15 results on '"Johan Desaeger"'
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2. Reproduction of Meloidogyne enterolobii on selected root-knot nematode resistant sweetpotato (Ipomoea batatas) cultivars
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Janete A. Brito, Johan Desaeger, and D.W. Dickson
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Guava root-knot nematode ,Meloidogyne enterolobii ,Pacara earpod tree root-knot nematode ,Reproduction ,Root-knot nematode ,Susceptibility ,Biology (General) ,QH301-705.5 - Published
- 2020
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3. New reduced-risk agricultural nematicides - rationale and review
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Johan Desaeger, Catherine Wram, and Inga Zasada
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Efficacy ,Fluazaindolizine ,Fluensulfone ,Fluopyram ,Plant-parasitic nematode ,Biology (General) ,QH301-705.5 - Published
- 2020
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4. Methyl Bromide Alternatives for Control of Root-knot Nematode (Meloidogyne spp.) in Tomato Production in Florida
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JOHAN DESAEGER, DONALD W. DICKSON, and S. J. LOCASCIO
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3-dichloropropene ,metam sodium ,fumigation ,plasticulture. ,Biology (General) ,QH301-705.5 - Published
- 2017
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5. Potential of nicotinamide adenine dinucleotide (NAD) for management of root-knot nematode in tomato
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Peter DiGennaro, Homan Regmi, Noor Abdelsamad, and Johan Desaeger
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QH301-705.5 ,Nicotinamide adenine dinucleotide ,Tomato ,chemistry.chemical_compound ,medicine ,Root-knot nematode ,Gall ,Transplanting ,Biology (General) ,Meloidogyne hapla ,Plant disease ,biology ,M. incognita ,Inoculation ,Life Sciences ,food and beverages ,medicine.disease ,biology.organism_classification ,Management ,Induced systemic resistance ,Horticulture ,Nematode infection ,chemistry ,Systemic acquired resistance ,NAD+ kinase - Abstract
Nicotinamide adenine dinucleotide (NAD) has been shown to induce plant defense responses to different plant pathogens, including reducing northern root-knot nematode, Meloidogyne hapla, penetration and increasing plant mass in tomato. We wanted to further evaluate NAD that are effective against the more economically important species, M. incognita and whether NAD treatments of tomato seedlings in transplant trays can protect plants in the field. Different NAD concentrations (1 mM, 0.1 mM and 0.01 mM) and three application timings (pre; post; pre and post inoculation) were evaluated in growth room and greenhouse trials. The highest tested NAD concentration (1 mM) suppressed second-stage juveniles (J2) infection for all three application methods. Root gall ratings at 30 days after inoculation (DAI) were also suppressed by 1 mM NAD compared to the other two concentrations, and egg mass number was significantly suppressed for all concentrations and application timings compared to the non-treated control. The rate of 1 mM NAD for all three application timings also improved plant growth at 30 DAI. Long-term effects of 1 mM NAD (pre, pre + post, or post applications) on nematode infection, growth and yield of tomato were evaluated in two additional experiments. All NAD applications suppressed root galls after 60 days, but only the pre + post 1 mM NAD application suppressed gall severity at 105 days, as well as suppressed egg counts by 50% at 60 DAT. No significant difference in plant biomass and fruit yield after 105 days was observed among the treatments. Two field trials were conducted in spring and fall 2020 using tomato seedlings (cv. HM 1823) treated with two different NAD concentrations (1 mM and 5 mM in spring; 5 mM and 10 mM in fall) and transplanting seedlings in fumigated (chloropicrin ± 1,3-dichloropropene) and non-fumigated plastic-mulch beds. No significant impact of NAD in terms of reducing RKN severity or overall tomato growth and production was seen in fumigated beds, but in non-fumigated beds 5 mM NAD slightly increased early fruit yield in spring, and 10 mM NAD reduced root-knot soil populations in fall. more...
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- 2021
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6. First Report of
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Alemayehu, Habteweld, Wade, Davidson, Johan, Desaeger, and William T, Crow
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Kratom (
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- 2022
7. Interaction Studies Between
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Homan, Regmi, Gary E, Vallad, Samuel F, Hutton, and Johan, Desaeger
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The
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- 2022
8. First Report of Meloidogyne incognita Infecting Mitragyna speciosa in the United States
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Alemayehu Habteweld, Wade Davidson, Johan Desaeger, and William T. Crow
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Kratom (Mitragyna speciosa) belongs to the coffee family of Rubiaceae. The tree is native to Southeast Asia and primarily grown in Malaysia, Thailand, and Indonesia. Recently, it has been introduced and cultivated in other countries including the United States. The leaves and extracts of the leaves are used for medicinal and recreational purposes. In February 2022, kratom root and soil samples were submitted to the University of Florida Nematode Assay Laboratory for diagnosis by a commercial grower in Florida. Root galls were observed on the roots. On examination of soil and root samples, it is revealed that high numbers of root-knot nematodes (Meloidogyne sp.) are present. Molecular species identification was performed by a combination of the mitochondria haplotyping and species-specific primer techniques using TRNAH/MHR106 and MORF/MTHIS primer sets and Meloidogyne incognita-specific primers (MIF/MIR). The root-knot nematode infecting kratom is identified as M. incognita by molecular analysis. To our knowledge, this paper is the first report of M. incognita infecting kratom in the United States. more...
