Fundam. appl. Nema/.Ol., 1995, 18 (3), 251-260

Plant parasitic of plantain and other crops in Cameroon, West Africa

John BRIDGE*, Nigel S. PRICE**, and Patrick KOFI** * International Institute ofParasitology, 395a Hatfield Road, St Albans, Herts, AL4 OXU, UK and ** Institut de la Recherche Agronomique, Ekona CentTe, PMB 25, Buea, S. W. Province, Cameroon. Accepted for publication 7July 1994.

Summary - In a survey of plantains mairùy from smallholder farms in Cameroon, 33 species of plant parasitic nematodes from eighteen genera were extracted from plantain soils; thirteen species were found as plantain root endoparasites. The most important in relation to root damage and occurrence were Pralylenchus goodeyi, Radopholus similis and Helieolylenchus muiliâncius. P. coffeae was also present in a few areas. This is the flfSt record of P. goodeyi occurring as a major root pest of plantains in West Africa, and it was present in a large proportion of the plantain farms. The distribution of P. goodeyi and R. similis was associated with temperature at different altitudes: P. goodeyi occurred mainly at or above an altitude of 900 m above sea level, whereas R. similis was always found below an altitude of 900 m. On the other crops, Seulellonema bradys was found causing dry rot of yam tubers.

Résumé - Nbnatodes parasites du bananier plantain et d'autres cultures au Cameroun, Afrique de l'Ouest - Une prospection nématologique du bananier plantain effectuée au Cameroun chez de petits exploitants agricoles a permis de récolter 33 espèces appartenant à dix-huit genres dont treize espèces endoparasites. En termes de dommages et d'extension géographique, les espèces les plus importantes sont Pralylenehus goodeyi, Radopholus similis et Helicolylenchus muilieinelUs. P. eoffeae est également présent dans quelques zones. C'est la prem.ière fois que P. goodevi est signalé comme parasite majeur des racines du bananier plantain en Afrique de l'Ouest et cela dans une importante proportion des plantations prospectées. La répartition de P. goodeyi et de R. similis est associée aux températures des différentes altitudes: P. goodeyi est principalement trouvé au-dessus de 900 m d'altitude tandis que R. similis est toujours trouvé au-dessous de 900 m. Sur les autres cultures, il convient de signaler la présence de Scuzellonema bradys, agent d'une pourriture sèche des tubercules d'igname.

Key-words : Nematodes, Cameroon, plantain, Pralylenehus goodeyi.

Plant parasitic and other nematodes have been identi­ Plantains are an extremely important staple food crop in fied from a range of crops and habitats in Cameroon West Africa. They are grown by a very large number of (Goodey, 1957; Luc, 1957; Luc & de Guiran, 1960; farmers mainly inside village compound gardens entire­ Seinhorst, 1963; Barat et al., 1969; Samsoen & Geraert, ly for local sale and consumption. West Africa produces 1975; Ali & Geraert, 1975; Chavez & Geraert, 1977; one-third of the total world output of plantains and they Geraert & Ali, 1978; Germani, 1978; Samsoen & Ali, are one of the most important and preferred food energy 1978; Sakwe & Geraert, 1991, 1992, 1993) including sources in me area (Swennen, 1990). In Cameroon, rain forests (Siddiqi & Lai, 1992; Price & Siddiqi, although dessert bananas are a major export crop, plan­ 1994). tains represent a much greater percentage of me total Previous srudies in Cameroon on nematodes associ­ Musa production in the country. It is estirnated that this ated with Musa species have concentrated almost exclu­ total Musa production in Cameroon is over 1.5 million sively on commercial dessert bananas (Musa AAA Ca­ tonnes annually (F.A.O., 1993). Of this, less man 10% vendish Group) grown in plantations (Price, 1960; Luc are Musa AAA Cavendish bananas for export & Vilardeb6, 1961; Vilardeb6 el al., 1972; Melin & Vi­ (116 000 t) and over 57 % are Musa AAB plantains for lardeb6, 1973 a, b; Vilardeb6 & Guérout, 1976 a, b) or domestic consumption (860 000 t) (F.A.O., 1993). on plantains (Musa AAB) grown in research stations (Melin & Vilardeb6, 1976; Melin el al., 1976). Because of this lack of information on nematodes of plantains, a Materials and methods survey of plant parasitic nematodes on this crop, mainly from smallholder farms in Cameroon was initiated in MAIN SURVEY 1989 and continued during 1990, 1991 and 1992. Dur­ ing the survey, samples were also taken from dessert and Plantain root and soil samples were collected from higWand bananas, and from other crops in different 113 sites in over 40 localities throughout the North­ provinces of Cameroon. The results from these are also West, West, South-West, Littoral and Central Provinces included in this paper. of Cameroon (Fig. 1, Table 3). Observations were

ISSN 1164-5571195/03 S 4.00 / © GauthieT-Vil/ars - ORSTOM 251 J. Bn"dge et al.

