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Fundam. app/. Nemawl., 1995,18 (4), 347-353

Ecology and pathogenicity of the (Nemata) from the sahelian zone of West Mrica. 3. clathricaudatum Whitehead, 1959

Pierre BAuJARD * and Bernard MARTINY ORSTOM, Laboratoire de Nématologie, B.P. 1386, Dakar, Sénégal. Accepted for publication 2 August 1994.

Swnmary - The distribution of Sculellonema clalhricaudalUrn in West Africa, the biotic and abiotic factors affecting its multiplica­ tion rate and its pathogeniciry to peanut and millet are studied. This species appeared to be adapted to the climatic conditions ofboth semi-arid and rainy tropics of West Africa. No pathogenic effects of the were recorded on peanut and millet. Since males have occurred during the laboratory experiments and" vaginal glands" (in fact the constrictor muscle of the vagina) are present in chis species, the taxonomie relationships between three closely related species, Sculellonema bradys, S. cavenessi and S. clalhricauda­ lum, need to be re-examined.

Résumé - Écologie et nocuité des Hoplolaimidae (Nemata) de la zone sahélienne d'Afrique de l'Ouest. 3. Scutellone­ ma clathricaudatum Whitehead, 1959 - La répartition géographique, les facteurs biotiques et abiotiques affectant le taux de multiplication et la nocuité de Sculellonerna clalhricaudalurn sont étudiés. Cette espèce apparaît bien adaptée aux conditions écologiques tant des zones semi-arides que des zones humides d'Afrique de l'Ouest. Aucun effet pathogène du nématode sur

l'arachide et le mil n'a été mis en évidence. Des mâles étant apparus au cours des expérimentations de laboratoire et les (1 glandes

vaginales l) (en réalité le muscle constricteur du vagin) étant présentes chez cette espèce, les relations taxonomiques entre trois espèces très proches, Scurellonema bradys, S. cavenessi et S. clalhricaudalum, devraient être réexaminées.

Key-words : Scure/lonema clalhricaudalUm, West Africa, distribution, multiplication rate, soil temperarure, soil moisture, host­ plants, pathogeniciry, taxonomie relationships.

Two species of the genus Scutellonema, S. cavenessi South-East of Mali up to the centre of Niger; it is absent Sher, 1964 and S. clalhricaudalum Whitehead, 1959, from Senegal and me West of Mali (Fig. 1). considered as serious pests of peanut in Senegal (Ger­ Previous work has shown the complicated biology of mani el al, 1985) and Niger (Sharma el al, 1992) re­ S. cavenessi (Baujard & Martiny, 1995 c, d), and the spectively, have been identified during the course of geographical distribution, ecology and pathogenicity of studies on ecology of soi! from the sahelian S. clalhn'caudatum have been studied. zone of West Africa (Baujard & Martiny, 1994 a, b; MATERlAL AND METHODS 1995 a, c). S. clalhricaudatum is widely distributed in UnJess otherwise stated, nematode extractions, nema­ Africa, Tanzania (Whitehead, 1959), Congo and Cen­ tode cultures and laboratory experiments were conduct­ traI African Republic (Luc el al, 1964), Zaire (Ali el al, ed as previously indicated; the same host-plants and 1973), South Africa (Van den Berg & Heyns, 1973 = S. cultivars (peanut [Arachis hypogea L. cv. 55437], millet aberrans) and especially in West Africa : Mali (Baujard [Pennisetum lyphoides Rich. cv. Souna III], sorghum & Martiny, 1994 b), Burkina Faso (Sharma, 1990), [Sorghum vu/gare L. cv. 51 69] and cowpea [Vigna un­ Niger (Sharma el al, 1988, 1990, 1992; Sharma, 1990), guicu/ata (L.) Walp. cv. N58 57]) were used in ail exper­ Sierra Leone (Vovlas el al, 1991), Ivory Coast (Malcev­ iments (Baujard, 1995). schi, 1978), Nigeria (Sher, 1964), Benin (Sharma, 1990) and Cameroon (Sakwe & Geraert, 1991, 1992). ORIGrN OF NEMATODES AND STOCK CULTURES Data originating from surveys conducted by the first Nematodes used for stock cultures and laboratory ex­ author in Mali, from slides deposited in the collection of perirnents were collected from peanut fields, Souroun­ the Muséum National d'Histoire Naturelle, Paris, touna, Mali in October 1986 (Baujard & Martiny, 1994 France and from literature showed that S. clathricauda­ b). Nematodes were cultured in the laboratory on millet lum is widely distributed below the latitude 15 ° N from at constant soil temperature (34 OC) and soil

