Selected Demographic Data of the Bird Cherry-Oat Aphid, Rhopalosiphum padi L. on Corn, Zea mays L. at Different Temperatures

The bird cherry-oat aphid, Rhopalosiphum padi (L.) (Hemiptera: Aphididae), is a serious pest of Poaceae plants, especially wheat and corn, in the world and in Iran. In this study, the demographic parameters of R. padi were determined at seven constant temperatures (۸.۵, ۱۵, ۲۰, ۲۵, ۲۷.۵, ۲۹ and ۳۱±۰.۵ °C), ۶۵±۵% RH, and ۱۴:۱۰ (L: D) photoperiods on Zea mays L., KSC۷۰۴ cultivar. The total lifespan, from birth to death, decreased with increasing the temperature from ۸.۵ to ۲۹ °C, but the nymphal stage duration increased a little at ۲۹ °C. The highest value of life expectancy (ex) was observed at ۸.۵ °C and at ۳۱ °C, the nymphs died before reaching the adult phase. The percentage of survival for nymphal stages was highest at ۱۵ and ۲۵ °C, and the net reproductive rate (R۰=۲۳.۶۷۱ female/generation) had the highest value at ۱۵ °C. The intrinsic rate of increase (rm) and the finite rates of increase (λ) increased at the temperature interval of ۸.۵ to ۲۵ °C. At this range, the doubling time (DT) and the mean generation time (T) decreased as the temperature increased. According to the highest value of rm (۰.۲۲ day-۱) and λ (۱.۱۳۴day-۱) and also the lower value of T (۹.۰۹۵ d) and DT (۲.۱۶ d), the temperature of ۲۵ °C was determined as the optimal temperature and the data showed that the proper temperature range for growth and reproduction of this aphid was between ۱۵-۲۵ °C. The effect of temperature on reproduction, especially the intrinsic rate of increase (rm), of R. padi would be useful for predicting its long-term population fluctuation over several generations and establishing integrated pest management (IPM) strategies against this pest.

Keywords:

Intrinsic rate of increase , Life table , Reproductive rate , Poaceae family , Insect pests. , نرخ ذاتی افزایش جمعیت , جدول زندگی , شته یولاف , دما , ذرت