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- 2022
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9. Interaction Studies between Meloidogyne javanica and Fusarium oxysporum f. sp. lycopersici (Fol) Race 3 on Different Isolines of Tomato cv. Tasti Lee
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Homan Regmi, Gary E. Vallad, Samuel F. Hutton, and Johan Desaeger
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The Mi gene in tomato confers resistance to Meloidogyne javanica, M. incognita, and M. arenaria, the most common tropical root-knot nematode (RKN) species found in Florida. Fusarium wilt (Fol) is another major problem in Florida tomatoes which may interact with RKN and cause more plant damage. To study the interactions between RKN, Fusarium, and Mi in tomato, two greenhouse experiments were conducted. Both experiments used different isolines (with and without I-3 and Mi genes) of the tomato cultivar Tasti Lee®. In the first experiment, all four isolines were subjected to two levels of RKN (~10,000 eggs/pot and no eggs) and two levels of Fol (1000 cc soil with 1,000 cfu/g at planting and no Fol), both applied at planting. In the second experiment, the two isolines without I-3 were exposed to the same two levels of RKN as described above and three levels of Fol (50 ml Fol with 1×106 cfu/m at planting, at 10 DAT, and no Fol). Fol reduced root-knot infection and reproduction when both Fol and RKN were inoculated at planting but not when Fol was inoculated 10 days later. Plant damage from Fol was exacerbated in the presence of RKN, especially when both pathogens were present at planting. Isolines with I-3 grew better in Fol-inoculated soil but had no effect when Fol and RKN were both present. Isolines with Mi gene reduced RKN infection and reproduction but did not affect plant damage caused by Fol. In summary, while RKN reproduction was reduced in the presence of Fol, the overall plant damage was more severe when both pathogens were present. more...
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- 2022
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10. Volatile compounds as potential bio-fumigants against plant-parasitic nematodes – a mini review
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Johan Desaeger and Hung Xuan Bui
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0106 biological sciences ,Soil health ,Nematology ,Microorganism ,fungi ,Arts & Humanities ,010607 zoology ,Fumigation ,Biological pest control ,food and beverages ,Biology ,Nematode management ,Bio-fumigant ,01 natural sciences ,Mini review ,Toxicology ,lcsh:Biology (General) ,Biological control ,Volatile compounds ,lcsh:QH301-705.5 ,010606 plant biology & botany ,Plant-parasitic nematodes - Abstract
Soil fumigation remains the standard practice to manage soilborne pathogens such as plant-parasitic nematodes, bacteria, and fungi, especially in high-value crops. However, increasing regulatory pressure due to the inherent and broad-spectrum toxicity and negative environmental impact of chemical soil fumigants, its negative effect on overall soil health, and increasing demand for organic produce, has created a growing interest in biological fumigants. Many plants and microorganisms emit volatile compounds, which can potentially be used as bio-fumigants. In this mini-review, we summarize the current status of nematology studies focused on the development of volatile compounds emitted from plants and microorganisms as fumigants to control plant-parasitic nematodes. The gap of knowledge and challenges of studying volatile compounds are also addressed. more...
