Estimation of maize crop losses due to stemborers, preliminary results of a national field survey in Kenya (original) (raw)
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Agriculture, Ecosystems & Environment, 1999
The effect of resource concentration on the population of stem-borers of maize in the maize-leucaena agroforestry system was evaluated. The studies covered six cropping seasons from October 1992 to August 1995, and were conducted at Mtwapa and Amoyo in coastal and western Kenya, respectively. Treatments included monocropped and intercropped (maize, leucaena) plots, weeded and unweeded plots, mulched and unmulched plots, and three spacing (1.5, 2.25 and 3.0 m) regimes for leucaena hedgerows. Maize was interplanted at the onset of the rainy season. Abundance of adult and larval/pupal stages of maize stem borers, oviposition preference, foliar damage, borer entry/exit holes, maize plant mortality and stem breakage because of borer damage were significantly greater in the maize monocrop than in the maize-leucaena intercrops. The reduced pest numbers were associated with reduced yield loss per plant, and the 3.0 m leucaena hedgerow spacing plots yielded more than the maize monocropped plots despite having 25% fewer initial maize plants. 0167-8809/99/$ -see front matter ©1999 Elsevier Science B.V. All rights reserved. PII: S 0 1 6 7 -8 8 0 9 ( 9 9 ) 0 0 0 7 7 -8
Agriculture, Forestry and Fisheries, 2015
The effects of location, maize types and borer control with carbofuran (Furadan 3G®) on the severity of maize stem borer infestation and damage was investigated in the late maize planting season of 2011. Treatments were laid out in randomized complete block design using a split-slip-plot factorial arrangement. Whole plot factor consisted of two locations (Southern Guinea Savanna and Rainforest agro-ecological zones of Nigeria), subplot factor consisted of 1.5 kg a.i.ha-1 and 0.0 kg a.i.ha-1 of carbofuran, while the sub-sub-plot factor comprised of three endosperm types of maize (flint, pop and sweet corn). Stem borer infestation (quantified by dead heart count and larval population per plant) and damage (quantified by %lodged stem, %bored internodes, %bored ears, number of exit holes, number of stem borer cavities and number of damaged seeds per plant) as well as yield were compared. Results revealed that borer infestation and damage were significantly higher (P < 0.05) in the Rainforest compared with the Savanna. Single dose application of carbofuran (1.5 kg a.i. ha-1) also significantly (P < 0.05) increased grain yield in all the maize types at both locations. For all parameters, no significant (P > 0.05) location × carbofuran × maize type and location × maize type effect was detected. However, significant (P < 0.05) location × carbofuran and carbofuran × maize type interaction effects were observed. We conclude that in both agro ecologies, flint corn was more tolerant of borer attack while sweet corn was more susceptible compared to either flint or popcorn. In addition, carbofuran at 1.5 kg a.i.ha-1 can significantly reduce stem borer population in the three maize types.
African Journal of …, 2011
technology is an effective way of controlling lepidopteran pests. However, the likelihood of development of resistance to the Bt toxins by the target stem borer species is a concern. Forages, sorghum and maize varieties were evaluated for stem borer preference and survivorship in the laboratory and field in four locations in Kenya to identify suitable species and varieties for refugia. The economics of using the different kinds of refugia was also investigated. Vegetation surveys were conducted in 15 districts of Kenya to quantify the area covered by natural refugia. The field and laboratory trials indicated highest egg production, survivorship and more exit holes in all sorghum and maize varieties and some forages. Sorghum, non-Bt Maize, and improved Napier grass varieties Kakamega 1 and Kakamega 2) should be promoted as refugia species in Kenya. Some species and cultivars were identified as cost-effective, flexible, easily adoptable and compatible with farmers' common production practices. Refugia cultivar with multiple uses is expected to give higher pay-offs than one with single use. However, for successful management of a refugia strategy, strict stewardship is required from appropriate government or community institutions.
