L'une des contraintes liée à la production maraîchère, est la pression exercée par les insectes ravageurs. Cette étude analyse quelques aspects du système de production légumière ainsi que la perception des producteurs de l'utilisation d'extraits botaniques dans la gestion des insectes ravageurs des cultures maraîchères. Elle a été réalisée à travers une enquête menée auprès de 217 maraîchers au Sud du Togo. L'analyse descriptive des données a révélé que plus d'hommes (72%) que de femmes (28%) pratiquent le maraîchage. Seul 33% a suivi une fois une formation en maraîchage. La contrainte majeure dans la production maraîchère est le problème de ravageurs et de maladies dont les principaux sont des insectes, des nématodes et des champignons. La lutte chimique constitue la principale méthode de lutte contre ces ravageurs. Néanmoins, les maraîchers connaissent des dangers induits par l'utilisation des pesticides de synthèse et sont au courant de l'utilisation des pesticides botaniques en maraîchage. Cependant, très peu les utilisent dans la gestion des ravageurs. Mais, ils sont disposés à utiliser les pesticides botaniques si ceux-ci sont disponibles, accessibles, efficaces et pas trop chers pour pallier les effets néfastes des pesticides de synthèse à la santé et à l'environnement.

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The sympatric bruchids Callosobruchus rhodesianus (Pic) and Callosobruchus maculatus (F.) (Coleoptera: Bruchidae) colonize cultures of cowpea, Vigna unguiculata (Walp.) (Papilionaceae), in Togo at the end of the rainy season. Seeds containing larvae of the two bruchid species were introduced into the storage systems. Callosobruchus rhodesianus adults emerged from the seeds at the beginning of storage, but this species disappeared quickly and C. maculatus became dominant. Analysis of the reproduction of females collected at the beginning of storage made it possible to distinguish between four groups of females differing in their reproductive activity. Three groups were sexually active but they differed in their fecundity and the duration of the latency period before the first oviposition phase. The fourth group of females was in reproductive diapause. In interspecific competition, the presence of C. maculatus larvae reduced the survival chances of C. rhodesianus and therefore is disadvantageous for this species. The main factors explaining the rapid decrease of the C. rhodesianus populations under storage conditions were the variability of female reproductive activity with the emergence of insects in reproductive diapause and the significant larval mortality in interspecific competition with C. maculatus.

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The age-dependent fecundity and offspring production of females of a solitary ectoparasitoid Dinarmus basalis Rond. (Hymenoptera : Pteromalidae) were determined on its host Callosobruchus maculatus F. (Coleoptera : Bruchidae). The resulting data were used to determine the longevity and reproductive potential of the species, by establishing its life and fertility tables. In the presence of 16 hosts renewed every 48 hours, D. basalis females had a mean longevity of 32.6 ± 1.6 days. They laid an average of 136.5 ± 55.2 eggs, parasitised 132.7 ± 53.9 hosts, and produced 111.8 ± 3 offspring, consisting of 58.3 % of males and 41.7 for females. The total mean development time was 14.0 ± 0.7 days for females and 11.8 ± 0.8 days for males. The net reproductive rate R o was 38.9 females progeny per adult female, and the intrinsic rate of population increase (r m ) 0.16 per day. The generation time (G) was 22.5 days and the doubling time (DT) 4.3 days. These parameters permitted to determine the reproductive potential of D. basalis as a biological control agent against the bruchid in West Africa.