scholarly journals First Report of the Root-Knot Nematode Meloidogyne arenaria on Cheeseweed Mallow (Malva parviflora) in the United States

Plant Disease ◽  
2012 ◽  
Vol 96 (2) ◽  
pp. 296-296 ◽  
Author(s):  
N. Kokalis-Burelle ◽  
E. N. Rosskopf ◽  
J. Holzinger

During a 2010 field trial for examining alternatives to methyl bromide soil fumigation for the production of field-grown cut flowers, weeds were collected for identification and evaluated for their potential as hosts for plant pathogenic nematodes. In one cut flower field located in Martin County, FL, six cheeseweed mallow (Malva parviflora L.) plants were collected that had root-galling typical of infection by a root-knot nematode (Meloidogyne spp.). Field collected plants were used for species identification of the weed and maintained in the greenhouse for seed production. Several gravid female nematodes were extracted from field collected mallow roots and individually identified as Meloidogyne arenaria based on their esterase phenotype (PhastSystem, GE Healthcare) (1). A single egg mass was then extracted from the field collected mallow roots and inoculated onto a tomato plant (Solanum lycopersicum, ‘Rutgers’) grown in steamed builders sand in the greenhouse. The single egg mass culture was increased for 8 weeks, until galling was sufficient to produce adequate nematode inoculum to complete Koch's postulates on the original mallow host. Ten mallow plants were inoculated with single egg masses originally isolated from mallow and increased on tomato. Ten additional plants were maintained in the greenhouse as uninoculated controls. Inoculated and control mallow plants were grown in the greenhouse for 8 weeks, after which the roots were evaluated for galling, and root-knot nematode J2 were extracted from roots and soil and counted. All inoculated plants produced galled roots and control plants did not. Gravid females were extracted from mallow roots and identified as M. arenaria based on esterase phenotype as previously described. Ten gravid females for each DNA extraction were collected from mallow roots and DNA was isolated with the PowerSoil DNA Isolation Kit (MO BIO Laboratories, Inc., Carlsbad, CA). Identification of M. arenaria was confirmed by using species-specific primers F5′-TCGAGGGCATCTAATAAAGG-3′ and R5′-GGGCTGAATAATCAAAGGAA-3′ (2) and F5′-TCGGCGATAGAGGTAAATGAC-3′ and R5′-TCGGCGATAGACACTACAACT-3′ (4), which produced single amplicon bands of the expected size of 420 and 950 bp, respectively. This weed species has been reported as a host for M. javanica in Algeria and as an experimental host in Egypt (3), but this report, to our knowledge, constitutes the first documentation of Malva parviflora as a natural host of M. arenaria. The importance of weeds as hosts for plant parasitic nematodes cannot be over emphasized. As growers, particularly in Florida and California, continue to lose tools for broad-spectrum pest control, the ability of nematodes to reproduce on uncontrolled weeds will become increasingly important. References: (1) J. A. Brito et al. Nematology 10:757, 2008. (2) K. Dong et al. Nematropica 31:273, 2001. (3) M. Quader et al. Australas. Plant Pathol. 30:357, 2001. (4) C. Zijlstra et al. Nematology 2:847, 2000.

1992 ◽  
Vol 19 (1) ◽  
pp. 35-37 ◽  
Author(s):  
C. Corley Holbrook ◽  
James P. Noe

Abstract The peanut root-knot nematode [Meloidogyne arenaria (Neal) Chitwood race 1] causes significant economic losses throughout the peanut (Arachis hypogaea L.) production area of the southern United States. Chemicals for control of this pest are becoming increasingly limited, and there are no known sources of resistance within the U. S. A. hypogaea collection. The objectives of this research were to screen 1,321 plant introductions for resistance or hypersusceptibility based on egg-mass ratings in greenhouse tests and to conduct more intensive greenhouse studies of selected genotypes to evaluate this method for identifying resistance to the peanut root-knot nematode. Twenty-seven genotypes with low and eight genotypes with high egg-mass ratings were selected and reevaluated in a more intensive greenhouse experiment. Seventeen of the low selections supported fewer (P≤0.05) egg masses, and seven supported less egg production per gram of fresh root weight than Florunner. Three selections for high egg-mass ratings supported more nematode eggs per plant than the cultivar Florunner and had a greater host efficiency. One of these genotypes supported more nematode eggs per gram of fresh root weight than Florunner. These results show that resistance to M. arenaria exists in the cultivated peanut species and can be selected by rating egg-mass production on greenhouse-grown plants.


