Biocidal Effect of the Leaves of Azadirachta indica A. Juss on A Resistant Strain of the Groundnut Bush Caryedon serratus (Olivier)

Groundnut (Arachis hypogaea L.) is a legume that is highly coveted by West African populations, particularly those in Senegal. However, it suffers enormous damage caused by a bruchidea beetle, Careydon seratus. Losses recorded can reach 83% for a period of 4 months of storage. To counter this damage, several authors have looked for alternative methods to the use of synthetic insecticides, often harmful to animal populations and the environment. The purpose of this study is to test, the biological impact of leaf-based formulations of native plants of Senegal (Azadichta indica) on the external forms of C. serratus. In this study, analysis of the biological parameters of strain C. serratus showed low adult mortality. This trend of mortality has been reversed from the second day to the ninth day when we have a mortality of 66.67% (C1) but for C3 we have a mortality of 33.33% on the third day. The extracts also affected female fecundity, which is 52% for C1 and 47% for C2. Nevertheless, the effect is more pronounced with Deltamethrin (36.5% for C1 and 35.7% for C2). For the lowest C3 concentration, the opposite is true: a 41.4% fecundity with Deltamethrin and 35.9% with A. indica. On the other hand, the extract affects the viability of eggs which depends on the dose and the fertility of the rescued females is reduce. On the other hand, there is an extension of the total development time. Aminata GNINGUE, Toffène DIOME*, Khady FALL, Mbacké SEMBENE 1,2,3,4 Genetic Team and Population Management, Department of Animal Biology, Cheikh Anta Diop University, Faculty of Sciences and Technology, Dakar, Senegal Submission: 23 September 2019 Accepted: 28 September 2019 Published: 30 October 2019 www.ijsrm. humanjournals.com Citation: Toffène DIOME et al. Ijsrm.Human, 2019; Vol. 13 (4): 41-53. 42 INTRODUCTION Peasant agriculture in Senegal occupies 60% of the active population and contributes 20% of GDP. It is dominated by several sectors including the peanut sector (Kouadio, 2007). It occupies a prominent place in the economic system of Senegal where its culture covers more than half of the cultivable surface. This leguminous crop yields around 80 billion FCFA each year, which represents 40% of the country's total exports (Sembène, 2006). High in protein and calories (50% fat, 25% protein), this oil seed is also a very important nutrient supply for local populations (Ndiaye, 1991). However, groundnut cultivation in Senegal faces many constraints. Indeed, few insects are able to attack in shell peanuts; among these, the one that causes the most damage in production is a Coleopteran insect belonging to the family Bruchidae: Caryedon serratus (Olivier), commonly called peanut brush. The damage it causes on peanuts can go up to 83% of quantitative loss for a storage period of 4 months (Sembène, 2000). The holes left in the hull by the larvae of this pest promote the attack of other pests and facilitate the development of a mold (Aspergillus flavus Link.) Producing a carcinogenic substance: aflatoxin. All these losses that occur at all stages, from harvesting to consumption, not only harm farmers but also cost the national economy. In the face of the threat posed by insects, which are the main pests of stocks, farmers often resort to synthetic insecticides, which have a great deal of adverse effects, including the selection of resistant strains (Benhalima et al., 2004), poisoning, environmental pollution, environment but also the reluctance of consumers to consume products treated with pesticides (Guèye et al., 2011). In the face of the perverse effects of synthetic insecticides, several authors today will rely on traditional methods of insect control, by the search for natural substances of plant origin adapted to the reduction of insect-induced damage harvests without endangering the population and the environment (Bambara and Tiemtoré, 2008 ; Faye et al. 2014 ; Mbaye et al. 2014). The application of extracts obtained from organic solvents is the most practiced, while it is difficult to apply by farmers. This because of the high cost of these solvents, their delicate handling, which often requires precautions to establish, which can be commonly ignored by peasant populations. We propose to use tap water as a solvent because it is more accessible and less expensive and also easy to handle without danger (Faye, 2015). It is in the context of the reduction of the post-harvest losses of peanuts by alternative methods of traditional control that which is part of this study which aims at evaluating the biocidal effect of the plant Azadirachta indica on the biggest parasite of peanut, C. serratus. The aim of this www.ijsrm. humanjournals.com Citation: Toffène DIOME et al. Ijsrm.Human, 2019; Vol. 13 (4): 41-53. 43 study is to evaluate the biocidal effect of the Azadirachta indica plant on the largest pest of peanuts, C. serratus. MATERIALS AND METHODS