* Presenr address : Muséum Nalional d'Hislaire NalUrelle, Laboraloire de Biologie Parasitaire, Prolislologie, Helminrhologie, 6/, rue Buffon, 75005 Paris, France.

ISSN //64-557//95/04 S 4.00/ © CaU/hier-Villars - ORSTOM 347 P. Baujard & B. Maniny

IS!"'w _

lO· __--j_ ....,.\ \

,-' "

Fig. 1. Krwwn geographical distribution ofScutellonema bradys, S. cavenessi and S. clathricaudatum in West Africa (S. cavenessi: stipped area; S. clathricaudatum : hau:hed area; stars =countries where S. bradys was recorded in association with yams).

moisture (10 %) in a growth chamber from October originating from a 100 day-old stock culture on millet 1986 until January 1990; after this date, they were cul­ were inoculated onto millet under COnstant soil temper­ tured under cOnstant soil temperature (36 OC) and soil ature (36 OC) and exposed to four constant soil moisture moisture (7 %) on millet. levels (5,7,9 or Il %) with seven replications per treat­ Another population collected in September 1990 ment for 60 days in a growth chamber. from the ICRlSAT station at Bengou, Niger, in fields under fallow, peanut and sorghum was cultured at the laboratory under constant soil temperature (36 OC) and HOST PLfu"lT AND SOIL DRYING soil moisture (7%) on millet.

SOIL TEMPERATURE 87 ± 10 nematodes (mixture of ail stages) originating Seventeen hand-picked nematodes (mixture of ail from a 100-day-old stock culture on millet were in­ stages) originating from a 100-day-old stock culture on oculated onto peanut, millet, sorghum or cowpea under millet were inoculated onto millet under constant soil constant soil temperature (36 OC) and soil moisture moisture (10%) and exposed to four constant soil tem­ (10 %) \vith rwenty replications per treatment in a perature levels (30, 32, 34 or 36 OC) with seven repli­ greenhouse. Nter 60 days, ten replications were extract­ cations per treatment for 75 days in a growth chamber. ed for nematode counting and watering was stopped for the other ten replications. After an additionnai 60 days, SOIL MOISTURE these ten replications were extracted for evaluation of Ten hand-picked nematodes (mixture of ail stages) the survival rate.

348 Fundam. appl. NernalOl. Ecology of Hoplolaimidae. 3

/' 5 A 5 ,/' c

./ 4 4 V :::;:;~g~ :~~:$E;; w w ~ ~ « « a: a: Wt:~:.>:t)o 3 V l./ <.» • z z 3 ,,"')<":.~;~" 0 0 >~3. ï= ï= >0"":-< :;:; « « '><">o>~ (,) (,) .:: ::i ::i 0- 2 V 0- 2 V ï= ~=>c .... ï=.... . ~ . ~ ><,,><:l< ".' ~ ~

b~.~··~ ~ ~ '~~*ii ~t~·; ~r ~ C> ~ ...""":~ o /F;<:;;:.' ,><,:-, :-. 30 32 34 36 PEANUT MillET SORGWUM COWPEA SOll TEMPERATURE CC) HOST PLANT

NEMA lODE CONDITION B 500 e'l A~YDROlllOllC • HYDROBIOnc D

êD 400 ­ a. .,CIl "0 o ; 300 .,E S z § 200 ....« ~ o0- 0- .... 100 « z ii: o o 5 7 9 11 PEANUT MillET SORGHUMCOWPEA SOll MOISTURE (%) HOST PLANT

Fig. 2. EffeclS ofsail temperature (A), sail moisture (B) and host-plants (C, D) on multiplication Tate ofScutelionema clathricaudarum and survival of the nemawde after sail drying in relation ID host-plant. (Data followed by the same lener are not significant1y different at p < 0.05).