HortScience ◽  
1997 ◽  
Vol 32 (5) ◽  
pp. 880-881 ◽  
Author(s):  
Perry E. Nugent ◽  
P.D. Dukes

The southern root-knot nematode, Meloidogyne incognita [(Kofoid & White) Chitwood], causes serious economic losses to melon (Cucumis melo L.) production in the United States. The present study was conducted to determine if separable differences in nematode resistance of Cucumis melo could be found at some inoculum level. Five C. melo lines were compared with Cucumis metuliferus Naud. (C701A), a highly resistant species, for root necrosis, galling, egg mass production, and reproduction when inoculated at 0, 500, 1000, 2000, or 5000 nematode eggs per plant. Using these criteria, melon line C880 inoculated with 1000 eggs per plant was highly susceptible, while PI140471, PI 183311, and the cultivars Chilton, Georgia 47, Gulf Coast, Planters Jumbo, and Southland were less susceptible. In greenhouse tests with an inoculum level of 1000 eggs per plant, low levels of resistance were evident. A thorough screening of the available germplasm against M. incognita may identify higher levels of root-knot nematode resistance for incorporation into improved melon cultivars.


HortScience ◽  
2014 ◽  
Vol 49 (8) ◽  
pp. 1046-1051 ◽  
Author(s):  
Wenjing Guan ◽  
Xin Zhao ◽  
Donald W. Dickson ◽  
Maria L. Mendes ◽  
Judy Thies

Interest in specialty melons (Cucumis melo) with distinctive fruit characteristics has grown in the United States in recent years. However, disease management remains a major challenge in specialty melon production. In this study, grafting experiments were conducted to determine the effectiveness of using Cucumis metulifer, a species known for its genetic resistance to root-knot nematodes (RKNs; Meloidogyne spp.), as a potential rootstock for managing RKNs in susceptible specialty melon cultivars. In the greenhouse experiment, honeydew melon ‘Honey Yellow’ was grafted onto C. metulifer and inoculated with M. incognita race 1. The grafted plants exhibited significantly lower gall and egg mass indices and fewer eggs compared with non- and self-grafted ‘Honey Yellow’. Cucumis metulifer was further tested as a rootstock in conventional and organic field trials using honeydew melon ‘Honey Yellow’ and galia melon ‘Arava’ as scions. ‘Honey Yellow’ and ‘Arava’ grafted onto C. metulifer exhibited significantly lower galling and reduced RKN population densities in the organic field; however, total and marketable fruit yields were not significantly different from non- and self-grafted plants. Although the improvement of RKN resistance did not translate into yield enhancements, incorporating grafted specialty melons with C. metulifer rootstock into double-cropping systems with RKN-susceptible vegetables may benefit the overall crop production by reducing RKN population densities in the soil. At the conventional field site, which was not infested with RKNs, ‘Honey Yellow’ grafted onto C. metulifer rootstock had a significantly lower total fruit yield than non-grafted ‘Honey Yellow’ plants; however, fruit yields were similar for ‘Arava’ grafted onto C. metulifer rootstock and non-grafted ‘Arava’ plants. Although no significant impacts on the fruit quality attributes of ‘Honey Yellow’ were observed, grafting onto C. metulifer decreased the flesh firmness of ‘Arava’ in both field trials and resulted in a reduction in total soluble solids content under conventional production. In summary, grafting RKN-susceptible melons onto C. metulifer rootstock offers promise for growing these specialty melons; however, more studies are needed to elucidate the scion–rootstock interaction effect on fruit yield and quality.


