#parasitoids

The Egyptian cotton leafworm Spodoptera littoralis Boisduval (Lepidoptera: Noctuidae) is among the serious cabbage pests in tropical countries. It can lead an intensive chemical insecticides use in market gardening perimeters. Alternative control methods such as biological control are necessary for the integrated management of this pest. The laboratory rearing of S. littoralis larvae sampled in the cabbage fields has been undertaken and the presence of parasitoids has been noticed. The population dynamic of S. littoralis larvae and these parasitoids has been studied in two market gardening perimeters on two crop cycles. The parasitoids of S. littoralis larvae are Apanteles sp, the hymenopterans belonging to the Braconids family, and the Microgastrin subfamily. Strong populations of Apanteles sp. involve weak populations of S. littoralis and weak populations of Apanteles sp. involve strong populations of S. littoralis. However, the correlations between Apanteles sp. adult’s number and S. littoralis larvae per ten plants are not significant for the crop cycles in all the sites. These parasitoids can be nevertheless taken to account for the integrated management program of S. littoralis. Identification of this insect up to the species could be undertaken for future studies.

The Egyptian cotton leafworm Spodoptera littoralis Boisduval (Lepidoptera: Noctuidae) is among the serious cabbage pests in tropical countries. It can lead an intensive chemical insecticides use in market gardening perimeters. Alternative control methods such as biological control are necessary for the integrated management of this pest. The laboratory rearing of S. littoralis larvae sampled in the cabbage fields has been undertaken and the presence of parasitoids has been noticed. The population dynamic of S. littoralis larvae and these parasitoids has been studied in two market gardening perimeters on two crop cycles. The parasitoids of S. littoralis larvae are Apanteles sp, the hymenopterans belonging to the Braconids family, and the Microgastrin subfamily. Strong populations of Apanteles sp. involve weak populations of S. littoralis and weak populations of Apanteles sp. involve strong populations of S. littoralis. However, the correlations between Apanteles sp. adult’s number and S. littoralis larvae per ten plants are not significant for the crop cycles in all the sites. These parasitoids can be nevertheless taken to account for the integrated management program of S. littoralis. Identification of this insect up to the species could be undertaken for future studies.

The pest Spodoptera frugiperda, when it invades Africa, is associated with a parasitic fauna, justifying the need to characterize the genetic diversity of its natural enemies in Senegal. Thus the rDNA of the large subunit, 28S was amplified. The study revealed the existence of 12 species of parasitoids obtained and 3 species of entomopathogenic nematodes. Parasitoids are divided into two orders (Hymenoptera and Diptera) and five families (Ichneumonidae, Braconidae, Eulophidae, Encyrtidae and Tachinidae). These parasitoids are Sinophorus exartemae, Chelonus sp., Parapanteles sp., Dolichogenidea sp. 1, Dolichogenidea sp. 2, Meteorus sp., Meteorus orocrambivorus, Euplectrus phthorimaeae, Prochiloneurus testaceus, Ooencyrtus masii, Drino sp. and Senometopia cariniforceps. Nematodes are members of the family Mermithidae and correspond to Hexamermis sp., Mermithidae sp. 1 and Mermithidae sp. 2. All these species attack the larval stage except O. masii which is oophagous. This study also reports new associations between S. frugiperda and the parasitoids S. exartemae, M. orocrambivorus, E. phthorimaeae, P. testaceus, O. masii and S. cariniforceps. To our knowledge, these six species, in addition to Drino sp., have just been known in the entomological fauna of Senegal. Therefore, it is urgent to protect these auxiliaries from the abusive and inappropriate use of chemical insecticides for sustainable management.