Der Verlauf der Progradation der Getreidelaus (Macrosiphum avenae (Fabricius)) im Winterweizen und die Möglichkeit der kurzfristigen Befallsvorhersage.

Abstract

In the years from 1969 to 1978 the dynamics of abundance of Macrosiphum avenae (Fabricius) and the devolement of gradations were studied on large fields of winther wheat in the district of Halle. The course of the progradation shows a high degree of regularity in its phasing and in its relation to the stages of devolement of the wheat plant. Of special interest with regard to a short-term forecasting of attacks are the quantitative aspects of the course of the progradation. Between the start of heading, the beginning and the end of the flowering one the one side and the maximum abundance on the other side the populations increased on the average of the years by 207,5 and 28,1 and 4,0 respectively. The actual values differed according to the specific ecological conditions of the season. The knowledge of the mass changes of Macrosiphum avenae (Fabricius) made it possible to develop a system of surveillance and to establish hresholds for control.