Full Length Research Paper

Resistance of maize varieties to the maize weevil Sitophilus zeamais (Motsch.) (Coleoptera: Curculionidae)

Fikremariam Abebe¹, Tadele Tefera²*, Stephen Mugo², Yoseph Beyene² and Stefan Vidal³

¹Ministry of Agriculture and Rural Development, Plant Regulatory Department, Addis Ababa, Ethiopia.

²International Maize and Wheat Improvement Center (CIMMYT), Nairobi, Kenya.

³Georg-August-Universität Göttingen, Department of Crop Science, Agricultural Entomology Section, Grisebachstraβe 6, D-37077 Göttingen, Germany.

*Corresponding author. E-mail: t.tefera@cgiar.org.

Accepted 7 September, 2009

   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.