The predatory mite Typhlodromalus aripo prefers greenmite induced plant odours from pubescent cassava varieties

Article PurchasedIt is well known that plant-inhabiting predators use herbivore-induced plant volatiles to locate herbivores being their prey. Much less known, however, is the phenomenon that genotypes of the same host plant species vary in the attractiveness of these induced chemical signals, whereas they also differ in characteristics that affect the predator’s foraging success, such as leaf pubescence. In a series of two-choice experiments (using a Y-tube olfactometer) we determined the preference of Typhlodromalus aripo for pubescent versus glabrous cassava cultivars infested with the cassava green mite Mononychellus tanajoa and also the preference for cultivars within each of the two groups. We found that when offered a choice between pubescent and glabrous cassava cultivars (either apex or leaves), T. aripo was significantly more attracted to pubescent cultivars. For each cultivar, M. tanajoa infested leaves and apices were equally attractive to T. aripo. There was however some variation in the response of T. aripo to M. tanajoa-infested plant parts within the group of pubescent cultivars, as well as within the group of glabrous cultivars. Our study confirms not only that T. aripo uses herbivore-induced plant volatiles to search for prey in cassava fields, but it also shows that it can discriminate between glabrous and pubescent cultivars and prefers the latter. This knowledge can be useful in selecting cultivars that are attractive and suitable to T. aripo, which, in turn, may promote biological control of the cassava green mite

Potential of the predatory mite, Amblyseius swirskii to suppress the broad mite, Polyphagotarsonemus latus on the gboma eggplant, Solanum macrocarpon

In Benin, the tarsonemid mite Polyphagotarsonemus latus (Banks) (Prostigmata: Tarsonemidae) is a key pest of gboma eggplant Solanum macrocarpon (L.) (Solanales: Solanaceae), a leafy vegetable on which it causes considerable damage to the plants and substantial reduction in yield. Predatory mites in the family Phytoseiidae have been successfully used in the biological control of numerous agricultural pests worldwide. In that respect, a population of the phytoseiid mite Amblyseius swirskii (Athias-Henriot) (Mesostigmata: Phytoseiidae) has been identified as a potential predator of P. latus, and is now a candidate for release against this pest in Benin. The objective of the present study is to determine, through laboratory experiments, the predation rate and life table parameters of A. swirskii when feeding on P. latus or alternative food such as maize pollen. Under laboratory conditions the mean number of P. latus consumed by A. swirskii, and daily oviposition, significantly increased as the number of prey increased. Total development time of A. swirskii was significantly shorter when it fed on P. latus than on maize pollen. Net reproduction rate, intrinsic rate of increase, mean generation time and the finite rate of increase of A. swirskii were were all significantly lower on P. latus than on maize pollen. However, doubling time was significantly higher on maize pollen. This study shows that A. swirskii is a good predator of P. latus, and that maize pollen can efficiently sustain A. swirskii populations when P. latus densities on plants become low. Consequently, A. swirskii can be used for the biological control of the broad mite P. latus on gboma eggplant, and on other solanaceous crops in Benin and elsewhere

Interactions between the predatory mite Typhlodromalus aripo and the entomopathogenic fungus Neozygites tanajoae and consequences for the suppression of their shared prey/host Mononychellus tanajoa

