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Innocent E.,Muhimbili University of Health and Allied Sciences | Nkunya M.H.H.,University of Dar es Salaam | Hassanali A.,Icipe African Insect science for Food and Health | Hassanali A.,Kenyatta University
Journal of Applied Pharmaceutical Science | Year: 2013

Polar constituents of Kotschya uguenensis Verdc. (Fabaceae) do not exhibit acute toxicity but cause growth disruption of Anopheles gambiae s.s. Gile (Diptera: Culicidae) larvae with eventual death. Time-course larvicidal effects of powders of root and stem barks and their crude methanol extracts in form of emulsions were compared in the laboratory and in artificial semi-field ponds. Kotschya uguenensis powders of root and stem barks and emulsions of their crude methanol extracts were assayed against An. gambiae s.s according to protocols of WHO 1996 & 2005. All formulations were equally effective under laboratory conditions giving 100% larval mortality within three days ata dose of 50 μg/ml of the extracts or concentrations of powders corresponding to the same level of extractable material. Under semi-field conditions, suspensions of the powder materials appeared to perform better than emulsions of methanol extracts. Time taken to give 80% mortality (LT80) of larvae and pupa at 0.1% w/v was 6.06 days for powders of root bark and 5.60 days for powders of stem bark. The LT80 for the root bark extract at 200 μg/ml was 8.28 days while that for the stem bark methanol extract was 12.47 days. No residualeffects of the testmaterials on the larvae or pupae were evident in semi-field ponds 14 days after the reintroduction of the test materials. Our results suggest that, for the control of anophelines in the field, a weekly application of appropriate amounts of powders of K. uguenensis may be effective. Source


Egonyu J.P.,Icipe African Insect science for Food and Health | Egonyu J.P.,University of Nairobi | Kabaru J.,University of Nairobi | Lrungu L.,University of Nairobi | Haas F.,Icipe African Insect science for Food and Health
Journal of Insect Science | Year: 2013

The coconut bug, Pseudotheraptus wayi Brown (Hemiptera: Heteroptera: Coreidae), is a serious pest of a number of crops in Eastern and Southern Africa. Both adults and nymphal stages are destructive because they suck sap from their hosts. The identity of the pest is currently based exclusively on the description of adults. This paper describes eggs and instars of P. wayi, with the goal to enhance identification of all stages for effective monitoring and management of the pest. Morphological illustrations are presented, and differences among the instars, as well as their relationship with the adult stage, are discussed. © This is an open access paper. Source


Teshome A.,Icipe African Insect science for Food and Health | Teshome A.,University of Nairobi | Onyari J.M.,University of Nairobi | Raina S.K.,Icipe African Insect science for Food and Health | And 2 more authors.
Journal of Applied Polymer Science | Year: 2013

Variations among silk of four African wild silkmoths, Argema mimosae, Anaphe panda, Gonometa postica, and Epiphora bauhiniae, was studied regarding their mechanical properties and thermal degradation behaviors. Cocoon shells and individual degummed fibers were examined using tensile testing, thermogravimetric analysis, and scanning electron microscope (SEM). A. mimosae and G. postica cocoon shells had marginally higher initial moduli and strains at maximum stress. The stress-strain curves of Bobmyx mori and A. panda degummed fibers lacked clear yielding points. G. postica fibers had the highest breaking energy (76.4 J/cm 3) and breaking strain (41.3%). The ultimate tensile strength was the highest for B. mori (427 MPa). Fiber pull-out and detachment was predominant in fracture surfaces of both the cocoon shells and the fibers. Wild cocoon shells and degummed fibers had higher temperature for dehydration loss than B. mori. A. mimosae fibers (11.9%) and G. postica cocoon shells (13.3 %) had the highest weight loss due to dehydration. E. bauhinae cocoon shells and B. mori fibers had the highest total weight losses of 97.2 and 93.4%, respectively. The African silks exhibited variations in their mechanical and thermal degradation properties related to their physical and chemical structure and composition. Copyright © 2012 Wiley Periodicals, Inc. Source


Teshome A.,Icipe African Insect science for Food and Health | Teshome A.,University of Nairobi | Vollrath F.,University of Oxford | Raina S.K.,Icipe African Insect science for Food and Health | And 2 more authors.
International Journal of Biological Macromolecules | Year: 2012

Silk fibers and cocoon shells from four African wild silkmoths Gonometa postica, Anaphe panda, Argema mimosae and Epiphora bauhiniae-were studied to gain insight into the structure-property-function relations and potential commercial application. The surface and cross-section of cocoon shells and fibers revealed the presence of prominent structural variations. Cocoon shells were multilayered and porous structures constructed from highly cross-linked fibers that are densely packed within the sericin/gum. Fibers had fibrillar sub-structures running along the fiber axis and with greater number and size of voids. The ecological significance and implication of these structures for further application are discussed. © 2011. Source


Overholt W.A.,University of Florida | Copeland R.S.,Icipe African Insect science for Food and Health
International Journal of Tropical Insect Science | Year: 2013

A South American leaf galling psyllid, Calophya schini Tuthill, has recently been discovered attacking the South American tree Schinus molle L. in Kenya and Ethiopia. This represents the first record of the psyllid in each country and the only record of C. schini in Africa outside of South Africa. In Kenya, the psyllid was parasitized by an unidentified tetrastichine (Eulophidae), probably of the genus Tamarixia, while in Ethiopia C. schini nymphs were heavily parasitized by an unidentified hymenopteran. Copyright © icipe 2013. Source

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