Assessing nontarget effects and host feeding of the exotic parasitoid Apanteles taragamae, a potential biological control agent of the cowpea pod borer Maruca vitrata

Article PurchasedApanteles taragamae Viereck is a larval parasitoid introduced in Benin for classical biological control of the cowpea pod borer Maruca vitrata Fabricius. In the laboratory, we evaluated the effects of A. taragamae on non-target herbivore species, and on another parasitoid of M. vitrata, i.e. the egg-larval parasitoid Phanerotoma leucobasis Kriechbaumer. Furthermore, we addressed the host feeding behaviour of A. taragamae. The host specificity of A. taragamae was assessed by offering six other lepidopteran species to the wasp. The competitive ability of A. taragamae was studied by providing the wasp with one- and two-days-old M. vitrata larvae that had hatched from eggs previously parasitized by P. leucobasis. Controls consisted of eggs and larvae offered only to P. leucobasis and A. taragamae, respectively. None of the other six lepidopteran species was successfully parasitized by A. taragamae. The larval parasitoid A. taragamae outcompeted the egg-larval parasitoid P. leucobasis when offered two-days-old host larvae. Competition between the two parasitoid species did not significantly affect one-day-old host larvae that were less suitable to A. taragamae. Host feeding by A. taragamae did not affect survival of one-day-old or two-days-old M. vitrata larvae. However, the percentage parasitism of two-days-old larvae was significantly reduced when exposed to female A. taragamae wasps that had been starved during 48 h. The data are discussed with regard to host specificity, host feeding patterns and to factors underlying the outcome of intrinsic competition between parasitoid species

Functional response and life history parameters of Apanteles taragamae, a larval parasitoid of Maruca vitrata

Open Access JournalThe legume pod borer Maruca vitrata Fabricius (Lepidoptera: Crambidae) is a serious pest of cowpea in West-Africa. The parasitoid Apanteles taragamae Viereck (Hymenoptera: Braconidae) that originates from Taiwan is a potential candidate for biological control of M. vitrata. We investigated under laboratory conditions the functional response of the parasitoid by offering each experienced female 10, 20, 30 and 40 larvae of M. vitrata. We studied the influence of different host larval ages on the development, longevity, sex ratio, lifetime fecundity and parasitization rate of the wasp. In a comparative study, we also investigated the life history of A. taragamae and M. vitrata at different temperatures in the range of 20–30°C. The parasitoid successfully parasitized two- and three-day-old host larvae (first and second instars). Younger larvae (one-day-old) were parasitized to a lesser extent, and only males developed in them. Older larvae were not parasitized, partly because of defensive host behaviour. The success of parasitization was positively correlated with the density of two-day-old M. vitrata larvae. Parasitoid developmental time and longevity decreased with increasing temperature. The intrinsic rate of population increase (rm) exhibited an optimum curve with a maximum at 24–28°C. For the host M. vitrata, rm was maximal at temperatures of 26–30°C. The data are discussed in the context of the potential of A. taragamae for biological control of M. vitrata

An assessment of learning gains from educational animated videos versus traditional extension presentations among farmers in Benin*

Article purchasedThis study compared the efficacy of linguistically and dialectically localized animated educational videos (LAV) against traditional learning extension (TLE) presentations for learning gains of knowledge around agricultural- and healthcare-related topics within a rural population in Benin. While both approaches demonstrated learning gains, LAV resulted in significantly higher test scores and more detailed knowledge retention. A key contribution of this research, moreover, involves the use of mobile phone technologies to further disseminate educational information. That is, a majority of participants expressed both a preference for the LAV teaching approach and a heightened interest in digitally sharing the information from the educational animations with others. Because the animations are, by design, readily accessible to mobile phones via Africa’s explosively expanding digital infrastructure, this heightened interest in sharing the animated videos also transforms each study participant into a potential a learning node and point of dissemination for the educational video’s material as well

Farmers knowledge and control of two major pests: Helicoverpa armigera (Hübner) (Lepidoptera, Noctuidae) and Aphis gossypii (Glover) (Homoptera: Aphididae) in five agroecological zones in Benin (West Africa)