Published online: 28 October 2012The predatory mite Typhlodromalus aripo and the entomopathogenic fungus Neozygites tanajoae, both introduced from Brazil for control of the cassava green mite (CGM) Mononychellus tanajoa, now co-occur in cassava fields in Benin. However, studies on interactions between these two natural enemies and how they might affect CGM biological control are lacking. We determined in screenhouse experiments the effects of single and combined releases of N. tanajoae and T. aripo on CGM suppression. In the single natural enemy treatment, both T. aripo and N. tanajoae significantly reduced CGM densities, but the results of the predator (T. aripo) are more quickly measurable than those of the pathogen (N. tanajoae) in our short-term experiment. The level of CGM suppression in the combined natural enemy treatment was reduced considerably compared with T. aripoalone, but only slightly when compared with N. tanajoae alone, with a simultaneous reduction in T. aripo and N. tanajoae abundance or prevalence. In a laboratory experiment, T. aripo fed more on N. tanajoae-infected CGM than on healthy CGM and its oviposition and survival were reduced when fed on the former compared with the latter, which can help in explaining the reduction in numbers of T. aripo and consequently the considerable loss in suppression of CGM in the combined natural enemy treatment in the screenhouse experiment. Together, the screenhouse and the laboratory experiments predicted negative interactions between the two natural enemies with negative consequences for CGM biological control. Long-term field observations and rigorous field experiments that simultaneously manipulate T. aripo and N. tanajoae abundance and prevalence are needed to validate the prediction of this study

Insect fauna associated with Anacardium occidentale (Sapindales: Anacardiaceae) in Benin, West Africa

First published online: 1 January 2014Cashew, Anacardium occidentale L. (Sapindales: Anacardiaceae), is an important cash crop in Benin. However, its production is threatened by several biotic factors, especially insects. In Benin, very few studies have focused on insects and just listed species commonly found on cashew worldwide. The present investigation fills this gap by presenting an exhaustive inventory of insect species associated with this crop in the country. The survey was carried out from September 2009 to August 2010 in 22 cashew orchards (5 young and 17 mature) distributed over three major agroecological zones where cashew is most produced in the country. Insects were collected using chemical knock-down technique and visual observation followed by capture with sweep net. In addition, infested plant organs were sampled and incubated to collect emerging insects. In total, 262 insect species were recorded and identified. Among them, the wood borer Apate terebrans Pallas, the leafminer Eteoryctis gemoniella Stainton, and the mirid bugs Helopeltis schoutedeni Reuter., and Helopeltis anacardii Miller., appeared as the most important insect species attacking cashew in Benin. Beneficial insects encountered included some predators, parasitoids, and pollinators. Few vertebrate predators were also recorded on the trees. Differences in agroecological conditions or in field cleanliness did not affect the number of insect species encountered in the cashew orchards. The results of this study represent an important baseline data for the design and implementation of strategies for cashew protection in Benin

Effectiveness of Neem Oil and Jatropha Oil in Controlling Spodoptera frugiperda (J.E Smith) on Maize in the Republic of Chad

Upon the evidence of its invasion in Chad in 2018, Spodoptera frugiperda has become a serious threat to maize production, thereby prompting farmers to a massive use of chemical pesticides to reduce its damage. However, given the adverse negative effects of chemical pesticides on human health and the environment, alternatives to chemical control are highly sought. In that respect, the effectiveness of Neem oil and Jatropha oil, two bio pesticides widely acknowledged for their insecticidal properties, was evaluated in the field in comparison with the chemical insecticide, Emamectin benzoate, in a Fisher Blocks design with 4 treatments and 4 replicates. The mean larval density per 25 plants was significantly the lowest (P < 0.0001) on Emamectin benzoate-treated plants(1.13 ± 0.70), followed by Jatropha oil (6.13 ± 0.87) and Neem oil treatments (7.13 ± 0.80) while the highest density was recorded on the untreated plants (12.31 ± 0.87). Similarly, the infestation rates were significantly lower on plots that received the chemical insecticide or the bio pesticides compared to the control plots (P < 0.0001). Foliar and ear damage scores were also significantly lower on the treated than on the control plots (P < 0.0001); and the number of ears attacked was significantly higher on the untreated control than on the other treatments. Maize grain yields were significantly higher in the treated plots compared to the control plots (P < 0.001). Yield gains over the control were 132.57%, 90.91% and 72.73% respectively for Emamectin benzoate, Jatropha oil and Neem oil treatments. It appears, therefore, that the use of Jatropha oil or Neem oil could significantly contribute to an effective and sustainable management of S. frugiperda on maize in Chad, thereby calling for the need for further investigations in that area in the frame of integrated pest management of this pest