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Fig. 1. Map of Cameroon {insel} and central and south western Provinces showing sampling sùes in lhe main plantain growing region of Cameroon. The circled numbers relate LO ntlmbers of sampling localùies lisIed in Table 3. made of the degree of cortical root necrosis (Bridge & inro 1 cm lengths, macerared and passed through sieves Gowen, 1993) from each planr and cultivars were iden­ of 250 f.Lm, 50 f.Lm and 32 f.Lm apertures. Marerial re­ tified whenever possible. Nematodes were extracted rained on the 250 f.Lm sieve afrer washing with a jer of from soil by a tray modification of the Baermann funnel warer was discarded; marerial coUecred on the other method (Hooper, 1990), and from planrain roots by screens was made up ro 100 ml in volume with water maceration and sieving (Pinochet, 1988). Twenry five and nematodes in a 1 ml aliquor from each sampie were grams of planrain root material were washed, chopped counred. Soil and roots from dessert and highland ba-

252 Ftmdam. appl. NemaLOI. NemalOdes of plantain in Carneroon

nanas were processed as described above. Nematodes in Table 1. Lisl ofplant parasitie nemalode genera and species found soil from around roots of other crops were also recov­ in Cameroon. ered by the tray method and from roots by maceration of 2 to lOg of roots which were placed on a plastic ling Crieonemella goodeyi (de Guiran, 1963) De Grisse & sieve, in a dish of water and left for a minimum of Loof, 1965 CIl'eonemella omata (Raski) Luc & Raski, 1981 24 hours. Crieonemella sphaerocephala (Taylor) Luc & Raski, 1981 Nematode identifications in ail cases were made or Diseocriconemella limitanea (Luc, 1959) De Grisse & verified by D.}. Hunt, M. R. Siddiqi and J. E. Machon Loof, 1965 of the International Institute of Parasitology, U. K. Data Gracilacus peperpoui Shoemaker, 1963 on temperatures were collected from research stations Helieolylenehus erenaeauda Sher, 1966 and other meterological monitoring sites at, or close to, HeliaJlylenchus dihystera «Cobb, 1893) Sher 1961 sampling sites. The altitudes of sampling sites were de­ Helieolyleru:hus erylhrinae (Zimmermann, 1904) Golden, rived from map data, meterological stations and hand­ 1956 held altimeters. HeliaJlylenehus microeephalus Sher, 1966 Helicolylenehus multiciru:IUS (Cobb, 1893) Golden, 1956 Helicolylenehus pseudorobuslus (Steiner, 1914) Golden, MONITORING R. SIMILIS POPULATIONS AT ALTITUDE 1956 The influence of altitude on root populations of R. Helicolylenchus variocaudalUs (Luc, 1960) Fortuner, similis was determined by transferring infested planting 1984 material from a low altitude to a higher altitude. An area Hemiericonemoides eoeophillus (Loos, 1949) Chitwood & of uncultivated land, dominated by elephant grass (Pen­ Birchfield, 1957 niselUm sp.) was cleared and planted with AAB plan­ Hemieycliophora sp. tains, variery French Sombre. The site was at Bokwan­ Heterodera sacehari Luc & Merny, 1963 go, Fako Division, South-West Province, at an altitude Hoplolaimus pararobtlSlus (Schuurmans, Srekhoven & of 820 m above sea level (ASL) on Mt. Cameroon. At Teunissen, 1938) Sher, 1963 this altitude mean minimum temperatures are estimated Longidorus laevicapilalus Williams, 1959 to be between 17 to 19 oC (see Table 5). Plantains were Longidorus sp. obtained from Nyombé, Moungo Division, Littoral Meloidogyne arenaria (Neal, 1889) Chitwood, 1949 Province, at an altitude of 80 m ASL from an area in­ Meloidogyne incognita (Kofoid & White, 1919) Chit­ fested with R. similis. Plantains were planted "un­ wood, 1949 trimmed " together with sorne attached roots and adher­ Meloidogyne sp. ing soil. Plots consisted of six plants each, spaced at Paralriehodorus sp. 2 x 2 m, and the trial had five replicate plots. Samples Paralylenehus sp. were taken after 12, 24 and 34 months. Roots were col­ Pralylenchus brachyurus (Godfrey, 1929) Filipjev & lected randomJy from three plants per plot and bulked to Schuurmans Stekhoven, 1941 form five replicated samples. Nematodes were extracted Pralylenehus coifeae (Zimmerman, 1898) Filipjev & Schuurmans Stekhoven, 1941 as described above. Pralylenehus goodeyi Sher & Allen, 1953 Pralylenehus zeae Graham, 1951 Results Pralylenehus sp. Radopholus similis (Cobb, 1893) Thorne, 1949 PLANTAJ:NS ROlylenchulus renijormis Linford & Oliveira, 1940 Out of a total of 42 species of plant parasitic nema­ Seulellonema bradys (Steiner & LeHew, 1933) Andrassy, rodes found in Cameroon (Table 1), 32 species from 1958 eighteen genera were extracted from plantain soils. SeUle/lonema eavenessi Sher, 1964 Thineen species were also found as root endoparasites Seulellonema elalhrieaudalum Whitehead, 1959 (Table 2), of which Helicolylenchus mullicinClus, Hoplo­ Tll'ehodorus cf. eoomansi De Wade & Carbonell, 1893 laimus pararobusluS, Meloidogyne incognùa, Prmylenchus Tropholylenehulus sp. goodeyi, and Radopholus similis occurred in more than Tylenchorhynchus annulalus (Cassidy, 1930) Golden, 30 % of the plantains sampled (Table 4), normally in 1971 mixed populations. Ali other endoparasitic species oc­ Tylenehulus sernipenelrans Cobb, 1913 curred in 7 % or less of the plants. Three of the most Xiphinema cf. doueeli Luc, 1973 commonly occurring root parasites (H. mullicinclus, P. Xiphinema ijacoLum Luc, 1961 goodeyi, R. similis) were found associated with 25 % to Xiphinema longicaudalum Luc, 1961 Xiphinema setariae Luc, 1958 greater than 75 % necrosis of the root cortex; M. in­ Xiphinema vuLgare Tarjan, 1964 cognùa caused slight ro moderate galling of the roots. P. Xiphinema n.sp. coffeae, which was found in plantain roots at only three

Vol. 18, n° 3 - 1995 253 J. Bn'dge et al.