A survey study was performed in five agro-ecological zones in Benin to assess farmers’ knowledge and perceptionon the identification, damage recognition, applied control methods of two cotton insect pests Helicoverpaarmigera Hübner and Aphis gossypii Glover. A total of 200 farmers were interviewed in the five agroecologicalzones in Benin, using semi-structured questionnaire interviews. Results revealed sound knowledge of farmers onthe identity of H. armigera and A. gossypii. Farmers easily recognized H. armigera through its damage ondifferent plant organs while A. gossypii was known only at high infestation stage. Moreover, many crops arelisted as host plants for H. armigera and A. gossypii with different economic injuries. Control of these insectpests was done mainly by the use of chemicals with various application numbers and frequencies. The mostapplied chemicals for the control of H. armigera on cotton were Nurelle D 236 EC in zone 4 and 6, Thunder145O-Teq in zone 5 and Tihan 175 O-Teq in zone 2, while protection against A. gossypii was done using mostly Thian175 O-Teq except in the zone 6 where Fanga was used. The time interval between two treatments was 3-14 daysdepending on the product in use, the target insect and the agro-ecological zone. The effectiveness of the differentproducts was diversely appreciated. Farmers claimed to be aware of the so many side effects of chemicalsapplication. In organic cotton area, alternative method consisting of the use of botanical extracts was beingexperimented

Repellent effect and insecticidal activities of Bridelia ferruginea, Blighia sapida, and Khaya senegalensis leaves powders and extracts against Dinoderus porcellus in infested dried yam chips

Open Access Article; Published online: 21 June 2017Dinoderus porcellus is considered as the most important pest of stored yam chips and compounds extracted from plants can be used for its control. The present study aimed to test the insecticidal and repellent activities of powders and extracts of leaves of Bridelia ferruginea, Blighia sapida, and Khaya senegalensis against D. porcellus. The efficacy of plant powders was compared with the synthetic pesticide Antouka (Permethrin 3 g/kg + pirimiphos 16 g/kg). The results of the experiment revealed that all plant powders were effective as repellents. Antouka was more effective as insecticidal than the plant powders and minimal weight loss was observed with B. sapida at 2%. Among treatments, propanol extract of K. senegalensis at 5% was found to elicit the highest repellent effect on D. porcellus. The LC50 results revealed that the acetone extract of K. senegalensis is the most toxic (0.29 μL/insect) to the pest, while the propanol extract of B. ferruginea at 5% exhibited strong fumigant toxicity against D. porcellus, with 88.89% of pest mortality at 160 μL/L air. The findings from the current work proved that plant powders and extracts of the three plants are sources of botanical insecticides which may be used in the integrated management of D. porcellus

