scholarly journals A Comparative Study of Three Widespread Methods for Extracting Plant-Parasitic Nematodes from Soil Samples

2019 ◽  
Vol 18 (2) ◽  
pp. 81-89
Author(s):  
Amr El-Marzoki
Plant Disease ◽  
2015 ◽  
Vol 99 (2) ◽  
pp. 291-291 ◽  
Author(s):  
W. Ye ◽  
Y. Zeng ◽  
J. Kerns

In May 2014, 11 sandy soil samples were collected at a depth of about 5 to 15 cm from a golf course community in Wilmington, NC, composed of Bermudagrass (Cynodon dactylon) from the fairway, St. Augustinegrass (Stenotaphrum secundatum) from the lawn, and Zoysiagrass (Zoysia japonica) from the tee, all of which showed spotted yellowing and necrosis. Plant-parasitic nematodes were extracted from soil samples by a combination of elutriation and sugar centrifugal-flotation methods at the North Carolina Department of Agriculture and Consumer Services, Nematode Assay Lab, Raleigh, NC. The results revealed the presence of several plant-parasitic nematodes, with a stubby-root nematode (Trichodoridae) present. Population densities of stubby-root nematodes were 10 to 90 (average 50) nematodes per 500 cm3 of soil. This species was clearly different from the parthenogenetic stubby-root nematode Nanidorus minor (Colbran, 1956) Siddiqi, 1974 commonly found in North Carolina because of the presence of males and larger body size. Morphological and molecular analyses of this nematode identified the species as Trichodorus obtusus Cobb, 1913. Morphological features of T. obtusus specimens were examined in glycerol permanent mounts. Males (n = 5) had a ventrally curved spicule, three ventromedian precloacal papillae (one ventromedian cervical papilla anterior to the excretory pore, one pair of lateral cervical pores at the level of the ventromedian cervical papilla), and a tail with a non-thickened terminal cuticle. Males were 860 to 1,120 (average 1,018) μm long, body width 38 to 48 (42) μm, onchiostyle 53 to 60 (56) μm, and spicule 54 to 62 (59) μm. Females (n = 5) had a pore-like vulva, a barrel-shaped vagina, and one or two postadvulvar lateral body pores on each side. Females were 990 to 1,330 (1,148) μm long, body width 43 to 56 (48) μm, onchiostyle 50 to 64 (58) μm, and V 49.0 to 57.5% (53.0%). The morphology agreed with the description of T. obtusus (2). DNA was prepared by squashing a single nematode (n = 3) on a microscope slide and collecting in 50 μl of AE buffer (10 mM Tris-Cl, 0.5 mM EDTA; pH 9.0). The 18S rDNA region was amplified with the forward primers 18S-G18S4 (5′ GCTTGTCTCAAAGATTAAGCC 3′), SSUF07 (AAAGATTAAGCCATGCATG), and 18S965 (GGCGATCAGATACCGCCCTAGTT) and reverse primers 18S-18P (TGATCCWKCYGCAGGTTCAC), SSUR26 (CATTCTTGGCAAATGCTTTCG), and 18S1573R (TACAAAGGGCAGGGACGTAAT). The 28S D2/D3 region was amplified with the forward primer 28S391a (AGCGGAGGAAAAGAAACTAA) and reverse primer 28S501 (TCGGAAGGAACCAGCTACTA) (4). The resulting 18S (1,547-bp) and 28S D2/D3 (925-bp) sequences were deposited in GenBank under the accession numbers KM276665 and KM276666. The 18S sequence data was 100% homologous with two populations of T. obtusus (JX279930, 898 bp, and JX289834, 897 bp) from South Carolina and one (AY146460, 634 bp) from an unknown source, each with a 1-bp difference in a Blastn search. The 28S D2/D3 sequence data was less than 90% homologous with many Trichodorus species, but no T. obtusus sequence data was available. T. obtusus is known to occur only in the United States and to damage turfgrasses. It is reported in the states of Virginia, Florida, South Carolina, Texas, Iowa, Kansas, Michigan, New York, and South Dakota. This nematode has been reported as a pathogen of bermudagrass in Florida (1) and South Carolina (3), but pathogenicity to St. Augustinegrass and Zoysiagrass is unknown. To our knowledge, this is the first report of T. obtusus on turfgrasses in North Carolina. References: (1) W. T. Crow and J. K. Welch. Nematropica 34:31, 2004. (2) W. Decraemer. The Family Trichodoridae: Stubby Root and Virus Vector Nematodes. Kluwer Academic Publishers, Dordrecht, The Netherlands, 1995. (3) J. B. Shaver et al. Plant Dis. 97:852, 2013. (4) G. R. Stirling et al. Nematology 15:401, 2013.


