Evaluation de l’efficacite de quatre formulations de chlorpyriphos ethyl contre la cochenille Farineuse du manguier Rastrococcus invadens Williams (Homoptera : Pseudococcidae) : bilan de dix annees d’experimentation en Côte D’Ivoire

La cochenille farineuse du manguier, Rastrococcus invadens (Homoptera : Pseudococcidae) est l’un des principaux ravageurs du manguier en Côte d’Ivoire, particulièrement dans la région nord qui fournit les mangues exportées. En attendant la mise en place de la lutte biologique envisagée, et devant l’ampleur des dégâts pouvant favoriser des traitements abusifs de la part des producteurs, des expérimentations ont été initiées pour sélectionner des insecticides efficaces en vue de leur homologation. Sur station de recherche, le premier screening a concerné 8 formulations d’insecticides appliquées à doses fortes (2 litres / ha) sur 100 m² de parcelle élémentaire de manguiers. Ensuite, pour chaque formulation retenue, trois doses ont été testées (2 litres / ha, 1 litre / ha et 0,5 litre / ha) sur 200 m². En milieu paysan, la dose optimale a été confirmée sur au moins 20 ha dans des essais couples. Le screening préliminaire a mis en évidence l’efficacité des formulations à base de chlorpyrifos éthyl avec une rémanence de 4 semaines. L’évaluation de 3 doses de ces formulations en station a permis de retenir la dose efficace de 1 litre / ha soit 480 g dechlorpyrifos-éthyl / ha. Les tests réalisés en milieu paysan ont confirmé l’efficacité des 4 formulations de chlorpyrifos-éthyl contre le ravageur : Dursban 4 E, Cyren 480 EC, Pyriforce 480 EC et Pyrical 480 EC. L’exécution raisonnée des traitements permet à la lutte chimique de s’intégrer harmonieusement dans un programme de gestion intégrée de la cochenille farineuse.Mots clés : Rastrococcus invadens, cochenille farineuse du manguier, lutte chimique, chlorpyrifos-éthyl.EVALUATION OF FOUR FORMULATIONS OF CHLORPYRIPHOS ETHYL AGAINST THE MANGO MEALY BUG Rastrococcus invadensWILLIAMS  (HOMOPTERA : PSEUDOCOCCIDAE) : ASSESSMENTOF TEN YEARS  EXPERIMENTATION IN CÔTE D’IVOIREThe mango mealy bug, Rastrococcus invadens (Homoptera,  Pseudococcidae) is one of the main pests of mango in Côte d’Ivoire,  particularly in the northern region that provides the exported mangoes. Before the using of biological control considered, and faced with the extent of damages that may promote abusive treatment by the producers,  experiments were initiated to select effective insecticides for their approval. On research station, the first screening has involved eight formulations of insecticides applied at high doses (2 L / ha) of 100 m² plot of mango trees. Then, for each formulation selected, three doses were tested (2 liters / ha, 1 liter / ha and 0.5 l / ha) on 200 m². On-farm, the optimal dose was confirmed at least 20 ha in trials couples. The preliminary  screening has shown the effectiveness of formulations containing  chlorpyrifos ethyl with a remanence of 4 weeks. The evaluation of three  doses of these formulations on station allowed to retain the effective dose of 1 l / ha or 480 g of chlorpyrifos-ethyl / ha. The on-farm tests have  confirmed the effectiveness of four formulations of chlorpyrifos-ethyl against the pest: Dursban 4 E, Cyren 480 EC, Pyriforce 480 EC and Pyrical 480 EC. The rational treatment allows to chemical control to integrate  seamlessly into an integrated management program against the mealy  bug.Key words : Rastrococcus invadens, mango mealy bug, chemical control, chlorpyrifos ethyl

Epidémiologie des nématodes gastro-intestinaux des bovins dans la région centre de la Côte d'Ivoire

From February to December 1997, six head of N’Dama cattle originating from the Central zone of humid savanna in Côte d’Ivoire were examined postmortem monthly. Fourteen species/genera of parasites were identified: 8 nematodes, 2 trematodes, 1 cestode and 3 protozoa. All animals were infected with at least one of the following gastrointestinal nematodes: Haemonchus sp. (95%), Cooperia punctata (50%), Oesophagostomum radiatum (35.5%), Trichostrongylus axei (30%), Cooperia pectinata (8.1%) and Trichuris sp. (1.6%). Setaria labiatopapillosa was found in 30.6% of the animals examined, microfilaria in 24.1%, paramphistomes in 80.6% and Moniezia sp. in 15%. Trypanosomes and Babesia spp. were found in 11.2 and 3.6% of the animals, respectively. The egg counts and worm burden of gastrointestinal nematodes varied with peaks in May and September/October, i.e. during the rainy seasons. Young animals 1-3 years of age had higher worm burdens than animals over 3 years old (P < 0.05). No larval hypobiosis was detected. In spite of a favorable humid climate, the worm burden of this N’Dama cattle originating from an extensive husbandry system was relatively low. Anthelmintic treatments appear necessary in younger animals only

Annual population dynamics of mango fruit flies (Diptera: Tephritidae) in West Africa: socioeconomic aspects, host phenology and implications for management

Introduction. Losses in West African commercial mango orchards due to fruit fly infestations have exceeded 50% by the middle of the crop season since 2005, resulting in considerable income loss for the growers. Materials and methods. In 2009, weekly monitoring of adult fruit fly species of economic significance was carried out in eight West African countries at 12 sites across five agro-ecological zones: (i) Humid Forest, (ii) Guinean savanna, (iii) Southern Sudan, (iv) Northern Sudan, and (v) Sahelian. Trapping was performed using methyl eugenol and terpinyl acetate in 288 Tephri-traps, targeting Bactrocera invadens and Ceratitis cosyra. Results. The data showed that B. invadens was present throughout the year in the Forest zone, abundant for 7 months, with a peak in May at the end of the mango season, C. cosyra being totally absent. In the Guinean savanna zone, B. invadens was abundant for 6-7 months, with a peak at the beginning of June coinciding with the season, with a few C. cosyra. In the Southern Sudan zone, B. invadens was abundant for 6 months, with a peak in mid-June during the season, C. cosyra peaking in April. In the Northern Sudan zone, B. invadens was abundant for 5 months, with a peak at the end of June at the end of the season, C. cosyra peaking in May. In the Sahelian zone, B. invadens was abundant for 4 months, peaking in August during the season, C. cosyra peaking just before. These preliminary results showed that the exotic species, B. invadens, was present at high levels [mean peak of 378 flies per trap per day (FTD)] in all agro-ecological zones, while the native species, C. cosyra, preferred the drier zones of West Africa, with lower population levels (mean peak of 77 FTD). Conclusion. Detection trapping of male flies with parapheromones is a useful indicator of field population levels and could be used to deploy control measures (IPM package) in a timely manner when the Economic Injury Level is reached. Control strategies for these quarantine mango fruit fly species are discussed with respect to agro-ecological zones and the phenological stages of the mango tree