult in 6-8 thanincontrolsforupto27monthsafter The IITA/UNBRP rapid rural appraisal weeks. described in ‘Pearls of Research’, above, planting. Weevil damage levels in controls was followed by a study on the geographic With low fecundity, population build-up is were 70-200% higher than in cleaned shifts of banana production, which high- slow and, following crop establishment, planting material treatments for the plant lighted the importance of banana weevil, weevil problems are most pronounced in crop. Plant loss to weevils and nematodes Cosmopolites sordidus, in the decline of ratoon crops. In one trial, yield loss was 21-34% in controls, compared to 2-6% cooking banana in central Uganda. The increased from 5% in the plant crop to 44% in treated plots. Bunch size was similar study focused on villages in central Uganda in the third ratoon. This loss reflects among treatments, but clean planting mate- in which banana had largely disappeared; reduced bunch size, snapping, toppling and rial plots provided higher yields resulting such villages presented a truer picture of mat die off. from the greater number of harvested crop dynamics in central Uganda than those bunches. Current research results suggest that no used in the initial IITA/UNBRP study (i.e. single control strategy will be likely to pro- Pseudostem trapping has also been widely sites still considered banana-producing vil- vide complete control for banana weevil. recommended in Uganda for weevil con- lages) described above. Farmers attributed Therefore, a broad IPM approach might trol. Farmer participatory research in increasing weevil pressure to reductions in provide the best chance for success. The Ntungamo district, Uganda showed that available labour and resulting changes in components of such a programme include intensive pseudostem trapping (1 trap/mat/ management practices. For example, crop habitat management (cultural control), bio- month) could substantially reduce weevil sanitation, trapping and other cultural con- logical control, host plant resistance and (in populations, while more moderate trapping trols have been largely abandoned. Field some cases) chemical control. The poor (0.3-0.6 trap/mat/month) could also lower verification confirmed very high weevil relationship between weevil adult density weevil numbers. However, most farmers levels in survey study sites. and damage suggest that factors which indicated that the labour and material Diagnostic surveys showed that the banana target the adult stage (e.g. trapping) may be required for intensive trapping was beyond weevil is widespread within Uganda, but less effective than those directed at imma- their resources. News 63N

IITA and the National Agricultural conducted in the first half of the 20th cen- could kill weevils (and nematodes) and (b) Research Organization (NARO) are cur- tury, provided only generalist predators be introduced into tissue culture plants to rently investigating enhanced trapping (e.g. histerids and hydrophilids) which provide extended protection against pests. using pheromones. The presence of a male attack the immature stages. Releases of Protocols include (a) isolation of endo- aggregation pheromone (i.e. produced by these natural enemies in Africa and else- phytes from banana plants, (b) screening males and attractive to both sexes) was first where met with little success. In against weevil immatures, (c) determina- recognized at ICIPE (the International collaboration with the Research Institute tion of modes of action, (d) identification Centre for Insect Physiology and Ecology, for Fruits in Solok, Indonesia, IITA will be and markers of candidate strains (especially Nairobi). The chemical structure of the undertaking further exploration for natural important if what is subsequently isolated is pheromone (called sordidin) has since been enemies later this year. It is hoped that such the same as what had been introduced), (e) identified. ChemTica in Costa Rica has searches may reveal the presence of egg studies on distribution and persistence synthesized and is distributing commer- parasites. within the host plant, (f) pathogenicity cially a mixture of the pheromone and testing, (g) efficacy in pot trials and (h) effi- weevil-attractive plant volatiles in a formu- ICIPE has conducted studies on endemic cacy in field trials under different lation called Cosmolure+. Preliminary natural enemies of banana weevil in environmental conditions. studies in Uganda show that Cosmolure+ Western Kenya. These included adults of can catch up to 30 times as many weevils as three staphylinids, three histerids, one Surveys of highland cooking banana and conventional pseudostem traps. Further hydrophilid, one carabid, one tenebrionid, revealed an abundance of work is being undertaken on field efficacy two labiids and one carcinophorid earwig. endophytes in the central cylinder and under farmer conditions in Uganda. In laboratory studies, these predators vari- cortex of the rhizome. In laboratory experi- ously searched the rhizomes of living plants ments, 12 of 200 strains killed a high Crop sanitation (i.e. destruction of crop res- and crop residues. Most of the predators percentage of weevil eggs. Some of these idues) is also widely recommended to attacked the egg and early larval instars, strains also produced moderate levels of control banana weevils. The supposition is although four also attacked older larvae. larval mortality. Weevil mortality was that crop residues left in the ground after Some of the predators were able to reduce caused by direct colonization and by fungal harvest serve as shelters and breeding weevil levels in pot trials, but predator den- exudates. The most promising strains are grounds/oviposition sites for banana wee- sities under field conditions suggest limited within the genus Fusarium.Anumberof vils, leading to population build-up and potential. these strains have been successfully inocu- increased damage on plants. Farmers lated into tissue culture plants. Preliminary implement a range of sanitation practices In contrast, the Cubans have employed the studies on the efficacy of the strains in con- including cutting and chopping of spent myrmicine ants, Pheidole megacephala trolling weevils in pot experiments have not stems and digging out or burying old rhi- and Tetramorium guineense,whichthey yet produced clear trends. Currently, fur- zomes. The intensity of sanitation practices report as providing partial control. The ants ther work is being undertaken on is often greater on commercial farms. In can be encouraged to nest in pseudostem endophyte persistence and efficacy against Ntungamo district, dominated by subsist- pieces which can then be transferred to weevils. ence banana production, nearly 80% of the other banana stands. IITA and NARO have farmers practised little or no sanitation. It is surveyed ants at several sites in Uganda and NARO has also screened strains of B. bas- also possible that crop residues serve as found P. megacephala, four other species siana for efficacy against banana weevil ‘trap crops’ drawing gravid females away of Pheidole and one unidentified Tetramo- adults. These strains were isolated from from growing plants. Current studies are rium species. A graduate student will begin banana weevils, Galleria baits placed in investigating weevil oviposition prefer- her Ph.D. research in late 2000 on the banana stands and from other insects. A ences, larval development and the effects of potential of controlling banana weevils number of isolates effected mortality of sanitation on weevil populations and with myrmicine ants. more than 95% in the laboratory. Tests on damage. potential delivery systems revealed that In West Africa, IITA explored the possi- maize-based substrates and oil formula- Prospects for Biological Control bility of secondary host association, by tions were more effective than water evaluating the potential of two strains of a suspensions. In field experiments, trap cap- Biological control efforts against banana carrot weevil parasitoid, Anaphes victus, tures and weevil damage were lower in weevil have included the use of exotic nat- for parasitizing banana weevil. These para- plots where maize-based formulations were ural enemies (classical biological control), sitoids readily oviposited in banana weevil applied to soil at the base of banana mats endemic natural enemies, secondary host eggs but failed to successfully complete than in controls. However, the quantity of associations and microbial control (e.g. their development or to be able to emerge substrate required was cost-ineffective. entomopathogens, endophytes, ento- from the weevil eggs due to their relatively Therefore, future work will continue to mophagous nematodes). Microbial control larger size. Larvae of A. victus failed to address the development of more cost- agents that require repeated applications consume all of the banana weevil egg con- effective delivery systems, as well as path- may be considered as biopesticides, tents with decomposition of unconsumed ogen performance under different although they lack the toxic side effects of material contributing to pupal failure. Most ecological conditions. chemical insecticides. As such, they may of the few parasitoids which successfully entail repeated application costs on the part reached the adult stage then failed to Host Plant Resistance of the farmer. emerge through the relatively thicker cho- rion of banana weevil eggs. In a screening trial in Uganda, plantains and Classical biological control of banana highland bananas appeared more suscep- weevilmaybepossible.Thebananaweevil IITA and NARO have also been collabo- tible than other groups. Cluster analysis originated in South-east Asia, coincident rating on microbial control of banana suggested 19 clones were highly suscep- with the centre of origin of bananas. The weevil, using endophytes and B. bassiana. tible, 17 clones were intermediate in banana weevil is not believed to be a Endophytes are mutualistic, non-patho- susceptibility and 9 clones were resistant. serious pest in most areas within its area of genic fungi that exist within a host plant. Within the highland group, 15 clones were origin. However, searches for arthropod The objective of this study was to identify susceptible, while 11 were intermediate in natural enemies of banana weevil in Asia, endophytes within banana plants which (a) susceptibility. Resistance did not appear to 64N BiocontrolNews and Information 2000 Vol. 21 No. 3 be related to host plant location or accept- opment and the withdrawal of averaged five or more adults per bait ance (antixenosis). There was no organochlorine insecticides, banana (recorded monthly.) Other authors have relationship between weevil trap captures, growers resorted to using systemic com- found this to be the level at which action is oviposition and damage. Instead, antibiosis pounds, but residues of these could make required to control the pest. appears to be the predominant mechanism their way into the fruit. This fact, combined Over the 12-month study period, four appli- affording resistance to the weevil, espe- with ecological disturbances resulting from cations and 20 evaluations were cially as it affected larval developmental the misuse of these products, stimulated undertaken. After the first application, there times and survivorship. For example, in one work on alternative methods for banana was a clear reduction in the population of study, survivorship in susceptible highland weevil control. The most promising avenue adult weevils in the treated area, from 9.0 to banana clones was 16-23 times as high as in is the use of entomopathogenic fungi, and 3.4 insects per bait (equivalent to a control resistant Pisang awak. Current work is research began by evaluating the efficiency efficiency of 46.7%). The last application attempting to explore compounds confer- and potential of the fungi Beauveria bas- reduced the pest population to a level below ring resistance against banana weevil. siana and Metarhizium anisopliae as that necessary for control. The control pop- biocontrol agents for the weevil. The Insti- By Cliff Gold ulation was 45.8% higher, with 7.0 adults tuto Biológico in São Paulo State has per bait. Work described in this article was con- carried out laboratory and field studies, the ducted by: C. S. Gold, S. Okech and P. R. latter in the Vale do Ribeira region. These results indicate that B. bassiana is Speijer (IITA-ESARC), E. B. Karamura The project was initiated back in 1984, capable of reducing weevil infestations (INIBAP), A. Kiggundu, C. M. Nankinga when the fungi were evaluated under labo- below damaging levels and, therefore, that and W. K. Tushemereirwe (NARO), D. ratory conditions. The pathogens were it should be possible to establish a pro- Rukazambuga (National Banana Pro- grown on two different substrates (moist gramme for management of C. sordidus gramme, Minagri, Tanzania) and M. autoclaved rice and sterile ground beans). based on the use of the fungus. Currently Griesbach (University of Bonn, Germany). Inoculations were carried out in two ways: we are looking at whether we can use phe- Contacts: Cliff Gold [weevil biology, pop- by making the insects crawl over the cul- romones in association with the fungus to ulation dynamics, pest status, cultural ture medium containing the fungi and then further increase disease incidence and controls; endophytes]; Deborah Karamura transferring them to pieces of banana pseu- improve weevil control. [weevil IPM]; A. Kiggundu [host plant dostem, and by placing the inoculum By: Antonio Batista Filho, Centro Experi- resistance]; Caroline Nankinga [microbial directly onto the pseudostem so that the mental do Instituto Biológico, control]; Suleman Okech [on-farm testing]; insects contaminated themselves as they Caixa Postal 70, 13001-970 – Campinas, Wilberforce Tushemereirwe [banana pro- entered. Pest mortality of more than 85% São Paulo, Brazil gramme strategy including benchmark was recorded in all treatments except for M. Email: [email protected] sites]. anisopliae grownonbeansubstrate(56%  c/o IITA-ESARC, P.O. Box 7878, mortality). Under field conditions, B. bas- Kampala, Uganda siana was found to be the most promising Fax: +256 41 223459 agent for controlling the weevil, particu- Weevil Control a Piece of Email: [email protected] larly when grown on rice medium, on Cake! or c/o UNBRP, which it developed best and to which the Kawanda Agricultural Research Institute, pest insect was attracted as a bait. A study conducted in West Africa comple- Box 7065, Kampala, Uganda mented the work conducted by Caroline The results of a study on the virulence of Email: [email protected] Nankinga in Uganda [described above], different isolates of B. bassiana identified  and may provide the basis for developing the isolate, CB-66 (originally obtained affordable biological control measures from the coffee berry borer, Hypothenemus using indigenous pathogens for the banana Beauveria Bait for Banana hampei), as most effective for banana weevil Cosmopolites sordidus in Africa. Borer weevil control. In field trials, isolate CB-66 waspreparedasapastewhichwasapplied Strains of Beauveria bassiana were iso- Brazil has also been at the forefront of to the cut surface of longitudinal sections of lated from a range of hosts (C. sordidus and research into biocontrol of banana weevil, banana pseudostems, and these (telha baits) Hypothenemus hampei)inEastandWest Cosmopolites sordidus. Amongst the crop were placed cut-side down on the soil sur- Africa by staff from IITA, IMI (now part of protection problems faced by Brazilian face next to the banana plant. Evaluations CABI Bioscience) and ARSEF (Agricul- banana growers, the banana weevil aptly over three seasons showed that B. bassiana tural Research Service Collection of known here as the ‘banana rogue’, stands could reduce the adult weevil population by Entomopathogenic Fungi), and the most out in importance. The damage caused by up to 61% over an extended period. virulent selected on the basis of patho- the insect ranges from a drop in plant pro- genicity tests. Mass-production techniques Under laboratory conditions, it was found ductivity to plant death. The tunnels the for them were adapted from a technique that mineral oil at 3-5% EC added to strain weevil makes in the rhizome allow the developed for Metarhizium production at CB-66 in paste form reduced C. sordidus entry of pathogenic microorganisms, which IITA under the LUBILOSA programme. populations by 77.5-100%, while the accelerate the decline of the plant. Research fungus alone gave only 37.5% control. Key to the success