| Summary: | 碩士 === 國立臺灣大學 === 昆蟲學研究所 === 94 === Phenacoccus madeirensis Green (Hemiptera: Pseudococcidae) is a newly invaded pest in Taiwan. Now it has been found in Yilan, Taipei, Taichung, Nantou, Changhua, Chiayi, Tainan and Pingtung. P. madeirensis has wide host range, including 57 species belonging to 19 families in Taiwan. Knowledge of the life cycle of P. madeirensis is essential to the success of its management program. The thesis investigated the effects of constant temperature (15, 20, 25, 28, 30, 32 and 35℃), with 70% RH and 12L: 12D photoperiod, on the development, survival, and reproduction of P. madeirensis on three representative host plants, namely tomato (Lycopersicon esculentum, Solanaceae), mung bean (Phaseolus radiatus, Fabaceae), and hairy beggarticks (Bidens pilosa, Asteraceae). P. madeirensis which reared on tomato at 15 and 35℃ and on mung bean and hairy beggarticks at 35℃ could not successfully complete the life cycle. The mealybug had the fastest development of all stages on three host plants at 30℃. The total duration of development of female mealybugs on tomato, mung bean and hairy beggarticks was about 25, 19 and 20 days, respectively. Males took about 3-7 days longer to develop than females. Developmental threshold (α,℃) from egg to adult on three host plants was 15.6, 19.1 and 18.0℃ for males, and 13.8, 16.6 and 17.4℃ for females, respectively. Adult males required a cumulated effective temperature (K, day-℃) of 399, 425 and 400 day-℃, respectively, while females 477, 411 and 404 day-℃, respectively. Cumulative mortality of the mealybug on tomato at 15 and 35℃ were 100%, on mung bean and hairy beggarticks at 15℃ was 100%, too. The lowest mortality on the three host plants were at 28℃, 25∼30℃ and 25∼30℃, respectively. The mean longevity of P. madeirensis decreased with increasing temperature. The highest fecundity was 67 eggs on tomato at 30℃, 493 eggs on mung bean at 28℃ and 141 eggs on hairy beggarticks at 25℃. Empty ovisac occurred at 28 and 32℃ on tomato, 32℃ on mung bean, and 30 and 32℃ on hairy beggarticks. The highest net reproductive rate (R0) on tomato was at 30℃, on mung bean at 28℃, and 25℃ on hairy beggarticks. The highest intrinsic rate of natural increase (rm ) was 0.0282, 0.0679 and 0.0229 respectively on tomato and mung bean at 30℃ and on hairy beggarticks at 25℃. Accordingly, the shortest doubling time (Dt) respectively on tomato and mung bean was 24.6 and 10.2 days at 30℃, and 30.3 days on hairy beggarticks at 25℃. The shortest mean generation time (T) was 28, 25 and 25 days at 30℃ on three plants, respectively. Thus, I concluded that the optimal range of temperature for P. madeirensis population growth was 25~30℃, and mung bean was the most suitable host plant among the three plants tested. But maybe hairy beggarticks was the most important host plant during the year.
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