The role of abiotic factors on both mango infestation and Sternochetus mangiferae abundances in mango agroecosystems in Benin

To develop management strategies for the mango seed weevil (Sternochetus mangiferae), we surveyed infestation levels of the pest in three agroecological zones of Benin and determined the influences of abiotic factors on mango infestation levels and population dynamics in mango orchards at IITA-Benin from 2009 to 2011. We collected immature and mature fruits from the canopy and fallen fruits from under the canopy from three randomly selected trees per cultivar, per orchard. Samples were examined to determine the number of the mango seed weevil eggs to adults during the rainy seasons of three years of the study. Our results show that the highest abundance of both the weevil and its eggs was from March to May of each year. In the first year of sampling, the cultivar Eldon was more infested than the other two cultivars, while during the second and third years, the cultivar Alphonse was most infested. The occurrence of the weevil was almost nil in the hot agroecological zones, while for the mango cultivars of IITA-Benin the percentage of infested fruit increased or decreased according to the studied variables, such as temperature, rainfall, and relative humidity. We found that the period from March to May with low temperatures and high rainfall was favourable to the population increase of mango seed weevils. We discuss possible implications of our findings for the management of the pest

Population biology and prospects for suppression of the solanaceous fruit fly, Bactrocera latifrons (Diptera: Tephritidae).

Bactrocera latifrons (Hendel) is a tephritid fruit fly native to South and Southeast Asia. First detected in Hawaii in 1983, it primarily infests fruits of solanaceous plants but has also been found to infest fruits of some species of cucurbitaceous plants in Hawaii. Because it has been known in Hawaii for a much shorter period of time than the other three introduced tephritid fruit flies of economic importance, there has been much less opportunity to study its basic biology and ecology. One area not yet sufficiently understood is the population ecology of this species. Here, we report on the population levels of B. latifrons as they relate to turkeyberry (Solanum torvum Sw) phenology in a cattle pasture with abundant turkeyberry patches in the vicinity of Haiku, Maui

Insects complex associated with the tropical basil, Ocimum gratissimum L. (Lamiaceae) in southern Benin.

Tropical basil is an aromatic leafy vegetable used for its medicinal and therapeutic properties in numerous countries in West Africa (Benin, Nigeria, Togo, etc.). In Benin, it is produced on almost all urban and periurban garden throughout the year for fresh market. Until now there are few or nearly no publications about the arthropod community of this specie, even less in the context of Benin. Thus, to assess this community, basil plots were mowed using a sweep net in three localities (Ouidah, Togba and Sèmè) of southern Benin. Preliminary results focus on the different insect families that colonized tropical basil in southern Benin environmental conditions. These include: Aphididae (Homoptera), Cercopidae (Homoptera), Chrysomelidae (Coleoptera), Coccinelledidea (Coleoptera), Meloidae (Coleoptera), Braconidae (Hymenoptera), Ichneumonidae (Hymenoptera), Formicidae (Hymenoptera), Vespidae (Hymenoptera), Apoidae (Hymenoptera), Reduviidae (Heteroptera), Pentatomidae (Heteroptera), Pyrgomorphidae (Orthoptera), Acrididae (Orthoptera), Syrphidae (Diptera), Diopsidae (Diptera). Among these families, there are pests: Aphis gossypii G. (Homoptera: Aphididae), Zonocerus variegatus L. (Orthoptera: Pyrgomorphidae), etc.; predators: Ischiodon aegyptius W. (Diptera: Syrphidae), Cheilomenes spp. (Coleoptera: Coccinelledidea), Rhynocoris spp. (Heteroptera: Reduviidae), etc.; parasitoids and pollinators. From this study, it appeared that there is a large diversity of families and functional groups (pests, predators, parasitoids and pollinators) associated with tropical basil . Moreover, the presence of natural enemies could be an advantage for farmers in intercropping systems. This would help reduce the use of synthetic insecticides. This result, which is a first knowledge of the insect fauna associated with tropical basil under the environmental conditions of Southern Benin, will be supplemented by a spatio temporal study to assess the variability and the dynamics of this insect fauna

Effet de la Poudre de Piper guineense Schumach & Thonn., 1827 (Piperaceae) sur les Paramètres Semenciers et la Mortalité de Sitophilus oryzae L., 1763 (Coleoptera Curculionidae) dans les Stocks des Semences de Riz

