Search

Root-lesion nematodes, Pratylenchus spp., are among the top three most significant nematode parasites of a wide range of vascular plants including several economically important crops. There are more than 100 described species. Identification at the species level is difficult due to morphological similarities and overlapping morphometric characters. This research was carried out between 2017 and 2019 with the aim of identifying Pratylenchus species associated with four crops in Costa Rica. Species of Pratylenchus were identified by their morphological features and with molecular methods. For molecular analysis, rDNA 28S expansion segments D2-D3 were amplified by PCR with D2A and D3B primers and the ITS1 region with the 18S and rDNA1 primers, which were subsequently sent for sequencing. Phylogenetic relationships between Pratylenchus species were established by Bayesian Inference, based on the sequences analyzed. Three species of Pratylenchus were detected: P. brachyurus associated with pineapple (Ananas comosus), P. coffeae with plantain (Musa paradisiaca), and P. zeae associated with rice (Oryza sativa) and star grass (Cynodon nlemfuensis). Of the three Pratylenchus species identified in this research, this is the first report of P. zeae associated with star grass in Costa Rica, however, this species had already been reported in rice in the country. [ABSTRACT FROM AUTHOR]

Plantain is one of the most important food and commercial crops in the Huetar Atlantica region of Costa Rica. Plant-parasitic nematodes (PPN) are one of the major constraints of plantain production and are therefore a threat to food security. The present study was part of an investigation that was carried out in Talamanca, Limón, Costa Rica with the objective to quantify and identify the main PPN genera associated with plantain cultivation. Nematodes were extracted from a total of 76 samples; 63 from soil and 13 from roots of plantain collected from 10 smallholder farms. In terms of absolute frequencies of distribution, the most abundant PPN genus in soil was Pratylenchus, which was detected in over 76.9% samples, followed by Helicotylenchus (69.2%), Meloidogyne and Radopholus (61.5%). In the roots, Helicotylenchus (100%), Meloidogyne (90.5%), Pratylenchus (74.6%), and Radopholus (66.7%) were the most frequently detected genera. In general, frequency and population densities of PPN were high in comparison to other similar surveys. Overall, the data suggest that PPNs could pose a serious threat to plantain production in Costa Rica and that control measures should be further developed and implemented. [ABSTRACT FROM AUTHOR]

In this study, plant-parasitic nematodes associated with blackberry plantations in Costa Rica were determined. From 2005 to 2014, 12 samples of roots and 36 samples of soil from blackberry plantations were collected in nine localities, and nematodes were extracted and identified to genus and some to species. Eighteen different genera of nematodes; plant-parasitic and other nematodes associated with roots; were identified these are: Aphelenchoides, Aphelenchus, Criconema, Criconemoides, Crossonema, Ditylenchus, Helicotylenchus, Hemicycliophora, Heterodera, Meloidogyne, Scutellonema, Pratylenchoides, Pratylenchus, Psilenchus, Trichodorus, Tylenchorhynchus, Tylenchus, and Xiphinema. Endoparasitic nematodes of importance like Meloidogyne sp. and Pratylenchus sp. were found in nine counties and three localities, respectively. The highest abundance of plant-parasitic nematodes of second-stage juveniles of Meloidogyne sp. was found in La Trinidad and San Martín. In La Luchita, Bajo Canet, Páramo, and Jardín high population densities of spiral nematodes of the genus Helicotylenchus were observed. Additionally, four species within the Criconematidae family (ring nematodes) were identified for the first time in association with blackberry in the country; these are Crossonema civellae, Criconema neopacificum, C. graminicola, and Criconemoides lizarbus. [ABSTRACT FROM AUTHOR]