18. Species complex and population dynamics of weevils of the genus sitona on the multifoliolate alfalfa (Medicago sativa L.) in the region of Pazardzhik

The study was carried out in 2006-2008 on a multifoliolate alfalfa field (3 ha – “Multifoliolate 1”) belonging to the Complex Experimental Station, Pazardzhik. The species Sitona hispidulus (Fabr.), S. humeralis Steph., S. longulus Gyll., S. lineatus L., S. puncticollis Steph., S. callosus Gyll. and S. macularius (Marsh.) were found in sweep net samplings. The dominant species was S. humeralis with 51% of weevil population. We found that the adults of S. puncticollis and S. longulus appeared on the alfalfa field at the beginning of April, which is a month earlier than reported until now.