Two correlative approaches to the challenge of ecological niche modeling (genetic algorithm, maximum entropy) were used to estimate the potential global distribution of the invasive fruit fly, Bactrocera invadens, based on associations between known occurrence records and a set of environmental predictor variables. The two models yielded similar estimates, largely corresponding to Equatorial climate classes with high levels of precipitation. The maximum entropy approach was somewhat more conservative in its evaluation of suitability, depending on thresholds for presence/absence that are selected, largely excluding areas with distinct dry seasons; the genetic algorithm models, in contrast, indicate that climate class as partly suitable. Predictive tests based on independent distributional data indicate that model predictions are quite robust. Field observations in Benin and Tanzania confirm relationships between seasonal occurrences of this species and humidity and temperature.

Chemical control has highly expanded over the last 30 years in sub-Saharan Africa to reduce bio-aggressors on all crops. Pest management of fruits and vegetables by small farmers in sub-Saharan Africa have developed anarchically in a fuzzy regulation framework. Pesticide toxicity and excessive application are often criticized both by farmers and consumers. Here, we review pesticide management in sub-Saharan Africa over the past 30 years. We then propose options to improve and reduce pesticide application, in order to decrease environmental and human hazards. The major points are as follows: (1) global changes in sub-Saharan Africa such as urbanization modify farmer practices and crop losses. (2) Pesticides are more and more used by small farmers in an unsustainable way. (3) The risk of pesticide application for human health and environment is poorly known. (4) We propose options to reduce pesticide application based upon integrated pest management (IPM) and agroecology. Moreover, IPM increases farmer economy, thus decreasing poverty. (Résumé d'auteur

A new Bactrocera species in Benin among mango fruit fly (Diptera: Tephritidae) species. Abstract-Introduction. Tephritidae have a major economic importance in the tropical areas. In Benin, we had only very little information available on the mango fruit fly species, except the demonstration of their damage. We therefore carried out the first investigations in Northern Benin during the mango season in 2005. Our objectives were to study fluctuations of tephritid populations in orchards and to assess mango fruit fly infestations and mango losses due to tephritid species. Materials and methods. Experiments were carried out in the Parakou area (Borgou department, Northern Benin). Fruit fly males were captured on mango trees, in two different orchards, with parapheromone traps. To sample and characterize fruit fly species involved in mango infestations, fruits of 17 cultivars were collected in mango orchards from February to June 2005; then, they were brought to the laboratory for emerging species identification. To assess the loss of fruits, sampling of different mango cultivars was achieved in the same orchards. Infested fruits were counted and eliminated; potentially infested fruits were dissected. Results and discussion. Among eight mango fruit fly species found in Benin, four can be considered as species of economic significance: Ceratitis cosyra, C. quinaria, C. silvestrii and Bactrocera invadens. During the dry season, C. cosyra was the most abundant, whereas B. invadens was the most numerous during the rainy season (abiotic factor), in phenological accordance with the ripening of the different mango varieties (biotic factor). From and after mid-May, B. invadens was found more frequently than C. cosyra in the traps and from emergence of infested mangos. Loss averages varied globally from 12% at the beginning of April to 50% in June. Conclusions. Most of the tephritid species found on mangos during our experiments had already been observed previously in other West African countries except B. invadens, an invasive species lately described. Ecological and behavioral studies will be necessary in order to plan and to apply optimal methods for controlling this new pest of major economic importance in West Africa.

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