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The tomato leaf miner Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) is an invasive pest that produces significant damage to tomato crops in Senegal. Biological control is one of the options for its control and a large number of natural enemies have been reported in association with the pest. A five-year field survey was conducted in the main tomato-producing area in Senegal (Niayes) to evaluate the parasitoid complex of T. absoluta in tomato crops. Seven parasitoid species were obtained including Apanteles litae, Chelonus sp., Cotesia vestalis and Meteorus laphygmarum belonging to Braconidae family; Diadegma insulare, Pristomerus pallidus (Ichneumonidae) and Elasmus sp. (Eulophidae). The parasitoid Chelonus sp. was largely the most dominant (60.67%). Larval parasitism was very low (1.05%) but greater during the last years of the study (2016 to 2019). Results showed that parasitism was not affected by time of season. However, diversity of parasitoids was variable across year (p < 0.001). This study is a first step toward development of research and extension programs for conservation of natural enemies of T. absoluta in Senegal. [ABSTRACT FROM AUTHOR]

The Fall armyworm (FAW), Spodoptera frugiperda is an insect pest that causes huge losses to maize crops. The study was conducted in Senegal for two agro-ecological zones of the country during the rainy season in 2021. Results showed that the entomopathogenic nematode, Hexamermis sp., is present on S. frugiperda with parasitism rates ranging from 25.4% in Ziguinchor, 32.06% in the Tambacounda region, and 57.2 in the Kolda region. The overall infection percentage of the fall armyworm parasite nematode was 33.1% in these three regions. This study shows a high potential of Hexamermis sp. in the control of the pest S. frugiperda. This is the first report in Senegal on the efficacy of Hexamermis sp. against S. frugiperda under field conditions. [ABSTRACT FROM AUTHOR]

Host range evolution is a central issue for pest management, particularly for invasive species of agricultural importance. The invasive tomato leaf miner, Tuta absoluta Meyrick (Lepidoptera: Gelechiidae), a key pest of tomato in Europe and recently in sub-Saharan Africa, is a good model organism to better understand underlying processes. We studied oviposition acceptance (proportion of females accepting a given plant as host for laying egg), oviposition preference (number of eggs laid by females on a given host plant) and performance (offspring development estimated as survival from egg to adult) of two T. absoluta populations originating from France (FRA) and Senegal (SEN) on six solanaceous plants (tomato, eggplant, Ethiopian eggplant, potato, sweet pepper and pepper). The ovipositional behavioral pattern differed between the two populations; the SEN population showed higher oviposition acceptance on Ethiopian eggplant and sweet pepper than the FRA population. In addition, SEN population showed higher oviposition preference toward sweet pepper and potato than the FRA population. By contrast, the FRA population showed higher preference toward tomato and eggplant than the SEN population. The two populations of T. absoluta performed best on tomato (the preferred host plant) and showed similar decreasing trend in performance when comparing the two populations on the various other host plants. For both populations, performance on solanaceous plant species was closely related to ovipositional response of females to these plants. The differences observed between the two populations may indicate an ongoing differentiation in the host range of T. absoluta in the two invaded areas, possibly due to the abundance of these alternative host crops in Senegal at a period when tomato crops are scarce. [ABSTRACT FROM AUTHOR]

In Senegal, damage caused by insect pests is a major obstacle to seasonal stability and an increase in cabbage production. Little is known about the spatial and temporal distribution of cabbage pests, which makes the design of management recommendations to small-scale farmers challenging. The objectives of this study were to: (i) evaluate the status of insect pests observed in cabbage farmers’ fields; (ii) give information on the spatial and temporal distribution of key pests and (iii) assess the effect of temperature, insecticide applications, and host crop abundance on their incidence. A total of 116 cabbage fields were monitored for insect pests and related damage over four crop cycles, from October 2012 to May 2014, in the main vegetable producing area of Senegal (Niayes). The diamondback moth Plutella xylostella (L.) was by far the most important pest present in all the fields and with high levels of incidence (37.1% infested plants), particularly in the latter part of the dry season in the South of Niayes (50% infested plants). The cabbage webworm Hellula undalis (F.) was mainly observed in the early dry season in the south of Niayes, with an incidence of up to 12.5% infested plants. More surprising was the detection of the tomato fruit worm Helicoverpa armigera (Hübner), with damage of up to 9.4% of cabbage heads. The incidence of sucking pests such as whiteflies Bemisia tabaci (Gennadius), or aphids (including Lipaphis pseudobrassicae (Davis, 1914), Myzus persicae (Sulzer) or Brevicoryne brassicae (L.)) was generally low. The incidence of P. xylostella increased significantly with the number of insecticide applications, indicating that control deployed by growers was ineffective. The incidence of H. undalis did not depend on the number of insecticide applications, but significantly increased with host crop abundance and decreased with temperature. This study is a first step towards developing alternative pest management strategies in the framework of sustainable vegetable production systems. [ABSTRACT FROM AUTHOR]