1986 ◽  
Vol 13 (2) ◽  
pp. 78-80 ◽  
Author(s):  
D. D. Baltensperger ◽  
G. M. Prine ◽  
R. A. Dunn

Abstract Peanut root-knot nematode (Meloidogyne arenaria race 1) is an important pest of cultivated peanuts (Arachis hypogaea L.). Experimental data do not exist, however, to indicate whether this nematode might be a potential pest of peanuts grown for forage production. Florigraze and Arbrook, two recently released cultivars of rhizoma peanut (Arachis glabrata Benth.) and P.I. 446898 (Arachis spp.) with perennial forage potential, were evaluated for their interaction with M. arenaria race 1, M. javanica, and M. incognita races I and III. Individual plants, grown in 150 cm3 ConetainersR, were inoculated with 3,000 eggs of one of the four Meloidogyne spp. populations. After three months gall and egg mass scores and soil-nematode counts were determined for each plant sample. A second long-term experiment evaluated Florigraze that was repeatedly inoculated with high levels of root-knot nematodes. Both rhizoma peanut cultivars were highly resistant to all root-knot nematodes tested; Florigraze appeared to be immune. P.I. 446898 was intermediate between the rhizoma peanuts and the susceptible alyceclover check. This is the first known report of such high levels of Meloidogyne arenaria resistance in Arachis spp. Further screending of A. hypogaea material can be justified based on these results and Vavilov's “Law of homologous series”. If no resistance is found in A. hypogaea, A. glabrata may provide a source of resistance that may be transferred to A. hypogea through hybridization.


Plant Disease ◽  
2020 ◽  
Author(s):  
Josiah Marquez ◽  
Fereidoun Forghani ◽  
Abolfazl Hajihassani

Meloidogyne floridensis, also known as the peach root-knot nematode (RKN), is a new emerging species found to break crop host-resistance to M. incognita (Stanley et al. 2009). It was first described from Florida (Handoo et al. 2004) parasitizing M. incognita-resistant rootstock cultivars of peach (Prunus persica), and tomato (Solanum lycopersicum) (Church 2005). The nematode has recently been reported in California’s almond orchards (Westphal et al. 2019) and peach rootstock (cv. Guardian) in South Carolina (Reighard et al. 2019). In a 2018 survey of vegetable fields sampled randomly in South Georgia, RKN was found with a high density (5,264 second-stage juveniles (J2)/100 cm3 of soil) from a tomato field in Ware County, GA. The soil sample consist of 30 soil cores sampled at 20-cm depth across the field in a zig-zag motion. To perform Koch’s postulate, 2,000 eggs from a single egg-mass culture were inoculated into deepots filled with mixture of sand and sterilized field soil (1:1 v/v) and grown with tomato cv. Rutgers for 60 days in the greenhouse. A reproduction factor of 21.1 ± 6.1 was obtained confirming the nematode parasitism on tomato (Fig. 1S). For molecular identification, DNA was extracted by smashing three individual females isolated from the galled roots in 50 µl sterile distilled water, followed by a freeze-thaw (95°C, 1 min). Results of PCR analyzes by species-specific primers (Fjav/Rjav, Finc/Rinc and Far/Rar) did not detect the nematode species (Zijlstra et al. 2000). PCR products were obtained and sequenced from two primer sets consisting of the forward NAD5F2 (5’-TATTTTTTGTTTGAGATATATTAG-3’) and the reverse NAD5R1 (5’-CGTGAATCTTGATTTTCCATTTTT-3’) for amplification of a fragment of the NADH dehydrogenase subunit 5 (NADH5) gene (Janssen et al. 2016), and the forward TRANH (5’-TGAATTTTTTATTGTGATTAA-3’) and the reverse MRH106 (5’-AATTTCTAAAGACTTTTCTTAGT-3’) for amplification covering a portion of the cytochrome c oxidase subunit II (COII) and large subunit 16SrDNA (16S) gene (Stanton et al. 1997). DNA sequence of NADH5 gene fragment (accession no. MT795954) was 100% identical (532/532 bp) with a M. floridensis isolate from California and South Carolina (accession no. MH729181 and MN072363), while fragment of the COII and 16S genes (accession no. MT787563) was 99.76% identical (421/422 bp) with an isolate from Florida (accession no. DQ228697). The nematode females were also used for morphometric and perennial pattern analysis. Several micrographs with the inverted microscope (ZEISS Axio Vert.A1, Germany) and camera (ZEISS Axiocam 305 color, Germany) were taken from ten J2s for mean, standard deviation and range of body length: 362.7 ± 11.2 (340.4-379) µm, maximum body width: 15 ± 1.3 (12.4-16.4) µm, stylet length: 12.3 ± 1.3 (9.5-14) µm, hyaline tail terminus: 8.9 ± 1.1 (7.5-10.9) µm and tail length: 35.7 ± 4.4 (28.5-39.5) µm. Morphological measurements and configuration of perineal patterns (Fig. 2S) were comparable to previous reports of M. floridensis isolates from Florida (Handoo et al. 2004; Stanley et al. 2009). To the best of our knowledge, this is the first report of M. floridensis in Georgia as the fourth state in the USA after South Carolina, California and Florida. This nematode has been reported to parasitize several vegetable crops, including cucumber, eggplant, tomato, snap bean and squash. Furthermore, RKN resistant cultivars of tomato (harboring Mi-1 gene), pepper (harboring N gene), corn cv. Mp-710 and tobacco cv. NC 95 have been found susceptible to M. floridensis (Stanley et al. 2009), making it a serious threat.


