13 research outputs found
EnquĂȘtes Ethnobotaniques et CaractĂ©risation des Pratiques EndogĂšnes de Gestion des Ravageurs sur Quelques Sites MaraĂźchers au Sud-BĂ©nin
Lâune des contraintes liĂ©es Ă la production maraĂźchĂšre, est la pression exercĂ©e par les insectes ravageurs. Ce travail a consistĂ© en une enquĂȘtes ethnobotaniques et caractĂ©risation des pratiques endogĂšnes de gestion des ravageurs sur quelques sites maraĂźchers au sud-BĂ©nin, dans le cadre de la formulation des pesticides botaniques pour la gestion des principaux ravageurs de cultures maraĂźchĂšres. Cette Ă©tude est basĂ©e sur les caractĂ©ristiques socioĂ©conomiques des enquĂȘtĂ©s, lâĂ©tat de connaissances du producteur sur les cultures maraĂźchĂšres, les contraintes et mĂ©thodes de lutte des cultures, et les mĂ©thodes dâutilisation de la plante. Un questionnaire dâenquĂȘte portant sur lâĂ©tude ethnobotanique des plantes et la caractĂ©risation des pratiques endogĂšnes de gestion des nuisible a Ă©tĂ© Ă©laborĂ©e et adressĂ© auprĂšs 240 maraĂźchers sur une pĂ©riode de trois mois (de mai 2018 Ă Juillet 2018) pour la collecte des donnĂ©es. Ces donnĂ©es ont Ă©tĂ© soumises Ă une analyse descriptive et une analyse en composante principale. LâĂ©tude a rĂ©vĂ©lĂ© que 12 espĂšces de lĂ©gumes sont cultivĂ©es par les maraĂźchers de la zone dâĂ©tude Ă cause de leur cycle assez court et leur prĂ©fĂ©rence par les consommateurs. Ces lĂ©gumes sont dominĂ©s par la grande morelle, le chou, la tomate et la carotte en termes de proportion. Le recours aux pesticides de synthĂšse non homologuĂ©s pour le contrĂŽle des ravageurs reste la mĂ©thode de lutte la plus utilisĂ©e. Les connaissances ethnobotaniques collectĂ©es sur quatre plantes Ă savoir : le neem, le moringa, le papayer et le tabac, au cours de nos enquĂȘtes sont trĂšs riches mais dĂ©tenues par trĂšs peu de personnes, majoritairement ĂągĂ©es dâau moins 50 ans (88,98%). Ces plantes se rĂ©partissent en quatre familles (Caricaceae, Moringaceae, MĂ©liacĂ©es, SolanacĂ©es) dont les MĂ©liacĂ©es sont les plus utilisĂ©es. Les parties des plantes les plus utilisĂ©es sont les feuilles et les graines. Cette collection de plantes indiquĂ©es par les maraĂźchers dans la lutte contre les ravageurs des cultures maraĂźchĂšres peut constituer une base des donnĂ©es pour des tests biologiques et des analyses phytochimiques.
One of the constraints related to vegetable production is the insect pests pressure. This work consisted of ethnobotanical surveys and characterization of endogenous pest management practices in a few gardening sites in southern Benin, as part of the formulation of botanical pesticides for the management of major gardening pests. This study is based on the socioeconomic characteristics of the surveyeds, the state of knowledge of the producer on gardening, constraints and methods of the crop control, and methods of the plant use. A survey quiz on the ethnobotanical study of plants and the characterization of endogenous pest management practices was developed and sent to 240 market gardeners over a period of three months (May 2018 to July 2018) for data collection. These data were subjected to a descriptive analysis and a principal component analysis. The study revealed that 12 species of vegetables are grown by market gardeners in the study area because of their rather short cycle and their preference by consumers. These vegetables are dominated by large nightshade, cabbage, tomato and carrot in terms of proportion. The use of unregistered synthetic pesticides for pest control remains the most widely used control method. The ethnobotanical knowledge collected on four plants namely: neem, moringa, papaya and tobacco, during our surveys are very rich but held by very few people, mostly aged at least 50 years (88,98 %). These plants are divided into four families (Caricaceae, Moringaceae, Meliaceae, Solanaceae) whose Meliaceae are the most used. The most used plant parts are leaves and seeds. This collection of plants indicated by market gardeners in the fight against vegetable crop pests can constitute a database for biological tests and phytochemical analyzes
