Natural & Applied Sciences

Natural & Applied Sciences Research Papers/Topics

Performance of cotesia flavipes cameron (hymenoptera: braconidae) on stem borers of cereals and wild crops.

Abstract: The braconid larval parasitoid Cotesia flavipes Cameron (Hymenoptera: Braconidae) was introduced into Kenya from Pakistan and India for the control of the exotic crambid stem borer Chilo partellus Swinhoe (Lepidoptera: Crambidae). In Africa, maize fields are usually islands surrounded by land occupied by wild gramineous plants. Many of the wild plants harbour borer species not found on crops. It is not known if the exotic parasitoid C. flavipes follows these borers into the wild ha...

Phylogeny And Antibiotic Activity Of Xenorhabdus Spp. Isolated From Nematode Symbionts In Kenya

Abstract: Xenorhabdus is a bacteria genus of the family Enterobacteriaceae. Bacteria of this genus form a mutualistic relationship with Steinernema entomopathogenic nematodes. More so, their antimicrobial production serves as a potential source of novel antibiotics in the wake of growing antimicrobial resistance. This study aimed to establish the phylogenetic relationship of three Xenorhabdus isolates to the 24 described species of the genus based on the 16s rRNA gene. Secondly, it aimed to ...

Responses To Pyrethroids In Heavy Metal Tolerant Anopheles Gambiae Vector Of Malaria

Abstract: Anopheles gambiae mosquito, the principle Afro-tropical vector of malaria, has been documented in habitats with heavy metals in excess of natural loads. The mosquito has also displayed resistance to most conventional insecticides, and potential to resist challenges by heavy metals. Investigations were conducted in strains of An. gambiae ss, in which tolerance to cadmium and lead heavy metals were established. This study was undertaken to determine any putative relationship between ...

Expression profiles of tsetse (glossina spp) glossina proteolytic lectin (gpl) gene

Abstract: Tsetse flies are important agricultural and medical vectors of African trypanosomes, the causative agents of trypanosomosis in humans and animals. The life cycle of the protozoan parasite Trypanosoma, in its invertebrate vector begins when the tsetse fly feeds on an infected mammalian host. An important step in the establishment of tsetse midgut infection involves transformation of bloodstream-form trypanosomes into procyclic forms. This process is mediated by a wide variety of fac...

An interaction model between Cotesia flavipes and Cotesia sesamiae, parasitoids of the gramineous stem-borers at the Kenya Coast

Abstract: One of the greatest challenges facing the people of sub-Saharan Africa is the production of sufficient food to feed a rapidly increasing population in the face of dwindling finances. As the population grows at 3% and food production at 2% per annum, an annual shortage of 250 million tons of food is expected by year 2020. The greatest obstacle to increasing the production of maize and sorghum, the staple food in many African communities south of the Sahara, is damage by phytophagous...

Experimental Infection of Malaria Mosquitoes with Entomopathogenic Fungus, Beauveria Bassiana under Field Conditions

Abstract: Many successful laboratory studies have demonstrated the potential of using the entomopathogenic fungus, Beauveria bassiana against malaria mosquitoes. This study focussed on infection of wild malaria mosquitoes with the entomopathogeriic fungus B. bassiana under field conditions. Four experiments were carried out under laboratory conditions by use of World Health Organization bioassay cones, for exposure of3-6 days old, non-blood fed laboratory-reared Anopheles arabiensis mosquito...

Screening Mosquitoes for Rift Valley Fever Virus and Blood Meal Sources during the 2006/2007 Outbreak in Kenya

Abstract: Rift Valley Fever (RVF) is a mosquito borne viral infection, first reported in the Rift Valley province of Kenya in 1912 and identified in 1931. Major outbreaks have been reported in Kenya in 1997/1998 and 2006/2007. Baringo, Garissa and Kilifi district of Kenya were hot spots in the last major RVF outbreak that occurred in the country in 2006/2007. Investigations were conducted during the outbreak to establish putative mosquito vectors and vertebrate host of RVF virus. Engorged fe...