CULTURE DURATION the treatment " 60 days " and t\vice for the treatments " 75 " and " 100 days ". In addition, nematodes orig­ Thirty hand-picked nematodes (mixture of aU stages) inating from the " 75 days " treatment were reinoculat­ originating from a 90-day-old stock cLÙture on millet at ed and maintained under the same experimental condi­ constant soil temperature (36 OC) and soil moisture tions for a culture period of 60 days; those originating (10 %) were inoculated onto millet at constant soil tem­ from the " 100 days " treatment were reinocLÙated for a perature (36 oC) and soil moisture (7 %) for three dif­ period of 60 or 75 days in order to evaluate the effect of ferent periods (60, 75 or 100 days) with seven repli­ the duration of the previous cLÙture on the multiplica­ cations per treatment in a growth chamber. At the end of tion rate. each culture period, nematodes were extracted, count­ ed, and maintained on the same plants under the same PATHOGENECITY ON PEANUT conditions (inocLÙum level, host-plant, soil temperature The multiplication rate and the effects on peanut of and moisture, periods). This was done three rimes for 420 ± 50 or 840 ± 100 nematodes originating from a

Vol. 18, n° 4 - 1995 349 P. Baujard & B. Marliny

120-day-old stock culture on millet at constant soil tem­ 100 /' perature (36 OC) and moisture (7 %) were compared to control plants without nematodes at constant soil tem­ perature (36 OC) and moisture (7 %) for 40 days in a greenhouse. 80 V

PATHOGENICITY ON MILLET The multiplication rate and the effects on millet of 550 ± 40 nematodes originating from a 100-day-old stock culture on millet at constant soil temperature (36 OC) and moisture (7 %) were compared to control plants without nematodes at constant soil temperature (36 OC) and moisture (7 %) for 100 days in a growth chamber.

Results

OBSERVATIONS MADE ON STOCK CULTVRES Fig. 3. Suruival rates ofScutellonema clathricaudatum after sail From October 1986 to January 1990, multiplication drying in relalion LO MSl-planl. rates varied from 0.11 to Il ex = 2.85 ± 3; n = 29); no males were observed. After January 1990, multiplication rates varied from 1 to 28 (x = 7.5 ± 5.7; n = 35); males SURVIVAL RATE AFTER SOIL DRYrNG began progressively ta occur, up ta 30 % of the cultures, The cessation of watering caused a decrease in soil representing 0.01-0.07 % of the total population. For moisture down to 0.2 % in 15 days. Nematode extrac­ the population originating from Niger, multiplication tion 45 days later revealed the presence of adults and 3rd rates varied from 1 to 10; males occurred erratically, and and 4th stage juveniJes. The mean survival rate was in low numbers. about 50 %, varying with host plants (Figs 2 D, 3).

MULTlPLICATION RATE PATHOGENICITY ON PEANUT AND MILLET The nematode did not have a significant effect on the Soil temperature and soil moisture did not significant­ growth of peanut or millet (Table 4). Iy affect (P < 0.05) multiplication rates (Fig. 2 A). The rate of multiplication observed during the experiment Discussion on soil temperature was rugher than that observed dur­ ing the experiment on soil moisture (Fig. 2 B). This S. clachn'caudatum appeared to be adapted to climatic observation could be related to the length of the IWO conditions of both semi-arid and rainy tropics. It is a experiments (75 vs 60 days). Host-plant significantly polyphagous species able to reproduce at medium ta affected the multiplication rate on ail the plants tested high soil temperature (30-36 OC) levels. Soil moisture that allowed reproduction (Fig. 2 C). Increases in cul­ did not appear to have a significant effect on multiplica­ ture duration from 60 to 100 days caused an increase in tion rate. The nematode was able ta enter a state of the multiplication from 2.33 to 4.41 for the treatrnents anhydrobiosis during drought periods. Pathogenicity to 100 days (Fig. 4 A), the daily multiplication rate for the peanut and millet appeared doubtful since the inoculum treatrnents 60, 75 and 100 days being stable: 0.038, levels tested corresponded with soil populations of 200­ 0.027 and 0.044 respectively. The length of the previous 1200 nematodes per dm3 of soil in Niger (Sharma, culture had no effect on the multiplication rates of the 1990; Sharma et al., 1988, 1990). nematode under the fo1Jowing culture (Fig. 4 B). When cornpared with S. cavenessi (Baujard & Marti­ Densities of S. clachn'caudatum in the roots varied ny, 1995 c, d), sorne differences and resemblances in from 9 ta 44 % of the total population and were not their characteristics appear. S. cavenessi is localized in directly affected by the differents treatrnents (Table 1). the West of the sahelian zone of West Africa whereas S. Observations on the occurrence of males in the experi­ clathricaudatum is localized in the centre and the East of ments showed a tendency toward an increase in the this area; further South, the IWO species appeared in the abundance of males from 0 to 61 % of the total popu­ same areas (Fig. 1). Soil temperature and soil moisture lation, and in their frequency ofoccurrence from 0 up to have a significant effect on the multiplication rate of S. 100 % (Tables 2, 3). cavenessi which was rugher than that of S. clathricauda-

