VOLATILE LEAF OIL CONSTITUENTS OF OCIMUM AMERICANUM L. OCCURING IN WESTERN KENYA

Steam distilled volatile oils from the leaves of Ocimum americanum L. growing in Western Kenya were analysed by GC and GC-MS. A total of 36 compounds, representing a total of 88.51% of the total oil, were identified. The oil was classified as terpinen-4-ol-type according to the terpinen-4-ol content (43.21%). To the best of our knowledge this chemotype of O. americanum has not yet been reported from the East African region. This chemotype of O. americanum has only been reported from Togo. Other notable components include 1,8-cineole (16.13%), α-terpineol (4.01%), trans-caryophyllene (3.06%), α-bergamotene (2.68%) and cis-sabinene hydrate (2.59%). The oil contains mainly oxygenated monoterpenes which accounted for 71.24% of the total oil. The yield obtained was 4% w/w on a dry weight basis. KEY WORDS: Ocimum americanum, Lamiaceae, Chemotype, Terpinen-4-ol, 1,8-Cineole, µ-Terpineol, trans-Caryophyllene, Kenya Bull. Chem. Soc. Ethiop. 2006, 20(1), 177-180

Factors determining the use of botanical insect pest control methods by small-holder farmers in the Lake Victoria basin, Kenya

A farm survey was conducted in three representative administrative districts of the Lake Victoria Basin (LVB), Kenya to document farmers’ indigenous knowledge and the factors that influence the use of botanicals instead of synthetic insecticides in insect pest management. A total of 65 farm households were randomly sampled using stratified sampling procedure. The maximum likelihood log model was used to determine factors that influence use of botanical and synthetic insect pest control methods (PCM). Results revealed that female gender as household head (HH) and age significantly (P < .001) increased the likelihood of a household using botanical PCM in the field by 0.15 and 0.021, respectively. In storage, female gender and severity of pest infestation significantly (P < .001) increased the probability of a household using botanical insecticide by 0.814 and 0.738, respectively. On the contrary, education of HH (0.342) and ownership of title to land (0.512) significantly (P < .001) reduced the likelihood of using botanical PCM in the field, while traditional rank (0.910) and cash rank (0.744) of the crops reduced the likelihood of using botanical insecticides in the store. With respect to synthetic pesticides, gender (3.407), area cultivated (0.295) and expected yield (5.315) significantly (P < .001) reduced likelihood of their use in the field, while food rank (3.967) reduced the probability of use in storage. In storage, female gender, crop type, food and traditional rank of crops were also the most important factors determining the use of botanical control methods. In conclusion, the study established that female gender, literacy levels, wealth endowments in form of land and old age are key determinants of botanical insecticides use in small-holder farming systems in the LVB, Kenya. It is recommended that the Government of Kenya enacts policies that empower youth and female gender economically in subsistence farming with the aim of improving their educational levels and farming skills to modernize agriculture among the rural communities.Key words: Botanical, Synthetic pesticide, Insects, Pest control method, Determinants, Small-holder farmers

Indigenous knowledge of field insect pests and their management around lake Victoria basin in Uganda

Food security and poverty alleviation has remained the primary agenda in the Eastern Africa regional food policies, and Uganda is no exception. Field pests that attack crops are among the greatest threat to increased food production. The subsistence farmers in the Lake Victoria Basin (LVB) rarely use synthetic pesticides in the field due to the high cost and availability issues. Therefore, some rely on the use of botanical pesticides and other natural methods of pest control. However, this indigenous knowledge (IK) on botanicals has remained largely unexploited with limited regional research and resources committed and these are the premises upon which this ethnobotanical fieldpests management survey was launched and conducted. Most of the respondents were women (59%). The study findings revealed that the major field pests reported by farmers in declining order of importance, included banana weevil, bean fly, cereal stem borers, pod feeders, grain moth, rodents, moths, termites, birds, aphids and cutworms. The anti-pest plants documented included, Capsicum frutescens, Tagetes spp, Nicotiana tabacum, Cypressus spp., Tephrosia vogelii, Azadirachta indica, Musa spp, Moringa oleifera, Tithonia diversifolia, Lantana camara, Phytollacca dodecandra, Vernonia amygdalina, Aloe spp., Eucalyptus spp., Cannabis sativa, Cofea species and Carica papaya. The study has demonstrated that usage of botanical pesticides in field pest management is normal around Lake Victoria basin for the subsistence farmers since all the 117 respondents had ever tried or used botanical pesticides. We recommend more specialized studies in the usage of the plant-based pesticides to ensure safety and effectiveness that will enhance food security and environment protection. In addition, appropriate recommendations generated on the issues investigated will be advanced as leads for further research, extension and regional industrial endeavors in the LVB.Key words: Indigenous knowledge, field pests, pesticide plants, Uganda, Lake Victoria Basin

