Molecular phylogeny of several species of Hoplolaimina (Nematoda: Tylenchida) associated with turfgrass in Korea, with comments on their morphology

Summary Seven species belonging to Suborder Hoplolaimina are characterised using integrative taxonomy, considering both morphological and molecular phylogenetic analyses of the 28S-rRNA, ITS-rRNA and COI gene sequences. It is evident that, as more populations of Pratylenchus zeae are continuously characterised, the species continues to display an ever-increasing intraspecific genetic variation within the 28S-rRNA and ITS-rRNA genes. However, the COI gene sequences exhibit minimum intraspecific variation and thus might be the most powerful DNA barcoding marker for the precise identification of P. zeae and should therefore be recommended as a complementary technique in the identification process of the species. Pratylenchus zeae, Meloidogyne graminicola and Heterodera pratensis are characterised herein for the first time in Korea, while the presence in Korea of P. penetrans, P. scribneri, H. avenae, and M. marylandi, is molecularly confirmed.

Diversity of plant parasitic nematodes associated with rhizosphere of maize from different areas of district Rajouri, Jammu and Kashmir, India

Diversity of plant parasitic nematodes in the rhizosphere of maize (Zea mays) from some areas of District Rajouri, Jammu and Kashmir was studied. A total of ten plant parasitic nematode species were found to be associated with the rhizosphere of maize plants in these areas. The nematode species were Pratylenchus zeae, P. brachyurus, Helicotylenchus dihystera, Longidorus brevicaudatus, L. elongatus, Xiphinema diversicadatum, X. elongatum, Tylenchorhynchus spp. Ditylenchus spp. and Criconemoides spp. The most dominant and frequently occurring species was found to be P. zeae, with absolute frequency of 86.66% followed by P. brachyurus (80%), H. dihystera, (76.66%) and L. brevicaudatus (73.33). Contrarily, the least frequent was Criconemoides spp. (36.66%) followed by Tylenchorhynchus spp. and Ditylenchus spp. with absolute frequencies of 53.33% and 60%. Similar trend was observed in case of relative frequencies. In case of P. zeae, mean density of 56 and relative density of 16.05% was observed followed by P. brachyurus and H. dihystera with mean densities and relative densities of 50.33, 14.43% and 49, 14.04% respectively. On the other hand, Criconemoides spp. and Tylenchorhynchus spp. showed mean densities of 6.33 and 23.33 and absolute densities of 1.81% and 6.68% respectively. P. zeae exhibited high prominence value of 57.85 followed by P. brachyurus (49.96). The least prominence value was found in Criconemoides spp. (4.05) followed by Tylenchorhynchus spp. with prominence value of 18.30.

Pathogenicity of the root-lesion nematode, Pratylenchus zeae, on rice genotypes under different hydro-ecologies in Tanzania

Summary The root-lesion nematode, Pratylenchus zeae, is commonly found in upland rice fields. To measure the impact of the nematode on rice production, a screenhouse experiment was conducted using two farmer-adapted Oryza sativa cultivars, ‘Supa’ (‘SurinamV-880’) and ‘SARO-5’ (‘TXD 306’), under flooded, upland and drought water regimes imposed at 7 days post-inoculation of mixed-stage nematodes (200, 500, 1000, 3000 and 10 000 plant−1). Growth and yield parameters were recorded, and the experiment was terminated after 5 months. ‘Supa’ was shown to be resistant to P. zeae, while ‘SARO-5’ was susceptible. Pratylenchus zeae reduced the growth and yield of both cultivars, though more for ‘SARO-5’ than for ‘Supa’. Yield decreased with increasing final nematode densities. Pratylenchus zeae reproduction was highest at 200 and 500 inoculum levels and under upland water conditions. The yield of ‘SARO-5’ was greater than that of ‘Supa’ under flooded conditions and with no or 200 and 500 nematode inoculum levels, but with high P. zeae inoculum ‘Supa’ yield was better than ‘SARO-5’.

REPRODUCTION OF Pratylenchus zeae AND P. brachyurus IN COVER CROPS

ABSTRACT This study aimed to evaluate the reproduction of Pratylenchus zeae and P. brachyurus in leguminous plants used as cover crops. Seedlings of sunn hemp (Crotalaria juncea and C. spectabilis), pigeon pea cultivar IPR 43 (Cajanus cajan), dwarf velvet bean (Mucuna deeringiana), black velvet bean (Stizolobium aterrimum), and jack bean (Canavalia ensiformis) were inoculated with each nematode separately. Maize cultivar IPR 114 and soybean cultivar Pintado were used as controls to measure the viability of the inoculation of P. zeae and P. brachyurus. After 90 days of inoculation, the plants were collected and nematode g-1 root, final population, and reproduction factors (RF) were evaluated. The experiment was carried out at two different times of the year. The nematode’s RF on cover crops from treatments with the two Crotalaria species, dwarf pigeon pea, and black velvet bean were lower than one (bad host plants) in both experiments for P. zeae. For P. brachyurus, the lowest RFs were obtained for C. juncea, C. spectabilis, and pigeon pea, while the other plants presented RF values close to or higher than one in at least one of the experiments. Therefore, C. spectabilis, C. juncea, and C. cajan cultivar IPR 43 are antagonistic plants that represent useful options for rotation or succession systems that aim to control P. zeae and P. brachyurus.