Table 2. Piani parasùil: nemar.odes ofplantain and o/her CTopS in Camemon. PAPAYA CTiamemeUa sp. ROlylelUhul1lJ rem/armis (Carial papaya) HeliaJiykndrus sp. Crop Soil Roo~ Heurodera saahnri (probably associaled wiIh f'u.'ITAIN Criton,melia g(J(Jdiyi Heliœlykndrus dJh}'1ltra groUDooll'er grasses) (MlIJoAAB) CritolltmtlIa sphairoœpiul/n Heliwly/elldu" erytitrilUlt MeJoidoKyne sp. DUwcriwntmtl1a IimilanetI HelilOl)'kndrus mullidJll/lIJ PraJy/enàluJ uae He/ieoty/elUhUJ Cll1lIIICIlUda Heliwl)'knchus pseudorobusuu Roly!elUlwlw renifarmis Heliwlylenlhm diirys/tTa HeliwIY"'ldlll.i rarioco/ldauu MM/GO He1imly!eIUhUJ ob=mai Heliwryltndn~ ,rytitrinaR HopwlaimllJ plJfllrobUJlu.s (Mallgi/tra ,/utial) Heliwcyi,nchllJ dihys/tTa Heliwrymu.s muliitilUUU MeloUJiJgy>~ inccgm'ra Heliwcylenchus sp. Heiimry!elUhu.s pseudorobUJuu Pra/ymllJ mfflDe Hemicrimnemoides mmphillllJ He/ieolyJetc

Xipmneman.sp. CASSAVA Hemicydioplwra sp. HIGHL\ND BA.~ANA Heliwly/elUhllJ dihys/tTa Heliwlyknchus d'hys/tTtl (Malllhot escuIenlll) MeIoidogy>~sp. (cooking) He1imtyknchus pseudorobustus Hopw/ninlUS pararobusuu PralymllJ brachY/l1llS (MusaAAA) MeloUJiJgynesp. Meloidogyne sp. POTATO Heliwlylenc"'" sp. ParaJridwdorus sp. PralymllJ goodryi (Solanum lUbe/oillml Hop/oia,mus sp. PralY!eIUhUJ goode), MeJoidoKyne sp. 5cuœ!lmcmw 11Il!<1llm' PralylctQzllJ sp. Xiphinemn sp. Swullonallil bradys

DESSERT BANA.\lA Crialr..muJJa sp. He/ieolyknchus muhicinaus BLACK PEPPER Mdoidagyne sp. Mewidogyne sp. (MusaAAA) DisctlCrialnemeUa u'llU= HopwliJlimUJ parorobUJuu (Piper nigrum) X,philtcnlll sp. Gracilacus f!"PtTPOla' Meloidogy>~ illCOgnito MAlZE He/ieolykndrus sp. Helieolylt7uhllJ muilici~lUS PraJyknchus goodeyi (lea mays) Salttflatlemtl branys Heleroderid sp. RadopholllJ n'milis SwcellJlliillll (il'IJerrelsi Hopw/ilimus pararobUJtus Rotyle1rchulw reni/ormis Pratylenchru 'p. Meloidogynesp. ConON Crie01lt111eUa 01llllUl Radop/w/w similis (Gossypium spp.) Swltiwrctlllll(I11JCIliSSi Ro/yknchu/iu reni/olmi.< COCOYAM Mtwidogyne artl1lJ,;" Meloid(!g}/i': artllll,;" CITRUS CriallltmeUa sphairoœplwla Proly/errdlUs bradl)'U1lIS (Xantho.soma spp.) MeIoidog},1l incognilll MtloUJiJgyne incogmla (CltIllS spp.) HeuCorylelUhllJ dihys/tTa Tym/llus semip'llilItlllS SOYABEAN Helieol)'lendrussp. HeliColymllJ muhicillCUls (Glycille1llllX) MeloUJiJgy"lsp. Heliwl)llertt.hUJ pseudorobusuu PraJylenclws sp. HemwnnnoideI sp. Heurodera sp. loCAL BEAN Crialll""ril/nsp. HopwlaimllJ pararobusuu (P!ttlseous vu/garisl Hopw/aimus pararobllJtus /;mgidorus laeviaJpillllllJ /;mgidorus iaroiœpililtus PraLylelUhus goodiyi Meloidogynesp. PralY~'rIChllJ braclryuru.s YMI Scuœ/Jonema brodys (rubers) ROlylenchulus reniformis (Diosœrea rowndow) TymulllJ sennpt1tllrallS Wll.DYMI SCW/JoIlillUl branys (rubers) Xiphillilllll i/lIClIlum (DWsCOlea sp.)

254 Fundam. appl. Nemalol. Nematodes ofplanlain in Cameroon

Table 3. Localùies sampled in Cameroon by Division/Deparl­ Table 4. Occurrence and populations ofendoparasùic nemalOdes ment and Province wùh altitudes. in roOlS ofplantains in CameToon.