EFFICACY OF VEGETABLE OIL EXTRACTS FOR CONTROL OF INSECT PESTS OF TOMATO IN SOUTHERN BENIN

Pests are a menace to production of tomato ( Lycopersicon esculentum Mill.) in sub-Sahara Africa. The objective of this study was to evaluate the efficacy of oil extracts of selected common plants for control of pests of tomato in Benin. The study was carried out on the Togba market garden sites in Benin. The botanical pesticides ( Tephrosia purpurea , Ricinus communis , Thevetia neriifolia and Cashew Nut Shell Cold Liquid (CNSL cold) were compared with a biological insecticide (Topbio), a synthetic insecticide (Lambda cyhalothrin) and an untreated negative control. The fish model and the generalised linear mixed or fixed effects model were used to explain the number of caterpillars per plot as a function of the products tested during the different plant phases. Tephrosia purpurea oil, cold CNSL, Topbio and lambda cyhalothrin treatments significantly reduced H. armigera, S. littoralis and T. absoluta populations. The average yields of marketable tomato ranged from 7.20 \ub1 0.89 t ha-1 for the controls and 21.14 \ub1 3.56 and 20.46\ub11.98 t ha-1 for the plots treated with Tephrosia purpurea and CNSL cold on tomato, respectively. Plots treated with the synthetic insecticide lambda cyhalothrin gave the best yields (31.15\ub13.20 t ha-1). Of all the extracts tested, cold extracted CNSL and T. purpurea oil showed very high larvicidal activity at doses of 10%, compared to R. communis and T. neriifolia oil on the farm. The larvicidal activity of the extracts observed at low doses on H. armigera and S. littoralis larvae seems to offer an alternative advantage for the control of tomato pests.Les ravageurs sont une menace pour la production de tomate (Lycopersicon esculentum Mill.) en Afrique sub-saharienne. L\u2019objectif de cette \ue9tude \ue9tait d\u2019\ue9valuer l\u2019efficacit\ue9 des extraits d\u2019huile de Tephrosia purpurea, Ricinus communis, Thevetia neriifolia et Cashew Nut Shell Cold Liquid (CNSL cold) pour le contr\uf4le des ravageurs de la tomate. L\u2019\ue9tude a \ue9t\ue9 r\ue9alis\ue9e sur les sites mara\ueechers de Togba au B\ue9nin. Les pesticides botaniques ont \ue9t\ue9 compar\ue9s \ue0 un insecticide biologique (Topbio), un insecticide de synth\ue8se (Lambda cyhalothrine) et un t\ue9moin n\ue9gatif non trait\ue9. Le mod\ue8le poisson z\ue8bre et le mod\ue8le lin\ue9aire g\ue9n\ue9ralis\ue9 \ue0 effets mixtes ou fixes ont \ue9t\ue9 utilis\ue9s pour expliquer le nombre de chenilles par parcelle \ue9l\ue9mentaire en fonction des produits test\ue9s lors des diff\ue9rentes phases de la plante. Les traitements \ue0 l\u2019huile de Tephrosia purpurea, au CNSL cold, au Topbio et \ue0 la lambda cyhalothrine ont significativement r\ue9duit les populations de H. armigera, S. littoralis et T. absoluta. 20,46\ub11,98 t ha-1 pour les parcelles trait\ue9es respectivement avec Tephrosia purpurea et CNSL cold sur tomate. Les parcelles trait\ue9es avec l\u2019insecticide de synth\ue8se lambda cyhalothrine ont donn\ue9 les meilleurs rendements (31,15\ub13,20 t ha-1). De tous les extraits test\ue9s, l\u2019huile de CNSL cold et de T. Purpurea extraite a montr\ue9 une activit\ue9 larvicide tr\ue8s \ue9lev\ue9e \ue0 des doses de 10% par rapport \ue0 l\u2019huile de R. communis et de T. neriifolia \ue0 la ferme. L\u2019activit\ue9 larvicide des extraits observ\ue9e \ue0 faible dose sur les larves de H. armigera et S. littoralis semble offrir un avantage alternatif pour la lutte contre les ravageurs de la tomate

Transcranial electrical and magnetic stimulation (tES and TMS) for addiction medicine: A consensus paper on the present state of the science and the road ahead

There is growing interest in non-invasive brain stimulation (NIBS) as a novel treatment option for substance-use disorders (SUDs). Recent momentum stems from a foundation of preclinical neuroscience demonstrating links between neural circuits and drug consuming behavior, as well as recent FDA-approval of NIBS treatments for mental health disorders that share overlapping pathology with SUDs. As with any emerging field, enthusiasm must be tempered by reason; lessons learned from the past should be prudently applied to future therapies. Here, an international ensemble of experts provides an overview of the state of transcranial-electrical (tES) and transcranial-magnetic (TMS) stimulation applied in SUDs. This consensus paper provides a systematic literature review on published data – emphasizing the heterogeneity of methods and outcome measures while suggesting strategies to help bridge knowledge gaps. The goal of this effort is to provide the community with guidelines for best practices in tES/TMS SUD research. We hope this will accelerate the speed at which the community translates basic neuroscience into advanced neuromodulation tools for clinical practice in addiction medicine

Distribution and sampling of Maruca vitrata (Fabricius) (Lep.: Pyralidae) larvae on Lonchocarpus sericeus (Poir) H.B. and K