of a fungal biocontrol on control of this pest increased from the Tests on the compatibility of the pathogen- agent is ease of mass production and the 1950s onwards. There was increasing use oil association showed that although spore development of an effective means for its of chemical control, initially organochlo- germination was reduced, virulence was application. Researchers in the University rine insecticides and more recently other increased. In the field, B. bassiana with 3% of Ghana and IITA chose to work with a types of active ingredient. mineral oil applied to telha baits reduced virulent B. bassiana isolate, IMI 330194, Continuous and prolonged use of organo- pest populations below economic damage that was also robust and able to resist inva- chlorine insecticides led to the levels. The timing of application of the sion of three common contaminating development of resistance in the weevil fungus was determined by the population competitor species (Aspergillus niger, populations. Following on from this devel- level of the insect. It was applied when this Fusarium moniliforme and Penicillium hir- News 65N sutum). They also developed a method for Contact: Ignace Godonou, CABI Africa Work is continuing on evaluating the path- formulating B. bassiana on oil-palm kernel Regional Centre, ICRAF Complex, ogenicity of B. bassiana to the larvae, and cake (OPKC), which it has since been PO Box 633, Village Market, also on formulations and mass production. shown to persist for several months in the Nairobi, Kenya field, and to control weevils during the first Email: [email protected] By: Enrique Arévalo, Oscar Cabezas, Luis few critical months after planting. This Fax: +254 2 522150 Zúñiga and Nilda Albornoz work may be the basis for an effective man-  Contact: Enrique Arévalo, agement tool for banana weevil. Instituto de Cultivos Tropicales (ICT), Plantain (Musa AAB) is the preferred Pathogens for a Pair of Jr. Tarapoto No. 247, Banda de Shilcayo – staple food of Ghana. The principal con- Weevils in Peru Tarapoto, San Martín, Peru straints to production are declining soil Fax: +51 94 522361 fertility, black Sigatoka disease, nema- Laboratory and field studies have been con- Email: [email protected] ducted in Peru to assess the prospects for todes, and banana weevils. For smallholder  farmers, biological control using Beauveria using local strains of Beauveria bassiana bassiana was considered the most prom- for control of not only Cosmopolites sor- ising management option for the weevil. didus (known locally as black weevil) but Effective and Economic also the streaky weevil, Metamasius hemi- Neem Researchers in Ghana began by looking at pterus. The black weevil is an important the efficacy of a water-based formulation of economic pest of bananas in Peru, as else- Studies conducted since 1996 at the Inter- the fungus. In laboratory studies they found where in the world. The larvae cause national Centre of Insect Physiology and that B. bassiana applied to corm and pseu- damage by eating developing stems, which Ecology (ICIPE) Mbita Point Field Station dostem pieces had the potential to control can cause wilting, stunted development and (MPFS) and in farmer’s fields in western all stages of C. sordidus, with up to 25%, reduced production in attacked plants. The Kenya have been directed at finding eco- 46% and 59% of eggs, larvae and adults, streaky weevil is a secondary pest. Its logically sound and affordable technology respectively, showing disease symptoms. larvae do not have the capacity to cause for control of banana pests. Results indicate In pot experiments they began to look at damage to healthy stems, and its presence is that neem products can give control that is other formulations and application always associated with damage from other not only as effective as that provided by methods. Adult mortality in pot experi- pests, including the black weevil. pesticide treatment, but also far cheaper. ments was in the range 26.4-62.0%, and The pests targeted were the banana weevil best results were obtained using dry conidia Laboratory assays were carried out at the (Cosmopolites sordidus) and the parasitic in a mixture of kerosene + groundnut oil National Agricultural University to assess nematodes Pratylenchus goodeyi and Mel- (70:30 v/v) applied to the soil surface. pathogenicity. A fungal strain was isolated oidogyne spp. These are the predominant These encouraging results translated to the from a natural infection of coffee berry pests in the major banana-growing areas in field. In preliminary trials, weevil mortality borer (Hypothenemus hampei), and this East Africa, which are normally over 1200 of 53-81% was recorded on suckers dusted was mass produced on rice grains. Weevils m above sea level. The pests occur together with B. bassiana, compared with 7-8% in were inoculated by either applying 10 g in the same plant and attack both root and an untreated control. rice-fungus substrate directly, or by spraying conidia at 2 × 109 conidia/ml. rhizome tissues causing severe fruit yield However, the researchers were looking for Inoculation method did not affect efficacy losses. Although effective synthetic pesti- a method that would not only control the (judged by mortality and percentage sporu- cides exist, they are expensive and weevil, but would do so over the critical lation). However, streaky weevil appeared hazardous to use. In recent years, neem establishment phase of young plantains. In to be the more susceptible, with 100% mor- (Azadirachta indica) has come under close trials to investigate how well the OPKC tality reached 10 days after inoculation, scientific scrutiny worldwide as a rich formulation performed in the field, they compared to 45-50% for black weevil. source of natural pesticides. lost no plantain suckers in the OPKC- treated plot, while 17% were lost in a plot Subsequently, field trials were conducted in Neem seed powder (NSP), neem kernel treated with dry spores of B. bassiana and two commercial plantations in Tingo Maria powder (NKP), neem cake (NC) and neem 19% in an untreated control. using two entomopathogenic strains (GM1 oil (NO) containing 4000, 5500, 5800 and and GG1) mass produced on rice substrate. 850 p.p.m. of azadirachtin, respectively, In further field trials, they looked at These strains were isolated from black were tested as such or in aqueous form. In whether conidia or conidial powder in weevil adults from banana plantations laboratory choice tests, less than 12% of OPKC gave best results. Both treatments around Tingo Maria. Traps used to attract weevils had settled under neem-treated gave equivalent and high levels of weevil the weevils were made from two discs of banana 48 h after release, while more than mortality (75.5%) in artificial infestations, plantain pseudo-steams with 10 g rice- 50% had settled under untreated corms. In comparedwithonly1%inanuntreated fungus substrate sandwiched between. a feeding test, weevil larvae caused little control. However, with natural infestations, These were laid out at a density of 30-40/ha damage to neem-treated corms, indicating a the conidial treatment led to 41.7% mor- at the stem-base of plantain trees and were strong antifeedant effect. In addition, tality, compared to only 5.7% for the changed every 7 days. Trapped weevils females laid 3-10 times fewer eggs in conidial powder treatment (and 3.3% for were recovered every 2-3 days and subse- neem-treated than untreated corms, and the control). No suckers were lost during quent mortality and sporulation were only 25% of eggs laid in neem-treated the 2-month study in the conidia-OPKC evaluated in the laboratory. Strain GM1 corms hatched. Forty to sixty per cent of treatment, but 17.7% and 19.4% were lost induced 55.3% and 86.7% mortality in 2nd-instar larvae died within 14 days when in the conidial powder-OPKC and control black and streaky weevils, respectively; confined to neem-treated banana pseu- treatments, respectively. A study of the sporulation occurred in 92.4% and 98.4% dostems; the survivors were small in body spread of fungal conidia using artificially of these, respectively. Strain GG1 gave size and weighed 4-6 times less than those infected and uninfected adult weevils indi- lower mortality (38.6% and 78.4%, respec- in the control. The higher the concentration, cated that B. bassiana conidia might be able tively) and sporulation (74.2% and 82.1%, the greater was the effect of neem to spread up to 18 m from the release point. respectively). materials. 66N BiocontrolNews and Information 2000 Vol. 21 No. 3

Effective methods, frequency and rates of Integrated Approach for caused severe damage and toppling in our application of neem materials were deter- Weevil in Cameroon field trial. mined at MPFS and in farmers' fields, under Wood ash, which is being used by more different levels of soil fertility and pest infes- An integrated approach to weevil control is than 30% of smallholder farmers in Cam- tations using a highly susceptible banana being pioneered in an INIBAP-CRBP eroon, because they believe it controls cultivar (Musa AAA-East Africa). Results (Centre de Recherches Régionales sur weevils, had a moderate repellent effect, indicated that application of 100 g NSP, Bananiers et Plantains) project in Cam- but did not have any effect on oviposition, NKP or NC at planting around the base of eroon. Four species of weevil are present in hatching of the eggs or adult survival. pared or unpared banana suckers, planted in smallholders’ fields in southwest Cam- Coffee husk (Coffea spp.), which is drums and inoculated with weevils and eroon: Cosmopolites sordidus, Metamasius reported to have an insecticidal effect, did mixed nematodes, significantly reduced the hemipterus, M. sericeus and Pollytus melle- not have any effect on weevils. Hot pepper nematode population and weevil damage, borgi, although the most severe infestations (Capsicum spp.) blocked the hatching of and results were on a par with Furadan treat- are caused by C. sordidus. Plantains with eggs under laboratory conditions and had a ment at 40 g/plant. In addition, 10 months the genotype AAB appear to be most sus- moderate repellent effect on adults. after inoculation, NSP- and NC-treated ceptible. Weevil larvae bore into the corm Three strains of entomopathogenic fungi unpared suckers supported eight times fewer and weaken the plant, resulting in high have been isolated from infected adult wee- nematodes than pared suckers treated with plant mortality, reduced bunch weight and vils in southwest and west Cameroon. the same neem product. Paring is generally reduced hand number. Pathogenicity and viability tests were done recommended because it reduces initial over various infection cycles under labora- infestations, but it is labour intensive. The Development of IPM strategies for C. sor- didus for plantain production in tory conditions. Germination tests have results of these studies indicate that NSP and smallholder conditions in Cameroon and indicated that viability of the strains had NC treatment obviates the need for paring. West Africa involves control with botanical diminished after multiplication and sporu- The NKP and NO applications were phyto- insecticides, biological control, genetic lation on artificial (Vegetal) media. toxic, however. control and chemical control. Studies on Nevertheless, in vitro, one strain caused population dynamics are on-going in order 94% mortality of weevils after 9 days in the Soil application of powdered NSP or NC to assess the mobility of weevils in relation first and second infection cycle. Strains will was more effective than their application in to the natural population build-up in plan- be re-isolated from infected adults in order aqueous forms. Application of powdered tain fields. Yield loss of plantain over to regenerate their viability and mass pro- NSP or NC at planting time and then at 1- different crop cycles is being assessed. Phe- duce them on an adequate delivery system. to 4-month intervals to plants grown with romone-baited traps have been tested on a Entomopathogenic nematodes have been controlled pest infestations in drums signif- small scale. Technology validation through isolated from dead C. sordidus larvae. icantly reduced nematode density and farmer participatory trials with NGOs and CRBP has one of the largest Musa collec- weevil damage. Their application at 5- extension agents is planned for 2000. tions in the world. Preliminary screening month intervals and above was ineffective. identified various genotypes with prom- Their application in the farmers’ fields at In a field trial in southwest Cameroon, ising levels of resistance, including plantain 60-100 g/mat at planting and then at neem (Azadirachta indica) seeds were effi- hybrids and parents used in the CRBP 4-month intervals significantly reduced cient in protecting young suckers of breeding programme, which are being eval- nematode density, and weevil and nema- plantain against weevil attack for 3 months uated in the field. Weevil resistance will be tode damage, and increased fruit yields by when they were dipped in a 20% solution of incorporated in the CRBP plantain- 30-60% in the second crop. Yields obtained crushed neem seeds before planting. breeding programme. with Furadan at 60 g/plant at 6-month inter- Weevil damage was tempered and sucker vals were equal or less than that in control mortality due to weevil attack was reduced Several new insecticides are being tested in plants. Even with low soil fertility and high by 25-30%. The efficiency of neem, when order to broaden the possibilities for chem- ical control. In Cameroon only one efficient pest infestation levels, the neem treatments applied closely to the sucker using this dip- insecticide (fipronil, as Regent) is available controlled the pests and markedly increased ping treatment, can be explained by the on the market for controlling weevils. the yield 7-10 times more than the control. multiple mode of action of neem on the life cycle of C. sordidus, which was assessed However, application of NSP or NC at In a field trial in southwest Cameroon pop- under laboratory conditions for neem and more than 200 g/mat at 6-month intervals ulation dynamics are being assessed using three other substances (household ashes, was phytotoxic. mark-recapture techniques. In this trial, coffee husk and hot pepper). Neem had a which had very low weevil populations at repellent effect on adult C. sordidus and Depending on the soil fertility and doses of time of planting (April 1999), the popula- slowed down oviposition. Fecundity of application, the net gain in the NSP or NC tion started to build up in July, with a peak females in contact with suckers rolled in in October 1999, at the end of the rainy treatments was in the range US$70-800/ha neem seed powder was affected. Hatching season, after which the population dropped while Furadan use led to a loss of $700/ha. of eggs in contact with a 10% solution of and remained constant for several months. neem seeds was blocked. The toxicity of Migration of weevils between plots was By: Thaddée Musabyimana neem seeds to adult C. sordidus was low observed in July and August, but not later. Current address: Agriculture and Agrifood compared to a classical contact insecticide, Trapping results indicated that C. sordidus Canada, Horticultural Research and which explains why a crown application migrates by flight. Daily trapping and Development Centre 430, (encircling the mat) with crushed neem removal of weevils reduced weevil popula- Boul. Gouin, Saint-Jean-sur-Richelieu, seeds at 40-100 g/mat did not reduce weevil tions, but did not control them. Quebec, Canada J3B 3E6 damage or weevil populations. The toxicity Email: [email protected] of neem seeds varied according to their The trapping efficiency of a ramp trap Fax: +1 450 346 7740 origin and storage conditions. Neem seeds baited with sordidin pheromone lures did not have any nematicidal effect on R. (commercialized by ChemTica in Costa  similis in the field, which was abundant and Rica) was compared to split pseudostem or News 67N sandwich traps in a small plantain plot in Managing Diseases in technologies being assessed. It will provide terms of number of weevils per traps per Uganda a better understanding of the effects of par- week. These ramp traps were only two to ticular farm management practices on plant three times more effective then the pseu- Banana diseases, including wilts, leaf spots health and on the prevalence and signifi- dostem traps, with the number of weevils and parasitic nematodes, have been found cance of major banana diseases. Direct caught being highly variable. Pheromone