EVALUATION OF POPULAR CASSAVA VARIETIES FOR YIELD AND CYANIDE CONTENT UNDER ASAL CONDITIONS IN KENYA

Cassava ( Manihot esculenta Crantz) is a staple food crop grown by smallholder farmers in the marginal regions of western, coastal and eastern Kenya. The objective of this study was to evaluate popular cassava varieties for yield and cyanide content in the arid and semi-arid regions of Kenya. The study was carried out at five sites located in three sub-counties of Nakuru county in Kenya. Treatments included a collection of 27 sweet cassava varieties obtained from Western Kenya. Results revealed significant variations among varieties in all sites, for all parameters measured. The highest yields were obtained at Subukia, with the variety MM99/0067 yielding up to 200 t ha-1. Cyanide content varied significant among the varieties and sites; and was high in most of the cultivars, with highest levels recorded in variety Rao Onyoni (17.3 mg100 g-1) grown at the Lare site. The highest dry matter content was recorded in variety Selele rabuor (60.5%), at the Solai III site. Participating farmers ranked the materials based on yield, taste and order of general preference as follows: Subukia site (MM96/0067, NyaTanga, Adhiambo Lera, KME-1 and MH95/0183); Lare site (Nyar AICAD, Nyar Maseno, NyaTanga, and MM96/2480); and Solai site (KME-1, Nyar AICAD, Adhiambo Lera, Karembo, and Obaro dak).Le manioc ( Manihot esculenta Crantz) est une culture vivri\ue8re de base cultiv\ue9e par les petits agriculteurs dans les r\ue9gions marginales de l\u2019Ouest, de Littoral et de l\u2018Est du Kenya. L\u2019objectif de cette \ue9tude \ue9tait d\u2019\ue9valuer les vari\ue9t\ue9s de manioc populaires pour le rendement et la teneur en cyanure dans les r\ue9gions arides et semi-arides du Kenya. L\u2019\ue9tude a \ue9t\ue9 r\ue9alis\ue9e sur cinq sites situ\ue9s dans trois sub-counties de Nakuru county in Kenya au Kenya. Les traitements comprenaient une collection de 27 vari\ue9t\ue9s de manioc sucr\ue9 obtenues dans l\u2019Ouest du Kenya. Les r\ue9sultats ont r\ue9v\ue9l\ue9 des variations importantes entre les vari\ue9t\ue9s dans tous les sites, pour tous les param\ue8tres mesur\ue9s. Les rendements les plus \ue9lev\ue9s ont \ue9t\ue9 obtenus \ue0 Subukia, la vari\ue9t\ue9 MM99 / 0067 produisant jusqu\u2019\ue0 200 t ha-1. La teneur en cyanure variait consid\ue9rablement selon les vari\ue9t\ue9s et les sites; et il \ue9tait \ue9lev\ue9 dans la plupart des cultivars, avec des niveaux plus \ue9lev\ue9s enregistr\ue9s dans la vari\ue9t\ue9 Rao Onyoni (17,3 mg 100 g-1) cultiv\ue9e sur le site de Lare. La teneur en mati\ue8re s\ue8che la plus \ue9lev\ue9e a \ue9t\ue9 enregistr\ue9e chez la vari\ue9t\ue9 Selele rabuor (60,5%), sur le site de Solai III. Les agriculteurs participants ont class\ue9 les mat\ue9riaux en fonction du rendement, du go\ufbt et de l\u2019ordre de pr\ue9f\ue9rence g\ue9n\ue9rale comme suit: Site de Subukia (MM96 / 0067, NyaTanga, Adhiambo Lera, KME-1 et MH95 / 0183); Site Lare (Nyar AICAD, Nyar Maseno, NyaTanga et MM96 / 2480); et le site de Solai (KME-1, Nyar AICAD, Adhiambo Lera, Karembo et Obaro dak)

