Survey and Identification of Phytonematodes and Their Fungal Antagonists Associated with Soybean in Different Ecological Locations of Egypt

Abstract

Survey and identification of plant-parasitic nematodes and their fungal antagonists associated with soybean in six locations at four governorates of Egypt i.e. Beni-Suef, Menia, Beheira and Alexandria were conducted during the summer growing season of 2020 year. Results indicated the presence of ten phytonematodes, these were Helicotylenchus, Heterodera, Hoplolaimus, Longidorus, Meloidogyne, Pratylenchus, Rotylenchulus, Trichodorus, Tylenchorhynchus and Xiphenema. The stunt nematodes (Tylenchorhynchus spp.) was the most frequent (50.4%) followed by the root-knot nematodes (Meloidogyne  spp.) with 15.6% frequency, the root-lesion nematodes (Pratylenchus spp.) with 12.0% and the spiral nematodes (Helicotylenchus spp.) with 8.4% frequency. Other nematodes were less frequent. Results also revealed the occurrence of three root-knot nematode species infecting soybean; Meloidogyne incognita, M. javanica and M. arenaria. M. incognita was the most prevalent species with 48.8% frequency followed by M. javanica (37.5%) and M. arenaria (13.7%). Also four nematophagous fungi were isolated from the rhizaosphere of soybean, three of them are predacious fungi; Arthrobotrys conoides, Dactelaria brochopaga, Monacrosporium sp. and one is endoparasitic, Verticillium sp. A. conoides and D. brochopaga were more frequent with 80% and 60% frequency, respectively followed by Verticillium sp. (40%) and Monacrosporium sp. (20%).