Detection and molecular identification of some plant parasitic nematodes associated with ornamental plants from Jimma, Ethiopia Molecular identification of some plant parasitic nematodes

Abstract

There has been a concerning presence of phytoparasitic nematodes on annual and biennial ornamental plants at Jimma University's agriculture campus. Rhizosphere soil samples were collected to elucidate the presence of plant parasitic nematodes associated with ornamental plants. The samples were collected from three locations of eleven different ornamental species, including Agapanthus africanus, Canna generalis, Cuphea ignea, Dahlia hybrids, Dianthus barbatus, Gerbera jamesonii, Impatiens balsamina, Impatiens hybrids, Pelargonium spp., Tagetes erecta and Zinnia elegans. Nematodes were extracted from 100 ml aliquot soil using the modified Baermann tray method. The study identified ten genera of plant parasitic nematodes, including Helicotylenchus, Hemicycliophora, Hoplotylus, Meloidogyne, Mesocriconema, Paratylenchus, Paratrichodorus, Scutellonema, Telotylenchus, and Trichodorus. Helicotylenchus was the most dominant genus with a mean population density of 126 individuals/100 ml soil, a frequency of occurrence (FO) of 64%, and a prominence value (PV) of 101 among all sampled ornamental plant species. Meloidogyne and Scutellonema followed with mean population densities of 129 and 70 individuals/100 ml soil, FOs of 48% and 39%, and PV of 89 and 44, respectively. The least important genera were Paratylenchus and Trichodorus, with an FO of 3% and mean nematode population densities of 10 and 17 individuals/100 ml soils, respectively. Molecular identification based on 18S small subunit (SSU) ribosomal DNA (rDNA) gene sequences revealed the species identity of Scutellonema bradys, Hemicycliophora conida and Telotylenchus ventralis. This study provides valuable information on nematodes associated with ornamental plant species vital for developing management plans in future landscape maintenance.