Evaluation Au Laboratoire De Lâeffet Larvicide Du Baume De Cajou Et De Trois Huiles VĂ©gĂ©tales Ă Base Des Plantes De Tephrosia Purpurea, Ricinus Communis Et Thevetia Neriifolia Pour ContrĂŽler Les Populations De Plutella Xylostella L. 1758 (Lepidoptere, Pl
Cette Ă©tude a Ă©valuĂ© lâeffet larvicide du baume de cajou extrait Ă froid et de trois huiles vĂ©gĂ©tales Ă base des plantes de Tephrosia purpurea, Ricinus communis et Thevetia neriifolia, dans les conditions dâĂ©levage au laboratoire de Plutella xylostella L. 1758 (Lepidoptera, Plutellidae) insecte ravageur du chou au BĂ©nin. LâefficacitĂ© des biopesticides Ă©tudiĂ©s a Ă©tĂ© comparĂ©e Ă celle dâun insecticide de synthĂšse (Lambda cyalothrine) et Ă celle dâun pesticide botanique de rĂ©fĂ©rence (Topbio). Des tests ont Ă©tĂ© rĂ©alisĂ©s sur les larves des stades 2 et 3 de P. xylostella. Deux expĂ©rimentations ont Ă©tĂ© rĂ©alisĂ©es dans cette Ă©tude. Dans la premiĂšre expĂ©rimentation, les produits ont Ă©tĂ© testĂ©s sur le stade L3 de P. xylostella, avec les doses de 100%, 75%, 50%, 25% et 10% de chacun des produits vĂ©gĂ©taux et de Lambda Cyhalothrine. A la deuxiĂšme expĂ©rimentation, les mĂȘmes produits vĂ©gĂ©taux ont Ă©tĂ© testĂ©es sur le stade L2 du mĂȘme insecte avec les doses de 50%, 25%, 10%, 5%, 3%, 2% et 1% comparĂ©es au tĂ©moin de rĂ©fĂ©rence Lambda cyalothrine aux doses de 10%, 5%, 3%, 2%,1%, 0,5%. Les mortalitĂ©s ont Ă©tĂ© observĂ©es toutes les 24 heures jusquâau neuviĂšme jour aprĂšs exposition. Le dispositif utilisĂ© pour les tests biologiques est un bloc complĂštement randomisĂ©. La formule dâAbbott a Ă©tĂ© utilisĂ©e pour corriger les taux de mortalitĂ© au niveau des insectes traitĂ©s. Les variables mesurĂ©es sont la mortalitĂ© des larves, la formation des chrysalides et lâĂ©mergence des adultes. Ces variables sont soumises Ă une analyse de variance avec le logiciel XLSTAT version 2019. Les DL 50 pour cinq jours ont Ă©tĂ© dĂ©terminĂ©es suivant le modĂšle de regression de Cox de dĂ©termination de la dose correspondante Ă une proportion. Les rĂ©sultats ont montrĂ© que les huiles vĂ©gĂ©tales et le baume de cajou sont les biopesticides prometteurs pour le contrĂŽle des populations de P. xylostella. Pour la premiĂšre expĂ©rimentation, les taux de mortalitĂ© des larves L3 de P. xylostella nâĂ©taient pas significativement diffĂ©rents entre les doses dâapplication de 25% de Topbio et dâhuile de T. purpurea. Des mortalitĂ©s de 100% ont Ă©tĂ© enregistrĂ©es avec les doses de 100%, 75%, 50% et 25% de tous les produits utilisĂ©s sur le stade L2 et L3. Lors de la deuxiĂšme expĂ©rimentation, 100% de mortalitĂ© ont Ă©tĂ© enregistrĂ©es Ă une dose dâapplication de 10% respectivement pour le Topbio, lâhuile de T. purpurea, le CNSL, et lâhuile de R. communis. Aucune diffĂ©rence significative nâa Ă©tĂ© enregistrĂ©e au seuil de 5% entre les doses de 10% dâhuile de T. purpurea et 3% du tĂ©moin de rĂ©fĂ©rence Lambda cyalothrine. Les tĂ©moins ont enregistrĂ© le plus fort taux de chrysalides et dâadultes. Ces deux paramĂštres ont Ă©tĂ© fonction de la dose. Pour tous les produits utilisĂ©s, quel que soit le stade larvaire de P. xylostella, la rĂ©ponse effet/dose a Ă©tĂ© significative. Le baume de cajou et les trois huiles vĂ©gĂ©tales se positionnent comme une alternative aux pesticides de synthĂšses pouvant ĂȘtre utilisĂ© en culture maraĂźchĂšre.