Somatechnics ◽  
2017 ◽  
Vol 7 (1) ◽  
pp. 74-94 ◽  
Author(s):  
Rae Rosenberg

This paper explores trans temporalities through the experiences of incarcerated trans feminine persons in the United States. The Prison Industrial Complex (PIC) has received increased attention for its disproportionate containment of trans feminine persons, notably trans women of colour. As a system of domination and control, the PIC uses disciplinary and heteronormative time to dominate the bodies and identities of transgender prisoners by limiting the ways in which they can express and experience their identified and embodied genders. By analyzing three case studies from my research with incarcerated trans feminine persons, this paper illustrates how temporality is complexly woven through trans feminine prisoners' experiences of transitioning in the PIC. For incarcerated trans feminine persons, the interruption, refusal, or permission of transitioning in the PIC invites several gendered pasts into a body's present and places these temporalities in conversation with varying futures as the body's potential. Analyzing trans temporalities reveals time as layered through gender, inviting multiple pasts and futures to circulate around and through the body's present in ways that can be both harmful to, and necessary for, the assertion and survival of trans feminine identities in the PIC.


1994 ◽  
Vol 30 (1) ◽  
pp. 167-175
Author(s):  
Alan H. Vicory ◽  
Peter A. Tennant

With the attainment of secondary treatment by virtually all municipal discharges in the United States, control of water pollution from combined sewer overflows (CSOs) has assumed a high priority. Accordingly, a national strategy was issued in 1989 which, in 1993, was expanded into a national policy on CSO control. The national policy establishes as an objective the attainment of receiving water quality standards, rather than a design storm/treatment technology based approach. A significant percentage of the CSOs in the U.S. are located along the Ohio River. The states along the Ohio have decided to coordinate their CSO control efforts through the Ohio River Valley Water Sanitation Commission (ORSANCO). With the Commission assigned the responsibility of developing a monitoring approach which would allow the definition of CSO impacts on the Ohio, research by the Commission found that very little information existed on the monitoring and assessment of large rivers for the determination of CSO impacts. It was therefore necessary to develop a strategy for coordinated efforts by the states, the CSO dischargers, and ORSANCO to identify and apply appropriate monitoring approaches. A workshop was held in June 1993 to receive input from a variety of experts. Taking into account this input, a strategy has been developed which sets forth certain approaches and concepts to be considered in assessing CSO impacts. In addition, the strategy calls for frequent sharing of findings in order that the data collection efforts by the several agencies can be mutually supportive and lead to technically sound answers regarding CSO impacts and control needs.


1994 ◽  
Vol 21 (1) ◽  
pp. 189-213
Author(s):  
Michael P. Schoderbek

This paper examines the early accounting practices that were used to administer the United States' national land system. These practices are of significance because they provide insights on early governmental accounting and they facilitated an orderly settlement of the western territories. The analysis focuses on the record-keeping and control practices that were developed to meet the provisions of the Land Act of 1800 and to account for land office transactions. These accounting procedures were extracted from the correspondence between the Department of the Treasury and the various land officers.


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