Biological control of cereal stem borers in Kenya: A cost benefit approach
Annales de la Société Entomologique de France, 2006
Lepidopteran stem borers are the key pests of maize in Sub-Saharan Africa. In the lowland tropics, dry mid-altitude, dry transitional and the moist mid-altitude zones of Kenya, the invasive crambid Chilo partellus (Swinhoe) (Lepidoptera: Crambidae) causes up to 73% yield loss. The International Centre of Insect Physiology and Ecology (ICIPE) started a biological control (BC) program in 1991 to control stem borers in subsistence agriculture in Africa with emphasis on classical BC of C. partellus. The project released the braconid larval parasitoid Cotesia fl avipes Cameron (Hymenoptera: Braconidae) in 1993 in coastal Kenya, where it got established and spread to other regions. This study assesses the economic impact of the introduced parasitoid. Temporal data on percentage parasitism by the introduced parasitoid and on stem borer density were collected between 1995 and 2004. Socioeconomic data was collected through administration of questionnaires to 300 farmers. Economic impact of the project was calculated as the value of the yield loss abated by the parasitoid based on a model of expected stem borer density and parasitism level. Average annual parasitism increased linearly from the time of introduction to reach 20% parasitism by 2004. The net reduction in total stem borer density over the last 10 years was 33.7%, thus abating 47.3% of yield loss. The region will accumulate a net present value of US $ 183 million in economic benefi ts in 20 years since release of the parasitoid. Introduction of other parasitoid species targeting the egg and pupal stages of the stem borer life cycle stages would be required for biological control to push yield loss by stem borers to an insignifi cant level. Résumé. Contrôle biologique des foreurs des céréales au Kenya : une approche économique. Les lépidoptères foreurs de graminées sont des ravageurs importants du maïs en Afrique subsaharienne. Dans les zones de faibles et moyennes altitudes du Kenya, le foreur exotique Chilo partellus (Swinhoe) (Lepidoptera : Crambidae) a causé jusqu'à 73% de perte de rendement. Le Centre international pour l'étude de la physiologie et de l'écologie des insectes (ICIPE, son abréviation anglo-saxonne) a initié en 1991 un programme de lutte biologique classique pour lutter contre ce ravageur. Ce programme a permis la libération en 1993 d'un parasitoïde braconide, Cotesia fl avipes Cameron (Hymenoptera : Braconidae), dans la région côtière du Kenya, où il s'est établi et à partir de laquelle il a colonisé d'autres régions. Cette étude détermine l'impact économique de l'introduction de ce parasitoïde. Des données temporelles sur le pourcentage de parasitisme et sur la densité de foreurs ont été collectées entre 1995 et 2004. Les données socio-économiques ont été obtenues à l'aide d'un questionnaire diffusé auprès de 300 fermiers. L'impact économique a été calculé à partir des données de perte de rendement inférées par un modèle d'estimation de la densité de foreurs et du taux de parasitisme. Le niveau moyen de parasitisme a augmenté linéairement au cours du temps depuis l'introduction du parasitoïde pour atteindre 20% de parasitisme en 2004. La réduction nette de la densité totale de foreurs a été de 33,7% lors de cette dernière décennie, réduisant de 47,3% la perte de rendement. La région devrait accumuler un bénéfi ce net économique de 183 millions de dollars américains dans ces 20 dernières années depuis que le parasitoïde a été lâché. L'introduction d'autres espèces de parasitoïdes actives contre les oeufs et chrysalides des foreurs devrait permettre de renforcer le contrôle biologique afi n de rendre les pertes de rendement causées par les foreurs insignifi antes.