- Published
- 2021
11. Steam-based thermotherapy for managing nematodes in strawberry transplants
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Johan Desaeger, Natalia A. Peres, Mengyi Gu, and Churamani Khanal
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0106 biological sciences ,Temperature sensitivity ,Non-chemical ,biology ,Inoculation ,Nematodes ,010607 zoology ,Arts & Humanities ,Greenhouse ,Biomass ,biology.organism_classification ,01 natural sciences ,Pratylenchus penetrans ,Strawberry ,Management ,Horticulture ,Nematode ,lcsh:Biology (General) ,Aphelenchoides besseyi ,Thermotherapy ,lcsh:QH301-705.5 ,010606 plant biology & botany - Abstract
Aerated steam-based thermotherapy was developed and evaluated for its efficacy in managing three nematode species (Aphelenchoides besseyi, Meloidogyne hapla, and Pratylenchus penetrans) that are often transported as quiescent passengers on strawberry transplants shipped to Florida from out-of-state nurseries. Initial studies were focused on evaluating the intrinsic temperature sensitivity of each nematode species to hot water in laboratory conditions. Each nematode species was exposed to hot water at 40, 44, 48, and 52°C for 1, 5, 10, 30, 60, 120, and 240 min. Exposure for 60 min or higher at 40°C paralyzed all three nematode species when examined immediately after heat treatment. Examination of the nematodes 24 hr post-treatment suggested that 100% mortality of all three nematode species was achieved when nematodes were exposed to hot water at a minimum temperature of 44°C for 120 min. Further studies were conducted to evaluate the efficacy of aerated steam to kill all three nematode species by exposing nematode-infested strawberry transplants at 44°C for 60, 120, and 240 min. Exposure of nematode inoculated plants to steam for 60 or 120 min reduced the populations of all three nematode species, but this was not enough to completely eradicate any of the three nematode species. Exposure for 240 min, however, was the most effective in reducing the populations of the three nematode species. A 240 min of exposure to aerated steam completely eradicated A. besseyi and M. hapla while P. penetrans populations were reduced only by 85%. Furthermore, the aerated steam had minimal to no adverse effect on plant biomass. Results from both the laboratory and greenhouse studies indicated that M. hapla was more sensitive to heat treatment followed by A. besseyi and P. penetrans. Results from this study suggested that aerated steam-based thermotherapy has good potential as a non-chemical method of management of nematodes of strawberry transplants. more...
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- 2020
12. Reproduction of
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Janete A, Brito, Johan, Desaeger, and D W, Dickson
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Root-knot nematode ,Susceptibility ,Sweetpotato ,Guava root-knot nematode ,Reproduction ,Arts & Humanities ,Meloidogyne enterolobii ,Pacara earpod tree root-knot nematode - Abstract
The ability of Meloidogyne enterolobii to reproduce on selected sweetpotato (Ipomoea batatas) cultivars (Beauregard, Covington, Evangeline, Hernandez, and Orleans (LA 05-111)) was evaluated in two greenhouse experiments, each with 10 replicates. All cultivars, except Beauregard (control) and Orleans, were reported previously as moderately resistant or resistant to M. incognita, Fusarium oxysporum f. sp. batatas, and Streptomyces ipomoeae. Plants were inoculated with M. enterolobii (5,000 eggs/plant) and arranged in a completely randomized design in a greenhouse with an average daily temperature of 24.8°C. Galls and egg masses per root system (0-5 scale), eggs per egg mass, eggs per gram of fresh root (gfr), and reproduction factor (RF) were determined. Meloidogyne enterolobii infected and reproduced on all the sweetpotato cultivars. The nematode induced galls on both fibrous and storage roots, regardless of the cultivar, as well as induced necrosis and cracks on storage roots. The lesions and cracks on the storage roots were more visually pronounced on Hernandez than those on other cultivars. Cultivar Orleans sustained less root galling and egg masses than other cultivars (p ≤ 0.01), and both Orleans and Beauregard cultivars had less eggs per gfr and a lower RF than Covington (5,683 eggs/gfr; RF = 16.92), Evangeline (7,161 eggs/gfr; RF = 30.01), and Hernandez (6,979 eggs/gfr; RF = 22.6). The latter two cultivars sustained the largest amount of reproduction of M. enterolobii. The number of eggs per egg mass ranged from 462 to 503 and was similar among all cultivars. In summary, M. enterolobii reproduced well on all sweetpotato cultivars; however, differences were observed among cultivars (p ≤ 0.001). The host status as previously reported for other root-knot nematode species was not a good predictor of host status to M. enterolobii. Some sweetpotato cultivars that were reported as resistant or moderately resistant to M. incognita race 3, such as Evangeline and Hernandez, were among the best hosts to M. enterolobii. Root growth of Evangeline and Orleans, but not of the other cultivars, was negatively correlated with nematode eggs per gfr. more...