Division Province No. Altitude Nematode % Occurrence Maximum Département Locatities (m above sea (and mean) Sampled level) populations/ 100 g roots PuNTAIN AND BANANA SAMPLES 1. Ndian South-West 4 2-80 Radopholus similis 39 184,000 (23,782) 2, Fako South-West 6 100-950 Pralylenchus cof- (Mt. Cameroon) feae 4.5 22,000 (9,400) 3. Fako South-West 12 5-75 Pralylenchus good- 4. Meme South-West 7 55-220 eyi 33 56,000 (15,375) 5. Manyu South-West 1 130 Hoplolaimus para- 6. Mouogo Linoral 40-190 8 robuslUs 43.5 6,000 (1,542) 7. Sanaga-Maritime Linoral 1 25 Meloidogyne ln- West 8. Mifi 2 1300 cognùa 35.5 14,800 (3,420) 9. Menoua West 2 1500 Helicolylenchus North-West 10. Mezam 10 1200-1600 mU/licinclus 38 56,800 (14,182) 11. Nyong-et-Soo Central 1 750 Helicolylenchus di- 12. Mayo-Banyo Adamaoua 1 1200 hyslera 5.5 13. Margui-Wandala Extreme-North 1 ? Helicolylenchus SAMPLES FROM OTHER CROPS ONLY erylhnnae 7 14. Noun West 1 100 Helicolylenchus 15. Mfoundi Central 750 pseudorobuslus 3.5 l6. Haute-Sanaga Central 700 Helicolylenchus 17, Benoué North 240 variocaudalus 2.5 ROlylenchulus re- niformis < 1 locations in South West Province (Fig. 2), was also asso­ Scurellonema cave- ciated with obvious cortical root necrosis. neSSl 3.5 Almost ail recordings of P. goodeyz were made close to Tropholylenchu/us or higher than 900 m ASL. In contrast, R. similis was sp. < 1 always found below an altitude of 900 m ASL (Fig. 2). Occasionally the two species occurred together at alti­ around plantain roots, additional plant parasitic nema­ tudes of800 to 900 m ASL. The annua] mean minimum tode species belonging to the genera Cn'conemel!a, Dis­ and maximum air temperatures at different altitudes in cocriconemella, Hemicn'conemoides, Longidon/s, Paralri­ the regions sampled are presented in Table 5. Temper­ chodorus, Paralylenchus, Tn'chodorus and Xiphinema atures above 900 m ASL drop to a mean minimum of were found. Five species of Xiphinema were identified 16 oC and reach a maximum of 27 oC, at the lower including a new species (Hunt, pers. comm.). altitudes mean temperatures do not drop below 20 oC The local names of plantain varieties sampied during and reach a maximum of 31°C. the surveys are listed in Table 7. Ali varieties were sus­ Root damage caused by P. goodeyi and R. similis was ceptible to R. similis, P. goodeyi or P. coffeae where these indistinguishable and, in both cases, was related to root nematodes occurred. However, the False Horn variery breakage and plant toppling in a proportion of the farms " Big Ebanga " showed few root symptoms even though sampled. H. pararobuslUs was very occasionally observ­ R. similis was recovered from the roots. ed associated with minor cortical necrosis, but no associ­ ated root damage was observed with other endoparasitic BANANAS and soil nematode species. H. pararobuslZlS was the most Highland bananas (Musa AAA) of the Lujugira group frequently found species in plantain roots, but mean including rypes similar to the " Intutu " rypes character­ root populations per 100 g of root were low (1542) istic of East Africa, were identified growing at high alti­ compared to mean populations of R. similis (23782), P. tude in South-West, North-West and West Provinces of goodeyi (15 375), H. multicinclZlS (14 182) and P. coffeae Cameroon during this survey. The nematode associated (9400) (Table 4). Other species found in plantain roots with root damage to the crop was P. goodeyi, although were Helicolylenchus dihystera, H. erylhrinae, H. pseudo­ Hoplolaimus pararobuslUs, Helicolylenchus dihyslera and robuslus, H. van'ocaudalUs, Rotylenchulus renzformis, Scu­ Meloidogyne sp. were also found in the roots. R. similis lellonema cavenessi and Tropholylenchulus sp. In the soil was absent from ail the highland banana samples.

Vol. 18, n° 3 - 1995 255 J. Bridge et al.

Radopholus similis rl Areas above 900m asl • ~ coffeae D,.• Pratylenchus goodeyi

C?

/Mt Cameroon / ,

/ / /// / ///

///// / / / /

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/// / / • /// ///////

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/ / /// / / / / / / / / / /// Fig. 2. Distribution ofRadopholus similis, PratyJenchus coffeae and P. goodeyi in the plantain growing regùms ofsouth western Cameroon.

