THE OCCURRENCE OF SIPHA (RUNGSIA) ELEGANS DEL GUERCIO ON AEGILOPS ANDPRIMITIVE TRITICUM SPECIES

The occurence of Sipha (Rungsia) elegans is recorded in 11 Aegilops sp ecies and in two wild Triticum species grown on an experimental plot i n Praha-Ruzyne in 1993-1995. Abundance of S. elegans varied in various years, and the infestation of species tested also differed. The highe st aphid number, 0.91 individuals per tiller, was recorded in 1995 at the latest date of counting. In 1994, at the earliest counting date, t he lowest aphid number was recorded, i.e. 0.14 individuals per tiller. The highest proportion of S. elegans, 42-48% of its total number on p lants, was recorded in wild einkorn T. boeoticum. In all years Ae, cyl indrica, Ae. tauschii and Ae. triuncialis were more infested than othe r Aegilops spp. tested. The aphid number on remaining eight Aegilops s pp. were either low or varied in particular years. A certain aphid num ber was observed on spring wheat plants in isolation strip in all thre e years. On both Aegilops and wheat plants S. elegans preferred the up per surface of the flag leaf tips where it caused clear-cut yellow pat ches.