Stem Borers of Cereal Crops in Africa and Their Management

The economic importance of the stem borer in Africa results in their severe damage that affect directly cereal yield factors such as the density of fertile tillers and the number of effective panicles. The objective of this paper is to describe and discuss the management options of the main prevalent stem borer of cereal crops in Africa. Host plant resistance, cultural practices, biological control and reasoning chemical control are among the most encouraging options. Integrated pest management combining several compatible methods was highlighted as the most sustainable control option. This paper will served as support for the current research on cereal crops but also as relevant prospect document for entomologists and breeders from across the world

Effets des associations culturales sur la dynamique de population des principaux insectes ravageurs et la production en graines de Jatropha curcas L. au Sud-Bénin

Jatropha curcas est l’une des cultures proposées actuellement pour la production de biocarburant, ce qui pourrait entraver les cultures vivrières. Il a alors été suggéré d’associer jatropha avec les cultures vivrières. L’effet des associations Jatropha+Maïs (JM), Jatropha+Niébé (JN), Jatropha+Manioc (JMc) et Jatropha seul (Js) a été évalué sur les populations des ravageurs de J. curcas en champ à Ouinhi au Sud-Est du Bénin. Les sept espèces d’insectes ravageurs recensées sont : Denticera divisella, Aulocophora africana, Calidea dregei, Lagria vilosa, Apion sp., Stomphastis thraustica et Clavigralla tomentosicollis dont les plus importantes sont : Apion sp., A. africana et D. divisella. Le niveau de population des ravageurs a varié suivant l’association et le stade phénologique de jatropha. Les pourcentages de feuilles attaquées sont de 56,0 ± 3%; 52,0 ± 3%; 47,0 ± 3% et 44,0 ± 3%, respectivement pour JM, JN, JMc et Js. Les rendements en graines de jatropha sont de 9,77 ± 1,57 g ; 9,40 ± 1,71 g ; 4,63 ± 1,34 g ; 2,25 ± 1,10 g par plant, respectivement pour Js, JM, JN et JMc. En général, l’association culturale a affecté négativement la productivité du jatropha notamment dans les associations Jatropha+Manioc et Jatropha+Niébé qu’il importe de déconseiller.Mots clés: Biocarburant, pourghère, associations culturales, insectes ravageurs de jatropha, Denticera divisella, rendement de jatropha

Storage insects on yam chips and their traditional management in Northern Benin

Twenty-five villages ofNorthern Beninwere surveyed to identify the constraints of yamchips production, assess the diversity of storage insects on yamchips, and document farmers’ perception of their impacts on the stocks and their traditional management practices. Damages due to storage insects (63.9% of responses) and insufficiency of insect-resistant varieties (16.7% of responses) were the major constraints of yam chips production. Twelve insect pest species were identified among which Dinoderus porcellus Lesne (Coleoptera, Bostrichidae) was by far the most important and the most distributed (97.44% of the samples). Three predators (Teretrius nigrescens Lewis, Xylocoris flavipes Reuter, and Alloeocranum biannulipesMontrouzier & Signoret) and one parasitoid (Dinarmus basalis Rondani) all Coleoptera, Bostrichidae were also identified. The most important traditional practices used to control or prevent insect attack in yam chips were documented and the producers’ preference criteria for yam cultivars used to produce chips were identified and prioritized. To further promote the production of yam chips, diversification of insect-resistant yam varieties, conception, and use of health-protective natural insecticides and popularization of modern storage structures were proposed

Horizon scanning to assess the bioclimatic potential for the alien species Spodoptera eridania and its parasitoids after pest detection in west and central Africa

BACKGROUND The southern armyworm (SAW) Spodoptera eridania (Stoll) (Lepidoptera: Noctuidae) is native to the tropical Americas where the pest can feed on more than 100 plant species. SAW was recently detected in West and Central Africa, feeding on various crops including cassava, cotton, amaranth and tomato. The current work was carried out to predict the potential spatial distribution of SAW and four of its co-evolved parasitoids at a global scale using the maximum entropy (Maxent) algorithm. RESULTS SAW may not be a huge problem outside its native range (the Americas) for the time being, but may compromise crop yields in specific hotspots in coming years. The analysis of its potential distribution anticipates that the pest might easily migrate east and south from Cameroon and Gabon. CONCLUSION The models used generally demonstrate that all the parasitoids considered are good candidates for the biological control of SAW globally, except they will not be able to establish in specific climates. The current paper discusses the potential role of biological control using parasitoids as a crucial component of a durable climate-smart integrated management of SAW to support decision making in Africa and in other regions of bioclimatic suitability

Measurement of pesticide residues from chemical control of the invasive Spodoptera frugiperda (Lepidoptera: Noctuidae) in a maize experimental field in Mokwa, Nigeria

Open Access JournalThe management of the fall armyworm Spodoptera frugiperda in maize field necessitates the use a big quantities of insecticides and sometimes the use of multiple types and formulations of chemicals. The use of insecticides in crops is associated with environmental risks and health hazards to both producers and consumers. This study was designed to evaluate the residue of 11 insecticides that were used to control high population of the fall armyworm in maize field in Mokwa, Nigeria. Maize and soil samples were collected from an experimental field to investigate the residue level using high performance liquid chromatography (HPLC, Agilent Technologies, Santa Clara, CA, USA) analysis techniques. Results revealed the presence of five insecticide compounds (Cypermethrin, Deltamethrin, Lambda-Cyhalothrin, Permethrin, and Chorpyrifos) in soil samples with possible adverse effects on soil born organisms and other non-targeted species. In contrast, no residue was found in maize stems and seeds. From these results, we conclude that the treated maize remains safe for consumption and the producers may not get any serious risk of contamination from the chemical control of the fall armywor