to be major constraints to the production of participation by farmers, extension services lures remained attractive for 3-4 weeks. both indigenous and exotic bananas in and national agricultural research pro- Uganda and a key contributor to a recent gramme staff will greatly enhance their By: Stijn Messiaen, INIBAP Regional and significant decline in production. Man- ability to recognise banana pest and disease Office for West and Central Africa, agement of these will be addressed in a constraints and increase their awareness of BP 12438, Douala, Cameroon programme for the integrated management the beneficial effects of cultural farming Email: [email protected] of banana diseases funded by the DFID practices. By identifying and facilitating Fax: +237 42 91 56 Crop Protection Programme. It began in the uptake of practices that most effectively January 2000, and is being led by CABI improve banana plant health and reduce  Bioscience in collaboration with the Uni- losses due to diseases, the project will versity of Reading, UK, the Uganda enable farmers to increase yields and pro- National Banana Research Programme duce a crop of higher quality, thereby UK Support for Bananas (UNBRP), the International Institute of helping to reverse the general decline in Tropical Agriculture (IITA), Uganda and banana production in Uganda seen in recent The UK government has recognized the the Natural Resources Institute, UK (NRI). years. This, in turn, will enhance the liveli- significance of bananas and plantains to the hood of smallholder banana farmers in UNBRP have already identified or devel- rural population of East Africa and, in a Uganda, by providing a more reliable staple oped a number of cultural farming cluster of programmes funded by the food source and by increasing farm income technologies with potential for alleviating Department for International Development generated through the sale of bananas at (DFID) through their Crop Protection Pro- disease constraints and, consequently, for local markets. The demonstrative and increasing yields and reversing the down- gramme (CPP), is providing financial training elements of farmer participation support for research into sustainable solu- ward trend in production. As part of its will contribute significantly to the rapid intervention or management phase, tions to pest and disease problems. uptake of suitable technologies to achieve UNBRP is now placing emphasis on the Collectively these projects address the early impact for improved and sustainable problems of banana weevil, foliar diseases, evaluation and transfer, to farmers, of such banana production. wilts, banana streak virus and nematodes. technologies as part of an IPM approach. In one of these, new technologies will be The DFID-funded programme will enable Contact:MikeA.Rutherford, incorporated into an IPM system for man- new technologies developed for banana CABI Bioscience UK Centre (Egham), agement of the banana weevil in Uganda. disease management to be evaluated under Bakeham Lane, Egham, There will be close linkages in this work farmer field conditions at benchmark sites Surrey TW20 9TY, UK with the regional project concerning on- in Uganda. These include banana varieties Email: [email protected] farm testing of technologies also funded by with different yield/growth characteristics Fax: +44 1491 829100 the UK government and with a project and disease and nematode resistance,  funded by the Gatsby Foundation which improved use of organic and mineral ferti- has similar objectives but emphasizes the lizers, and related cultural treatments to large-scale introduction of new disease-free improve plant vigour, clean planting mate- Managing Banana Streak varieties to many farmers in the central rial and break crops. Virus region of Uganda. The project will identify technologies that AnotheroftheDFIDclusterofprojectsin The DFID Crop Protection Programme has are most effective in minimizing losses due Uganda is concerned with epidemiology, recognized that the Uganda National to banana diseases under different agroeco- vector studies and control of banana streak Banana Research Programme (UNBRP) logical and farm management conditions. virus in highland bananas, which is per- has the trained staff available to address the Those technologies found to be most ceived as one of the major threats to this different constraints to banana produc- appropriate for widespread adoption in crop in the country. tivity. With several promising techniques Ugandan farming systems will then be selected with a view to subsequent wide- Banana streak virus disease (BSV) is now a and practices available together with some major constraint to increasing banana pro- new varieties developed by the Interna- spread adoption by farmers as part of an IPM approach. ductioninmanyregionsofthetropics.In tional Institute of Tropical Agriculture Uganda, and other countries of East Africa (IITA) and FHIA (Fundación Hondureña A new wilt syndrome, referred to locally as where bananas are a major component of de Investigación Agrícola) banana ‘ wilt’, has recently been observed the diet, declining yields and the abandon- improvement programmes, work in on highland banana types. Its development ment of banana plantations by some Uganda should make significant advances appears to be related to particular farm growers is attributed to the effects of the in alleviating poverty and improving rural management practices, including the use of virus. BSV is widely distributed in most livelihoods: the major purpose of the cur- household refuse and manure. The project common cultivars of banana across the rent DFID policy. will investigate these and other factors. country, with high incidence near the bor- Options for more effective management of ders. The disease appears to be causing Contact: Simon Gowen, Department of this newly emerged problem by farmers significant yield loss in certain locations, Agriculture, The University of Reading, may then be developed. although reliable information on the rela- Earley Gate, Reading, RG6 6AT UK tionship between disease severity and yield The project aims to provide stakeholders, Email: [email protected] loss is lacking. Fax +44 1189352421 including farmers, with information to allow them to judge and decide on the suit- Because many aspects of the dynamics of  ability of the various disease management BSV are poorly understood, disease man- 68N BiocontrolNews and Information 2000 Vol. 21 No. 3 agement strategies are poorly developed bugs nor in the field. An identification key conditions, the disease first appears on leaf and banana farmers in Uganda have no to banana mealybugs is being developed 3 or older leaves, or not at all. There is a clear control options available. This by Jerome Kubiriba (NARO) and Gillian gradient of evolution of the disease from project, which began in November 1999, is Watson (CABI Bioscience). the top to the bottom of the banana tree, and led by the Natural Resources Institute fungicide applications should be aimed at Contact: Tim Chancellor, Pest Manage- (NRI) in collaboration with the National the top of banana trees to control new ment Department, Natural Resources Agricultural Research Organization in infections. Institute, University of Greenwich, Uganda (NARO), the University of Central Avenue, Chatham Maritime, The incubation period (from stomatal pen- Reading and the International Institute for Kent ME4 4TB, UK etration to first symptom of disease) and the Tropical Agriculture (IITA) in Ibadan. It Email: [email protected] transition period (from stage 1 (minute aims to gain a better understanding of the Fax: +44 1634883379 yellow point) to stage 5 (necrotic grey epidemiology and ecology of BSV, and its spot), according to Brun’s scale) vary importance and effect on banana produc-  widely with climatic conditions, and can be tion in Uganda. The information generated up to 100 days. Several steps of the disease will be used to provide recommendations Forecasting Less cycle are highly dependent on the water on optimum crop and pest management Fungicide for Sigatoka status at the leaf surface. With such varia- practices to limit the spread of BSV and Disease in Guadeloupe bility in the development of the disease, a reduce its effect on crop productivity. forecasting system has real potential to Yellow Sigatoka disease caused by Many of the activities in the project will be reduce fungicide applications. Mycosphaerella musicola (anamorph conducted in selected ‘benchmark’ sites Pseudocercospora musae)isoneofthe In the field, it is essential to control the dis- where related studies on constraints to most important threats the ease before necrotic formation, as banana production are being carried out has to face in Guadeloupe. The disease sporulation occurs in stages 4 (waterborne with groups of participating farmers. One causes leaf spot, and heavy attacks can conidia) and 5 (airborne ascospores). such activity is an examination of the main reduce considerably the number of leaves Where leaves are heavily spotted they factors influencing the activation of the and, ultimately, bunch weight. Neverthe- should be removed since they can produce virus, the expression of disease symptoms less the most important effect of this ascospores for many months. Contact fun- and the damage caused to the plant. The disease is indirect. Heavy spotting results in gicides are not curative and are effective interaction of the virus with the host plant is a reduction in the greenlife of the fruit, only before fungal penetration, so they are complex; symptoms can be very variable, which considerably depreciates its export useless in forecasting strategies that rely on often being similar to symptoms of nutrient marketability. At least ten viable leaves at symptom observations. Systemic fungi- or water stress, and there can be periods of harvest are necessary for good fruit market- cides have a curative effect on streaks symptom remission. Most, if not all, Musa ability and therefore excellent control of (stages 1, 2, 3), but not on necrotic lesions species and varieties tested to date have this disease is essential. (stages 4, 5), although sporulation is tempo- BSV-like sequences integrated into their rarily decreased. genomes, which cause no symptoms in the From 1937, when yellow Sigatoka disease host. However, it is suspected that some of was first reported in Guadeloupe, 40-50 Area-wide control is important, as wind- the integrated forms can be activated under fungicide treatments per year have been transported ascospores can disseminate the certain conditions. This may be influenced used to control the disease, and treatments disease over long distances, and failure of by climatic factors, plant nutrient status, have been applied systematically according control in one area can affect neighbouring and crop management. For example, water to a pre-established ‘calendar’ programme. areas. stress and cool temperatures are suspected The main objective of CIRAD-FLHOR Four Keys to Successful Forecasting to be the cause of localized outbreaks of (Centre de Coopération Internationale en BSV. Recherche Agronomique pour le Dévelop- The forecasting system relies on the timing pement – Département Productions of decisions and applications, treatment Spread of BSV will be examined through Fruitières et Horticoles) (ex-IFAC, ex- efficacy, and organization of control. field experiments at the benchmark sites to IRFA) research has been to reduce the monitor the natural spread of BSV in 1. Decision Making. In Guadeloupe, both number of treatments to the minimum nec- blocks of ‘trap plants’ of virus-indexed biological and climatic data recorded every essary for ensuring good fruit quality, so Cavendish ‘Williams’. The experimental week are used to decide on the application decreasing the cost of control, as well as plots will be monitored visually for timing. The information they give is com- minimizing risks of fungicide resistance symptom expression and by enzyme-linked plementary. Climatic information is and environmental effects. Key to this was immunosorbent assay for the presence of predictive and is useful in preventing gaining a better knowledge of the disease, BSV. In a related study, researchers at the spread of the disease. However, more so that a forecasting system could be devel- John Innes Institute, UK are investigating importance is attributed to biological data, oped for optimizing fungicide applications. the possibility that BSV is present in dif- since they represent the real status of the ferent strains in Uganda. Disease Epidemiology and Disease disease. Comparison of theoretical and Control The role of insect vectors in the spread of observed data is also essential to detect any disruption in the control strategy. the virus in the field is being assessed. BSV Germination and stomatal penetration by is a badnavirus, most of which occur in the fungal agent of Sigatoka disease are The biological forecasting system is based clonally-propagated tropical crops. In nat- impeded by fungal antagonism in old on early detection of new attacks by contin- ural systems, the most important means of leaves. Stomatal penetration only occurs on uous monitoring. The stage of evolution of spread for badnaviruses is probably by veg- the unfurled leaf (cigar) or on the first full the disease (SED) is calculated as the etative propagation, but transmission by leaf (leaf 1). Bananas produce new leaves at product of the rate of new leaf production mealybug vectors has been demonstrated. a rate of about one per week. Under cli- (foliar emission rate) and the speed of Indeed BSV has been transmitted to banana matic conditions most favourable to disease development of the disease. The speed of under experimental conditions by three development, first symptoms are observed disease development is monitored continu- species, although not by African mealy- after 12 days on leaf 2. In less favourable ously by inspecting the youngest five News 69N leaves on ten plants in a plot each week. ergosterol biosynthesis inhibitors of group the environment have been reduced 8-10 The most advanced stage of the disease 1 (DMI group) and 2. Oil carriers fold by the forecasting system. Neverthe- (according to Brun’s scale) is scored for strengthen the curative effect because min- less, we should not be complacent, for new each leaf. A coefficient for each leaf eral oils have a fungistatic effect. fungicide resistance may develop. There is number/disease stage association (which a need for more new fungicides with more It is important to manage development of increases with disease severity and novel modes of action, especially since fungicide resistance, and alternation of decreases with leaf age) has been calcu- antimitotic fungicide resistance is wide- groups of fungicides with different sites of lated, and these are summed to provide an spread in banana plantations. Products action is essential. Regular monitoring of estimate of the speed of disease develop- belonging to the strobilurin family are still resistant strains using a methodology based ment. The foliar emission rate is an under evaluation. on a germination test of conidia determines indicator of plant vigour, and the more vig- any changes in sensitivity. The problems faced by the banana industry orous the growth of the banana trees, the are quite different to those for other crops, faster the disease develops. Keeping the sources of inoculum at a very because only one group of cultivars (the low level is also important. Chemical SED is an indicator of the potential of Cavendish group) with low genetic varia- sprays do not eliminate the disease from development of the disease and graphic bility is grown for export. A new approach spotted leaves, so where extensive spotting representation of its weekly value is used to yellow Sigatoka disease control should is present, new infections will develop for decision timing. There is a threshold combine genetic resistance or tolerance quickly and the only solution is to remove value for spraying, but attention is also paid with a rational use of fungicides. It is vital leaves mechanically from the banana tree. to the slope of the graph of SED against to begin to look at these options because time. Experience has also shown the level 4. Organization. Since ascospores are another important curse of bananas, black of SED up to which fungicide efficacy is transported by wind over long distances, Sigatoka (or black leaf streak disease) maintained. the control strategy should be the same in (Mycosphaerella fijiensis), which is similar all banana plantations. Organization is to yellow