Ökologische Untersuchungen an Aphiden. II. Über die Fortpflanzungspotenz von Myzus persicae (Sulzer) und Aphis nasturtii (Kaltenbach) auf Kartoffeln (Homoptera: Aphididae).

Abstract

The propagative power of Myzus persicae (Sulzer) and Aphis nasturtii (Kaltenbach) on potatoes was tested with constant temperatures of 20, 23 and 25 degrees and changing temperatures of 20/30, 20/33, 20/35 degrees in temperature-keeping cabins. The high temperatures were used for three hours a day (from 11 a. m. to 2 p. m.). The evaluation followed the population analysis according to Birch (1948). Aphis nasturtii had the highest rate of increase at changing temperatures of 20/30 and 20/33 degrees (k = 0.33). It reacts promptly to changes of temperature and may be called heat-loving but temperature-sensitive. Myzus persicae tolerates temperatures better than Aphis nasturtii. The potato was a better host for Aphis nasturtii than for Myzus persicae. To facilitate international comparisons ot the results of such tests, they should be based on a suitable population analysis. For virginoparous aphids the determination of the growth factor "k" (or "r" according to Birch 1948) is recommended.