2016 ◽  
Vol 17 (3) ◽  
pp. 175-176 ◽  
Author(s):  
D. Sharma-Poudyal ◽  
C. Fraley ◽  
N. K. Osterbauer

The goal of this study was to determine the risk of finding virus-vectoring nematodes in containerized blueberry plants placed on gravel. To detect dagger nematode, soil, and potting media samples were collected from blueberry nurseries growing plants in containers using soilless potting media, with the containers placed on a gravel bed or, for one nursery, on a plastic sheet placed on the soil surface. Potting media samples were collected from containers holding plants and soil samples were collected from beneath the gravel or plastic barrier. Nematodes were extracted from all of the samples using sucrose centrifugation. No dagger or other plant parasitic nematodes were detected in any of the samples tested. These results suggest no treatment of soilless potting media is necessary before planting blueberries into containers. Similarly, the gravel layer seems to be an effective barrier for suppressing dagger and other plant parasitic nematodes. Accepted for publication 25 July 2016. Published 8 August 2016.


1978 ◽  
Vol 18 (90) ◽  
pp. 148 ◽  
Author(s):  
RH Brown

Citrus orchards in the Cobram district of northern Victoria were surveyed in 1976 for the presence of plant parasitic nematodes; in particular for the citrus nematode Tylenchulus semipenetrans. One hundred and forty-six soil samples were collected from 38 orchards. Nine genera were recorded, the most prevalant being Tylenchulus and Paratrichodorus (95 per cent and 37 per cent respectively, of all samples). T. semipenetrans was present in all orchards sampled. Population levels of T. semipenetrans larvae exceeded 1000 per 500 g of soil in 60 per cent of samples.


Agronomy ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 123
Author(s):  
Oliver Knox ◽  
David Backhouse ◽  
Vadakattu Gupta

Soil nematode populations have the potential to indicate ecosystem disturbances. In response to questions about nematode interactions with soilborne diseases and whether genetically modified cotton altered nematode populations, several fields in the Namoi cotton growing area of Australia were sampled between 2005 and 2007. No significant interactions were observed, but nematodes numbers were low and postulated to be due to the use of the nematicide aldicarb. Aldicarb was removed from the system in 2011 and in 2015 funding allowed some fields to be resampled to determine if there had been a change in the nematode numbers following aldicarb removal. No significant changes in the total nematode numbers were observed, implying that the removal of aldicarb had little impact on the total nematode population size. However, an increase in plant parasitic nematodes was observed in both fields, but the species identified and the levels of change were not considered a threat to cotton production nor driven solely by altered pesticide chemistry. Additionally, greater numbers of higher order coloniser-persisters in the 2015 samples suggests that the current cotton production system is less disruptive to the soil ecosystem than that of a decade ago.


Biologia ◽  
2012 ◽  
Vol 67 (3) ◽  
Author(s):  
Loukrakpam Bina Chanu ◽  
Naorem Mohilal ◽  
Mohammad Shah

AbstractAnalysis of the soil samples collected from around rhizospheric region of mulberry plants grown in Yurembam Rose Garden, Yurembam, Imphal West, Manipur yielded several soil and plant parasitic nematodes. Among them four species of Aphelenchoides were recorded. Upon detailed study, two species of Aphelenchoides were found to be new to science. Aphelenchoides dhanachandi sp. n. is characterized by ventrally curved body, clearly set off cephalic region and tail ending into a sharp pointed terminus, and stylet slender, 13.6–15.3 (14 ± 0.7) μm long with indistinct basal swellings and tamarind seed-shaped median bulb. Aphelenchoides neoechinocaudatus sp. n. is characterized by straight body with four incisures in the lateral field, flatten cephalic region, slender stylet with indistinct basal swellings, 11.9 μm long, elongated pear-shaped median bulb and short tail with pointed mucro. The two species are illustrated here.


2017 ◽  
Vol 54 (2) ◽  
pp. 179-182
Author(s):  
F. W. Kornobis ◽  
U. Sobczyńska

SummaryDuring a survey on the occurrence of the plant parasitic nematodes of the family Longidoridae in Poland, 925 soil samples were taken. Longidorus distinctus was present in 10 (1.08 %) of these samples. In this Research Note we provide: 1) distribution map of these populations, 2) morphometric data, 3) sequence data for D2-D3 28S rDNA and (partial)18S-ITS1 -5.8S(partial) markers and 4) LdistFOR primer (5′-GGCTGTAAAGATATATGCGT-3’) effective in obtaining ITS1 sequence for the species. Morphometric similarities and dissimilarities with data on other published populations are discussed.


Nematology ◽  
2019 ◽  
Vol 21 (3) ◽  
pp. 275-292 ◽  
Author(s):  
Dongwoo Kim ◽  
Hwal-Su Hwang ◽  
Jae-Kyoung Shim ◽  
JiYoung Yang ◽  
Jae Hong Pak ◽  
...  