Sigatoka disease but more diffi- Climatic information identifies periods more efficient if centralized under a single cult to control, is now a serious threat for when conditions are not favourable to dis- technical service operating according to the Caribbean banana industry. ease development. As thermal conditions rational guidelines, rather than each grower are always favourable to disease develop- By: L. de Lapeyre de Bellaire, implementing his own strategy, often with ment in Guadeloupe, temperature is not CIRAD-FLHOR, Station de Neufchâteau, short-term objectives. Banana growers are used for forecasting. On the other hand, Sainte Marie, 97130 Capesterre belle eau, grouped in an association that performs the Piche evaporation, assessed under an open- Guadeloupe, French West Indies control strategy. The cost of the phytosani- air station, represents well the water status and J. Ganry and X. Mourichon, tarycampaigniscoveredbyataxon at the leaf surface, taking into account CIRAD-AMIS, BP 5035, 3 exported bananas. global , air saturation, wind and 4032 Montpellier, France temperature. A relationship found between Progress and Prospects Contact: Luc de Lapeyre de Bellaire Piche evaporation and duration of treat- In Guadeloupe, the forecasting system has Email: [email protected] / ment efficacy is used in decision timing. been operating for 25 years and conse- [email protected] 2. Spray Timing. The time between deci- quently the control has been centralized Fax: +590 86 80 77 sion and execution of one application over 6000-7000 ha of bananas. Disease  should not exceed 7 days and the whole assessment is done and meteorological spraying area should be sprayed on the records are recorded by a technical team same day. Treatments are made by aero- from the banana growers association, and Integrated Action against plane, which facilitates a swift operation, treatments are applied by the banana Nematodes in Uganda growers association or by a private com- but good logistics are essential. The cli- Plant parasitic nematodes are a major con- pany. An equilibrium of six treatments/year matic conditions required for aerial straint to sustainable Musa production. In has been achieved since 1973 through a spraying are limiting, and the ‘windows’ Uganda, which is the world’s largest pro- control strategy including timing of deci- are small: only in the early morning and late ducer of East African highland bananas sions and the use of a systemic fungicide in afternoon do thermal inversion and air tur- (Musa spp., AAA group), nematodes have pure oil, compared with 10-20 treatments/ bulence not interfere with spray deposition. been identified as a major factor contrib- year in other countries (Ecuador, Surinam, Aerial application is not possible at all on uting to declining production. The major Dominican Republic, Jamaica, Windward rainy and windy days. Miss a ‘window’ and nematode species affecting banana in Islands) where fungicides are applied on a control may break down. Uganda are Radopholus similis and Heli- calendar basis. 3. Effective Treatment. This is dependent cotylenchus multicinctus at an elevation of on the quality of the foliar application and However, forecasting did not eliminate all between 1000-1300 m above sea level. At good coverage is essential. Bad weather problems. The exclusive use of benomyl higher elevations, the most common nema- conditions on the day of application, irreg- from 1973-1982 led to the build-up of fun- tode species is Pratylenchus goodeyi.At ular topography in the spray zone or the gicide resistance. Fortunately, fungicides Sendusu, near Kampala (1120 m), produc- presence of obstacles can alter its uni- with novel modes of action were available tion losses in the commonly grown cultivar, formity. The use of mineral oil carriers has at that time and their introduction in an Mbwazirume, from R. similis and H. multi- considerably improved the quality of cov- alternation strategy enabled us to return to cinctus were 30-38% under a variety of erage through aerial spraying with low equilibrium. management regimes. Damage is charac- volumes (at 12-15 litres/ha). terized by reduced flower production and Today, yellow Sigatoka disease is under bunch weight, and an increase in plant top- Efficacy relies also on a strong curative effective control and is not affecting the pling because of poor root development. effect and systemic fungicides are thus pre- quality of export fruit. The cost of control ferred to contact fungicides. The systemic (0.08FF/kg) represents less than 3% of the Nematodes can be controlled with chemi- fungicides used for yellow Sigatoka control production costs. The number of treatments cals, but these may have adverse have an antimitotic mode of action or are and the quantity of pesticides discharged in environmental effects and the use of nema- 70N BiocontrolNews and Information 2000 Vol. 21 No. 3 ticides is too expensive and the products screened further for possible inclusion in compared with standard farmers’ material too dangerous for subsistence farmers. An the breeding programme and eventual in Uganda. integrated strategy (cultural, biological, release. cultivar selection) may be the best solution In Uganda, the project is carried out in four Currently, representatives of each clone set for nematode control, and this is being districts. The NGO Environmental Alert from the East African highland bananas are developed by staff at IITA-ESARC (the was involved in the mobilization and super- being screened. Hybrids derived from the International Institute of Tropical Agricul- vision of the farmers’ activities and East African highland bananas are also ture – Eastern and Southern Africa extension contact in Mpigi, while district being evaluated. Progeny of the cross Regional Centre). agricultural officers performed these func- TMB2x 6142  TMB2x 8075 look particu- tions in Luwero, Masaka and Ntungamo. Diagnostic survey activities in Uganda larly promising. Both parents are also being Baseline data were collected to establish were carried out in representative banana- screened against banana weevil, and first initial damage and production levels. In growing villages. Data were collected on results indicate that they are resistant to the pest and disease incidence and severity and pest. They are also resistant to black Siga- total 1713 farmers were trained and 4487 current pest management methods. In col- toka and fusarium wilt. TMB2x 8075 has suckers were treated and planted. Moni- laboration with the Uganda National Pisang Jari Buaya (PJB) in its pedigree, toring and data collection will be carried Banana Research Programme (UNBRP), which is highly resistant to R. similis. out in the areas where the planting has been four benchmark sites have been selected for done. A hot water tank has been con- Fungal Endophytes in-depth research and farmer participatory structed and the Minister of Agriculture for research. Currently work is focusing on Investigation of the potential of endophytic handed it over to farmers in that three control strategies: host plant resist- isolates of Fusarium oxysporum from region. Similar projects are in operation in ance, biological control by the use of banana for the control of plant parasitic and in Zanzibar. endophytes and clean planting material. At nematodes began in 1997. The fungal cul- the moment, most of our work is concen- tures used in screenings for nematode Nematode-Root System Interactions trated on R. similis,asthisisthemost control were isolated from Ugandan banana damaging nematode species. roots, cv. Mbwazirume, at the University of The spatial distribution of nematode popula- Bonn. Selection of candidate isolates was tion densities and damage in roots of the Host Plant Resistance based on the nematode inactivating effects varieties Pisang Awak, Sukali Ndizi and Research is directed at identification of of their culture filtrates. None of the isolates Nabusa were investigated at three localities durable nematode resistance sources and screened to date were vegetatively compat- in Uganda, each with a distinctive nematode genetic analysis of nematode resistance. ible with the tester strain of the wilt fungus, population composition. At Namulonge R. Screening for resistance to nematodes Fusarium oxysporum f. sp. cubense,indi- similis dominates, at Ntungamo the domi- using field trials is a very time and labour- cating that they are non-pathogenic. The nant species is P. goodeyi, while at Mbarara consuming effort. To screen the large avail- fungal cultures were re-imported into the two species coexist. At all three sites, able Musa germplasm, including landraces, Uganda through quarantine. suckers were removed from mats and commonly used exotic bananas and the assessed for nematode reproduction and Standard protocols for screening fungal IITA hybrids, a fast and reliable screening damage. Nematode population densities endophytes against the most damaging protocol is needed. were randomly distributed along the primary nematode, R. similis, have been estab- roots while nematode damage was signifi- The method of single root inoculation was lished. Preliminary results of pot trials cantly higher close to the corm than further initiated in 1998, and improvements since show that certain endophytic isolates along the primary roots, independent of cul- have meant that the protocol is now fully reduced both nematode damage and repro- tivar and location. It was also observed that standardized and can be used as a routine duction in some banana clones. Plant R. similis-infected banana mats had weaker screening method. Four weeks after growth-promoting effects have also been plants and a reduced root system compared planting, three roots are selected from each observed. Pot trials are on-going to deter- with those infected by P. goodeyi. The total plant and a cup is placed around them. Fifty mine the optimal combination of banana length of dead roots was significantly higher females of R. similis in suspension are cultivar and fungal endophyte. The most when R. similis was present. placed directly on the selected root. Evalu- promising endophyte, V5w2, is currently ation 8 weeks later includes root health being tested in the field. A study was also conducted on the relation- assessment and nematode counts. For each Clean Planting Material ship between banana nutritional status and genotype the reproduction ratio is calcu- nematode infection and damage. Nematode lated. The advantages of this method are Using pest- and disease-free planting mate- infection impairs nutrient absorption and that a lower nematode inoculum and fewer rial can reduce the spread of both plant distribution in the banana tissues. plants per genotype are needed (since more parasitic nematodes and banana weevils. was shown to be the most impeded. When roots per plant can be inoculated) and more The objective of this technology-transfer ‘complete’ nutrients were supplied to nema- hybrids can be screened at the same time. In project is the delivery of healthy banana tode inoculated plants, it was observed that each experiment, R. similis susceptible planting material to farmer communities. In nematode populations and damage in roots (Valery) and resistant (Yangambi-km 5) May 1999, a workshop was organized in were reduced. Excess or deficient nutrient cultivars are included. Valery shows a high Namulonge, Uganda to give training in hot supply resulted in increased nematode popu- reproduction ratio with this protocol, while water technology and to provide basic lation and damage. very low or no reproduction ratio is found understanding of banana and yam pests and in Yangambi-km 5. diseases. By: Carine Dochez, Using this method, a number of promising Before planting, suckers are pared (to IITA-ESARC, hybrids have been identified in Uganda. remove roots and infested rhizome tissue), P.O. Box 7878, Kampala, Uganda These have low reproduction ratios, that are after which they are hot-water treated (for Email: [email protected] not significant different from Yangambi- 20 minutes at 53-55ºC). The use of clean Fax: +256 41 223459 km 5, indicating that they support low planting material can increase production nematode densities, and these will be by 30-50% per cycle for at least four cycles  News 71N

Soil Suppression and Seeking the Root Cause also being assessed for their antagonistic potential toward burrowing nematode in Nematode Biocontrol in The next stage in developing a successful bananas. Screening of isolates by Tony Pat- Australia biological control is to identify candidate tison and Caroline Versteeg has commenced organisms that are antagonistic to burrowing in north Queensland. Initial results suggest The Australian banana industry produces nematodes. Various microorganisms may be some suppression of R. similis by ten rhizo- approximately 250,000 tonnes of bananas responsible, and the Queensland team have bacterial isolates, and further screening is for Australian domestic consumption. The been looking at the range that may be continuing. most damaging nematode to banana pro- involved. duction in Australia and worldwide is the Finally, Tony Pattison and Caroline Vers- burrowing nematode (Radopholus similis). Julie Stanton and Jenny Cobon conducted teeg have been conducting pot trials to look The nematode causes toppling of bunched glasshouse trials with a number of fungi (all at the antagonistic potential of mycorrhiza pseudostems, reduced bunch weight and Fusarium oxysporum) they isolated from isolated from banana-growing soil in north increased cycling time. Nematode damage the cortex and the stele of surface-sterilized Queensland. They found that the presence on bananas has been managed by the rou- banana roots. The isolates included three of R. similis appeared to reduce mycor- tine use of chemical nematicides which are from naturally suppressive sites and four rhizal colonization within banana roots. expensive and hazardous. Some nemati- from non-suppressive sites in southeast Conversely, there were significantly fewer cides are becoming less effective due to the Queensland.Threemoreisolatesweresup- nematodes in plants colonized by mycor- development of enhanced biodegradation, plied by Kendle Gerlach of the University rhiza, but there was no growth reducing the chemical’s efficacy. of Queensland. Banana cv. Williams plants improvement in plants colonized by mycor- were inoculated with fungi at repotting by rhiza. The use of mycorrhiza as a treatment However, the incidence of burrowing nem- placing inoculated grain sorghum under the to reduce R. similis infection for tissue-cul- atode attack in Queensland is patchy. Some roots. The plants were inoculated with tured banana plants is a good avenue farms have been producing bananas for up nematodes 3, 6 and 9 weeks later. Ten worthy of further investigation. to 30 years with little loss to nematode weeks after inoculation, nematodes were Aiming for Suite Success damage, and they have no need for nemati- extracted from the roots for 7 days in a cides. We investigated some of these farms misting chamber, counted and the fungi By conducting this research we hope to to see if their soil naturally suppressed bur- reisolated from the banana roots. identify organisms that are antagonistic to rowing nematodes and, if so, whether this There was a reduced recovery of nema- burrowing nematodes and can be devel- could provide a basis for a biological con- todes from a fungal isolate taken from a oped for biological control. Such trol method. Burrowing nematodes feed suppressive soil site in plants inoculated organisms could be introduced to banana and reproduce within the root cortex of with nematodes 3 weeks after inoculation plants either at the repotting stage in a tissue banana plants, and this does not make them with fungus, but there was no reduction culture nursery, as a dip for vegetative particularly amenable to biological or other with the later inoculation dates. planting material prior to planting in the any other form of control. ground, or by injection into an established Caroline Versteeg investigated endophytic plant. The endoparasitic behaviour of bur- Glasshouse trials were conducted by Julie actinomycetes she isolated from surface- rowing nematode means that no single Stanton and Jenny Cobon (Queensland sterilized banana roots taken from a site inundative organism is likely to provide the Department of Primary Industries (QDPI), which showed suppression of burrowing solution to nematode problems in bananas. Indooroopilly) and Tony Pattison and nematode in north Queensland. The actino- By developing a suite of organisms with Caroline Versteeg (Centre for Wet Tropics mycetes were obtained as pure cultures and different niches on the banana root system, Agriculture) to assess soil from ten banana initially tested for their ability to reduce the chances of successful biocontrol of bur- crops in southeast Queensland and six in nematode motility. Three isolates were rowing nematodes on bananas should be north Queensland, respectively, for natural found to significantly reduce nematode increased. suppression of burrowing nematodes. motility. These isolates were grown on ster- By: Tony Pattison, Queensland Banana cv. Williams were planted in either ilized wheat bran, which was then mixed Department of Primary Industries, sterilized or unsterilized soil from each site, with sterilized soil, in which a tissue-cul- Centre for Wet Tropic Agriculture, and three weeks later were inoculated with tured banana plant, cv. Williams was PO Box 20, South Johnstone, nematodes. Any biological effects in the grown. The banana plants were inoculated Qld 4859, Australia soil were assessed by counting nematodes with motile burrowing nematode 7 days Email: [email protected] extracted from the banana root system in a after inoculation with the actinomycetes. Fax: +61 7 4064 2249 misting chamber ten weeks after In the pot trials no actinomycete isolates inoculation.  