A comparative study on infestation of three varieties of maize (Zea mays (L.) with maize weevil (Sitophilus zeamais) Motschulsky (Coleoptera: Curculionidae)

Abstract

A study was carried out to study the infestation of three maize varieties (Maize suwan I–Y, Maize T2 USR – White single cross and Maize suwan 123) by Sitophilus zeamais Motsch. Infestation was assessed by counting the numbers of alive and dead adults and the number of infested and uninfested seeds. It was found out that none of the variety was completely resistant to infestation, though infestation varied significantly among the maize varieties. More pests progeny were found in the susceptible varieties (suwan 123 with 55.8% and T2 USR – White single cross with 39.3%) while the resistant variety (Suwan has 35.3%). The size and hardness of the maize grains of the three varieties were found to be associated with resistance. Suwan I-Y, with its small size, is hardest and difficult to penetrate by Sitophilus and hence has the lowest seed infestation of 5.5%, followed by T2USR-White single cross with 50% Suwan 123, with its large size, appeared loose and soft, hence easy to penetrate. It had the highest number of seed infestation of 69.1%. The order of preference of S. zeamais was maize suwan 123, maize T2USR-white single cross and maize suwan I-Y. There was a continuous but gradual decrease in temperature and an increase in relative humidity. Infestation increased with decrease in temperature and increase in relative humidity. This should be considered during storage by tropical farmers.

Keywords: Sitophilus zeamais, maize suwan I-Y, maize T2 USR-white single cross, maize suwan 123

Global Journal of Pure and Applied Sciences Vol. 12(1) 2006: 7-9