Observations on the community dynamics of plant parasitic nematodes of rice in Cote d'Ivoire

Abstract The population dynamics of nematode communities were studied during a rice cropping season in 22 fields in the humid forest zone of Cote d'Ivoire. Rainfed upland, hydromorphic, and lowland rice fields were examined during the 1996 growing season and compared to nematode communities in adjacent undisturbed forest and vegetation. Forest clearance and burning had little immediate influence on nematode species diversity. Thirty days after the introduction of rice, nematode species diversity across ecosystems was reduced by 57% to seventeen species. At harvest, species diversity was 55% lower than in adjacent forest and vegetation. With progression of the season, a small percentage of nematode genera became numerically dominant, while the greater proportion of nematode genera were present at low mean intensity. At harvest Meloidogyne spp. were numerically dominant in upland rice and Hemicycliophora oostenbrinki numerically dominant in hydromorphic rice, accounting for 74 and 75% of total mean intensity in upland and hydromorphic ecosystems, respectively. Lowland rice communities were characterised by low nematode intensity and low species diversity. Dominant species at harvest were Helicotylenchus spp. (52% of total mean intensity) which were undetected at sowing. Other nematodes which persisted under rice at low mean intensity in various ecosystems were Trichodorus eburneus, Xiphinema hygrophilum and Pratylenchus brachyurus. Observation sur la dynamique des peuplements de nematodes parasites du riz en Cote d'Ivoire - La dynamique des peuplements de nematodes a ete etudiee au cours d'une saison rizicole dans 22 champs de Cote d'Ivoire situes en zone forestiere humide. Ces champs (riz de plateau, pluvial et de bas-fonds) ont ete explores durant la periode de culture en 1996 et leurs peuplements compares a ceux des forets et autres vegetations naturelles avoisinantes. L'essartage et le brulis n'ont qu'une influence immediate faible sur la diversite specifique des nematodes. Trente jours apres la mise en place du riz cette diversite liee aux ecosystemes etait reduite de 57%, c'est a dire a dix-sept especes. Au moment de la recolte, la diversite specifique etail inferieure de 55% a celle de la foret ou de la vegetation voisines. Avec l'avancement de la saison de culture, un faible pourcentage de genres de nematodes devient numeriquement dominant tandis que la majeure partie des genres demeurent presents a des taux moyens faibles. Au moment de la recolte, les Meloidogyne sont numeriquement dominants pour le riz de plateau tandis que c'est Hemicycliophora oostenbrinki pour le riz pluvial, ces deux espece representant respectivement 74 et 75% des taux moyens des peuplements. Les peuplements de riz de bas-fonds se caracterisent par des taux de population et une diversite faibles. A la recolte, les especes dominantes sont celles du genre Helicotylenchus (52%) alors qu'elles etaient indetectables au moment du semis. Les autres nematodes persistants a des taux faibles dans les differents eco-systemes sont Trichodorus eburneus, Xiphinema hygrophilum et Pratylenchus brachyurus.

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Assessment of the importance of individual plant-parasitic nematode species in a community dominated by Heterodera sacchari on upland rice in Côte d'Ivoire

Nematology ◽

10.1163/156854102760396511 ◽

2002 ◽

Vol 4 (6) ◽

pp. 661-669 ◽

Cited By ~ 4

Author(s):

Richard Plowright ◽

Daniel Coyne

Keyword(s):

Cote D'ivoire ◽

Côte D’Ivoire ◽

Parasitic Nematode ◽

Upland Rice ◽

Nematode Species ◽

Plant Parasitic Nematode ◽

Damage Potential ◽

Cote D’Ivoire ◽

Côte D'ivoire ◽

Plant Parasitic

AbstractIn temperate climates, densities of plant-parasitic nematodes at or shortly before sowing are a useful predictor of their damage potential. Re-examination of data from nematode communities on upland rice in Côte d'Ivoire showed that interpretation of nematode pest potentials and the damage caused by either individual species, or by the community as a whole, is less simple. The numerical proportion of individual nematode species within a plant-parasitic nematode community, comprising Heterodera sacchari, Pratylenchus zeae , Meloidogyne incognita, Helicotylenchus dihystera, Mesocriconema tescorum and Xiphinema spp., changed with duration of the cropping cycle. The relative importance to the crop of the different species changed with time, and with development of the community structure over the course of the season. Analysis suggested that for H.sacchari, the mid-season population densities were most highly correlated with crop damage (yield loss) and therefore its damage potential for that particular season. The pest potential of other known rice pest species, such as M. incognita and P.zeae, was likely indicated earlier in the season, but the population increase of other nematode species in the community, particularly H. sacchari, compounded the interpretation of the data for other species. The use of single linear regression to assess the importance of individual nematode species conflicted with results of analyses using multiple stepwise regression, while use of cluster analysis permitted the identification of species groups at early and late stages in the cropping season.