significantly reduced the number of bur- rowing nematode in the roots of the banana More nematodes were recovered from ster- plants relative to an untreated control. IPM Leads to Increased ilized than unsterilized soil in eight of the However, more endophytic bacteria iso- and Sustained Yields in ten soils from southeast Queensland, which lated from suppressive soils are currently Ghana indicated some kind of natural suppression being evaluated in pot trials. Modification due to a biological factor. However, only Plantain is a primary staple food in Ghana, of the screening procedures may be needed one soil from north Queensland showed providing a source of food and cash income to determine the biocontrol potential of the similar suppression. Work is continuing to for resource-poor farmers throughout the candidate organisms. determine whether soil can be induced to year, thus contributing to national food become suppressive by the addition of Rhizobacterial isolates collected from security. In recent years, there has been a organic amendments such as chitin and ash, banana fields in north and southeast substantial decline and reduction in planta- and whether indigenous antagonistic organ- Queensland are being investigated by tion life (<3 years) within the country. isms present in these soils may be Linda Smith (QDPI, Indooroopilly) for Severe plant toppling in the first season and encouraged to reduce nematode damage in their role in suppression of Fusarium rapidly diminishing yields in ratoon cycles bananas. oxysporum f. sp. cubense. The isolates are mean that plantain is commonly treated as 72N BiocontrolNews and Information 2000 Vol. 21 No. 3 an annual rather than a perennial crop. This plants grown from hot-water treated clearly that the production and rapid multi- situation necessitates frequent land clearing suckers. The percentage of bunches lost plication of clean planting materials can be whichiscostlytothefarmerandtheenvi- prior to maturity (due to toppling, stem profitable even when there are adverse ronment. The decline in plantain breakage, failure to flower or premature price fluctuations. Farmers producing clean production is attributed to high levels of death) exceeded 75% for untreated mate- suckers can benefit both through the use of nematodes, banana weevils and foliar dis- rials under traditional management, their own clean planting material to pro- ease (black Sigatoka) together with poor compared with 43% for hot water-treated duce improved yields and also by soil fertility (resulting from shortened fal- materials under improved management. diversifying their farm income through the lows) and the high cost of crop The yield from hot water-treated materials sale of clean suckers to other farmers. management. Plantain damage due to nem- that had regular weeding was more than tre- Cost/benefit analyses showed that the use atodes and weevils is frequently bled compared with untreated materials. of clean planting material and improved compounded by the use of infested planting Moreover, it was observed from the 1995 management practices for plantain produc- material since farmers are usually unaware trial that planting material treatment, in tion was profitable compared with that suckers are the main source of inoc- combination with regular weeding, sub- traditional practices. For example, hot ulum for these pests. Lack of healthy stantially lengthened plantation longevity. water-treated suckers under improved crop planting material represents a major con- Farmer-managed plots with untreated management (optimum plant spacing and straint to plantain farmers in Ghana. materials were largely abandoned after the regular weeding) gave an economic return Suckers are costly, they are often infested first season due to the high incidence of of US$800/ha over a 2-year period, repre- with nematodes and weevils, and may not plant toppling. In contrast, hot water- senting net additional returns of $300/ha be available when the farmer is ready to treated materials that were well-managed compared with traditional practices. plant. continued to yield for 4 years. Dissemination Raising Clean Planting Material Farmers’ Perceptions Technologies developed for the production In 1999, Farmers’ Fora held at three pilot These pest and disease problems have been and rapid multiplication of clean plantain sites gave farmers an opportunity to discuss addressed through farmer-participatory planting material formed the basis of the and evaluate the technologies tested. research. The development of a simple curriculum for a plantain IPM Farmer Field Farmers stated that nursery production pro- scheme for the production and rapid multi- School in Ghana (1997-1999). Twelve vided a means to generate and multiply plication of healthy planting material in extension agents (from six major plantain- clean suckers as required. Moreover, community nurseries has provided the growing regions) were trained in methods nursery-derived materials performed better foundation for improved plantain produc- for improved plantain production. Tech- than untreated suckers and could also be tion. Plantain suckers collected from a niques learned were transferred to plantain sold at a higher price than untreated suckers healthy plantation are pared (roots and farmers’ groups in each of the officers’ when required. The major constraints in corm outer layers removed) with a cutlass districts. to remove nematodes, and weevil eggs and nursery production were the need for larvae. The pared suckers are then multi- watering during the dry season and the cost By: Kim R. Green, Project Coordinator of labour for regular weeding. In addition, it plied using a ‘split-corm’ technique, Research was funded by BMZ, Germany was realized that use of the hot water tank whereby they are split into several setts (4- and executed by the International Institute of for sucker treatment would be more fea- 10 depending on sucker size) which are Tropical Agriculture (IITA) in collaboration sible for farmers’ groups than for germinated for 4-6 weeks in seed beds or with the Ministry of Food and Agriculture, individuals. boxes containing sawdust or other locally Ghana (MoFA) and the Agricultural available sprouting media. The sprouted When asked to discus the performance of Research Station of the University of Ghana suckers are transferred to a field nursery at treated suckers, farmers’ perceptions at Kade. The Plantain Farmer Field School a spacing of 60 × 60 cm where they are closely reflected the results of both agro- was funded by the UN Development Pro- maintained for 4-6 months before transfer nomic and economic analyses. They gramme (UNDP) (through FAO) with to the farmers’ fields. The advantage of the observed that plots with hot water-treated assistance from MoFA and GTZ (Gesells- field nursery is that plants can be carefully materials under improved management chaft für Technische Zusammenarbeit). maintained in a relatively small area at a (optimum plant spacing and regular Contact: Kwame Afreh-Nuamah, National stage when they are particularly susceptible weeding), required more labour but that IPM Coordinator, Facility of Agriculture, to environmental stress. Prior to trans- this disadvantage was outweighed by better University of Ghana, Legon-Accra, Ghana planting to the farmers’ fields, suckers are plant establishment, higher numbers of Email: [email protected] pruned (pseudostem cut back to a height of suckers, a shorter time to maturity, a higher Fax: +233 21 500184 10 cm) and pared. If equipment is available, number of bunches, longer plantation life pared suckers are hot water-treated (53- and higher cash returns. For example, one Peter Neuenschwander, 55ºC for 20 minutes) before planting, as farmer stated that “Plantain can survive on Plant Health Management Division, IITA, this is a highly efficient method for elimi- the farm for several years before dying-off, BP08-0932, Cotonou, Benin nating nematode inoculum in the suckers. unlike previous years where the plant dies Email: [email protected] Farmer-Participatory Trials off after one harvest”. Paring had been Fax: +229 350 556 adopted by at least 40% of the plantain  On-farm trials were established in 1995 and farmers at three pilot sites, representing 1997 to study the influence of planting good progress since a participatory rural material treatment (hot water treatment) appraisal in 1993 when farmers were una- Post-Harvest Diseases of andimprovedcropmanagement(regular ware of the need for planting material Banana weeding) on pest and disease dynamics, treatment. Diseases of Economic Importance growth and yield of plantain. At flowering, Economic Feasibility the density of Pratylenchus coffeae (the The most important post-harvest disease of most damaging nematode on plantain in Financial appraisal of plantain nursery pro- banana is crown rot, which is caused by a Ghana) in roots, was significantly lower in duction at three villages in Ghana showed complex of fungi with Colletotrichum News 73N musae being the main pathogen. Addition- Breeding programmes, most notably at biological or integrated disease control. ally, Fusarium spp. are ubiquitous FHIA (Fundación Hondureña de Investi- Whereas only few bacteria appeared effec- secondary invaders and Acremonium sp., gación Agrícola) in Honduras, have tive, mycoparasites (fungi parasitizing Botryodiplodia theobromae, Fusarium mon- produced crown rot-resistant hybrids but other fungi) showed great promise. Some iliforme, Fusarium pallidoroseum (formerly these have different organoleptic character- of them attacked the whole range of fungi F. semitectum), Nigrospora sphaerica, Pen- istics from Cavendish clones and are not involved in the disease complex, including icillium spp. and Verticillium spp. are of well accepted by the mainstream customer. structures which are very resistant to fungi- regional importance. These secondary cidal attack such as conidia and haustoria. Cultural management options include invaders are often isolated from severely dis- Others showed great tolerance to fungi- reduction of inoculum and earlier har- eased fruit in higher frequencies than C. cides themselves and could thus be vesting which is sometimes combined with musae and therefore blamed as the causal combined with reduced concentrations of techniques that accelerate fruit develop- agent. However, whenever quantitative fungicide in an integrated disease manage- ment in order to minimize yield loss. inoculation studies were carried out in order ment system. The highly diverse Physical approaches require first and fore- to fulfil Koch’s postulates, C. musae population structure of C. musae renders a most a rapid cooling of the fruit after required at least one log unit less inoculum single-strain biocontrol agent unlikely to harvest and a continuous cooling chain than the other fungi to evoke symptoms. provide consistent crown rot control. How- throughout transit which should be of min- ever, mixtures of strains could overcome imum duration. Due to the highly Colletotrichum musae establishes a latent this problem. Each mycoparasite was found perishable nature of banana fruit, the chain infection in the field at early stages of fruit to act via a different main mechanism, i.e. of operations has to be well organized at all development. When the banana hands are parasitism, antibiosis, competition. Combi- levels. Smooth crown cuts and immediate severed from the rachis during harvest, nations of up to four strains of transfer of fruit into an alum solution for spores of fungal inoculum enter the wound mycoparasites belonging to different spe- delatexing also reduces crown rot. During and initiate disease development at this cies (mostly Gliocladium spp. and shipment, modified and controlled atmos- window of opportunity. Crown rot symp- Paecilomyces spp.) complemented each pheres have shown promise but many of toms usually only become visible during other and progressively increased the bio- them either proved too expensive for rou- fruit ripening in the countries of destina- control efficacy against mixed infection. tine use or had negative side effects on tion. Then, however, the disease can Preliminary studies suggest that incompati- other fruit quality characteristics. Natural progress rapidly and, in severe cases, the rot bility is not a problem. Future research and non-synthetic chemicals have been penetrates the pulp which renders the fruit should thus focus on mycoparasite mix- investigated, among them calcium prepara- unmarketable. Crown rot causes losses of tures in compatible formulations such as tions, plant extracts, organic acids and 2-10% in all banana-exporting countries. alginate-calcium gels. Its incidence rises periodically in the rainy waxes. One of the most promising com- season. pounds, a citrus seed extract, is now rarely Further information: Krauss, U., Bidwell, used because of its inconsistent effect, pos- R.; Ince, J. (1998) Isolation and preliminary Other post-harvest diseases include anthra- sibly due to the low shelf-life of the evaluation of mycoparasites as biocontrol cnose, also caused by C. musae, cigar-end product. Alginate-calcium gels reduced agents against crown rot of banana. Biolog- rot caused by Trachysphaera and Verticil- crown rot under experimental conditions. ical Control – Theory and Application 13, lium spp., finger rots caused mainly by B. They are likely to form part of an integrated 111-119. theobromae, Ceratocystis paradoxa, Pes- approach with biological control rather Krauss, U.; Matthews, P. (1997) Biocontrol talozzia leprogena, Phomopsis sp. and than on their own. crown rot of banana by strain mixtures of Sclerotina sclerotiorum, and squirter dis- mycoparasites. In:IglesiasL.,J.(ed) Among the biological options, induced sys- ease associated with N. sphaerica in Primer Taller Internacional sobre Control temic resistance and antagonists have been combination with physiological stress fac- Biológico y Producción Integrada en al tried. Induced systemic resistance is opera- tors. Other fruit spots caused by Cultivo de Banano Fundación Ambio, tional in a wide range of crops but has not Cercospora hayi and Deightoniella toru- EARTH, Guápiles, Costa Rica, November yet been exploited in any post-harvest situ- losa, and pitting disease caused by 1997, pp. 51-63. Pyricularia grisae aremoreaccurately ation. However, culture filtrates or cell wall regarded as field diseases but symptoms fragments of C. musae induce the produc- By: Ulrike Krauss, CABI-CATIE Project, exacerbate after harvest. Also, the tion of antifungal components in the peel of CATIE, 7170 Turrialba, Costa Rica boundary between field and post-harvest green banana fruit. As a result, conidial ger- Email: [email protected] diseases is gradual because many post-har- mination of C. musae was inhibited on Fax: +506 556 0606 vest pathogens can establish asymptomatic treated skins. Subsequent attempts to  infections in the field. employ the more easily obtainable dead conidia of C. musae as a resistance- Crown Rot Control inducing post-harvest treatment were Alternatives to Chemical unsuccessful. However, as a pre-harvest Control for Anthracnose Crown rot is commercially controlled by treatment (injection of the rachis 1-2 weeks in Guadeloupe the fungicides thiabendazole (TBZ) and before harvest) high crown rot levels could imazalil, alone or in combination, applied Anthracnose of bananas, caused by Colle- be reduced to ca 70% of control. More data, as a post-harvest dip or spray. Cross-resist- totrichum musae, is the most important however, are required to substantiate and ance to benomyl, formerly used in Sigatoka postharvest disease affecting the quality of quantify these tendencies. control, renders TBZ relatively ineffective exported fruits from the French West in many traditional banana areas. Other A programme funded by ODA (the UK Indies. This disease develops during fruit fungicides have been tested on an experi- Overseas Development Administration, conservation and ripening and it depreci- mental scale but are not registered for use now DFID, the Department for Interna- ates the fruit marketability. Anthracnose is on export bananas. Several projects have tional Development) and managed by NRI in practice controlled by a postharvest fun- addressed non-chemical control options for (Natural Resources Institute, UK) in the gicide. However, under Guadeloupe environmental concerns as well as the Windward Islands identified several indig- conditions, this chemical control has now health of banana workers and consumers. enous organisms with potential for reached deadlock for three main reasons: 74N BiocontrolNews and Information 2000 Vol. 21 No. 3