Comparison of toxic and repellent effects of Lantana camara L. with Tephrosia vogelii hook and a synthetic pesticide against Sitophilus zeamais motschulsky (Coleoptera: Curculionidae) in stored maize grain

The insecticidal and repellent properties of Lantana camara and Tephrosia vogelii were evaluated against Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae) in stored maize grain. Five treatment rates (1.0, 2.5, 5.0, 7.5 and 10.0% w/w) of each powdered plant material, an untreated control and a synthetic insecticide (Actellic Super™ 2% dust) were used to investigate treatment efficacy on mortality of the adult insect (five to eight days old), F1 progeny emergence and repellency against S. zeamais adults. After 21 days, L. camara and T. vogelii caused 82.7–90.0% and 85.0–93.7% insect mortality, respectively. The mean lethal exposure times (LT50) to achieve 50% mortality varied from five to six days (7.5–10.0% w/w) to seven to eight days (2.5–5.0% w/w) for both plants. Probit regression analysis showed a significant relationship between plant powder concentration and insect mortality. The plant powders and synthetic insecticide reduced adult F1 insects by more than 75% compared to the untreated control. Tephrosia vogelii was most repellent to S. zeamais at 7.5–10.0% (w/w), repelling 87.5% of the insects, followed by T. vogelii at 2.5% w/w and L. camara at 10% w/w which repelled 65.0 and 62.5% of insects respectively. The implications of these results are discussed in the context of smallscale farmer usage of these plants for stored product protection

<b>Volatile leaf oil constituents of <i>Ocimum americanum</i> L. occuring in Western Kenya</b>

Steam distilled volatile oils from the leaves of Ocimum americanum L. growing in Western Kenya were analysed by GC and GC-MS. A total of 36 compounds, representing a total of 88.51% of the total oil, were identified. The oil was classified as terpinen-4-ol-type according to the terpinen-4-ol content (43.21%). To the best of our knowledge this chemotype of O. americanum has not yet been reported from the East African region. This chemotype of O. americanum has only been reported from Togo. Other notable components include 1,8-cineole (16.13%), α-terpineol (4.01%), trans-caryophyllene (3.06%), α-bergamotene (2.68%) and cis-sabinene hydrate (2.59%). The oil contains mainly oxygenated monoterpenes which accounted for 71.24% of the total oil. The yield obtained was 4% w/w on a dry weight basis

The ASOS Surgical Risk Calculator: development and validation of a tool for identifying African surgical patients at risk of severe postoperative complications

Background: The African Surgical Outcomes Study (ASOS) showed that surgical patients in Africa have a mortality twice the global average. Existing risk assessment tools are not valid for use in this population because the pattern of risk for poor outcomes differs from high-income countries. The objective of this study was to derive and validate a simple, preoperative risk stratification tool to identify African surgical patients at risk for in-hospital postoperative mortality and severe complications. Methods: ASOS was a 7-day prospective cohort study of adult patients undergoing surgery in Africa. The ASOS Surgical Risk Calculator was constructed with a multivariable logistic regression model for the outcome of in-hospital mortality and severe postoperative complications. The following preoperative risk factors were entered into the model; age, sex, smoking status, ASA physical status, preoperative chronic comorbid conditions, indication for surgery, urgency, severity, and type of surgery. Results: The model was derived from 8799 patients from 168 African hospitals. The composite outcome of severe postoperative complications and death occurred in 423/8799 (4.8%) patients. The ASOS Surgical Risk Calculator includes the following risk factors: age, ASA physical status, indication for surgery, urgency, severity, and type of surgery. The model showed good discrimination with an area under the receiver operating characteristic curve of 0.805 and good calibration with c-statistic corrected for optimism of 0.784. Conclusions: This simple preoperative risk calculator could be used to identify high-risk surgical patients in African hospitals and facilitate increased postoperative surveillance. © 2018 British Journal of Anaesthesia. Published by Elsevier Ltd. All rights reserved.Medical Research Council of South Africa gran