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Strepsipteran parasitism of white leafhoppers, Cofana spp. (Hemiptera: Cicadellidae) in lowland rice in Cote d'Ivoire

International Journal of Pest Management ◽

10.1080/096708700227507 ◽

2000 ◽

Vol 46 (2) ◽

pp. 141-147 ◽

Cited By ~ 3

Author(s):

I. O. Oyediran ◽

A. Ndongidila ◽

E. A. Heinrichs

Keyword(s):

Cote D'ivoire ◽

Côte D’Ivoire ◽

Lowland Rice ◽

Cote D’Ivoire ◽

Côte D'ivoire

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Assessing Anopheles vector species diversity and transmission of malaria in four health districts along the borders of Côte d’Ivoire

Malaria Journal ◽

10.1186/s12936-021-03938-1 ◽

2021 ◽

Vol 20 (1) ◽

Author(s):

Firmain N. Yokoly ◽

Julien B. Z. Zahouli ◽

Graham Small ◽

Allassane F. Ouattara ◽

Millicent Opoku ◽

...

Keyword(s):

Species Diversity ◽

Anopheles Gambiae ◽

Cote D'ivoire ◽

Côte D’Ivoire ◽

Malaria Incidence ◽

Vector Species ◽

Cote D’Ivoire ◽

Côte D'ivoire ◽

Health Districts ◽

Sporozoite Infection

Abstract Background Although malaria and Anopheles mosquito vectors are highly prevalent in Côte d’Ivoire, limited data are available to help understand the malaria vector density and transmission dynamics in areas bordering the country. To address this gap, the Anopheles mosquito species diversity, the members of the Anopheles gambiae complex and the transmission of malaria were assessed in four health districts along the borders of Côte d’Ivoire. Methods From July 2016 through December 2016 and July 2017 through December 2017, adult Anopheles mosquitoes were collected in four health districts of Côte d’Ivoire (Aboisso, Bloléquin, Odienné and Ouangolodougou) using standardized window exit trap (WET) and pyrethrum knockdown spray collection (PSC) methods. The collected mosquitoes were identified morphologically at species level and the members of the An. gambiae complex were separated using short interspersed nuclear element-based polymerase chain reaction (SINE-PCR). Anopheles gambiae sensu lato (s.l.), Anopheles funestus s.l. and Anopheles nili specimens were analysed for malaria Plasmodium parasite detection using the cytochrome oxidase I gene (COX-I), and malaria prevalence among human population through local Ministry of Health (MoH) statistical yearbooks. Results A total of 281 female Anopheles were collected in Aboisso, 754 in Bloléquin, 1319 in Odienné and 2443 in Ouangolodougou. Seven Anopheles species were recorded including An. gambiae s.l. (94.8–99.1%) as the main vector, followed by An. funestus s.l. (0.4–4.3%) and An. nili (0–0.7%). Among An. gambiae s.l., Anopheles coluzzii represented the predominant species in Aboisso (89.2%) and Bloléquin (92.2%), while An. gambiae sensu stricto (s.s.) was the major species in Odienné (96.0%) and Ouangolodougou (94.2%). The Plasmodium sporozoite infection rate in An. gambiae s.l. was highest in Odienné (11.0%; n = 100) followed by Bloléquin (7.8%, n = 115), Aboisso (3.1%; n = 65) and Ouangologoudou (2.5%; n = 120). In An. funestus s.l., Plasmodium falciparum sporozoite infection rate was estimated at 6.2% (n = 32) in Bloléquin, 8.7% (n = 23) in Odienné. No An. funestus s.l. specimens were found infected with P. falciparum sporozoite infection in Ouangolodougou and Aboisso. No P. falciparum sporozoite was detected in An. nili specimens in the four health districts. Among the local human populations, malaria incidence was higher in Odienné (39.7%; n = 45,376) and Bloléquin (37.6%; n = 150,205) compared to that in Ouangolodougou (18.3%; n = 131,629) and Aboisso (19.7%; n = 364,585). Conclusion Anopheles vector species diversity, abundance and Plasmodium sporozoite infection were high within the health districts along the borders of the country of Côte d’Ivoire, resulting in high malaria transmission among the local populations. Anopheles gambiae s.l. and An. funestus s.l. were found to be highly infected with Plasmodium in the health districts of Bloléquin and Odienné where higher malaria incidence was observed than the other districts. This study provides important information that can be used to guide Côte d’Ivoire National Malaria Control Programme for vector control decision-making, mainly in districts that are at the country borders.

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