(a) aerial fungicidal sprays to control Siga- Mn2+ by the plant, accompanied by a low- observed at harvest and to the cumulative toka disease have resulted in the ering of the leaf Ca2+ content. For many number of conidia trapped in rainwater run- appearance of strains resistant to the active plants, it has been shown that root anoxia off from flowering to harvest. ingredients used for anthracnose posthar- causes ethylene synthesis by the plant In the absence of rainwater, inoculum is not vest control; (b) fungicidal treatments are shoots. It is then possible that the fruit from dispersed and does not reach the fruit sur- not effective in all production zones, quite banana plants subjected to anoxic condi- face. All the floral parts of bunches from apart from the appearance of resistance; (c) tions may have a greater ability to plants grown under rain-out shelters were consumer demand is for a reduction in pes- synthesize ethylene. Work is still in inoculated with C. musae conidia and a ticide use, especially those applied progress to test this hypothesis experimen- large amount of inoculum was isolated postharvest. So, there is a need for new con- tally in order to manage fruit susceptibility from them. No anthracnose lesions were trol strategies, and these could be to anthracnose through optimized farming observed on the fruit at harvest. developed from a better knowledge of the practices. bioecology of the pathogens. Sleeving of bunches limits rainwater runoff The Phytopathology of Fruit and inoculum dispersal to the fruit surface. Disease expression is dependent on a Contamination A reduction of more than 80% in the level number of factors present at different steps of fruit contamination is observed on in banana production, from fruit production Fruit pollution occurs in the field. Conidia sleeved bunches compared with unsleeved in the field, to fruit packing, transport and germinate rapidly and form a melanized bunches, even though there is no effect on conservation, maturation in ripening appressorium which remains inactive until inoculum production by the floral parts. rooms, and marketing. Of these, the varia- the fruit ripens. A penetration hypha then tion in potential fruit quality at the field develops and the mycelium enters the skin Fruit Contamination level is particularly important, since it is and later the fruit pulp, forming brown We developed a methodology to assess the responsible for seasonal (disease is more lesions. Once quiescent infections are level of fruit contamination through the severe from September to January) and formed, the pathogen is permanently number of anthracnose lesions that develop spatial (disease is more severe in low alti- installed on the host because dark appres- on fruit (the technique is applicable to tude lands of Guadeloupe) variations. soria can survive very adverse immature fruits aged 4 weeks). A good cor- Potential fruit quality is governed by a environmental conditions. So, potential fruit relation between the number of anthracnose physiological (fruit susceptibility) and a quality depends on the quantity of conidia lesions and the quantity of appressoria is phytopathological (level of fruit contami- that reach the fruit surface (fruit pollution) achieved when the fruit are conserved at nation) component. Recent work has been and the quantity of conidia that form a dark high temperatures with elevated levels of carried out in Guadeloupe on these two appressorium (fruit contamination). ethylene. components in order to propose alternative Fruit Pollution strategies to chemical postharvest control. The formation of melanized appressoria Colletotrichum musae does not sporulate was evaluated, with a constant inoculum The Physiology of Fruit Susceptibility on the green parts of the banana plant but concentration, in controlled temperature A diagnostic survey was conducted on 106 only on senescent organs. We have con- and humidity conditions close to the natural banana plots in order to identify the factors ducted studies in order to (a) identify the contamination. The presence of free water which might explain variation in fruit sus- inoculum sources contributing mostly to is essential and appressoria formation does ceptibility to wound anthracnose as fruit pollution; (b) determine the dynamics not occur within six hours. This indicates measured through artificial inoculation at of fruit pollution from flowering to harvest; again the importance of rain or long dew flowering and wounding the fruit at har- (c) establish the mode of transport of this periods for contamination. vest. This study showed that fruit inoculum to the surface of the fruit; and (d) Alternatives to Chemical Control susceptibility varies widely with pedocli- evaluate the effect of covering the bunches matic conditions and farming practices. with a plastic sleeve on fruit pollution. The above results suggest there are a number of strategies for managing anthrac- In the pedoclimatic area of halloysitic and Fruit pollution occurs mainly from inoc- nose at various stages in the production ferralitic (low altitude) soils, where fruit ulum produced on the floral parts and the system that could be investigated as alter- anthracnose lesions developed most (54 last bunch bract. Because they are closest to natives to chemical postharvest control. plots), a relationship was found between the fruit, the floral parts are the most effec- the manganese (Mn) content of fruit and tive inoculum source for fruit pollution. 1. At the Field Level. Fruit pollution can susceptibility to anthracnose: the plants The elimination of the floral parts and of be reduced by removing the floral parts and producing the most susceptible fruit had the last bunch bract at the flowering stage the last bunch bract. The operation must be higher foliar Mn concentrations and lower reduces considerably the quantity of carried out as soon as possible to minimize calcium (Ca) concentrations, and had conidia trapped, from flowering to harvest, inoculum development. This practice, com- grown on rather acid soils. in rainwater run-off under the bunches, and bined with sleeving bunches, gives a very the level of fruit contamination measured at It is possible that the high Mn content of the significant reduction in the level of contam- harvest. Moreover, C. musae is readily iso- fruit could have arisen from stress situa- ination of the fruit. Particular attention must lated from floral parts. tions which could reinforce the ability of be paid to early sleeving, which should be done before the fingers reach a horizontal the fruit to synthesize ethylene, a hormone Fruit pollution occurs mostly during the that can play a very important role at dif- first month after bunch emergence (the crit- position (or before all have fallen). A better knowledge of the regulation of eth- ferent levels in the host-pathogen ical period) and strongly decreases interaction. It has been shown that ethylene thereafter. Most conidia were trapped in ylene biosynthesis would allow farming activates germination, formation of appres- rainwater run-off under the bunches during practices to be developed which could improve fruit resistance to anthracnose. soria and lesion extension. Anoxic this critical period. Most inoculum was iso- conditions resulting from soil compaction lated from the floral parts during this 2. In the Packing Station. Fruitmustbe or bad drainage can lead to a reduction of period. Lastly, the climatic conditions pre- handled carefully during transport to the different forms of manganese into Mn2+ in vailing during this critical period were packing station and packaging in order to the soil, and to a massive absorption of related to the levels of fruit contamination avoid bruising, as this enhances disease News 75N expression. Maintaining good quality for reconsidered: high ethylene rates (>1000 By: L. de Lapeyre de Bellaire and the water used in de-handing and in the p.p.m.) are used even though small rates (1 M. Chillet, washing tanks is also important to avoid p.p.m.) can induce the climacteric rise. CIRAD-FLHOR, contamination of crowns. Lastly, packing Station de Neufchâteau, Testing the Alternatives the fruit in polybags allows the formation Sainte Marie, 97130 Capesterre belle eau, of a modified atmosphere (higher CO2 and The possibility of eliminating postharvest Guadeloupe, French West Indies lower O2 content), which is important to treatment through these different non- and X. Mourichon, CIRAD-AMIS, improve fruit conservation and slow down chemical measures will be evaluated in a BP 5035, 34032 Montpellier, France fungal development. trial on pilot farms. The level of fruit con- 3. In Ripening Rooms. The quantity of tamination at harvest will be forecast using Contact: Luc de Lapeyre de Bellaire ethylene used in the ripening rooms, as well the assessment test on 6-week-old fruits, Email: [email protected] / as the time of ethylene contact and the tem- and actual contamination will then be [email protected] perature of fruit conservation can increase assessed. These results will provide useful Fax: +590 86 80 77 disease development during fruit matura- feedback on the performance of the new tion. Present practices should be measures.  Training News

In this section we welcome all your experi- on – what aspects of training they were con- FFS facilitators, each taking responsibility ences in working directly with the end- fident in and what needed reinforcing. A for facilitating activities with five farmers users of arthropod and microbial biocon- survey revealed that of the ten FFS farmer in each FFS group. Good local networks trol agents, or in educational activities on groups trained in 1997, five were still very have been built up as a result of this com- natural enemies aimed at students, farmers, active. At least 80% of the graduates were munity-level participation and their extension staff or policymakers. still involved in active FFS groups and the effectiveness was demonstrated by the fact most visible effect of the training was that that over 90% of non-participating farmers Feedback on Farmer Field they were familiar with various stages of in the five FFS communities also reduced Schools pests and beneficials and many were con- or eliminated insecticide application on ducting agro-ecosystem analysis (AESA) their cotton in 1999. Since 1998, we have reported on many par- in their own fields, outside the group ses- During the 1999 season, FFS groups again ticipatory training and research initiatives sions. At the five other sites, FFS groups avoided early season insecticide applica- around the world. In this issue, we are were less active but insecticide application tion in all plots and were able to eliminate revisiting two programmes based on the remained much reduced compared with chemical control altogether in some of the Farmer Field School (FFS) approach, to before the training. IPM plots. Net profits for IPM and farmers’ report on what has happened since, and see practice plots averaged 16,451 and 11,413 if there are any general lessons to be There was evidence for limited spread of Rupees/ha, respectively, confirming again learned. A message that comes through IPM concepts and practices to farmers in the economic benefits of IPM for a second clearly in both these studies is that farmer districts neighbouring those targeted by the season. In the Punjab context it is critical commitment to biocontrol and IPM participatory research programme, for FFS projects to convince farmers and remains high, but follow-up training is cru- although not sufficient to enable new extension staff that IPM can be viable over cial (for both trainers and farmers) to farmers to carry out IPM in practice. Some a range of pest pressure, climate and eco- reinforce understanding of IPM and fill in of the farmers in adjacent districts who nomic variability. However, there is now the inevitable gaps in knowledge. were interviewed were familiar with some beneficials, and even more were familiar acceptance in wider circles in Pakistan of  with IPM terminology. But they had no the FFS approach, and this recognition will understanding of the concepts, or how to help to facilitate implementation of future Keeping off the Treadmill practise IPM. It was concluded that insuffi- cotton IPM programmes. cient dissemination of IPM technology had When farmers were questioned about cur- We begin with an update to the first article taken place to give untrained farmers a rent problems in cotton production, high to be published in ‘Training News’ [BNI sound basis for changing their management price of cottonseed was identified as the 19(2), 41N-42N, ‘Stepping off the cotton practices. most severe constraint at all five sites, and pesticide treadmill’]. The article described at three sites pest control came second. how, in 1997, a farmer participatory Interviews were conducted with 15 FFS However, at the other two, pest control was training programme involving Training of graduates from 1997 and 15 untrained not considered a main issue, and most FFS- Trainers (TOT) and Farmer Field School farmers in each of the five localities where trained farmers said that the presence of (FFS) approaches had enabled cotton the FFS groups were still most active to beneficials meant that there was no need to farmers from Vehari District of Punjab assess farmer perceptions of the effective- apply insecticides. Most trained farmers at Province in Pakistan to become IPM practi- ness of FFS training and IPM. The findings all sites were familiar with various, if not tioners. The trained farmers made decisions were used to revise the curriculum for all, stages of pests and beneficials, while that lowered their input costs by 68% while 1999. untrained farmers were overwhelmingly maintaining or even increasing crop yield FFS training in 1999 was carried out in not. At one locality, most trained farmers and quality. close collaboration with five community- hadalsoretainedanunderstandingofIPM The continuing impact of the programme based organizations (CBOs) coordinated terminology, its philosophy and impor- was assessed at the beginning of the 1999 by the NGO Catholic Relief Service. Five tance. At other localities, the farmers’ level growing season. The aim was to find out trainers from each CBO, many of whom are of familiarity had dropped considerably, what the FFS graduates were doing 2 years cotton farmers themselves, were trained as although it still greatly exceeded that of 76N BiocontrolNews and Information 2000 Vol. 21 No. 3 untrained farmers. However, when asked to Crops targeted by FFSs were mainly the locations there are specific problems, and assess, on a five-point scale, their confi- TOT crops (tomato and cabbage), but vali- lack of irrigation facilities, access to land, dence at making IPM decisions without dation trials and/or FFSs have been or good quality seed were cited as impedi- back-stopping, one-third of all trained undertaken on other crops at other sites, for ments in various places. On the whole, farmers expressed no confidence at all, and example, onion, hot pepper, aubergine though, farmers felt they had benefited the median level of confidence was 50%. [eggplant], okra and lettuce. In many loca- greatly from FFSs, and agreed that more tions, although tomato was a familiar crop, farmers