Monitoring et méthodes alternatives de lutte contre Spodoptera frugiperda J.E Smith dans la région du Centre-Ouest du Burkina Faso

Abstract

The fall armyworm (Spodoptera frugiperda Smith, 1797) is a moth native to tropical and subtropical regions of the Americas. Reported in Burkina Faso since the 2017/2018 crop season, it is now present in all regions of the country. A survey on the management methods of the pest was carried nearby producers in the Centre-West region of Burkina Faso. In order to assess the impact of the pest on crops, monitoring was carried out using pheromone traps and scouting 20 vegetable growing plots and 30 cereal fields. Consumption tests on cabbage, onion, lettuce and tomato as well as biological efficacy tests of Azadirachta indica seed aqueous extract, leaf association of Azadirachta indica, Eucalyptus camaldulensis and Ocimum americanum, commercial formulation of Beauveria bassiana and Bacillus thurengiensis were carried during this research. Investigations were carried to search for potential natural enemies. Infestations in maize fields started as soon as the season started, especially in the southern part of the region with average infestation rates of 71%. Sorghum and cabbage were also targets of the pest in the region. Chemical control with mainly avermectin insecticides is the main method of S. frugiperda control in the study area. All tested speculations were consumed by L3 stage larvae with cabbage as the most desired speculation (363.1 mg consumed after 72 hours). Aqueous extracts of neem seeds and the commercial formulation of Bacillus thuringiensis gave satisfactory results in vitro and in greenhouse. Significant differences in the biomass consumption rate of seedlings treated with the different doses of these insecticides were observed compared to the untreated control. The LC50 for these two insecticides are 170 g/L and 8.73 g/L, respectively. Two potential parasitoids of the Tachinidae family and the Platygastridae family as well as nine potential predators were encountered during our investigations.