Species diversity of nematode communites of the rapeseed (Brassica napus) and their economic importance in the Republic of Moldova

Abstract

Species and trophic composition of nematode communities of the rapeseed (Brassica napus), their abundance and distribution have been studied in eight administrative regions of the Republic of Moldova. Forty two species of free-living and plant parasitic nematodes with density 730 - 1,350 ind./100 g soil were revealed in rapeseed fields. Plant parasitic species were predominant (37 - 58%) followed by bacterivores (15 - 30%), omnivore-carnivores (11 - 27%) and fungivores (8 - 15%). Among plant parasitic species with pathogenic effects there were identified the endoparasites Pratylenchus pratensis, P. penetrans, P. thornei, Ditylenchus dipsaci, migratory ectoparasites Rotylenchus robustus, Helicotylenchus dihystera, H. multicinctus and the sedentary ectoparasite Paratylenchus hamatus. Most bacterivores were represented by species from the families Cephalobidae, Panagrolaimidae and fungivores – families Aphelenchidae, Aphelenchoididae. Maturity index values were varied 2.2 - 3.02 due to the predominance cp2 bacterivores, fungivores, plant parasites and partly cp 4, 5 omnivores - carnivores.