Determination of the Putative Insect Vector of Napier Grass Stunt Phytoplasma using Molecular and Bioassay techniques in Western Kenya

Abstract: Sampling insects in and around Napier grass fields revealed that 21 Homopteran insect species exploit Napier Grass (Pennisetum purpureum Schumach 1827) canopy. Leafhopper Cicadulina sp., and plant hoppers; Leptodelphax dymas Young, and Sogatella manentho Horvath, are the most dominant Napier canopy insects. This study developed a Loop Mediated Isothermal Amplification of DNA (LAMP) for rapid detection of phytoplasma 16S rDNA. LAMP was simple, sensitive, specific, robust and very ra...

Entomopathogenicity of Hyphomycete Fungi to Fruit Fly Bactrocera invadens (Diptera: Tephritidae) and their Potential for Biological Control on Mango

Abstract: Sustainable mango production will rely increasingly on alternatives to conventional chemical insecticides that are environmentally friendly for the management of fruit flies. The use of microbial control agents such as fungi in pest suppression is considered suitable since micro-organisms usually exert low environmental impact and are target specific. Application methods of bio-pesticides in the environment, which use minimal amount of inoculum is currently under improvement from i...

Genetic Variation in Two Populations of the Brown Ear Tick, Rhipicephalus Appendicula tus, in Kenya

Abstract: Several studies have shown that Rhipicephalus appendiculatus from geographically isolated areas differ in their susceptibilities to Theileria paIva, the haemoprotozoan causative agent of East Coast Fever. In Kenya, R. appendiculatus from Muguga have been reported to be less susceptible to T parva infection than those from Rusinga Islands. As the same tick species from different areas shows variation in vector competence, it was considered to be of epidemiological interest to determ...

The Role of Termites in Litter Decomposition and Soil Translocation with Special Reference to Odontotermes in Arid Lands of Northern Kenya

Abstract: This research work on the role of termites in an arid ecosystem covered eleven months (August 1981 to .June 1982). It was conducted at the site of the UNESCO integrated project in Arid Lands (UNESCO - !PAL} . This area is in Western Marsabit district, Kenya . About 80% of this area is semi-arid thorn bush scrubland and receives annual rainfall from about 100 to 600 mm. A survey of the termite fauna as a whole was carried out around most of the !PAL Field camps. Main investigation s...

Synergistic effect of Artemisia annua Fraction against in Vitro Cultures of Plasmodium Falciparum

Abstract: Malaria is an infectious disease that continues to be associated with considerable morbidity and mortality and significant social and economic impact on developing societies. Approximately 300 million people worldwide are affected and between 1 and 1.5 million people die from it every year. The disease is caused by a protozoan parasite of the genus Plasmodium. Four species are known to cause malaria in man; these are Plasmodium falciparum, P, vivax, P.ovale and P malariae. The para...

Adaptation of Field Strains of Rhipicephalus Appendiculatus, Neumann to Host Resistance to Tick Infestation

Abstract: The possibility of adaptation to host resistance by field strains of R. appendiculatus was investigated by comparing the feeding and breeding performance of two field strains with a laboratory strain (Muguga) which has been bred and maintained for about 30 years on susceptible rabbits. Results have shown that the laboratory strain has smaller eggs and smaller unfed larvae, nymphs and adults than the field strains. When fed on susceptible rabbits the laboratory strain females laid e...

Bio-Prospecting for Insecticidal Scorpion Venoms and Identification of Bioactive Toxins

Abstract: Scorpion venom contains insect and mammal selective toxins. However, despite their significance and potential application in insect-pest control, bioactivity of Kenyan scorpions is still unknown. As such this study initiated investigations on the inherent insecticidal activity of the venoms of scorpions collected in Kenya. Venom from four scorpion species namely Parabuthus leiosoma, Parabuthus pallidus, Hottentotta trilimeatus and Hottentotta eminii was collected upon stinging a pa...

PCR-high Resolution Melting Analysis of the COI, cyt b and 16S rRNA Mini-barcode Genes: A Tool for Species Identification and Discrimination in Illegal Bushmeat Trade

Abstract: Reliable molecular identification of vertebrate species from morphologically unidentifiable tissue is critical to the prosecution of illegally traded wildlife products to limit their trade, as well us for surveillance to inform conservation policies and identification of blood-meal hosts. Currently, this is mainly dependent on sequencing of the cytochrome c oxidase subunit I (COI) ‘barcode’ genes, which remains costly for purposes of screening large numbers of unknown samples a...


1381 - 1395 Of 8876 Results