Annales de la Société entomologique de France (N.S.), 2006
Lepidopterous stem borers are the main field insect pests that attack maize, Zea mays L. in tropical Africa. A survey was carried during the long and short rain cropping seasons of 2002 / 2003 across six main agro-climatic zones (ACZs) to determine the spatial distribution of important stem borer species in Kenya. A total of 474 visits were made in the seventy-eight localities conveniently chosen to represent each of the six ACZs. 189,600 stems were checked for infestation, of which 27,799 infested stems were destructively cut and dissected for stem borer larvae identification. An average of 1.4 stem borer larvae were recovered per infested plant. 54.5% of the recovered larvae were identified as Chilo partellus (Swinhoe) (Crambidae), 39.7% as Busseola fusca (Fuller) (Noctuidae), 4.5% as Sesamia calamistis Hampson (Noctuidae) and 0.8% as Chilo orichalcociliellus (Strand) (Crambidae). Minor species present included Eldana saccharina Walker (Pyralidae), Sesamia nonagrioides (Lefebvre) (Noctuidae), Sesamia cretica Lederer (Noctuidae), Sesamia sp. (Noctuidae), Sciomesa piscator Fletcher (Noctuidae), Busseola sp near phaia (Noctuidae), Chilo sp, Ematheudes sp 1 (Pyralidae) and Ematheudes sp 2 (Pyralidae). Farms were grouped into respective ACZs for statistical analysis and subsequent comparison of dominant species. Results indicated that B. fusca was the dominant stem borer species in high potential zones (highland tropics, moist transitional zone and moist midaltitude) while the exotic C. partellus dominated smallholder farms in low potential zones (dry midaltitude, dry transional and lowland tropical zone). Within each ACZs, there was evidence of variation in species proportions between seasons. These spatio-temporal differences in community structure are discussed in terms of agro-climatic biological adaptations. Résumé. Distribution, ravages et préférences agro-climatiques des lépidoptères foreurs de tige du maïs au Kenya. Une enquête a été menée dans les 6 principales régions agro-écologiques du Kenya, pendant les longues et courtes saisons des pluies de 2002/2003, afin de déterminer la distribution spatiale des lépidoptères foreurs de graminées attaquant le maïs Zea mays L. Un total de 474 échantillonnages a été réalisé dans les 78 localités représentatives des six régions agroécologiques. On a vérifié l'infestation de 189,600 tiges et les 27799 tiges infestées ont été récoltées et disséquées afin d'identifier les foreurs. En moyenne, 1,4 larves de foreur ont été trouvées par plante infestée; 54,5% des larves récoltées étaient des Chilo partellus Swinhoe (Crambidae), 39,7% des Busseola fusca (Fuller) (Noctuidae), 4,5% des Sesamia calamistis Hampson (Noctuidae) et 0,8% des Chilo orichalcociliellus Strand (Crambidae). Des espèces peu importantes ont également été trouvées telles que Eldana saccharina Walker (Pyralidae), Sesamia nonagrioides Lefebvre (Noctuidae), Sesamia cretica Lederer (Noctuidae), Sesamia sp. (Noctuidae), Sciomesa piscator Fletcher (Noctuidae), Busseola sp near phaia (Noctuidae), Chilo sp, Ematheudes sp 1 (Pyralidae) et Ematheudes sp 2 (Pyralidae). Les localités ont été regroupées par région agro-écologique pour les analyses statistiques et la comparaison des 4 principales espèces. Les résultats indiquent que B. fusca est l'espèce dominante dans les régions à haut potentiel de production (hautes terres tropicales, zone humide de transition et zone d'altitude moyenne humide) alors que l'espèce exotique C. partellus est dominante dans les petites exploitations à faible potentiel de production (zone d'altitude moyenne sèche, zone sèche de transition et zone tropicale de basse altitude). On a pu mettre en évidence, dans chaque région agro-écologique, une variation de la proportion des différentes espèces selon la saison. On discute de ces différences spatio-temporelles de la structure des communautés en relation avec des adaptations biologiques aux conditions agro-climatiques.
Afr. J. …, 2011
Transgenic maize (Zea mays L), developed using modified genes from the bacterium Bacillus thuringiensis (Bt), controls stem borers without observable negative effects to humans, livestock or the environment, and is now sown on 134 million hectares globally. Bt maize could contribute to increasing maize production in Kenya. Nine public Bt maize events of cry1Ab and cry1Ba genes were tested in confined field trials site (CFTs) to assess the control of four major Kenyan stem borer species. Leaf damage rating, number of exit holes and tunnel length were scored in the field evaluations. Leaf area consumed and mortality rates among stem borers were scored in the leaf bioassays in a Biosafety Level II laboratory, located at the Kenya Agricultural Research Institute (KARI), National Agricultural Research Laboratories (NARL). Field evaluations showed that Bt maize controlled Chilo partellus with mean damage scores of 1.2 against 2.7 for the non-Bt CML216 control. Laboratory bioassays showed high control for Eldana saccharina and Sesamia calamistis, with mean larval mortality of 64 and 92%, respectively. However, substantial control was not observed for Busseola fusca. These results showed that Bt maize could control three of the four major stem borers in Kenya with mortality records of 52.7% for B. fusca, 62.3% for E. saccharina and 85.8% for S. calamistis. Additional Bt genes need to be sought and tested for effective stem borer control in all maize growing ecologies in Kenya.