Molecular cartography of the metabolome of typical food products of the Basilicata region by using high resolution mass spectrometry

2019 - 2020Protected Designation of Origin (PDO) and Protected Geographical Indication (PGI) are, together with Traditional Speciality Guaranteed (TSG), the instruments created by the European Union (EU) to protect Geographical Indications (GIs) within the European framework as indications which identify a good as originating in a specific location, where a given quality, reputation or other characteristic of the good is essentially attributable to its geographical origin. Food products with a protected geographical status distinguish from other similar products of the same category for the link with the region they originate from. Despite the improvement this quality scheme provided to the protection of unique foodstuff, the threat of food fraud is still present and sophistication of adulteration of food products is making the utilization of the most advanced technologies compulsory for labelled food product protection. Mass spectral characterization of food materials has advanced rapidly in the past few years, mostly due to the development and now routine availability of electrospray ionization (ESI). However, it is now clear that food products exist as complex mixtures and High resolution Electrospray Ionization Fourier transform Ion Cyclotron Resonance Mass Spectrometry (ESI FT-ICR MS) at high magnetic fields is currently a techniques capable of resolving thousands of individual molecules in few minutes. In this work, a Mass Spectrometry-based phytochemical screening was performed on several traditional food products produced in the Basilicata region (Italy) labelled with geographical indication marks of quality. High Resolution ESI-FT-ICR MS data obtained from food sample analyses were used to perform a rapid evaluation of metabolome by converting accurate m/z values in putative elemental formulas. Molecular formula maps, or molecular fingerprints, were obtained by making 2D Van Krevelen plots, that lead to a direct identification of different classes of metabolites. The presence of important metabolite classes, i.e. fatty acid derivatives, tannins, amino acids and peptides, carbohydrates and polyphenolic derivatives, was assessed. Moreover, differences among Van Krevelen plots could be noticed from their direct comparison, thus reflecting differences in promoted biochemical pathways and suggesting the presence of biomarkers, that can eventually be identified by a target approach. Thus, molecular fingerprints prove to be an innovative tool that could be useful for food authentication and traceability. ... [edited by Author]XXXII

Efficacité du ramassage et du brûlage systématiques des bois morts dans la lutte contre le foreur de bois, Apate terebrans, dans les anacarderaies du Nord- Bénin

Objectifs : La présente étude vise à réduire de façon écologique  l’infestation des anacarderaies du Nord-Bénin par le foreur de bois, Apate terebrans, un coléoptère ravageur de l’anacardier en Afrique de l’Ouest.Méthodologie et résultats : Les travaux ont été conduits d’août 2015 à mars 2016 à N’dali, Parakou et Tchaourou, trois communes du  Nord-Bénin. Par commune deux vergers ont été sélectionnés dont le premier comme témoin tandis que le second a été soumis à des mesures prophylactiques, notamment, le ramassage-brûlage systématique des bois morts à l’intérieur comme aux alentours du verger. Les données collectées sont le taux d’infestation des anacarderaies et la densité par arbre de A.  terebrans. Des résultats des essais, il ressort que les taux d’infestation des anacarderaies par A. terebrans ainsi que les densitésactuelles de A. terebrans par anacardier ont été significativement plus élevées dans les plantations témoins (respectivement 60,0 ± 9,0% et 10,73 ± 2,10 trous/arbre) que dans celles soumises au ramassage-brûlage (respectivement 43,0 ± 9,0% et 6,83 ± 2,10 trous/arbre).Conclusion et application des résultats : Il ressort de cette étude que les anacarderaies soumises au ramassage-brûlage systématiques des bois morts ont été moins attaquées par le foreur. Une application plus généralisée et à long terme de cette pratique réduira remarquablement la pression de A. terebrans dans les anacarderaies, pour une augmentation quantitative et qualitative de leur productivité.Mots-clés : Anacardium occidentale, Insectes foreurs de bois,  Bostrichidae, Mesures prophylactiques, Noix de cajou