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Seasonal fluctuations and damage of lepidopteran stemborers of maize in a major agroecozone of Uganda Kalule, T.; Ogenga-Latigo, M.W. & Okoth, V.A.O. Abstract The distribution and damage of stemborers of maize, Chilo partellus (Swinhoe), Busseola fusca (Fuller), Eldana saccharina Walker, and Sesamia calamistis Hampson, were studied in two locations in Uganda. The species composition of the stemborers was influenced by crop phenology. Distribution of stem borer larvae in the plant was similar at both locations. At 2-3 weeks after plant emergence (WAE), 100% of larvae recovered was from the funnel of the plant with the proportion decreasing as the stem elongated. Busseola fusca and Chilo partellus were more injurious as indicated by the extent of leaf and stem injury. Sesamia calamistis predominantly attacked the maize ears. This phenological relationship of variation in stemborer incidence and damage to crop phenology is crucial in devising management strategies of the pests. Keywords Busseola fusca, Chilo partellus, Sesamia calamistis, Eldana saccharina, crop phenology, stem tunnelling, Zea mays

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Kalule, T.; Ogenga-Latigo, M.W. & Okoth, V.A.O. Résumé La distribution et les degets causes par les insectes terebrants (stemborers) des tiges du mais, Chillo partellus (Swinhoe), Busseola fusca (Fuller), Eldama Saccharina Walker, et Sesamia calamistis Hampson, ont ete etudies dans deux endroits en Ouganda. La composition specifique des insectes terebrants a ete influencee par la phenologie de la culture. La distribution des larves des insectes terebrants dans la plantes s'est revelee semblable dans les deux sites. Deux a trois semaines apres l'emergence de la plante (WAE), 100% des larves retrouvees provenaient de la cheminee de la plante avec une proportion decroissant avec l'elongation de la tige. Busseola fusca et Chilo partellus etaient plus agressives comme l'indiquaient l'etendue de la feuille et la blessure de la tige. Sesamia calamistis attaquait surtout les epis du mais. Cette relation phenologique de la variation dans l'incidence des insectes terebrants sur les tiges et les degets causee a la phenologie de la culture est cruciale dans les strategies combinees du controle des pestes. Mots Clés Busseola fusca, Chilo partellus, Sesamia calamistis, Eldama saccharina, phenologie de la culture,tunnel de la tige, Zea mays

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