Dessert bananas sampled from farmers' fields, mainJy numbers of P. brachyurus were also found in citrus roots cv. Gros Michel, were infested by both P. goodeyi and R. at the same locality. Species from nine other genera were similis with their distribution being again linked to alti­ found in soil around citrus (Table 2). rude. Other species extracted from dessert banana roots were H. muiticinctus, H. pararobuslUS, and R. renijormis. The yam nematode, Scutellonema bradys, was found ra be the cause of severe dry rot disease of yam tubers OTHER CROPS (Dioscorea rOlundata) srared in a yam barn at IRA Nyom­ Tylenchulus semipenelrans was present in large num­ bé Research Station, Littoral Province. S. bradys was bers on different citrus rootsrocks (Citrus spp.) at the also found causing dry rot disease ofwild yam (Dloscorea IRA Fombout Research Station, West Province. Low sp.) rubers growing at the forest edge in Edéa, Littoral

256 Fundarn. appl. Nematol. Nematodes ofplantain in Cameroon

Table 5. Altitudes and annual mean maximum and minimum air Table 7. Occurrence ofRadopholus similis, Pratylenchus good­ temperatures at selecled meteorological stations from the main eyi and P. coffeae in raots ofdifferent cultivars ofplantains sam­ plalllain growing areas of Cameroon. pied in the Cameroon. MeteorologicaJ Altitude Air temperatures (oC) station (m above Cultivar R. similis P. goodeyi P. coffeae sea level) Mean Mean maximum minimum Big Ebanga + A. Tiko, Bobby Tan­ Fako Division nup + South·West Provo Brocaca + ince 50 30.1 22.4 Ebanga + + + Enyale + + B Njombé, Enyale-Liko + Moungo Depart­ French ment Claire + + + Linoral Province 80 3Ll 21.4 French C. Mamfé, Rouge + Manyu Division French South-West Prov­ Sombre + ince 130 3Ll 21.8 Giant D. Ekona, French + Fako Division Kamaliko + South-West Prov­ Kedong ince 400 27.6 19.7 Mekitu + Kundong­ G. Yaoundé, Mufi + Mfoundi Depart­ Lifongo + ment Mweni-Liko + Central Province 700 28.0 194 Naningo + H. Buea, Neni + Fako Division Ngomba + + South-West Prov­ Ntie + ince 950 250 16.7 Ovang + + I. N'Koundja, Twin Plan­ Mifi Department tain + West Province 1210 27.1 16.0 Two-Hand Planty + J. Dschang, Menoua Depart­ ment West Province 1410 25.4 15.5 Province. S. bradys also occurred in soils collected from K. Bamenda, around Solanum potato and maize (Zea mays) (Table 2). Mezam Division The root knot nematode species, M. arenaria and M. North-West Prov­ incogniLa, caused marked root galling of cocoyam (Xan­ ince 1610 23.8 15.4 thosoma sp.) growing in Mezam District, N. W. Prov­ ince. Juveniles of A1eloidogyne spp. were found in soil around many crops including papaya (Carica papaya), Table 6. Numbers of Radopholus simil.is juveniles and adult females per 100 g roOl fresh weight on ME plantain var. French soyabean (Glycine max), cassava (Manihot esculenta), po­ Sombre grown at Bokwango, 820 m above sea level. tato (Solanum tuberosum) and black pepper (Piper ni­ gntm), but were not associated with any observable root Months mer p1anting galling of these crops. 12 24 34 R. remformis was the only species of Rotylenchulus identified from soil samples around roots of citrus and Radoplwlus 6437 2390 22 sugarcane (Sacchantm offïcinarum), and in large numbers similis per 100 g around papaya. Juveniles of Heterodera or related genera root * occurred in soils around citrus and sugarcane without cysts being detected. H. sacchari was identified from soil Figures de-transformed from me Gog, n + 1) mean. ANOVA for around papaya but was probably parasitic on roots of (log, n + 1) values significant a[ P =0.017. * Means of 5 replicates. surrounding groundcover grasses.

Vol. 18, n° 3 - 1995 257 J. Bn'dge et al.