should be exposed to its methods. The reasons for this lack of confidence may cabbage was rare if not completely new. Buttheystressedthatitwasimportantfor lie at least in part in the arsenal of pests that Farmers reported learning about a range of trained farmers to continue to meet for dis- attacks cotton in the Punjab: pest status and new or modified practices and ideas: about cussion and information exchange. levels can differ hugely between seasons. insect pests and beneficials, use of neem, The 1997 season, for example, was marked mulching, regular monitoring through Facilitators also felt their FFSs had been a by low Helicoverpa pressure in some areas agro-ecosystem analysis (AESA), regular success. They cited the information while whitefly and associated viral disease planting schemes, and nursery practices. offered, training methods used and willing- was critical. Farmers who trained during Many also talked about learning to work ness of the farmers to learn as the key that year will have had ample reinforce- together as a team. However, some tech- factors. Master trainers provided good back ment during the season of IPM practices niques were mentioned less often, up during first FFSs, but there has been no appropriate for whitefly outbreaks. How- including balancing organic and inorganic refresher training. Facilitators also stressed ever, in 1998 Helicoverpa bollworm fertilizers, composting, staking for toma- the need for continuing learning for them- caused havoc in most areas, but FFS- toes, how diseases spread, and the selves, and suggested that they should meet trained farmers had had little experience of importance of good seed. this pest in the IPM context. Insecticide once or twice a year for additional informa- application frequency increased but in Benefits farmers reported were varied and tion and exchange of experiences. A more many cases failed to control the problem. many. There has been a significant cut in integrated approach to all pest management Then in 1999, spotted bollworm (Earias input costs because of reduced pesticide use and improved facilitation of farmer deci- spp.) was identified by many farmers as the combined with the switch to locally pro- sion-making could be addressed in major production constraint. Yields have duced and cheaper neem-based products. workshops, which could focus on gaps in also fluctuated considerably over the last 3 Labour inputs have been cut because there the current FFS curriculum. years. It is evident that one season’s are fewer pesticide applications, and time training alone is not sufficient to prepare savings are also made through mulching Farmers, post-FFS, have adopted a wide farmers or facilitators to manage the varia- (less watering and weeding). Farmers range of practices, indicating that the FFS tion. Follow-up and post-training support report improved health from less pesticide facilitators successfully addressed a wide are therefore particularly important to help use and better working practices, but also range of topics. Not only have FFS-trained FFS graduates, farmer groups and facilita- from the addition of cabbage to the family farmers gained economically from tors cope with the huge variability in pest diet. The training has enabled them to plan improvements in the target crops (tomato dynamics. their work better, and they report better and and cabbage) by adopting a wide range of more sustainable production from rela- practices learned in FFSs, but there has also Contact: Ashraf Poswal, tively small areas of land. Better crop been a clear adaptation of the cabbage and CABI Bioscience Centre, sanitation has led to a reduction in disease tomato IPM curricula to other crops (and PO Box 8, and grasshopper attack. Overall, adoption this includes staples and cocoa, as well as Rawalpindi, of IPM has meant better quality produce other vegetables). If farmers are focusing Pakistan with less rejected by the market, and now on some components of IPM and Email: [email protected] farmers feel they have benefited by neglecting others, this can be addressed by working together to solve problems. Fax: +92 51 451 147 appropriate follow-up activities.  Yields and farmer incomes both improved dramatically post-FFS. In most locations, All it takes is time, and particularly facilita- farmers experienced a two- to three-fold tors with more time on the ground and able Extending Vegetable IPM increase in tomato production, and at one to travel around their districts. If, as seems location the increase was four-fold. Cab- likely, the FFS approach is adopted as the bage production changed from none or common extension methodology in Ghana This second update is for a much more hardly any to good (for example, 80% of recent report [BNI 20(4), 119N-120N, (a process that has already been initiated by plants producing marketable heads). ‘Vegetable IPM gains ground in Ghana’], the central Ministry of Food and Agricul- Farmers’ incomes also increased by up to which described the detailed planning that ture office), resources and time will be less four times, and this has meant not only an had gone into designing a season-long tautly stretched between conventional improvement in their living standards, but ‘Training of Trainers’ (TOT) course in extension and participatory approaches. also further investment and diversification Weija in 1998. Since then, the trainers (as in their farms. FFS facilitators) and master trainers have Contact: Janny Vos, been developing and executing FFS activi- There are a few thorns in this otherwise CABI Bioscience UK Centre, ties in their respective districts of Ghana. In rosy picture. The marketing situation (fluc- Silwood Park, a more recent survey, IPM FFS graduates tuating prices and buyers monopolies) is Buckhurst Road, and their facilitators were asked what they not favourable, and credit is hard to come Ascot, felt they had gained from the training expe- by. Farmers are perhaps currently over- Berks. SL5 7TA, UK rience. Here we are able not only to reliant on neem, which they have tended to Email: [email protected] describe farm-based results and on-going adopt as the answer to all pest (and dis- Fax: +44 1491 829123 activities, but also to report the facilitators’ ease!) problems. Whether this will lead to and farmers’ views. new problems remains to be seen. In some  News 77N

Internet Round-up

By: Tony Little, Technical Support Group Banana link at: http://vwww.netcom.net.uk/~n/nri/ to the Global IPM Facility, CABI pcpp/r6391.htm http://www.geocities.com/NapaValley/ Bioscience. 1702/ Details of CABI Bioscience’s work on This quarter Internet Roundup virtually goes is definitely worth a visit, although it deals adapting novel techniques for detection and bananas. I was delighted to discover that The more with the political issues of bananas. It characterization of fungi causing fusarium Consortium for International Crop Protec- has a section on organic bananas, and a list wilt and sigatoka leaf spots of banana and tion (CICP) had already made a start tralian Banana Growers Council (ABCG) for me, by compiling a list of internet IPM http://www.cabi.org/bioscience/ annualreport_projects_egham.htm#pdn resources on banana, covering a wide range is a good site too. Details of current activi- of banana IPM issues, including biological ties, research programmes and banana links There are a range of on-line papers and news control at: are at: items dotted around. For example, Florida Entomologist has ‘Timing and distribution of attack by the banana.html There is a number of project reports and banana weevil (Coleoptera: Curculionidae) in The International Network for the Improve- summaries available online, for instance, as East African highland banana (Musa spp.) at: ment of Banana and Plantain (INIBAP) at: part of the CGIAR’s Systemwide Pro- gramme for IPM , the International Insti- fe82p631.htm tute of Tropical Agriculture (IITA) is is also good source of information on pest There is a paper on the banana moth from managing a project, ‘Improving plantain- management, and is also very well linked. Hort Digest at: The Department of Primary Industries, which is posted at: http://www.hortdigest.com/archives/2- Queensland produces DPI notes projects/iitaipd.html giving pest management advice, and prac- And another from Agropolis at: tical information on managing various pest DfID’s Crop Protection Programme and disease problem in a range of crops, also has a summary of a project actualiteevenements/lettre/spe1099gb/ on development of nematode resistance in integraprotec.html http://www.dpi.qld.gov.au/dpinotes/ bananas and plantain, with further details hortic/tropfruit/h00059.html at:  Announcements

Are you producing a newsletter, holding a http://www2.ufla.br/~siconbio companies involved in the production and meeting, running an organization or rearing The deadline for submission of abstracts is commercialization of biological products, a natural enemy that you want other biocon- likelytobe16March2001. and growers interested in the development trol workers to know about? Send us the of cooperative projects based on biological Contact: the Organizing Committee details and we will announce it in BNI. products in agriculture pest control in (preferably by e-mail) UFLA, Departamento de Entomologia, Brazil. It will bring together many different VII SICONBIOL Campus Universitário, stakeholders to develop and conduct projects in biological pest control in its The VII Symposium on Biological Control Caixa Postal 37, widest sense. The site covers a range of bio- (SICONBIOL) will be held in Poços de CEP 37200-000, logical products, including pheromones Caldas, Minas Gerais, Brazil on 3-7 June Lavras-MG, Brazil 2001. Themes for the symposium include: Email: [email protected] and biopesticides, and also legislation ecology and biological control, taxonomic Fax: +55 35 8291288 relating to them in Brazil. The site (only in Portuguese at present) is hosted by the Uni- identification and selection of natural ene-  mies, attributes of a good natural enemy, versidade Federal de Viçosa and improving the efficiency of natural ene- coordinated by Professor Evaldo Ferreira mies, commercial production of biological FEROBIO Website Vilela. control agents, risk analysis and environ- Brazil is virtual home to a new website, mental impact evaluation in the Contact: Evaldo Ferreira Vilela, FEROBIO – a platform for the develop- Universidade Federal de Viçosa, introduction of natural enemies, quality ment and use of biological control and MG,Brazil36571-000 control of natural enemies, and case studies pheromones in pest control at: of success in biological control. Applica- Email: [email protected] http://www.ferobio.ufv.br/ tion forms and instructions for the Fax: +55 31 899 2537 submission of abstracts will become avail- The aim of this initiative is to promote able on the website: interaction among researchers and private  78N BiocontrolNews and Information 2000 Vol. 21 No. 3

Landcare News on the New Zealand Madison, WI 53706, USA Web Email: [email protected] Email: [email protected] Fax:+6433252418 Fax: +1 608 2623322 Landcare Research/Manaaki Whenua, New  Zealand now posts some of its newsletters  on its website at: Lost the Midwest But http://www.landcare.cri.nz/ Water Hyacinth information_services/publications/#news Going Strong! Newsletter Re-surfaces Amongst them is ‘What’s New in Biolog- After 5 years of providing biological con- ical Control of Weeds?’, an informative trol news for the US Midwest, the The CABI Bioscience IMPECCA pro- and entertaining newsletter (with three ‘Midwest Biological Control News’ has gramme (International Mycoherbicide issues per year) about weed biocontrol in undergone a change of name and face, and Programme for Eichhornia crassipes Con- New Zealand, and well worth reading even re-emerged as ‘Biological Control News’. trol in Africa) and the Plant Protection if you aren’t a weed biocontrol person, It is no longer appearing in printed form, Research Institute, South Africa (PPRI) because it’s so well written. but on the Internet, and its new home is at: have re-launched the IOBC water hyacinth newsletter, with funding from Danida This issue includes an in-depth account of http://www.entomology.wisc.edu/mbcn/ mbcn.html (Danish International Development Assist- the programme against Californian thistle ance) through the Environment, Peace and (Cirsium arvense) in New Zealand, and Itisbeingpublishedonanirregularbasis Stability Facility (EPSF). Water Hyacinth also summarizes what agents have been (approximately quarterly), but readers can News will appear twice a year, and will introduced against the weed elsewhere in sign up for email notification of new issues cover biological and integrated control of the world. being posted. water hyacinth. Contributions are wel- There is also a new variant of the board The paper version may have died, but the come. The first issue, published midyear, game ‘snakes and ladders’, which was objectives remain the same: to provide dealt principally with recent developments developed to enhance the understanding practical information regarding beneficial in Africa. The second issue is scheduled to amongst stakeholders of why biological organisms and their use in the control of appear in time for the October 2000 control projects succeed or fail. The game pest organisms that include insects and meeting in Beijing of the IOBC Global progresses through each stage in the bio- mites, weeds, nematodes, and plant patho- Working Group on Water Hyacinth. control process, from getting started and gens. The target audience was formerly finding suitable agents, to monitoring university (state and local) and extension Contact: Rebecca Murphy, establishment success of the agents and personnel in the midwest states of the USA. CABI Bioscience, Silwood Park, Ascot, evaluation of the programme. The ‘snakes’ However, it is now expanding coverage to Berks. SL5 7TA, UK and ‘ladders’ in this version are based on include all geographical regions and all Email: [email protected] real events that happened to biological con- crops and other applications of biological Fax: +44 1491 829123 trol researchers in New Zealand. control in the USA. Martin Hill, PPRI, Private Bag X 134, Pretoria, South Africa 000l Contact: Lynley Hayes, Contact: Dr. Susan E. Rice Mahr, Email: [email protected] Manaaki Whenua – The Editor, Biological Control News, Fax: +27 12 3293278 Landcare Research NZ Ltd, Department of Entomology, PO Box 69, Lincoln, University of Wisconsin – Madison,  Conference Reports