Rice is one of the highly strategic food crops in Africa, particularly in Benin. However, constraints such as storage compels producers to use chemical pesticides that are very dangerous and harmful to the health and well-being of consumers. This study, conducted at AfricaRice's entomology laboratory, therefore aimsto assessthe persistence of Piper guineense powder for the control of S. oryzae in rice stock. Thus, 100 g samples of seeds of two rice varieties were treated with seven treatments: 0.25g; 0.5g; 0.75g; 1g; 1.4g; 1.85g and 2.5g and in 4 repetitions and then infested with 20 adults of adult S. oryzae and arranged in a complete random block system. Neem oil (0.5 ml) and the untreated sample were checks. The results obtained show that after three months of storage, the different treatments with P. guineense powder and neem oil had an insecticidal effect on S. oryzae regardless of the rice variety. Indeed, the optimal dose that ensures the 3-month efficacity of the biopesticide on the NERICA 1 variety is 1.85g per 100g of rice and 1.4g per 100g of rice on the WAB 56-104 variety. The dose of neem oil showed a three-month duration of action on all rice varieties. The germination rate of the stored seeds is not influenced by the powder of the spice. This work enabled to identify the optimal doses and persistence of P. guineense powder according to each rice variety, with a view to better management of S. oryzae.Le riz, est l’une des cultures vivrières hautement stratégique en Afrique et notamment au Bénin. Cependant, les contraintes du stockage obligent les producteurs à l’utilisation des pesticides chimiques qui sont très nocifs pour la santé des consommateurs. L’étude menée au laboratoire d’entomologie d’AfricaRice, vise à évaluer l’efficacité de la poudre de Piper guineense (PPg) contre S. oryzae dans les stocks de semences de riz. Ainsi, des échantillons de 100g des semences de 2 variétés de riz ont été traités avec 7 traitements : 0,25g; 0,5g; 0,75g; 1g; 1,4g; 1,85g et 2,5g et en 4 répétitions, puis infestés avec 20 individus adultes S. oryzae. L’huile de neem (HN) (0,5ml) et l’échantillon non traité ont été les témoins. Les résultats montrent qu’après 3 mois de conservation, les différents traitements à la PPg ainsi que celui à l’HN ont eu un effet insecticide sur S. oryzae quelle que soit la variété de riz. En effet, la dose optimale qui assure 3 mois d’efficacité du biopesticide sur la variété NERICA 1 est de 1,85g pour 100g de riz et de 1,4g pour 100g de riz sur la variété WAB 56-104. L’HN a montré une durée de persistance de 3 mois sur toutes les variétés de riz. Le taux de germination des semences stockées, n’est pas influencé par la poudre de l’épice. Ce travail a permis de mettre en évidence les doses optimales et l’efficacité de la PPg selon chaque variété de riz, en vue d’une meilleure gestion de S. oryzae

Étude comparative du développement de Bactrocera dorsalis (Hendel) (Diptera : Tephritidae) sur Irvingia gabonensis et Musa sp.

Bactrocera dorsalis est la Tephritidae la plus nuisible à la production fruitière au Bénin. Son introduction en 2004 a été à l’origine de l’accroissement des dégâts et des pertes économiques. Des travaux de recherche se sont orientés vers l’étude de sa biologie par la mise au point d’une colonie de laboratoire par desméthodes simples et peu coûteuses. L’objectif de cette étude était d’identifier parmi les fruits usuels disponibles sur le marché tout au long de l’année, le meilleur substrat pour la ponte et de développement de B. dorsalis. Ainsi, une étude comparative de différents paramètres biologiques a permis d’identifier le meilleur substrat pour sa production au laboratoire. Son développement a été étudié en condition de choix et de non choix sur la banane rose, Musa sp. et la pomme africaine, Irvingia gabonensis. Il ressort que les deux fruits testés favorisent un bon développement de B. dorsalis. Toutefois, la durée de développement varie selon que la mouche est placée en condition de choix ou de non choix. En comparaison à la banane rose, la pomme africaine se révèle être le substrat fruit le plus favorable pour la production de B. dorsalis au vu de la durée de développement des différents stades, du taux d’émergence, du sex-ratio et de la survie des adultes.© 2016 International Formulae Group. All rights reserved.Mots clés: Production fruitière, durée de développement, Paramètres biologiques, fruits hôtesEnglish Title: Comparative study of the development of Bactrocera dorsalis (Hendel) (Diptera: Tephritidae) on Irvingia gabonensis and Musa sp.English AbstractBactrocera dorsalis is the most harmful Tephritid fly to fruit production in Benin. Its introduction in 2004 was the origin of the increase in damage and economic losses for fruit growers. Research has turned to the study of biology of B. dorsalis through the establishment of a laboratory colony by simple and affordable methods. The objective of this study was to identify from the usual fruits available on the market throughout the year, the best substrate for eggs laying and larval development of B. dorsalis. Its development has been  studied in both choice and no choice condition on the pink banana, Musa sp. and the bush mango, Irvingia gabonensis. It appears that the two fruit facilitate proper development of B. dorsalis. However, the development time depends on whether the fly is placed in choice or not choice condition. Compared to the pink banana, wild apple proves to be the most favorable substrate for B. dorsalis production in view of the duration of development of the various stages, the emergence rate, sex ratio and survival adults.© 2016 International Formulae Group. All rights reservedKeywords: Fruit production, duration of development, Biological parameters, hosts fruit