350 Fundam. appl. NemaLOI. Ecowgy of Hoplolaimidae. 3

~ 0 D 1- culttle • 2° culture [] 3' ~tur. O.' culture l' cuth.r. • 2° cuthMe CD 3' culture E.1 .. culture 10 10 A ~I----- B 8 8 W w 1- 1- <1: <1: a: a: z 6 z 6 0 0 t= t= <1: <1: () () :J :J [l. 4 [l. 4 t= t= ...J ...J ::::l ::::l ::E ::E 2 2

o 60 DAYS 75 DAYS 100 DAYS 60/60 75/60 100/60 75/75 100/75 CULTURE LENGTH PREVIOUS/ACTUAL CULTURE LENGTH (number 01 days)

Fig. 4. Effect ofculture duration (A) and ofprevious culture duration (B) on multiplication rate of Scutellonema clathricaudarum.

Table 1. Percentages ofthe populations ofScutellonema clathri­ Table 2. Abundance (in % of the total population per treatment) caudarum in the TOotS at the end ofthe dijferent experimentations. and frequency (in % of replùation ofeach treatment) ofoceun'ence ofmales ofScutellonema clathricaudarum in the soiltemperature and soil moisture experiments. Experiment Root population as a % and treatments of total tube population Experiment Abundance-Frequency Soil temperature and treatments of males 30 oC 29 32 oC 12 Soil temperature 34°C 9 30 oC o 36°C 12 32 oC o Soil moisture 34°C o 5% 15 36°C o 7% 27 Soil moisture 9% 22 5% 6-43 Il % 18 7% 6-14 Host plants 9% o peanut 44 11% 17-43 millet 25 Host plants ND sorghum 9 cowpea 39 * inoculum per tube. Culture duration 60/60 days 28 tum (1-15 vs 1-5 respectively) under laboratory condi­ 75/75 days 13 tions. Both species exhibited the same host range, the 100/100 days 12 same mean survival rate of 50 % after soil desiccation Pathogenicity and the same reaction to culture duration. peanut S. cavenessi and S. clathn'caudatum are morphological­ *420 nematodes 24 ly closely re1ated species differing only by two charac­ *840 nematodes 11 ters : presence/absence of males and presence/absence millet of spermatheca (Germani et al., 1986). A third species, *550 nematodes 19 S. bradys (Steiner & LeHew, 1933) Andrassy, 1958 be­ longs to this group and is characterized by 1) presence of * inoculum per tube. males, ii) presence of spermatheca, iii) presence of vagi-