MONITORING R. SIMIUS AT ALTITUDE areas of Cameroon. Two samples at low altitude (both Populations of R. similis (juveniles and adult females) in South West Province, at Ekona Research Station and in roots of plantain are given in Table 6. Twelve months an Agricultural Training College) in which P. goodeyi after planting, R. similis numbers at Bokwango were was found could represent recent introductions from P. 6437 per 100 g root fresh weight, nearly identical to the goodeyi infeeted areas and which were unlikely to sur­ 6633 R. similis per 100 g root found in a trial at Nyom­ vive. bé, close to the source of the infested material (Price, The mean minimwn temperatures at the higher alti­ 1994 a). A year later, numbers of R. similis had fallen by tudes where P. goodeyi was present and R. similis absent over 95 % and at the fmal sampling, 34 months after were less than 19 oC (Table 4). Conversely, mean maxi­ planting, R. similis numbers had declined to insignifi­ mum temperatures at the lower altitudes where R. similis cant levels. only was present were greater than 27 oc. The distribu­ tion of these two nematades is almost certainly affected by day-degree accumulations over a period of time and Discussion not simply minimum and maximum temperatures. This Many more nematode species were found as root par­ was indicated by results of the monitoring of R. similis at asites of plantain in Cameroon than have previously altitude which showed that when R. similis was moved to been recorded elsewhere. The most important in rela­ a border-line altitude/temperature between the two spe­ tion to root damage and widespread occurrence were P. cies it did not disappear immediately at the cooler tem­ gOOdeYI~ R. similis and H. mulLicinetus. The root-knot peratures but did decline to insignificant levels over a nematode, M. incognita, was very common, in most period of 34 months. During the survey it was observed cases associated with relatively minor galling of root tips that at one site close to Dschang, West Province, at an but in sorne instances with severe galling. H. pararobus­ altitude ofapproximately 1300 m ASL, AAA Cavendish lUS was commonly found in roots but root necrosis, bananas originally obtained from Nyombé Research although present, was comparatively limited. P. coffeae Centre three years previously, and thus almost certainly was present only in a few areas but the root damage originally infested with R. similis, were free of R. similis associated with this species was equal to that caused by but infested with P. goodeyi. Sarah (1989) made a simi­ P. goodeyi or R. similis. R. remformis was present in less lar observation in Rwanda with plants imported from than 1 % of the root samples examined in contrast to Nyombé Research Station where R. similis had been results from Ivory Coast where R. renijormis occurred in displaced by P. goodeyi in the roots because, he suggest­ approximately 10 % of the samples in large nwnbers ed, R. similis could not adapt to the cooler climate. P. (Adiko, 1988). Three Helicolylenchus spp., H. dihyslera, goodeyi has only previously been found in the tropics at H. erylhrinae and H. pseudoro6ttslus, were present in 7 % high altitudes in East Africa or in the warm temperate or less of the root samples and are probably of minor climates of Canary Islands, Egypt and Crete. The find­ econornic importance. S. cavenessi was the only species ing in West Arrica is further evidence that P. goodeyi is a of ScUlellonema found in the roots. pest ofbananas and plantains growing in cooler climates Two unusual root parasites of plantain were Helicoly­ outside the tropical lowlands in which the majority of lenchus van'oeaudams, a species originally identified from commercial bananas are grown, and has a lower temper­ black pepper roOts in Ivory Coast (Luc, 1960), and ature preference than R. similis. In Cameroon, P. goodeyi juveniles of Tropholylenchulus sp. which could be the represents a pest exclusively of small holder cultivation species T. obscurus found by Samsoen and Ali (1978) on and is absent from the commercial banana plantations of grass roots in Cameroon. the lowland areas. This similarly applies to its presence Pralylenchus goodeyi was identified for the first time as in East Africa and wouId explain why the species has not a pest of plantains in Cameroon and West Africa during been disseminated worldwide, as R. similis has, on com­ this survey which is surprising as it was the major root mercial bananas. However, P. goodeyi has the potential nematode pest in a large proportion of the plantain to becorne an important pest of bananas where they are farms. It has previously been considered a species indig­ grown in cooler climatic zones such as in the Mediterra­ enous ta E. Africa, where it is recognised as an impor­ nean and Middle East countries. As in other areas of the tant pest of highland bananas in Uganda, Tanzania, wodd, including other African countries, R. similis has Kenya, Rwanda and Burundi, and of EnseLe in Ethiopia almost certainly been introduced with planting material (Gichure & Ondieki, 1977; Bridge, 1988; Sarah, 1989; used ta establish commercial plantations, originally the Peregrine & Bridge, 1992). It is also the main nematade AAA variety Gros Michel and subsequently with the pest ofbananas in Canary Islands (de Guiran & Vilarde­ AAA Cavendish types in use today. The species has bé, 1962) and has been found in Egypt (Oteifa, 1962) spread to the already present banana and plantain varie­ and in Crete (Machon & Hunt, 1985) but not elsewhere ties and continues to spread with the use and distribu­ in the wodd (Bridge, 1994). The distribution ofP. good­ tion of R. similis infected material. Older farms are often eyi was very closely linked to altitude and, presumably, R. similis free, where H. mulLicincLUs is common, where­ temperature as it was found almost exclusively in upland as newly established farms, commonly planted with pur-

