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The infestation of the fall armyworm (FAW), Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) in Africa since 2016 has been a major threat to maize production. Previous studies in Togo and Ghana from 2016 to 2018 did not correlate FAW infestation to yield losses. Thus, the aim of this study which assesses the impact of FAW infestation by inspecting 150 maize farms throughout the five Agro-Ecological Zones (AEZs) of Togo for FAW plant damage, and third instar larvae were used to infest 10-day-old maize plants in netted plots under controlled conditions at an experiment station (Station d'Expérimentations Agronomiques de Lomé) in 2019 and 2020. As control plots at the experiment station, plots were both netted and treated with emamectin benzoate, simply netted, or open to natural infestation. The number of larvae, egg masses, percent damaged plants, and damage proportions of leaves and ears were scored until harvest. Infestations and damages on maize plant throughout Togo were similar between the two years but were higher in the southern part of the county (AEZ5). At the experiment station, the yield losses were significantly considerable and increased from 25% infestation. The losses were 0.37 t ha−1 for 25% infestation, 0.34 t ha−1 for 30%, 0.59 t ha−1 for the open plots, 0.70 t ha−1 for simple netted and 50% infestation, 1.03 t ha−1 for 75%, and 1.27 t ha−1 for 100% infestation. This current study suggested thorough inspection on maize farms to set off management practices from 25% of infestation.

Invasive alien species (IAS) continue to shape the global landscape through their effects on biological diversity and agricultural productivity. The effects are particularly pronounced in Sub-Saharan Africa, which has seen the arrival of many IAS in recent years. This has been attributed to porous borders, weak cross border biosecurity, and inadequate capacity to limit or stop invasions. Prediction and early detection of IAS, as well as mechanisms of containment and eradication, are needed in the fight against this global threat. Horizon scanning is an approach that enables gathering of information on risk and impact that can support IAS management. A study was conducted in Ghana to establish two ranked lists of potential invasive alien plant pest species that could be harmful to agriculture, forestry, and the environment, and to rank them according to their potential threat. The ultimate objective was to enable prioritization of actions including pest risk analysis, prevention, surveillance and contingency plans. Prioritisation was carried out using an adapted version of horizon scanning and consensus methods developed for ranking IAS worldwide. Following a horizon scan of invasive alien species not yet officially present in Ghana, a total of 110 arthropod and 64 pathogenic species were assessed through a simplified pest risk assessment. Sixteen species, of which 14 were arthropods and two pathogens, had not been recorded on the African continent at the time of assessment. The species recorded in Africa included 19 arthropod and 46 pathogenic species which were already recorded in the neighbouring countries of Burkina Faso, Côte d’Ivoire, and Togo. The majority of arthropod species were likely to arrive as contaminants on commodities, followed by a sizable number which were likely to arrive as stowaways, while some species were capable of long distance dispersal unaided. The main actions suggested for species that scored highly included full pest risk analyses and, for species recorded in neighbouring countries, surveys to determine their presence in Ghana were recommended.

The larger grain borer, Prostephanus truncatus (Horn) and the maize weevil, Sitophilus zeamais Motschulsky continue to cause tremendous losses to stored maize. Research in the UK has identified Beauveria bassiana, IMI 389521 as a suitable control agent for grain storage pests in the UK. The pathogenicity of B. bassiana, IMI 389521 was evaluated against adult P. truncatus, S. zeamais and Teretrius nigrescens in Ghana. Fifty adults of each insect species were treated with 0.5 g dry conidia powder of this isolate at 8.65 × 108 conidia/g for 1 minute and mortality recorded daily for 14 days. The results indicated that B. bassiana, is pathogenic against P. truncatus and S. zeamais, inducing over 90% mortality by day 7. Teretrius nigrescens was, however less susceptible to the fungus with 30% mortality. To determine the most effective concentration of B. bassiana for the control of P. truncatus, a laboratory dose response experiment using four concentrations of B. bassiana (108–1011 cfu/kg maize) was also conducted. Maize grains (250 g) in separate jars were treated with the four concentrations of the product. Fifty adults of P. truncatus were placed into the jars containing the treated maize and mortality was assessed weekly for 3 weeks. The most effective dose was 1010 cfu/kg maize, which resulted in 96% and 100% mortality of P. truncatus after 2 and 3 weeks, respectively. This study shows that B. bassiana could effectively be integrated into bio-control programme of these two key pests of maize in Ghana after further field trials.