Abstract
This study aimed at evaluating commonly used maize varieties, collected from Melkasa and Bako Agricultural Research Centers and Haramaya University, Ethiopia, against the maize weevil Sitophilus zeamais Motsch., one of the most important cosmopolitan stored product pests in maize. A total of 13 improved maize varieties were screened for their relative susceptibility to S. zeamais. The Dobie index of susceptibility was used to group the varieties. The variety, ‘BHQP-542’, had the least index of susceptibility and was regarded as resistant. The varieties, ‘Katumani’, ‘Melkasa-I’, ‘Melkasa-II’, ‘Melkasa-III’, ‘Coree’, ‘BH-541’, ‘BH-660’, ‘BH-540’, ‘Rare-I’, ‘Awasa-511’, ‘ACV3’ and ‘ACV6’, were moderately resistant. Weevils fed with the resistant variety produced low numbers of F1 progeny, had a high median developmental time and a low percentage of seed damage and seed weight loss. Maize varieties with a high F1 progeny tended to have a short median developmental time. An increasing number of F1 progeny resulted in an increasing seed damage and seed weight loss. We found an inverse relationship between the susceptibility index and percent mortality and median developmental time; however, the numbers of F1 progeny, percent seed damage and seed weight loss were positively related with the susceptibility index. The use of resistant varieties should be promoted in managing S. zeamais in stored maize under subsistence farming conditions in Africa. Key words: Grain damage, maize; resistant variety, Sitophilus zeamais, susceptibility index.
Highlights
Post-harvest losses to storage insect pests such as the maize weevil Sitophilus zeamais have been recognized as an increasingly important problem in Africa (Markham et al, 1994)
We found an inverse relationship between the susceptibility index and percent mortality and median developmental time; the numbers of F1 progeny, percent seed damage and seed weight loss were positively related with the susceptibility index
In our experiments we found considerable variation among the maize varieties with respect to F1 progeny, median developmental time, seed damage, seed weight loss and the susceptibility index
Summary
Post-harvest losses to storage insect pests such as the maize weevil Sitophilus zeamais have been recognized as an increasingly important problem in Africa (Markham et al, 1994). The widespread use of insecticides for the control of stored-product insect pests is of global concern with respect to environmental hazards, insecticide resistance development, chemical residues in food, side effects on non-target organisms and the associated high costs (Cherry et al, 2005). To this effect, the increased public awareness and concern for environmental safety has directed research to the development of alternative control strategies such as the use of resistant maize varieties against S. zeamais. The main objective of this study was, to evaluate popular maize varieties from Ethiopia for
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