258 Fundam. appl. NemalOl. NemaLOdes of plantain in Cameroon

chased (and infested) planting material, are frequently Acknowledgements infested with R. similis. Such a situation may be expect­ We gratefu]]y acknowledge the support of the Directors and ed to continue with the expansion in plantain growing as staff of the IRA research stations at Ekona and Nyombé and a response to high urban demand and present economic throughout Cameroon, We are also pleased tO acknowledge circumstanees (Temple el al., 1984). Many lowland ar­ the taxonomie and other expertise provided by D.]. Hunt, M. eas of Cameroon are still relatively free of R. similis, for R. Siddiqi, ]. E. Machon and other members of staff of the example, in the Mamfé region only one out of six farms International Institute of Parasitology. This work was funded sampled was found to be infested. It was also interesting by the UK Overseas Development Administration, to note that R. similis was absent from plantains and bananas in a reeent nematode survey of farms in the References southwestern and middle belt states of Nigeria (Fademi ALI, S, S, & GERAERT, E, (1975), Helicolylenchus species from & Bayero, 1993). This illustrates the potential benefit Cameroon, Meded. Fac. Landbouww. Gent, 40 : 517-520, for programmes to restrict the spread of R. similis in this BARAT, H., DELASSUS, M. & Huu-HN-VUONG (1969). The region ofWest Africa, for example by promoting the use geographical distribution of white tip disease of rice in trop­ of nematode free planting material. ical Africa and Madagascar. In : Peachey,]. E, (Ed), Nema­ There was no clear evidenee of resistance to R. similis IOdes of lropical crops, Techn, Comm, No, 40, Common­ or Pralylenchus among any of the plantain varieties sam­ wealth Bureau of Helminthology, St Albans, Herts, pied during the survey. This was also true of field trial England : 269-273, screening for resistanee (Priee, 1994 a, b). The variety BRlDGE,]. (1982), Nematodes of yams, In : Miège,]. & Lyon­ " Big Ebanga ", however, may warrant further study as ga, S, N, (Eds). Yams, Ignames. Oxford, Clarendon Press: in both the survey and field trials its appeared to be less 253-264, susceptible to both R. similis and P. goodeyi. BRlDGE,]. (1988), Plant nematode pests of banana in East Many different nematode genera and species were Africa with particu1ar reference to Tanzania, In : NemaLOdes found associated with crops other than bananas and and lhe borer weevil in bananas : presenl scaeus of research and plantains in Cameroon (Table 1). The most important oU/look, Proc, Worksh INIBAP, Bujumbura, Burundi, 7­ of these were S. bradys on yams, T. semipenelrans on 11 Dec. 1987 : 35-39. citrus, and Meloidogyne spp. on various crops. The yam BRlDGE,]. (1994). Worldwide distribution of the major nema­ nematode, S. bradys, was found for the flfSt time in tode parasites of bananas and plantains, Proc, Res. Coord, Cameroon during this survey although it has previously Meel. Biol. integr, Conlrol Highland Banana and Plantain been found to be a serious pest of yams in the neigh­ Pesls and Dis. Cotonou, Bénin, 12-14 Nov. 1991 : 185-198, bouring country of Nigeria and in other West African BRlDGE,]. & GOWEN, S. R. (1994), VisuaJ assessment of plant countries, Gambia, Ivory Coast, Senegal and Togo parasitic nematode and weevil damage on bananas and plan­ (Bridge, 1982). The dry rot disease symptoms of D. tains. Proc, Res, Coord. Meel. Biol. inlegr. Control Highland rOlundala tubers were characteristic of those found on Banana and Plantain Pesls and Dis, Cotonou, Bénin, 12­ yam tubers elsewhere in West Africa. The fmding of S. 14 Nov. 1991: 147-154, bradys causing dry rot in tubers of wild yam from forest CHA VEZ, E. & GERAERT, E. (1977), Observations sur quel­ soils indicates that the nematode is indigenous to Cam­ ques Mononchides et Dorylaimides du Cameroun et du eroon. Zaïre, Revue Zoo/. afr., 91 : 766-780, The citrus nematode, T. semipenelrans, is present in FADEM1, 0, A. & BAYERO, A. (1993), Plantain and banana Cameroon and population estimates from root and soil nematodes in south western and middle belt States of Nige­ extracts indicate that it is causing damage. It was not ria, Infomusa, 2 : 13-14. present in ail citrus orchards sampled, only at the IRA F.A.O. (1993). F.A.O. 1992 Yearbook, Rome: Food and Agri­ Fombout Research Station on various rootstocks. As culture Organisation, infestation is normally caused by the movement of in­ fected plants, preventing the spread of the nematode by GERAERT, E. & Au, S. S, (1978), Observations on Para­ using eertified planting material which is nematode free lylenchus CU/ualicus (syn. P. humilis) and P, OblUsical/daeus could be realistically achieved, from Africa. ( : Nematoda). Meded. Fac. Landb­ WeI. Rljksuniv. Gent, 43 : 813-816, Both M. incognita and kI. arenaria were found caus­ ing root galling ofcocoyam, Xanthosoma spp, Root-knot GERMANl, G, (1978), Caractères morpho-biométriques de nematodes are known to occur on Xanthosoma world­ trois espèces ouest-africaines de ROlylenchulus Linford & Oliveira, 1940 (Nematoda : Tylenchida). Revue NémaLO/., wide including Nigeria. Many reports suggest that Xan­ 1: 241-250, lhosoma spp. are generally tolerant of Meloidogyne, but both M. incognita and M. arenaria can cause corm dam­ G1CHURE, E, & ONDIEKl, ]. ]. (1977), A survey of banana age and there is the suggestion that M. incognita could be nematodes in Kenya, Z. PflKrankh PflSchulz, 84 : 724-728, involved in a root rot disease of the crop Oatala & GOODEY,]. B. (1957). Hoplolaimus proporicus n. sp. (Hoplo­ Bridge, 1990), lairninae: Tylenchida). Nemalologica, 2: 108-113.

Vol. 18, n° 3 - 1995 259 J Bridge et al.

