Rice is the second most important cereal in Togo. Among constraints that affect rice production, plant parasitic nematodes are of great importance. The objective of this study was to determine the distribution, abundance and frequency of plant nematodes in different agroecological zones of Togo. A total of 50 composite soil and root samples (25 each) were taken from 25 fields (5 per zone) randomly selected from the five agroecological zones. Nematodes were extracted from 100 ml soil and 1g fresh root samples using the Hermann techniques. Nematodes were then fixed and mounted on slide and identified to genus level using identification keys. The survey documented twelve plant-parasitic nematode genera among which ten, (Hirschmanniella spp., Meloidogyne spp., Xiphinema spp., Scutellonema spp., Helicotylenchus spp., Heterodera spp., Criconema spp., Pratylenchus spp., Trichodorus spp. and Tylenchid spp.), were recorded from lowland, two (Helicotylenchus and Scutellonema) from upland and five (Dolichodorus spp., Helicotylenchus spp., Tylenchorhynchus spp., Scutellonema spp. and Xiphinema spp.), from flooded ecosystem. Hirschmanniella spp., Meloidogyne spp and Helicotylenchus spp. were the most frequent and abundant plant-parasitic nematode genera recorded from more than 71% of the samples. Helicotylenchus spp., Hirschmanniella spp., Meloidogyne spp. and Scutellonema spp., were recorded in both soil and root samples while Pratylenchus spp., Heterodera spp. and Tylenchorhynchus spp., were found to be associated to root and Trichodorus spp., Tylenchid spp., Xiphinema spp., Criconema spp. and Dolichodorus spp., were recorded from soil samples only. The high diversity of nematode genera recorded in the survey is attributed to the rice ecosystem, which is mostly characterized by lowland ecosystem with intensive cropping. This study established the evidence that nematodes could be important constraints for rice production, suggesting further research focusing on their damage potential and development of effective rice nematode management strategy for sustainable rice production in Togo.

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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.

The study was undertaken to contribute to the sustainable management of Spodoptera frugiperda Smith on maize. It aims to evaluate the insecticidal efficacy of Jatropha curcas L. oil on S. frugiperda larvae. Two concentrations of J. curcas oil (10 and 20ml.l-1) were tested by ingestion on the six larval stages of S. frugiperda grouped into (L1-2 (3-5 days of age); L3-4 (6-8 days of age); L5-6 (>10 days of age)). The insecticidal efficacy of the oil was determined in the laboratory and the phytosanitary protection tests on maize were carried out in the field. In the laboratory, the concentration of 10 ml.l-1 with/without emulsifier caused a mortality rate of (87-92%) at stage L1-2, (51-58%) at stage L3-4, and (57- 68%) at L5-6 stage after 72 hours of ingestion. Concentration of 20 ml.l-1 caused over 70% mortality whether applied with or without an emulsifier at all stages. Adult emergence was nil for L1-2 stages at 20 ml.l-1 and <10% for the other stages. Plots subjected to jatropha oil treatments (2l.ha-1 and 4l.ha-1 with or without emulsifier) were less infested like the plots treated with Emamectine benzoate (Emacot) compared to control plots untreated. The present results indicated that jatropha oil has insecticidal potential against S. frugiperda.

Spodoptera frugiperda, est un ravageur exotique du maïs qui menace la sécurité alimentaire en Afrique subsaharienne en général et du Togo en particulier. Dans le but de contribuer à une gestion durable du ravageur, la présente étude vise à évaluer l’effet des associations maïs– soja et maïs-manioc sur la dynamique de la population et les dégâts du ravageur. Les traitements (culture pure de maïs, de soja, de manioc, association maïs-soja, et maïs-manioc) ont été installés suivant un dispositif en blocs aléatoires complets avec quatre répétitions. Les boutures de manioc ont été mises en terre un mois avant le maïs. Le maïs et le soja ont été semés simultanément. Les associations maïs-manioc et maïs-soja ont réduit respectivement l’infestation (56 et 40%), le nombre d’amas d’oeufs (50 et 25%) et de larves (57 et 43%), le taux d’attaque (45 et 34%) et les dégâts (40 et 27%) comparé à la monoculture du maïs. L’association maïs-manioc est plus efficace dans le contrôle du ravageur. En termes d’utilisation du sol, les associations maïs-soja et maïs-manioc (LER> 1) sont plus efficientes que la monoculture mais n’entrainent pas l’amélioration des rendements du maïs. Ces associations peuvent être envisageables pour une gestion durable de S. frugiperda. Spodoptera frugiperda is an exotic maize pest that threatens food security in sub-Saharan Africa in general and Togo in particular. In the present study, the effect of intercropping maize with soybean and cassava on the infestation of the pest were studied. Field experiments were conducted using a device in complete random blocks with four repetitions. Cassava were planted one month before the maize and soybeans were planted simultaneously maize. Maize-cassava and maize-soybean intercropping respectively reduced infestation (56 and 40%), the number of egg (50 and 25%), larvae (57 and 43%) and damage (40 and 27%) of S. frugiperda compared with the monocrop. In terms of land use, maize-soya and maize-cassava associations (LER> 1) are more efficient than monoculture but do not lead to improved maize yields. The maize-cassava association is more effective in controlling the pest. These associations may be possible for the sustainable management of S. frugiperda.