Environmental & Physical Sciences

Research Papers/Topics Environmental & Physical Sciences

DE LA REPULSION CHEZ LES INSECTES - Cas d’étude du moustique Anopheles gambiae et de la mouche blanche Bemisia tabaci -

Abstract: D’après la FAO, il faudra nourrir 9 milliards de personnes en 2050 ce qui équivaudrait à augmenter de 70% la production actuelle. Une manière simple d’augmenter la production serait de limiter les pertes de rendement et de récolte en luttant contre les insectes. Il faudra donc produire plus mais il faut produire mieux. Les insecticides ont été et sont largement utilisés mais avec l’apparition de résistances, la pollution de l’environnement et l’impact sur la sant...

Patterns of Relationship between Banana (musa spp.) types and the Banana weevil, Cosmopolites Sordidus (germar)(Coleoptera:Curculionidae)

Abstract: Banana (Musa spp.) is an important food crop of the humid tropical lowland areas of the world. Banana production is beset by several problems, related to crop husbandry, selection of planting material, soils, diseases, and pests. Although more than 25 borers have been recorded on banana, the banana weevil Cosmopolites sordidus (Germar) (Curculionidae) is regarded as the major contributor to the general loss in plant vigour and yield. However, some banana cultivars have been found t...

Understanding agronomic and phytochemical properties of Brachiaria for management of cereal stemborers in East Africa

Abstract: Grasses in the genus Brachiaria, commonly known as brachiaria are grown as a fodder crop in sub-Saharan Africa, with some genotypes being used in management of the spotted stemborer Chilo partellus (Swinhoe) (Lepidoptera: Crambidae) through a habitat management strategy. Stemborer is a major insect pest of sorghum (Sorghum bicolor L. Moench) and maize (Zea mays L.) in Africa. However, utilization of brachiaria in cereal-livestock based farming systems in the region faces several bi...

Microorganism-mediated behaviour of Malaria Mosquitoes

Abstract: Host-seeking is an important component of mosquito vectorial capacity on which the success of the other behavioural determinants depends. Blood-seeking mosquitoes are mainly guided by chemical cues released by their blood hosts. This thesis describes results of a study that determined the effect of microorganisms – host skin bacteria as well as malaria parasites – on host-seeking behaviour of female Anopheles gambiae sensu stricto and An. arabiensis in Homabay county, western K...

Development and Implementation of Pre and Post-harvest Management Measures for Bactrocera (invadens) dorsalis (Drew, Tsuruta and White) and Ceratitis cosyra (Walker) (Diptera: Tephritidae) on

Abstract: Mango, Mangifera indica L (Anacardiaceae) is an important tropical fruit providing opportunities for income generation and improvement of livelihoods of millions of farmers across Africa. However, fruit production is limited by several constraints; ranking high among these is the infestation by Tephritid fruit flies such as Bactrocera invadens and Ceratitis cosyra.

Relationship between virulence and repellency of Metarhizium anisopliae and Beauveria bassiana towards Macrotermes michaelseni and chemical identification of the mediating signals

Abstract: It is not well understood how termites survive in hemiedaphic habitats with diverse array of potentially infective fungi. In the present study, it was initially found that Macrotermes michaelseni detected a virulent isolate of Metarhizium anisopliae from some distance in a specially designed Y-olfactometer and avoided direct physical contact through olfaction. The overall objective of the study was to evaluate the relationship between virulence and repellency of different isolates ...

Diversity of honeybee Apis melifera (Hymenoptera: Apidae) Sub-species and their Assocaiated Arthropod pests in Cameroon

Abstract: Conservation of Apis mellifera requires detailed knowledge of the subspecies identity, diversity and factors threatening their survival. Despite the increasing reports on the spread and damage caused by both exotic and indigenous honey bee pests to bee populations in many parts of Africa, there is dearth of knowledge on the ecology of honey bees and their pests in Central Africa and Cameroon in particular. Furthermore, management practices such as use of different beehive types acr...