Vol. 18, n° 4 - 1995 351 P. Baujard & B. Martiny

Table 3. Abundance (in % of lhe lolal populalion per lrealment) same populations of S. cavenessi and S. clathl1caudalum andfrequency (in % of replicalion ofeach lrealmenl) ofoccurrence as in the present work). It has been noted (Whitehead, ofmales ofScutellonema c1athricaudatum in lhe cullure duralion 1959 a; Sher, 1964; Van den Berg & Heyns, 1973; Vov­ experimenl (ND .' non d.elermined). las el al., 1991) that no spermatheca occurred in S. clathncaudatum whereas Sakwe and Geraert (1992) ob­ served the presence of a " spermatheca empty and col­ Treatments Abundance-Frequency of males lapsed". Study of a population originating from the nd rd th 1st cycle 2 cycle 3 cycle 4 cycle rhizosphere of Vigna sinensis in the Ondo Province of Nigeria identified by Sher (1964) as S. aberrans revealed 60/60 days 0 8-14 45-100 13-43 the presence of an empty spermatheca in ail the females 75/60 days 8-43 ND (n = 5). Occurrence of males during the clÙture process 100/60 days 12-29 51-86 of S. clathricaudatum in the laboratory makes the taxo­ 75175 days 3-43 6-43 ND nomical situation more confused (Table 4). 100175 days 10-57 10-57 Study of i) the biology of S. bradys under the same 100/100 days 5-43 45-57 61-86 conditions as for the two other species, ii) the sexual behaviour of the three species, iii) the biochernical and , inoculum per rube. molecular characteristics of the three species rnight give new information on the relationships between what we Table 4. Mulliplicalion rare and effecLS ofScutellonema c1athri­ cali the "s. bradys complex ". caudatum on peanul and millel (numbers fol/owed by lhe same References leller are nol significantly dijferenl al P < O. 05). ALI, S. S., GERAERT, E. & COOMANS, A. (1973). Sorne spiral nematodes from Africa. Biol. Jaarb., Dodonaea, 41 : 53-70. Plant Inoculurn Multiplication Fresh weight Dr)' weight BAUJARD, P. (1995). Laboratory methods used for the study rate (g) (g) of the ecology and pathogenicity of , Longjdori­ Roots Shoots Shoots dae and Trichodoridae from rainy and serni-arid tropics of West Africa. Fundam. app/. NemalOl., 18: 63-66. Peanut 0 1.68 a 5.06a 0.97 a BAUJARD, P. & MARTTNY, B. (1994 a). Études nématolo­ 420 0.88 1.77 a 5.66 a \.08 a giques au Mali, Afrique de l'Ouest. 1. Prospections de deux 840 0.81 1.77 a 5.36 a 0.99 a zones arachidières sur J'arachide et le mil. J. afro Zoo/., 108 : Millet 0 \.03 a \.03 a 0.26 a 217-226. 550 5.78 1.34 a 1.48 a 0.36 a BA UJARD , P. & MARTTNY, B. (1994 b). Études nématolo­ giques au Mali, Afrique de l'Ouest. II. Effets des traitements nématicides sur l'arachide et le mil. J. afro Zool., 108 : 329­ Table 5. Characlers dislinguishing , S. 334. cavenessi and S. c1athricaudatum (+ =presence; - =absence; in BAUJARD, P. & MARTTNY, B. (1995 a). Études nématolo­ brackels .' previous situalion). gjques en Mauritanie et au Niger, Afrique de l'Ouest: né­ matodes associés au mil sauvage (penniselum violaceum). J. afro Zool., 109: (in press). Characters S. bradys S. cavenessi S. CIaUtriCllllda- tum BAUJARD, P. & MARTTNY, B. (1995 b). Characteristics of the soil nematode populations from the peanut cropping area of Senegal, West Africa. J. afro Zool., 109: 51-69. Spermatheca (+) + (+) + (-) -1+ Males (+) + (+) + H-!+ BAUJARD, P. & MARTTNY, B. (1995 c). Ecology and pathogen­ " Vaginal glandes " icity of the Hoplolairrùdae from the sahelian zone of West (constrictor muscles) (+) + (-) + (-) + Africa. 1. Field studies on Scurellonema cavenessi Sher, 1964. Fundam. appl. NemalO/., 18: 261-269. BAUJARD, P. & MARTTNY, B. (1995 d). Ecology and patho­ nal glands around vagina (Germani el al., 1986); this genicity of the Hoplolairrùdae from the sahelian zone of species showed the same geographical distribution in the West Africa. 2. Laboratory studies on Scurellonema cavenessi south of West Africa (Fig. 1). No other morphological Sher, 1964. Fundam. appl. Nemalol., 18: 335-345. or biometrical differences were reported between the GERMANl, G., BAU}ARD, P. & Luc, M. (1985). Control of three species (Germani el al., 1986). Vaginal glands are phytoparasitic nemawdes in the Bassin Arachidier of Senegal. reported by Whitehead, 1959 b in S. aberrans (now S. Dakar, Sénégal, ORSTOM, 16 p. clalhricaudalum, see Germani el al., 1986) by Van den GERMANl, G., BALDWIN, J. G., BELL, A. H. & Wu, X. Y. Berg and Heyns (1973); Mounport el al. (1991) showed (1986). Revision of the genus Sculellonema Andrassy, 1958 that vaginal glands are in fact constrictor muscles pre­ (Nematoda : Tylenchida). Revue Némalol., 8 (1985) : 289­ sent in the three species (TEM studies conducted on the 320.

