Occurrence of biotic harmful agents in Czech grass seed production (1995-2004)

Abstract

In the years 1995–2004 the spectra of weeds, diseases and pests in grasses grown for seed in the Czech Republic were examined and the effect of external factors on their changes was assessed. The species spectrum of weeds evaluated both at the time of vegetation and in samples of natural seeds was stable throughout the period and the changes in the number of individual species were caused by different proportions of grass species and stand age. The most abundant weeds were <i>Elytrigia repens</i>, <i>Matricaria</i> sp.div., <i>Anthemis<i> sp.div., <i>Apera spica-venti</i>, <i>Cirsium arvense</i>, <i>Poa trivialis</i>, <i>Rumex</i> sp.div. and <i>Chenopodium</i> sp.div. The most serious diseases were parasitic silvertop, graminicolous rusts (<i>Puccinia</i> sp.div.), <i>Blumeria graminis</i> and ergot (<i>Claviceps purpurea</i>). The rate of rust occurrence was affected by climatic conditions; the spectrum of other diseases was stable throughout this period. The most important animal pests were <i>Muridae</i> rodents.