Biodiversity and Ecosystem Services: Pollination, Biological Control, and Nature Conservation in Agricultural Landscapes

Abstract: Agriculture has done more damage to nature than any other human activity, and yet food production could need to be doubled by the middle of this century. As agricultural land is expanded and intensified, critical thresholds in the loss of natural habitats are crossed. This loss of non-crop habitats can have negative feedback on crop production,because it can cause a loss of “ecosystem services” that support and regulate crop production, such as the pollination of crops by bees ...

Olfactory preferences of gravid female stable flies, Stomoxys calcitrans L. (Diptera: Muscidae), and their fitness consequences

Abstract: Oviposition decisions are a prominent example of behaviour directly affecting the fitness,abundance, distribution, and population dynamics of holometabolous insects. Due to eggs being immobile and adult insects often not practicing biparental and/or maternal care, gravid females, when ovipositing, should select substrate(s) that maximise fitness of their offspring.Studies have revealed that this selection is influenced by biotic (intra and interspecific competition, parasitism, lar...

An Autodissemination Strategy using Entomopathogenic Fungi and kairomonal attractants for Managing thrips on Grain Legumes

Abstract: Grain legumes are among the key economical crops widely grown in western and eastern Africa as important sources of food and animal fodder. However, the production of grain legumes in Kenya is seriously affected by a complex of insect pests particularly thrips. Yield losses of 20 to 100% have often been reported in some areas. The bean flower thrips (BFT), Megalurothrips sjostedti is considered to be the most important thrips pest of grain legumes. Chemical control is still the mai...

Ecosystem services and disservices in small-scale tropical agriculture

Abstract: Small-scale farmlands are dynamic systems crucial to the food-security and livelihoods of more than two billion people and there is political pressure in many developing nations to consolidate and expand small farms into larger units of management. This could have consequences for agro-ecosystem processes and the ecosystem services and disservices that regulate crop production. This thesis aims to highlight and address these issues in smallholder farming landscapes, which are poorl...

Host-seeking behaviour of Anopheles mosquitoes in response to olfactory and visual cue

Abstract: Chapter 18 IntroductionSuccess in malaria vector control in recent years has been attributed largely to the widespread distribution and utilization of long lasting insecticide-treated nets (LLINs) and indoor residual spraying (IRS)(WHO, 2019). The disruption of contact between the human host and the vector remains a very effective mechanism of controlling mosquito-borne diseases when applied in combination with other tools such as effective diagnosis, prevention of mother to child ...

Understanding Striga occurrence and risk under changing climatic conditions across different agroecological farming systems at local and regional scales

Abstract: The invasion by Striga in most cereal crop fields in Africa has posed an acute threat to food security and socioeconomic integrity. Consequently, numerous technological and research developments have been made to minimize and even control the Striga impacts on crop production. So far, efforts to control Striga have primarily focused on the manipulation of the genetics of the host crops, as well as understanding the phenological and physiological traits, along with the chemical comp...

Chemical ecology of plant-to-plant communication and opportunities for maize stemborer management in Africa

Abstract: Maize is the most widely grown cereal crop worldwide, and is the most important staple crop in sub-Sahara Africa. The spotted stemborer, Chilo partellus (Swinhoe) (Lepidoptera:Crambidae) is considered among the most important pests of maize and the damage it causes may result in yield losses of up to 88%. Previous studies showed that plants damaged by herbivores release huge amounts of volatile compounds, known as herbivore-induced plant volatiles (HIPVs) into the environment, whic...

Damage to citrus and vegetables by Thaumatotibia leucotreta (Lepidoptera: Tortricidae) and prospects for control with entomopathogenic fungi

Abstract: Globally, orange is one of the major fruit crops contributing to nutrition and monetary income. False codling moth (FCM), Thaumatotibia leucotreta, is one of the major constraints of orange production. Before this study, little was known regarding the bioecology of FCM in orange and vegetables in Kenya and Tanzania and the potential use of dry conidia of entomopathogenic fungi for control of T. leucotreta moths has not been tested. There is also no IPM strategy available for FCM in...


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