| Abstrakt: |
The alfalfa longhorn beetle Plagionotus floralis Pall. is a widespread alfalfa pest in Europe and the Middle East. In Bulgaria it is found in the whole country. The observations were made during the period 2010-2015 at the experimental field of IASS “Obraztsov Chiflik” - Rousse. A variation was determined at different levels of early onset and duration of development of the different phases of alfalfa longhorn beetle for 2010 - 2015, depending on the weather conditions during the years of the study. The beginning of the pupa phase, for the period mentioned, was found in the first and second decade of May; the beginning of imago phase – from the third decade of May to the end of the second decade June; the laying eggs period – from the second ten days of June to the end of the first decade July; the hatching of larvae – from the third decade of June to the end of the second decade of July. The average daily temperatures for the periods of occurrence of the different phases and for the previous ten-day periods are reliable criterion to predict their beginning of appearance. The beginning of imago phase of alfalfa longhorn beetle, target of the chemical control, can be expected in the last ten days of May, first or second ten days of June, when the average daily temperatures for these and previous tenday periods are around and above 19оС. [ABSTRACT FROM AUTHOR] |