DE GU1RAN, G. & VILARDEB6, A (1962). Le bananier aux PRlCE, N. S. (1994 b). Field trial evaluation of MU5a varieties, Iles Canaries. IV. Les nématodes parasites du bananier. and of other crops as hosts of Pralylenchu5 goodeyi in Cam­ F/Uils: 17: 263-277. eroon. Afro-Asian J NemalOl., 4 : 11-16. HOOPER, D.]. (1990). Extraction and processing of plant and PRlCE, N. S. & SIDDrQl, M. R.( 1994). Rain Forest nematodes soil nematodes. In: Luc, M., Sikora, R. A. & Bridge, ]. with particuJar reference to the Korup National Park, Cam­ (Eds). Plant parasilic nemalOdes in sublropical and lropical eroon. Afro-Asian J. NemalOl.) 4 : 117-128. agriculwre. Wallingford, UK, CAB International, U.K. : 45­ 68. SAKWE, P. N. & GERAERT, E. (1991). Sorne plant parasitic ]ATALA, P. & BRlDGE,]. (1990). Nematodes parasites of rOot nematodes from Cameroon with a description of Cn·cone­ and tuber crops. In: Luc, M., Sikora, R. A. & Bridge, ]. mella pelerenlsi sp. n. (Tylenchida: Criconematidae). Ne­ (Eds). Planl parasilic nemalOdes in sublropical and tropical rnalologica, 37 : 263-274. agnàtlture. Wallingford, u.K., CAB International: 137­ SA.KWE, P. N. & GERAERT, E. (1992). Plant parasitic nema­ 180. todes from Cameroon: Belonolaimidae, Criconematidae Luc, M. (1957). Radopholus lavabri n. sp. (Nematoda : Ty­ and Hoplolaimidae (Nematoda : Tylenchida). Meded. Fac. Ienchidae) parasite du riz au Cameroun français. NemalOlo­ LandbWelensch. Univ. Gent, 57: 857-877. gica, 2 : 144-148. Luc, M. (1960). Trois nouvelles espèces du genre Rotylen­ SAKWE, P. N. & GERAERT, E.(1993). The genus Dilylenchus choides Whitehead, 1958 (Nematoda-Tylenchida). Nema­ Filip'ev, 1936 from Cameroon (Nematoda : Anguinidae). tologica, 5: 7-17. Fundam. app!. Nernatol., 16: 339-353. Luc, M. & DE GUIRAN, G. (1960). Les nématodes associés SA.t\1S0EN, L. & Au, S. S. (1978). Problems concerning Ty­ aux plantes de l'Ouest africain. Liste préliminaire. Agron. lenchulus, Tropholylenchulus and Trophonema (Nematoda : lrop., Nogenl, XV : 434-443. Tylenchulidae). Scientific report of the Belgian Mt Kenya Luc, M. & VLLARDEB6, A. (1961). Les nématodes associés bio-expedition, or. 14. Meded. Fac. LandbWelensch. Rijksu­ aux bananiers cultivés dans l'Ouest Africain. Fnlils, 16: niv. Gent, 43 : 803-805. 205-219,261-279 SAMSOEN, L. & GERAERT, E. (1975). La faune nématolo­ MACHON, ]. E. & HUNT, D.]. (1985). Pralylenchu5 goodeyi. gique des rizières du Cameroun.!. Ordre des Tylenchides. C.1.H. Descript. PI.-Parasit. Nematodes. Set 8, No. 120, Revue Zoo!. afr.) 3 : 536-554. 2 p. SARAH,]. L. (1989). Banana nematodes and their control in MEuN, P., PALUD, G. & TEZENAS Du MONTCEL, H. (1976). Africa. Nemalroplca, 19: 199-21 S. Influence des nématod~s sur la culture du plantain. Fmi/s, 31 : 688-691. SEINHORST,]. W. (1963). Five new Tylenchorhynchus species lV1.tLlN, P. & VLLARDEB6, A. (1973 a). Efficacité de quelques from West Africa. NemalOlogica, 9: 173-180. nématicides en bananeraie dans les sols volcaniques de la région du Mungo (Cameroun). Fmils, 28: 3-17. SIDDIQI, M. R. & LAL, A. (1992). of the genus Ouolenchus Husain & Khan, 1967 (Nematoda: Tylenchi­ Mf:LlN, P. & VILARDEB6, A (1973 b). Nématicide et désin­ dae) with descriptions of fifteen new species. Afro-Asian J. fection à l'eau chaude dans la lutte contre Radopholus similis Nernatol., 2 : 89-106. en bananeraie. FruiLS, 28 : 843-849. lV1.tLlN, P. & VILARDEB6, A. (1976). Chemical control of SWENNEN, R. (1990). Plantaln cullivalion under Wesl Afncan Radopholus similis on plantains. Nemalropica, 6 : 49-50. conditions. International Institute of Tropical Agriculture, Nigeria, 24 p. OTEIFA, B. A. (1962). Species of root-1esion nematodes com­ monly associated with economic crops in the delta of the TEMPLE, L., GENETTAlS, T., GANRY,]. & CHATAIGNIER,]. DAR. Pl. Dis. Repli·) 46 : 572-575. (1993). Plantains production systems and intensification PEREGRlNE) W. T. H. & BRlDGE,]. (1992). The lesion nema­ prospects in southwest Cameroon. Fruils, 48: 119-123. tode, Pralylenchu5 goodeyi, an important pest of Ensele in VILARDEB6, A & GUÉROUT, R. (1976 a). A review of experi­ Ethiopia. Trop. Pesl Manag., 38: 325-326. ments on nematode control with ethroprop (prophos); phe­ PINOCHET, ]. (1988). A method of screening bananas and namiphos and carbofuran in French-speaking West Africa. plantains to les ion forrning nematodes. In: Nematodes and Nemalropica, 6: SI-53. lhe borer weevil in bananas: presenl 5LaWS of re5earch and ouLlook. Proc. Worksh., INIBAP, Bujumbura, Burundi, 7­ VLLARDEB6, A. & GUÉROUT, R. (1976 b). Nematode species 11 Dec. 1987: 62-65. in West Africa, J\1adagascar and Reunion, with some com­ PR1CE, D. (1960). The control of parasitic eelworms in ba­ ments on their biology. Nemalropica, 6 : 53-57. nanas. Trop. Agric. 37 : 107-109. VLLARDEB6, A, GUÉROUT, R., PfNON, A & MELIN, PH. PRlCE, N. S. (1994 a). 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260 Fundarn. appl. NemalOl.