Summary Dokdo Island has a unique biodiversity that has been preserved as a natural monument. Although the biodiversity of Dokdo has been investigated, little information is available regarding the nematodes. The diversity of plant-parasitic nematodes was investigated using both ITS and D2-D3 sequences. Nematodes extracted from 59 rhizosphere soil samples were morphologically identified as belonging to eight genera: Geocenamus, Helicotylenchus, Rotylenchulus, Heterodera, Paratylenchus, Pratylenchus, Pratylenchoides and Xiphinema. Further, nucleotide sequences were determined from 85 individuals of different genera for species diagnosis. We identified 13 species, including three species of the genus Pratylenchus (P. crenatus, P. kumamotoensis and P. neglectus), Helicotylenchus sp. 1, Rotylenchulus sp. 1, Paratylenchus nanus, Heterodera trifolii, Heterodera spp., Pratylenchoides ritteri, Geocenamus sp. 1, Geocenamus sp. 2, Xiphinema brevicollum and Xiphinema sp. 1. The dominant plant-parasitic nematode on Dokdo was P. crenatus, which was found in 25.4% of the samples. Our study provides important information about the biodiversity of plant-parasitic nematodes on Dokdo Island.


Plant Disease ◽  
2011 ◽  
Vol 95 (4) ◽  
pp. 413-418 ◽  
Author(s):  
Tesfamariam Mekete ◽  
Kimberly Reynolds ◽  
Horacio D. Lopez-Nicora ◽  
Michael E. Gray ◽  
Terry L. Niblack

A survey of Miscanthus × giganteus and switchgrass plots throughout the midwestern and southeastern United States was conducted to determine the occurrence and distribution of plant-parasitic nematodes associated with these biofuel crops. During 2008, rhizosphere soil samples were collected from 24 Miscanthus × giganteus and 38 switchgrass plots in South Dakota, Iowa, and Illinois. Additional samples were collected from 11 Miscanthus × giganteus and 10 switchgrass plots in Illinois, Kentucky, Georgia, and Tennessee the following year. The 11 dominant genera recovered from the samples were Pratylenchus, Helicotylenchus, Xiphinema, Longidorus, Heterodera, Hoplolaimus, Tylenchorhynchus, Criconemella, Paratrichodorus, Hemicriconemoides, and Paratylenchus. Populations of Helicotylenchus, Xiphinema, and Pratylenchus were common and recorded in 90.5, 83.8, and 91.9% of the soil samples from Miscanthus × giganteus, respectively, and in 91.6, 75, and 83.3% of the soil samples from switchgrass, respectively. Prominence value (PV) (PV = population density × √frequency of occurrence/10) was calculated for the nematodes identified. Helicotylenchus had the highest PV (PV = 384) and was followed by Xiphinema (PV = 152) and Pratylenchus (PV = 72). Several of the nematode species associated with the two biofuels crops were plant parasites. Of these, Pratylenchus penetrans, P. scribneri, P. crenatus, Helicotylenchus pseudorobustus, Hoplolaimus galeatus, X. americanum, and X. rivesi are potentially the most damaging pests to Miscanthus × giganteus and switchgrass. Due to a lack of information, the damaging population thresholds of plant-parasitic nematodes to Miscanthus × giganteus and switchgrass are currently unknown. However, damage threshold value ranges have been reported for other monocotyledon hosts. If these damage threshold value ranges are any indication of the population densities required to impact Miscanthus × giganteus and switchgrass, then every state surveyed has potential for yield losses due to plant-parasitic nematodes. Specifically, Helicotylenchus, Xiphinema, Pratylenchus, Hoplolaimus, Tylenchorhynchus, Criconemella, and Longidorus spp. were all found to have population densities within or above the threshold value ranges reported for other monocotyledon hosts.


2008 ◽  
Vol 48 (4) ◽  
pp. 421-428 ◽  
Author(s):  
Ayodele Adegbite ◽  
Jelili Saka ◽  
Gideon Agbaje ◽  
Felix Osuloye

Survey of Plant-Parasitic Nematodes Associated with Yams in Ogun and Osun States of NigeriaA survey was conducted to determine the types, frequency and population of plant parasitic nematodes associated with the soils and roots of Yam (Dioscoreaspecies) in all the Local Government Areas of Ogun and Osun States of Nigeria using random sampling soil and root and pie pan modification of Baerman funnel for plant parasitic nematode extraction. Ten and nine genera of plant parasitic nematodes were encountered both from the soils and root samples from the two States. Plant parasitic nematodes recovered includedScutellonemaspp.,Meloidogynespp.,Pratylenchusspp.,Trichodorusspp.,Helicotylenchusspp.,Radopholusspp.,Longidorusspp.,Xiphinemaspp.,Rotylenchulusspp andAphelenchoidesspecies.Scutellonemaspp.,Meloidogynespp., andPratylenchusspp were most widely distributed with frequency ratings of 70, 65 and 60% respectively in soil samples from Ogun State and in the root samples the three genera predominated with 60, 55 and 45% frequency ratings respectively.Meloidogynespp.,Scutellonemaspp., andPratylenchusspp were most widely distributed with frequency ratings of 65, 45 and 35% respectively in soil samples from Osun State and in the root samples the three genera predominated with 55, 35 and 35% frequency ratings respectively.


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