352 Fundam. appl. Nemawl. Ecology ofHoplolaimidae. 3

Luc, M., MERNY, G. & NETSCHER, C. (1964). Enquête sur SHARMA, S. B., SUBRAHMANYAM, P., SARR, E. & VAN RIEL, les nématodes parasites des cultures de la République Cen­ H. (1988). Plant parasitic nematodes associated with tre-Africaine et du Congo-Brazzaville. Agron. trop., Nogent, groundnut at Sadoré in Niger. Int. Arachis Newsl., 4 : 10-11. 19: 723-746. SHARMA, S. B., WALlYAR, F., SUBRAHMANYAM, P. & NDUN­ MALcEvSCHl, S. (1978). Considérations quantitatives sur la GURU, B.]. (1992). Role of Scutellonema clathricaudatum in nématofaune d'une savane herbeuse à Andropogonées de etiology ofgroundnut growth variability in Niger. Pl. & Soil, Lamto (Côte d'Ivoire). Revue Ecol. Biol. Sol, 15: 487-496. 143: 133-139. MOUNPORT, D., BAUJARD, P. & N1ARTINY, B. (1991). Ultra­ structure de la cuticule et de la région vaginale de Scutellone­ SHER, S. A. (1964). Revision of the Hoplolaiminae (Nemato­ ma bradys, S. cavenessi et S. clathrnaudatum (Nemata : Ho­ da). III. Scutellonema Andràssy, 1958. Nematologica, 9 plolairnidae). Revue Nématol., 14: 261-275. (1963) : 421-443. SAKWE, P. N. & GERAERT, E. (1991). Sorne plant parasitic VAN DEN BERG, E. & HEYNS,]. (1973). South African Hoplo­ nematodes from Cameroon with a description of Cricone­ lainùnae. 2. The genus Scutellonema Andrassy, 1958. Phy­ mella pelerentsi sp. n. (Tylenchida: Criconematidae). Ne­ wphylactica, 5 : 23-39. mawlogica, 37: 263-274. SAKWE, P. N. & GERAERT, E. (1992). Plant parasitic nema­ VOVLAS, N., TROCCOLl, A. & LAMBERTI, F. (1991). Mor­ todes from Cameroon: Belonolainùdae, Criconematidae pho-anatomical observations on Aphasmatylenchus nigerien­ and Hoplolaimidae (Nematoda : Tylenchida). Meded. Fac. sis and Scutellonema clathn'caudatum from West-Africa. Ne­ Landbouww. Univ. Gent, 57 : 857-877. malOl. medit. : 19 : 259-264. SHARMA, S. B. (1990). Further investigations on the raie of WHITEHEAD, A. G. (1959 a). Scutellonema clathn'caudatum n. plant parasitic nematodes in crop growth variability of sp. (Hoplolairninae: Tylenchida), a suspected ectoparasite groundnut in Niger. Legumes Pathol. Progr. Rep., fCRfSAT, of the raots of the conon plant (Gossypium hirsutum L. var. India, 8 : 61 p. UK 51). NemalOlogica, 4 : 56-59. SHARMA, S. B., SUBRAHMANYAM, P. & SARR, E. (1990). Plant parasitic nematodes associated with groundnut in Nig­ WHlTEHEAD, A. G. (1959 b). aberrans n. sp. (Ho­ er. Trop. Pest Manag., 36: 71-72. plolaiminae: Tylenchida). NemalOlogica, 4 : 268-271.

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