M. Atapour - Department of Plant Production and Sustainable Agriculture. Institute of Agriculture, Iranian Research Organization for Science and Technology (IROST), P. O. Box: ۳۳۵۳۵۱۱۱, Tehran, Islamic Republic of Iran.
Sh. Osouli - Depratment of Plant Protection, Nuclear Agriculture Research School, Nuclear Science and Technology Research Institute. Karaj, Islamic Republic of Iran.

The European corn borer Ostrinia nubilalis (Hübner), as a worldwide corn pest, causes serious damages. In the present study, some biological aspects of O. nubilalis were investigated on three different host plants including corn stalks, potato, and soybean stems, and a specific semi-artificial diet. Once appropriate host was selected, developmental rates of eggs, larval and pupal stages as well as moth emergence, longevity, and female fecundity were determined at four constant temperatures (۲۰, ۲۴, ۲۸, and ۳۲±۱°C). The relationship between temperature and developmental rate was estimated with two linear models under laboratory condition (۷۰-۸۰% RH and a photoperiod of ۱۶L:۸D hour). Results showed significant differences between studied foods, such that corn stalk sections and semi-artificial diet were appropriate host for O. nubilalis compared to the other two hosts. It was also revealed that optimum temperature for growth of this pest was ۲۸°C. Lower developmental threshold estimated by traditional and Ikemoto-Takai linear models for whole immature stages were about ۹ and ۱۰°C, and thermal constants were ۴۷۳ and ۴۳۱ degree day (DD), respectively. Compared to previous studies, these values were similar in the immature stages, except for the larval stage, which could indicate the importance of nutrition and role of the plant host in temperature requirements.

Corn pest, Host plant, Artificial diet, Temperature requirements, Linear models.