This study aims to evaluate the larvicidal effect of three vegetable oils: Tephrosia purpurea, Ricinus communis, Thevetia neriifolia, and cashew balm in the management of Plutella xylostella L. 1758 (Lepidoptere, plutellidae) pest insects of cabbage in the laboratory. The efficacy of the extracts has been compared to that of a synthetic insecticide (Lambda cyalothrin) and that of a botanical pesticide (Topbio). Larval tests were carried out on larvae of stages 2 and 3. Two experiments were set up in this study. In the first experiment, the products were tested on the L3 stage of P. xylostella, with the doses of 100%, 75%, 50%, 25% and 10% while in the second, the same products were tested on the L2 stage of the same insect with the doses of 50%, 25%, 10%, 5%, 3%, 2% and 1% compared to the reference control Lambda cyalothrin at the doses of 10%, 5%, 3 %, 2%, 1%, 0.5%. The mortalities were read 24 hours after exposure until the ninth day. The device used for biological tests is a completely randomized block. Abbott's formula has been used to correct mortality rates for treated insects. The variables measured are the mortality rate, the formation of pupae and the emergence of adults. These variables are subjected to an analysis of variance with the XLSTAT software version 2019. The LD 50 for eight days were determined according to the Cox regression method of determining the dose corresponding to a proportion. The results showed that vegetable oils and cashew balm are the promising species in the management of dose-dependent P. xylostella. For the first experiment, the mortality rates of L3 larvae of P. xylostella were not significantly different between the 25% application doses of Topbio and T. purpurea. Mortalities ranging from 100% were recorded with the doses of 100%, 75%, 50% and 25% of all the products used on the L2 and L3 stages. During the second experiment, 100% mortality was recorded at an application dose of 10% respectively for Topbio, T. purpurea, CNSL, and R. communis. No significant difference was recorded at the 5% threshold between the 10% doses of T. purpurea and 3% of the reference control Lambda cyalothrin. Witnesses recorded the highest rate of pupae and adults. These two parameters were a function of the dose. For all the products used, whatever the larval stage of P. xylostella, the effect / dose response was significant. Cashew balm and the three vegetable oils are positioned as an alternative to synthetic pesticides that can be used in market gardening
Existence of solutions of a dynamic Signorini's problem with nonlocal friction in viscoelasticity
ĐĐœŃĐ”ŃĐżĐŸĐ»: ĐČ ĐžŃŃĐŸŃĐžŃĐ”ŃĐșĐŸĐč ŃĐ”ŃŃĐŸŃпДĐșŃĐžĐČĐ”
The publication discusses the history of the creation and development of the International Police Organization â Interpol. The authors analyse the legal and organizational foundations of the activities of Interpol, its role in the law enforcement system in order to ensure the rights, freedoms, interests of human and citizen, society and the state. The authors study the role of Interpol in the fight against international crime. © 2020 Rossiiskaya Akademiya Nauk, Institut Istorii (Russian Academy of Sciences, Institute of General Hist. All rights reserved
Variational and numerical analysis of a quasistatic viscoelastic contact problem with normal compliance and friction
Approximation results and subspace correction algorithms for implicit variational inequalities
Analysis of a quasistatic contact problem with adhesion and nonlocal friction for viscoelastic materials
Analysis of a dynamic viscoelastic-viscoplastic piezoelectric contact problem
In this paper, we study, from both variational and numerical points of view, a dynamic contact problem between a viscoelastic-viscoplastic piezoelectric body and a deformable obstacle. The contact is modelled using the classical normal compliance contact condition. The variational formulation is written as a nonlinear ordinary differential equation for the stress field, a nonlinear hyperbolic variational equation for the displacement field and a linear variational equation for the electric potential field. An existence and uniqueness result is proved using Gronwallâs lemma, adequate auxiliary problems and fixed-point arguments. Then, fully discrete approximations are introduced using an Euler scheme and the finite element method, for which some a priori error estimates are derived, leading to the linear convergence of the algorithm under suitable additional regularity conditions. Finally, some two-dimensional numerical simulations are presented to show the accuracy of the algorithm and the behaviour of the solution