D. S. PETKOVA and E. D. ZHEKOVA
The Institute of Agriculture and Seed Science “Obraztsov Chiflik”, BG-7007 Rousse, Bulgaria
PETKOVA, D. S. and E. D. ZHEKOVA, 2012. Forage and seed productivity in alfalfa, attacked by Plagionotusfloralis Pall. (Coleoptera: Cerambycidae). Bulg. J. Agric. Sci., 18: 708-712
During the period 2007 – 2010 at IASS “Obraztsov Chiflik”, Rousse forage and seed productivity of 21 genotypes alfalfa varieties, lines and hybrids in two competitive variety trials and nine genotypes – free populations, lines, crosses and hybrids in polycross field was examined. The objective of the study was the degree of damages caused by larva of Lucerne longhorn beetle (Plagionotus floralis Pall.) to be determined also and its influence on forage and seed productivity of alfalfa varieties, lines and hybrids. Several economic traits and persistence of alfalfa genotypes were determined. At the end of the vegetation of the forth year for competitive variety trials and third year for polycross field eight variants of both competitive variety trials and nine variants of polycross field were removed and examined for damages caused by Lucerne longhorn beetle. It was registered that hybrid L – 114 showed the highest dry matter yield and seed yield, as the difference was very well proven. Alfalfa hybrids with the highest forage and seed productivity were the least attacked by Lucerne longhorn beetle. Infestation of Lucerne longhorn beetle was less in alfalfa stands with merged surface, compared with individual plants, located according to the scheme of polycross field (70 x 70 cm). For the first time eight live larvae were found in an alfalfa plant.