Pathogenicity of Beauveria bassiana (Balsamo-Crivelli) and Metarhizium anisopliae (Metschnikof) isolates against life stages of Zeugodacus cucurbitae (Coquillett) (Diptera: Tephritidae)

Background Entomopathogenic fungi are primary pathogens that naturally afect insect pests by suppressing their populations and considered as an ecofriendly agents. The present study aimed to evaluate in vitro activity of diferent isolates of Beauveria bassiana and Metarhizium anisopliae against the development of larval stages of the Cucurbit fruit fy, Zeugodacus cucurbitae (Coquillett) (Diptera: Tephritidae). Results Larval mortality was signifcantly high with B. bassiana isolate Bb337 (5.82–21.70%) and with the lowest in M. anisopliae isolate MaD (1.49–6.33%). Pupal mortality rate was comparatively higher with more than 50%. The cadavers of all host instars produced conidia (sporulation). Sporulated dead larvae were signifcantly higher in Bb337 (61.10%) than at the least in MaD (18.60%) at 105 conidia/ml. At 108 conidia/ml, MaD induced the highest pupal cadavers with mycosis (32.42%). Regardless of applied fungal species, host instars mortality signifcantly increased with increasing concentration of B. bassiana isolates, suggesting a concentration-dependent response of Z. cucurbitae. Conclusion The tested isolates demonstrated their pathogenicity through vertical transmission of mycosis from one instar to another, regardless of the concentrations used

Efficiency of Food-Based Attractants for Monitoring Tephritid Fruit Flies Diversity and Abundance in Mango Systems Across Three West African Agro-Ecological Zones

Food baits are effective and widely used tools for monitoring diversity and abundance of tephritid fruit flies. Four food-baits-Nulure, BioLure, Mazoferm at 3 and 6%, and Torula yeast-were used in multi-lure traps over a 4-yr period in mango orchards in three Benin agro-ecological zones (AEZ) representing a large swath of environments in western Africa. Twelve tephritid fruit fly species were captured during the trials, with the highest richness in the Forest Savannah Mosaic (FSM), followed by the Southern Guinea Savannah (SGS), and the Northern Guinea Savannah (NGS) AEZ. Despite previous reports of displacement, the native species Ceratitis cosyra remained the dominant tephritid species in mango orchards in the NGS, with the invasive and exotic species Bactrocera dorsalis dominating the tephritid fauna in the SGS and FSM. Torula yeast captured the greatest number of fruit flies in each AEZ. Mazoferm-3% captures were similar to Torula yeast, except for lower captures in the NGS where it tended to harden. The rank order of relative efficiency indices (REI) of the food baits (relative to Torula yeast) is Mazoferm-3% > Nulure > Mazoferm-6% and BioLure. The latter captured more Ceratitis spp. than all the other baits, particularly at very low Ceratitis spp. abundance. To our knowledge, the study is the first to report relative efficiency indices for the selection of food baits in monitoring diversity and abundance of fruit flies. Ecological and practical implications for the use of food baits in comparison with male lures are discussed

Susceptibility of Spodoptera frugiperda to chemical insecticides and control failure likelihood estimation in Burkina Faso