2002
1. Africa faces serious challenges in feeding its rapidly growing human population owing to the poor productivity of maize and sorghum, the most important staple crops for millions of smallholder farmers in the continent, with yields being among the lowest in the world. 2. A complex of lepidopterous stemborers attack cereals in Africa. However, their effective control is difficult, largely as a result of the cryptic and nocturnal habits of moths, and protection provided by host stem for immature pest stages. Moreover, current control measures are uneconomical and impractical for resource-poor farmers. 3. An ecological approach, based on companion planting, known as 'push-pull', provides effective management of these pests, and involves combined use of inter-and trap cropping systems where stemborers are attracted and trapped on trap plants with added economic value ('pull'), and are driven away from the cereal crop by antagonistic intercrops ('push'). 4. Novel defence strategies inducible by stemborer oviposition have recently been discovered, leading to the attraction of egg and larval parasitoids, in locally adapted maize lines but not in elite hybrids. We also established that landscape complexity did not improve the ecosystem service of biological control, but rather provided a disservice by acting as a 'source' of stemborer pests colonising the crop. 5. Here we review and provide new data on the direct and indirect effects of the push-pull approach on stemborers and their natural enemies, including the mechanisms involved, and highlight opportunities for exploiting intrinsic plant defences and natural ecosystem services in pest management in smallholder farming systems in Africa.
2004
Maize is the staple food crop and source of income for majority of the Kenyan population and many sub-Saharan African countries. The increasing Kenyan population demands an increase in maize production if intermittent food deficits have to be averted. Since the introduction of improved maize varieties in mid-1960, the start of Green Revolution period, maize yields increased drastically up to 1970s and started declining from 1980s to-date. The key contributory factors are nutrient mining, sub-optimal input use and insect pest damage. Of the insect pests, stalk borer is of economic importance. Currently, KARI and CIMMYT are developing maize varieties that are tolerant to stalk borer damage. In order to evaluate the potential impact of these interventions economics of stalk borer control at farm level was evaluated. Surveys complemented with on-farm trials were executed in six major maize growing zones of Kenya. Farmers were randomly selected and a sample-frame established after which ...
2018
The stem borer is one of the most destructive pests of maize crop. Research experimentations were carried out on maize to control stem borer. The experiment was 2x3 factorial experiments using randomized complete block design with ten replications. A total of two maize varieties (Melkassa hybrid 130 and local varieties) and three different stem borer management packages (Control, inter-cropping with cowpea and inter-cropping with Cowpea and Sudan Grass) were used. Data was collected on Days to maturity, Plant height, Ear length, Grain yield, Biomass yield, Harvest index, Biomass production rate and Grain yield per day. The results of analysis revealed that the interaction effect of Control mechanisms of stem borer and Maize varieties was significantly (P≤0.05) affected in all agronomic traits recorded except DTM, PH, EL and HI which is not significant. While, they were significantly (P≤0.05) affected by the maize variety. Treatment combination Improved Maize Variety (MH-130) mono-cr...
2017
Working Document Series 4 This IPM series record assesses farmer's knowledge, attitudes and current pest management practices in Nakuru and Bomet counties in Kenya. The intent is to identify major pests and diseases affecting Maize production, to test and promote the appropriate technology that combat challenges in maize production and productivity in the areas. The series also ensures that recorded data and other information gathered, generated and analyzed are part of the research work of International Centre of Insect Physiology and Ecology (http://www.icipe.org). The series is reviewed internally by icipe staff. It can be freely accessible both in hard copy and electronically and cited due acknowledgement. About ICIPE icipe's mission is to help alleviate poverty, ensure food security and improve the overall health status of peoples of the tropics, by developing and extending management tools and strategies for harmful and useful arthropods, while preserving the natural resource base through research and capacity building. The Centre's vision is to pioneer global science in entomology, to improve the wellbeing and resilience of people and the environment to the challenges of a changing world, through innovative and applied research, alongside deep exploratory study, impact assessment, evaluation and sustainable capacity building.