The spatio-temporal distribution of the pod borer Maruca vitrata was assessed on Lonchocarpus sericeus over a period of 6 months, in order to develop sampling plans and facilitate sampling on this host plant. Lonchocarpus sericeus, one of the preferred alternative host plants of M. vitrata is widely spread in Benin and should therefore be included in the ecological management of the insect. Some experiments were conducted at an ecological site in south Benin, where L. sericeus can be found. The analysis of 17 weekly samples showed that tree canopy did not have a significant effect (P=0.3471) on larval distribution. Significant differences (P=0.0001) were obtained between the sizes of flowers (10, 20, 30 and 40 racemes). Geographical quadrants consisting of the upper east branches, lower east branches, upper west branches and lower west branches did not differ significantly (P=0.8713). The time of infestation of L. sericeus by M. vitrata was investigated by taking samples every 2 days. Data analysis of these samples revealed that L. sericeus was infested at the open flower stage. Temporal distribution of larvae showed the greatest abundance of larvae occurred in June. The index of aggregation was 1.37 with the TAYLOR law and 1.26 with the Iwao procedure. These values showed that the larval dispersion pattern is negative binomial. On this basis, sequential sampling plans were developed and these could permit an accurate estimate of tree data for sampling

Mortality of Maruca vitrata (Lepidoptera: Crambidae) larval stages induced by different doses of the entomopathogenic fungi Metarhizium anisopliae and Beauveria bassiana

Thedose-dependent mortality of second (3-4 days old),third (5-6 days old) and fourth (7-9 days old) larval instars of Marucavitrataas induced by the entomopathogenic fungal isolates, MetarhiziumanisopliaeMa 29 and BeauveriabassianaBb 115 was determined in a laboratory experiment. For each fungal isolate, five doses (0, 2x104, 2x105, 2x106and 2x107conidia/larva, respectively) were applied topically to one individual larva at the rate of 2 ?l ofan oil formulation. Observations were focused on mortality and sporulation of treated larvae. Cox regression was used to determine the lethal dose 50 (LD50). Results revealed high mortality of the third larval stage (L3) at 2 x 10?conidia for Ma 29 and Bb 115 with 49% and 96% mortality, respectively. No significant difference in mortality was observed between larval stages exposed to 2x107 conidia/ larva. The sporulation rate did not differ significantly between larval stages. Regardless of application doses, the Mean Survival Times (MSTs) of larvae were significantly different between doses for both fungal species. The lowest MSTs were recorded for the younger larvae (L2, L3) at higher doses (2x106 and 2x107 conidia/larva). Larval mortality increased with increasing dose, regardless of fungal species and larval stages, suggesting a dose-dependent response of M. vitrata larvae

Effect of Maruca vitrata (Lepidoptera: Crambidae) host plants on lifehistory parameters of the parasitoid Apanteles taragamae (Hymenoptera: Braconidae)

The effect of four host plant species of the herbivore Maruca vitrata Fabricius (Lepidoptera: Crambidae) on development time, longevity, fecundity and sex ratio of the parasitoid Apanteles taragamae Viereck (Hymenoptera: Braconidae) was investigated under laboratory conditions. The larvae were parasitized when in the second instar. Maruca vitrata larvae were fed with flowers of four legumes, that is, Vigna unguiculata (cowpea), Sesbania rostrata, Lonchocarpus sericeus and Pterocarpus santalinoides, or an artificial diet both before and after parasitization. The parasitoid did not develop in hosts feeding on L. sericeus or V. unguiculata at 25◦C, or on P. santalinoides at 25◦C or 29◦C. Apanteles taragamae had the shortest development time on artificial diet at both 25◦C and 29◦C while the longest development time was recorded on L. sericeus at 29◦C. Female wasps took longer to develop compared to males at the two temperatures, regardless of the feeding substrate of their host. The longevity of the wasps at 25◦C varied among feeding substrates, but not at 29◦C. Survival rate of parasitized larvae depends on the feeding substrate. Moreover, infection of host larvae with Maruca vitrata multi-nucleopolyhedrovirus (MaviMNPV) killed larger proportions of parasitized larvae at 25◦C than at 29◦C, which was likely caused by the difference in parasitoid developmental rate. The proportion of female parasitoids was lowest on L. sericeus. The daily fecundity showed a nonlinear trend regardless of the feeding substrate, indicating that A. taragamae is a pro-ovigenic species. The data support the slow growth–high mortality hypothesis