The fall armyworm, Spodoptera frugiperda Smith (Lepidoptera: Noctuidae) has recently invaded sub-Saharan African countries. It has been causing significant losses to maize, pearl millet, sorghum, rice, and other crops since 2016. Several insecticides have been promoted, but farmers have reported control failures. In this work, we collected seven fall armyworm populations in as many maize-producing areas of Burkina Faso. We used the approved IRAC foliar bioassay protocol to evaluate the susceptibility of third instar larvae to six chemical insecticides commonly used by maize farmers, including different modes of action (active ingredient): acetylcholinesterase inhibitors (methomyl, chlorpyriphos-ethyl), sodium channel modulators (deltamethrin, lambda-cyhalothrin), chloride channel activators (emamectin benzoate, abamectin). Lethal concentrations and control failure likelihood (CFL, using Guedes' 2017 formula) were calculated for each population and active ingredient. For all seven populations of S. frugiperda, LC80 values are significantly higher than the manufacturer's recommended rates and CFL values are high, 66-100% for both pyrethroids (deltamethrin, lambda-cyhalothrin) and abamectin. In contrast, the LC80 values for emamectin benzoate emamectin benzoate (0.001 mg/l), methomyl (43 - 278 mg/l) and chlorpyrifos-ethyl (284 - 659 mg/l) are lower than the recommended rates. Emamectin benzoate, methomyl and chlorpyriphos-ethyl insecticides have a negligible risk of control failure (i.e. their CFL values are below 0%) and are the most efficient for the control of the fall armyworm in Burkina Faso. These active ingredients should be alternated in the control of the pest to delay the development of resistance.PRD AGRO-EC

Susceptibility of fall armyworm Spodoptera frugiperda (JE Smith) to microbial and botanical bioinsecticides and control failure likelihood estimation

peer reviewedDescription of the subject. The fall armyworm Spodoptera frugiperda (JE Smith) has become one of the most devastating pests of maize and other important economic crops in Africa since 2016. Among the alternatives to chemical insecticides, bioinsecticides are an interesting option that needs to be explored. Objectives. The susceptibility of fall armyworm to seven bioinsecticides available on the West African market was evaluated in Burkina Faso. Method. Bioassays were conducted following the approved IRAC 020 protocol. Results. Spinetoram (LC80 = 85.3 µg·l-1) and spinosad (LC80 = 437.9 µg·l-1) were the most toxic at concentrations below those recommended by the manufacturer, and had control failure likelihoods close to 0%. Bacillus thuringiensis and products based on Azadirachta indica and Carapa procera extracts were less effective (at the manufacturers' recommended doses), even though they showed significant levels of toxicity on young instars. Conclusions. A list of effective bioinsecticides should be communicated for sustainable management of fall armyworm in West Africa

Efficacite Du Baume De Cajou Contre Les Chenilles Carpophages Du Cotonnier Au Nord Du Benin

Cotton remains the main source of foreign exchange for Benin. This study aims to contribute to increased yield of organic cotton through the evaluation of the effectiveness of cashew balm as an alternative method of management of carpophagous pests of cotton. The experimental setup consists of Fisher Blocks with 6 objects in 4 repetitions. The objects compared are '' Unprocessed '', the Agri-bio-pesticide dosed at 1 l / ha, two concentrations (1% and 2%) of the hot and cold-extracted cashew balm. Linear mixed or fixed effects models and generalized linear models with mixed or fixed effects were used to determine the influence of the objects on the carpophagous larva and their damage in 2015 and 2016 in Thya to the north of Benin. The number of Helicoverpa armigera larva found in 30 plants ranged from 1.2 (Agri-biopesticide) to 2.3 (Untreated) in 2015. The percentages of green capsules with holes varied by 36.08% (Agri-bio-pesticide) at 53.68% (1% cold-extracted balm) in 2015. The percentages of ripe capsules with holes varied from 32.05% (hot-pressed balm at 2%) to 45.00% (Untreated) in 2016. Seed cotton yield ranged from 229.91 kg / ha (Untreated) to 500 kg / ha (Agri-biopesticide) in 2016. It is noted that Agri-bio-pesticide and the 2% dose of cashew balm, were more effective than that of 1%. The cashew balm is positioned as an alternative to biopesticides used in organic cotton farming