Weedy Types Converge on cially the economic as well as the biocontrol agents with other methods’ (C. Brazil ecological benefits, with biocontrol of rag- Quimby), which concentrated on the inte- weed (Senecio jacobea) in the USA being gration of biological control and The III International Weed Science Con- used as an example (15:1 benefit cost ratio). management systems using leafy spurge gress (IWSC), held at Foz do Iguaçu, Brazil Of all the projects analysed, 25% were (Euphorbia esula) control in the USA as a on 6-11 June 2000 was attended by 600- regarded as successful with benefit cost model system. Earlier, a specialist session 700 scientists. There were 53 scientific ses- ratios varying from 112:1 to 2:1. The nega- on ‘Modelling biocontrol effects’ (M. sions and 16 specialist workshops. Of tive impacts of classical biocontrol were Smith) had included presentations on the these, six were devoted to biocontrol and also addressed. use of models for problem solving and three to invasive weeds; in addition, one of assessing the impact of biocontrol, as well the five all-Congress lectures had invasive There followed sessions on ‘Inundative as in the dynamics of weed populations. weedsasthetheme. biocontrol using fungal pathogens’ Weeders in Waders There were two sessions on classical bio- (chaired by B. Auld), which involved an logical control of weeds. One, chaired by L. overview of bioherbicide research develop- A workshop on invasive species in aquatic Morin, reviewed the issues and provided an ments, with specific papers on Striga ecosystems held during the Congress on 6 update on actual and potential classical bio- biocontrol, phytotoxins and formulation; June, was attended by approximately 25 control projects, particularly relating to and ‘Promising developments in bioherbi- people from institutes, universities, govern- pathogens, and how to create a framework cide research’ (D. Sands), which covered mental and non-governmental agencies for their implementation based on Aus- novel formulations to enhance efficiency from countries all over the world, including tralian experiences. The second session, and also risk analysis relating to broad Brazil, Argentina, the USA, Italy, New chaired by J. Hoffmann, concentrated on spectrum pathogens. A final session was Zealand, the UK and South Africa. The ‘The impacts of classical biocontrol’, espe- devoted to ‘Synergy and the interaction of meetingwaschairedbyDr.R.Charudattan News 79N from the University of Florida, USA, and chemical herbicides from amenity areas, *Anon. (2000) Abstracts of the III Interna- two formal presentations were given. R. public rights-of-way and forestry. At the tional Weed Science Congress, Foz do Pitelli (University of Sao Paulo, Jaboti- Agriculture and Agri-Food Canada Iguaçu, Brazil, June 2000. Corvallis, OR, cabal) discussed the impact of native Research Centre at Saskatoon, research is USA; International Weed Science Society, aquatic plant species, in particular sub- focusing on trying to exploit indigenous 301pp.ISBN1891276166. merged species, on hydroelectric power pathogens, even for alien weeds, but collab- Contact: International Weed Science generation schemes in Brazil. H. Evans oration is also being sought in Europe for Society, 107 Crop Science Building, (CABI Bioscience) introduced a new certain weed species against which no local Oregon State University, Corvallis, project to identify pathogens from water pathogens have been found. OR 97331-3002, USA. hyacinth which are native to Africa for  development into a mycoherbicide. He also Several bioherbicide projects under devel- presented data on a recent survey trip to the opment were discussed including those Challenges for Upper Amazon River in Peru which, based targeting Alternanthera philoxeroides, on the diversity of insect natural enemies Amaranthus spp., Cyperus rotundus, Eich- Augmentative Biological collected there, appears to be the centre of hornia crassipes (in USA and African Control origin of the weed, from where the plant countries), Matricaria perforata, Prosopis Understanding constraints to the adoption radiated throughout South America ini- spp. and Striga hermonthica. of augmentative biological control is a key tially and then to the rest of the world. issue in making it a success. The Indian However, the diversity of pathogen species Of particular interest is the on-going Council of Agricultural Research (ICAR) was poor in this area. research of A. Watson’s group at McGill and CAB International (CABI) Workshop University, which is developing a ‘low- These papers were followed by an informal on Augmentative Biocontrol, held in Ban- tech’ product for use against Striga in Mali. discussion on a range of topics, which galore from 29 June to 1 July 2000, BasedonastrainofFusarium oxysporum, included: the role of eutrophication in a addressed the problem by tackling a wide chlamydospore powder formulations aquatic weed problems; the role of changes range of issues in depth. Discussions applied to the soil at sowing or to the seed in hydrology in aquatic weed problems; the ranged from policy matters to details of completely inhibit weed emergence. The success of biological control of water hya- research and production, to constraints in control strategy is geared to local needs and cinth on ; the need for new quality control and distribution and through natural enemy species; sometimes weeds operates at a cottage industry level, uti- to extension issues. lizing a simple liquid fermentation process escape their natural enemies even in their and cheap, easily available substrates such The workshop was funded by the Partner- region of origin and there might be a need as sorghum straw. Women prepare the ship Facility of CABI, organized by the to introduce natural enemies from another Project Directorate of Biological Control area; and the need for better integration of starter cultures in traditional cooking pots, using centrally produced primary inoculum (PDBC–Director,DrS.P.Singh),jointly biological and other control options for with CABI Bioscience, UK and was facili- aquatic plant species. (as gelatine capsules) to assure quality con- trol, and then harvest, dry and store the tated by Mans Lanting of Agriculture Man While water hyacinth formed the major powder. Prior to planting, the crop seeds are Ecology, (AME, Bangalore; AME is a topic of discussion at this workshop, other covered with an arabic gum-spore coating. bilateral programme between the govern- aquatic were also discussed, including Sal- This is being linked with a tree planting ments of the Netherlands and India and vinia molesta, Myriophyllum aquaticum, programme not only to provide arabic gum works on sustainable livelihoods in the several submerged aquatic plants and algae. locally, but also to address the regional southern states). ‘Macrobials’ and micro- deforestation problem. This will give bials (insect and pathogen biocontrol Pathological Weeders women in rural communities more socio- agents, respectively) were covered and the main purpose was to assess opportunities The Congress was preceded by the V Inter- economic power. After further testing and and constraints in the development of national Bioherbicide Group (IBG) refining, it is planned to transfer this tech- implementation. Thus a broad spectrum of Workshop on 5-6 June. Sixteen papers nology to other countries in Africa affected stakeholders attended including govern- were presented during this 2-day work- by Striga weed. ment and university research staff, shop, which was attended by 35-40 government extension staff, biocontrol spe- scientists and organized by R. Barreto J. Gressel (Israel) discussed some novel cialists, commercial producers and NGO (Federal University of Viçosa). Encour- approaches to improve the efficacy and and government biocontrol laboratory rep- aging advances in weed-pathogen targeting safety of bioherbicide agents by physiolog- resentatives. The workshop consisted of and product development were reported, ical and transgenic methods. M. Vurro day and a half of presentations and nearly ranging from new pathogens of rice weeds (Italy) reviewed the prospects for using the same on working groups for the produc- in the Philippines and Vietnam, to the phytotoxins produced by fungi to improve tion of recommendations. potential commercialization of Fusarium the efficacy of bioherbicide agents through tumidum as a bioherbicide against gorse additive or synergistic effects. An overview on the Indian scenario for and broom in New Zealand and Ralstonia augmentative biocontrol was given by S. P. solanacearum against tropical soda apple The abstracts of the Congress have been Singh, and covered aspects relating to in Florida, USA, to the relaunch of BioMal published*. The next International Weed selection of superior strains, economical (under the new name Mallet) against mal- Science Congress will be held in Durban, methods of mass production and applica- vaceous weeds in North America. Canada, South Africa in 2004. The next meeting of tion of bioagents, quality control, storage, in particular, seems to be putting consider- the International Bioherbicide Group will shipment, safety issues, registration and ably more resources into bioherbicide be held in 2003 in conjunction with either identification of niche markets. Overviews research, especially as new weed problems the International Symposium on Biological of the global situation for augmentation, arise and old ones are exacerbated by herbi- Control of Weeds in Canberra, Australia or quality control and regulations were given cide resistance and changing agricultural the International Congress of Plant for macrobials by S. Murphy, and for practices (e.g. zero tillage). A further stim- Pathology in Christchurch, New Zealand microbials by N. Jenkins, both of CABI ulus is the government policy to ban all (to be decided). Bioscience. Further presentations were 80N BiocontrolNews and Information 2000 Vol. 21 No. 3 grouped under sessions on: augmentation now gazetted, and PDBC has begun to interface between research and commer- within the BIPM (Bio-Intensive Pest Man- assess the quality of Trichogramma spp. cialization, the government purchase agement) system (with models from cotton, used for the management of Helicoverpa in system, tax exemption, health and safety in rice and vegetables), the role of extension, cotton. Despite these moves there is still production, and patenting); and extension quality control, registration procedures, the need for methodology. Another major con- (production of biocontrol agents at dif- role of NGOs, and commercial production. straint identified was the availability of ferent levels, distribution and promotional funding at the farm and village levels. activities, hygiene, and impact assessment). In general, apart from the sugarcane Securing this for either purchase or produc- industry, uptake of augmentative biocon- tion is frequently a problem. It was agreed Although there is clearly much work still trol in India is patchy. There is, however, that the relationships between, and impor- needed, this workshop was a landmark. Its good general support and in a few areas/ tance of, all these issues is far from clear real strength lay in the fact that it happened crops, good demonstration (e.g. cotton in and needs further analysis. and that all sectors are beginning to speak Andhra Pradesh and Gujarat; tobacco in with one voice. This was the first formal Andhra Pradesh; and tomato and cabbage A series of recommendations was drawn up interaction between all the different parties in Karnataka). The extent of uptake was by the working groups. These covered: involved in augmentative biocontrol in found to be related to major factors such as policy matters; research and production India, and the significance of this was extent of linkages (between research, (priority crops and research priorities); acknowledged during the workshop. extension and NGOs, for example), extent quality control (both general recommenda- of government infrastructure, effectiveness tions and specific ones for microbials and Contact:DrS.P.Singh,PDBC, of distribution, lack of biocontrol knowl- macrobials); industrial production (product Post Bag No. 2491, H. A. Farm Post, edge of farmers, and variability in the quality, staff competence, extension and Bellary Road, Bangalore 560 024, India. quality of products between commercial training, distribution and product availa- Email: [email protected] and also government producers. Attempts bility, cost effectiveness of production, Fax: +91 80 3411961 are now being made to address the last of storage and shelf-life, packaging, simplifi- these points: all the major microbials are cation of registration regulations, the  Proceedings

Production of Biocontrol argue that the ultimate success of any pro- stressing the importance of monitoring Agents and Transgenics gramme will be dependent on the quality results. and performance of laboratory reared Critical issues in the production of bioa- insects. They identify eight elements in S. S. Hussaini tackles a wide range of issues concerning the use of entomopathogenic gents and transgenics were the subject of a insect rearing system management: objec- brainstorming session held at PDBC (the tives for the system, colony establishment, nematodes in biocontrol. He compares con- ventional and newer, molecular, methods for Project Directorate of Biological Control) the rearing laboratory, research and devel- identification and selection of suitable nem- in Bangalore on 13 May 1999. The out- opment of techniques, resources, quality atode strains. Amongst issues in mass come of this meeting has now been control, production, and supply. They pro- production, he tackles pilot scale liquid cul- published as a book of the same name*, and vide a guide to the kinds of problems that provides a thoughtful summary of impor- can be encountered, and the questions that ture, the economics of product development, formulation and storage, application tech- tant issues in this field. need to be answered. They stress the impor- nology and transport. S. P. Singh highlights in the Introduction tance of genetic issues that should be the importance of mass production for bio- tackled to avoid inbreeding and genetic R. D. Prasad deals with mass production of control. He notes that although biocontrol drift. They also make the important point microbials. He looks for reasons for the has been identified as an important tool in that host plant, host and natural enemy scarcity of commercially available prod- pest management, its uptake in India is con- rearingneedtobesimultaneous,andlookat ucts, despite a preponderance of microbial strained by an inadequate mass production key factors and constraints in each of these. biocontrol demonstrations at the laboratory capability – although India has a far greater level. Amongst pre-production issues, he Next,H.Nagaraja&B.Rameshlookspe- capability than many developed and discusses limitations in screening and strain cifically at mass production of developing countries. Singh identifies com- selection, and strain improvement. He also trichogrammatids, and discuss host cul- mercial production of reasonably priced discusses advantages and disadvantages of turing, the importance of the source colony, bioagents as the great challenge. He argues solid-state fermentation, and lists the and mass culturing for field release or com- the need for a code of conduct to help regu- advantages of liquid fermentation. He mercial sale. In particular, they suggest late the production of good quality examines key factors in adopting liquid fer- improved methods for culturing Corcyra biocontrol agents. He also highlights the mentation for mass production, including cephalonica as a host for both trichogram- importance of generating data for registra- the post-production phase. matids and other natural enemies. Then K. tion of bioagents, particularly pathogens, P. Jayanth discusses critical issues in mass Finally, there are two interesting papers and identifies other constraints currently production of insect biocontrol agents for dealingwithtransgeniccrops.T.M.Man- faced in culturing and mass production, weeds. He discusses ways of tackling prob- junath & Farah Deeba argue that transgenic shipment and marketing. lems posed by the necessity of large-scale (Bt) cotton could play a major role in com- In the first paper, Chandish R. Ballal & S. raising of host plants. He considers redistri- bating Helicoverpa armigera in the crop in P. Singh reiterate the message that progress bution of natural enemies within a specified India. They look at the status of transgenic in biological control depends on the ability action plan, and suggests that this could crops in other countries, and of current to develop successful mass production sys- help overcome many problems of labora- research in India, and point to the better tems for parasitoids and predators. They tory-based mass rearing, He ends by suppression of the pest in transgenic crop News 81N trials. However, they say that transgenic amount and at the right time. They argue openness, better information and greater technology has created new social and reg- that transgenic crops that are developed and education for the public to overcome what ulatory challenges, and they highlight some used wisely can be very helpful, and may they describe as ‘fear of the unknown’. concerns, including those related to tox- be essential, to world food and fibre pro- icity, cross pollination and sustainability. duction, agricultural sustainability and *Singh, S.P.; Ballal, C.R. (eds) (2000) They discuss the benefits and safety of preserving the environment. However, they Critical issues in production of bioagents insect-resistant cotton, and outline meas- say that the technology is new, and for Bt and transgenics. Bangalore, India; ures to limit resistance development. They cotton the relative importance of various PDBC, 66 pp. call for concerns to be addressed openly factors affecting its performance is still Contact:DrS.P.Singh,PDBC, and debated logically. K. S. Mohan & K. C. unclear. More research and more data are Post Bag No. 2491, H. A. Farm Post, Ravi look at factors affecting the perform- called for. All these authors are confident Bellary Road, Bangalore 560 024, India ance of Bt cottoninthefield.They that transgenic crops have great promise, Email: [email protected] summarize the ideal situation as proper but agree that the technology is in its Fax: +91 80 3411961 expression of the transgene to yield a bio- infancy and much more research is needed. logically active molecule in the right They also stress the importance of more  82N BiocontrolNews and Information 2000 Vol. 21 No. 3