Changes in the distribution of lepidopteran maize stemborers in Kenya from the 1950s to 1990s

Annales de la Société entomologique de France (N.S.)

Dupas

et al. 2006

Abstract. 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 s...

Section: Discussionsupporting

confidence: 88%

mentioning

confidence: 99%

Distribution, pest status and agro-climatic preferences of lepidopteran stem borers of maize in Kenya

Annales de la Société entomologique de France (N.S.)

Dupas

et al. 2006

“…Th is fi ndings support earlier reports on variations in the distribution of Busseola fusca and Chilo partellus according to altitude (Seshu Reddy 1983;Songa et al 1998;Guofa et al 2002). Th e diff erence Nye (1960) ascribed to climatic variations especially the temperature.…”

Section: Discussionsupporting

confidence: 88%

“…George O. Ong'amo (1) , Bruno P. Le Rü (1) (Schulthess et al 1997;Overholt et al 2001;Guofa et al 2002). In East and Southern Africa, Chilo partellus (Swinhoe 1884) and Busseola fusca (Fuller 1901) are the most important species while Eldana saccharina Walker 1865 and Sesamia calamistis Hampson 1910 constitute the minor species (Seshu Reddy 1998;Kfi r 1997).…”

mentioning

confidence: 99%

The role of wild host plants in the abundance of lepidopteran stem borers along altitudinal gradient in Kenya

Annales de la Société entomologique de France (N.S.)

Dupas

et al. 2006

Abstract. Presence of wild host plants of stem borers in cereal-growing areas has been considered as reservoirs of lepidopteran stem borers, responsible for attack of crops during the growing season. Surveys to catalogue hosts and borers as well as to assess the abundance of the hosts were carried out during the cropping and non-cropping seasons in different agro-ecological zones along varying altitude gradient in Kenya. A total of 61 stem borer species belonging to families Noctuidae (25), Crambidae (14), Pyralidae (9), Tortricidae (11) and Cossidae (2) were recovered from 42 wild plant species. Two noctuids, Busseola fusca (Fuller), Sesamia calamistis Hampson, and two crambids, Chilo partellus (Swinhoe) and Chilo orichalcociliellus (Strand) were the four main borer species found associated with maize plants. In the wild, B. fusca was recovered from a limited number of host plant species and among them were Sorghum arundinaceum (Desvaux) Stapf, Setaria megaphylla (Steudel) T. Durand & Schinz, Arundo donax L. and Pennisetum purpureum Schumacher. In contrast, the host range of C. partellus was considerably wider [13 for S. calamistis]. However, the number of larvae of these species was lower in the wild compared to cultivated fi elds, thus the role of natural habitat as a reservoir for cereal stem borers requires further studies. Importance of the wild host plants as well as borer diversity along the altitudinal gradient is discussed.Résumé. Le rôle des plantes hôtes sauvages dans l'abondance des lépidoptères foreurs de graminées selon un gradient altitudinal au Kenya. La présence de plantes hôtes sauvages de foreurs autour des parcelles cultivées a toujours été considérée comme préjudiciable à la production des céréales dans la mesure où elles constituent des réservoirs pour les foreurs. Des enquêtes ont été menées au Kenya, pendant et en dehors des périodes culturales, selon un gradient altitudinal, afi n de déterminer le rôle de ces plantes hôtes sur les populations de ravageurs. Soixante et une espèces de lépidoptères foreurs appartenant aux familles des Noctuidae (25), Crambidae (14), Pyralidae (9), Tortricidae (11) et Cossidae (2) ont été récoltées sur 42 plantes hôtes sauvages. Les principales espèces de foreurs associées au maïs sont Busseola fusca (Fuller) et Sesamia calamistis Hampson (Noctuidae) et Chilo partellus (Swinhoe) et Chilo orichalcociliellus (Strand) (Crambidae). Dans les habitats sauvages, B. fusca a été trouvé sur un nombre restreint de plantes hôtes sauvages telles que Sorghum arundinaceum (Desvaux) Stapf, Setaria megaphylla (Steudel) T. Durand & Schinz, Arundo donax L. and Pennisetum purpureum Schumacher. A l`inverse, S. calamistis et C. partellus ont été trouvées associées à plus de plantes hôtes sauvages [S. calamistis (13), C. partellus (5)]. Toutefois, le nombre total de chenilles de ces quatre espèces de ravageur trouvé dans les habitats sauvages est très inférieur à celui trouvé dans les parcelles cultivées, aussi le rôle des habitats sauvages en tant que réservoir pour les lépidopt...

“…Institut de Recherche pour le Développement / International Centre of Insect Physiology and Ecology (IRD/ICIPE), Nairobi, (Kenya) (2) Institut de Recherche pour le Développement (IRD), CNRS, Laboratoire Evolution, Génomes et Spéciation, Gif-sur-Yvette cedex (France) (3) Jomo Kenyatta University of Agriculture and Technology (JKUAT), Nairobi, (Kenya) I n East Africa, Busseola fusca (Fuller, 1901) (Noctuidae) and Chilo partellus (Swinhoe, 1884) (Crambidae) are the most important insect pests in the crop fi elds (Seshu Reddy 1983;Guofa et al 2002). B. fusca dominates high altitude areas whereas C. partellus is well established in low and mid altitude areas (Seshu Reddy, 1983).…”

mentioning

confidence: 99%

Diversity and abundance of wild host plants of lepidopteran stem borers in two different agroecological zones of Kenya

Otieno

Annales de la Société entomologique de France (N.S.)

et al. 2006

Abstract.A survey was carried out between 2004 and 2005 in two ecologically different locations, Kakamega and Muhaka to assess diversity and abundance of wild host plants of lepidopteran stem borers as compared to maize plots during the cropping and non-cropping seasons. Kakamega in Western Kenya is characterized by a Guineo-Congolian rain forest mosaic and Muhaka at the Kenyan coast by a Zanzibar Inhambane mosaic with secondary grassy and woody vegetation. In Kakamega, wild host plants and maize covered 2 and 43% of the surveyed area. No variation in diversity and relative abundance of wild host plants was observed between both the cropping and non-cropping seasons. In Muhaka, the diversity and relative abundance of wild host plant species differed between seasons, with the Shannon Weaver Index (H) of 1.67 and 0.95 for cropping and non-cropping seasons, respectively. Similarly in this location, wild host plant cover varied between cropping (23%) and noncropping (17.9%). During both seasons, this was higher than the maize cover, with 10.7% and 0% for the cropping and non-cropping seasons, respectively. For both localities, the implication of the differences found in the abundance and diversity between the cropping and non-cropping seasons is discussed.