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- 2020
13. New reduced-risk agricultural nematicides - rationale and review
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Catherine L. Wram, Johan Desaeger, and Inga A. Zasada
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Reduced risk ,Fluopyram ,Efficacy ,business.industry ,Arts & Humanities ,Biology ,Fluazaindolizine ,Crop protection ,Biotechnology ,Fluensulfone ,lcsh:Biology (General) ,Agriculture ,SAFER ,business ,Plant-parasitic nematode ,lcsh:QH301-705.5 - Abstract
The last decade has seen a sharp increase in nematicide research in the agricultural industry. As a result, several new synthetic nematicides have become available to growers, and several more are expected in the near future. This new interest in nematicides is directly related to the growing demand for safer and more selective products, and the increasing regulatory pressure on many of the traditional nematicides. This has led to a ban of several widely used fumigant (e.g. methyl bromide) and non-fumigant (e.g. aldicarb) nematicides. The loss of traditional nematicides, combined with a lack of replacement products and awareness of the damage that nematodes can cause, has not only raised concern among growers, but has also created new opportunities for the crop protection industry. Nematicides have become a priority, and many companies are now allocating significant research dollars to discover new nematicides. The new nematicides are very different from previous products: (i) they are more selective, often only targeting nematodes, and (ii) they are less toxic, and safer to use. This review article describes these new developments by discussing the challenges that are associated with finding new nematicides, reviewing the nature, characteristics, and efficacy of new nematicides, and discussing the impact they could have on future nematode management. more...
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- 2020
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14. Plant-parasitic nematodes associated with the root zone of hop cultivars planted in a Florida field soil
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Johan Desaeger, Tristan T. Watson, Marco Suarez, and Zhanao Deng
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0106 biological sciences ,Paratrichodorus minor ,Meloidogyne javanica ,biology ,Pratylenchus brachyurus ,010607 zoology ,Arts & Humanities ,Nematode management ,biology.organism_classification ,01 natural sciences ,Population density ,Horticulture ,lcsh:Biology (General) ,Belonolaimus longicaudatus ,Hop cultivars ,Cultivar ,Helicotylenchus dihystera ,lcsh:QH301-705.5 ,Humulus lupulus ,010606 plant biology & botany ,Mesocriconema xenoplax - Abstract
In early 2016, hop plants were introduced into Florida. By late 2016, the hop plants were showing stunted growth and were heavily parasitized by Meloidogyne javanica. In this study, we determined host susceptibility of 14 hop cultivars to M. javanica in a greenhouse experiment and monitored population development of plant-parasitic nematode species in the root zone of 17 hop cultivars planted in three newly established hop yards in Florida. Plant-parasitic nematodes in the rooting zone soil of field grown hop plants included M. javanica, Pratylenchus brachyurus, Paratrichodorus minor, Belonolaimus longicaudatus, Xiphinema setariae/vulgare complex, Mesocriconema xenoplax, and Helicotylenchus dihystera; however, soil population densities of P. minor, B. longicaudatus, X. setariae/vulgare complex, M. xenoplax, and H. dihystera remained low through the study. Root galling, M. javanica egg production, and soil population densities of M. javanica were consistently large on the 'Canadian Red Vine', 'Centennial', 'Chinook', and 'Comet' cultivars, and small on the 'Galena' and 'Triple Perle' cultivars. No differences were observed in soil population densities of P. brachyurus among hop cultivars. Overall, our study provides the first report of plant-parasitic nematode population development in the root zone on hop cultivars planted in Florida. In early 2016, hop plants were introduced into Florida. By late 2016, the hop plants were showing stunted growth and were heavily parasitized by Meloidogyne javanica. In this study, we determined host susceptibility of 14 hop cultivars to M. javanica in a greenhouse experiment and monitored population development of plant-parasitic nematode species in the root zone of 17 hop cultivars planted in three newly established hop yards in Florida. Plant-parasitic nematodes in the rooting zone soil of field grown hop plants included M. javanica, Pratylenchus brachyurus, Paratrichodorus minor, Belonolaimus longicaudatus, Xiphinema setariae/vulgare complex, Mesocriconema xenoplax, and Helicotylenchus dihystera; however, soil population densities of P. minor, B. longicaudatus, X. setariae/vulgare complex, M. xenoplax, and H. dihystera remained low through the study. Root galling, M. javanica egg production, and soil population densities of M. javanica were consistently large on the ‘Canadian Red Vine’, ‘Centennial’, ‘Chinook’, and ‘Comet’ cultivars, and small on the ‘Galena’ and ‘Triple Perle’ cultivars. No differences were observed in soil population densities of P. brachyurus among hop cultivars. Overall, our study provides the first report of plant-parasitic nematode population development in the root zone on hop cultivars planted in Florida. more...
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- 2020
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15. First Report of the Root-Knot Nematode (Meloidogyne javanica) Infecting Hops (Humulus lupulus) in Florida, USA
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J. A. Brito, F. Achinelly, Johan Desaeger, S Qiu, and Sergei A. Subbotin
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0106 biological sciences ,Humulus lupulus ,010607 zoology ,MELOIDOGYNE JAVANICA ,First report ,01 natural sciences ,FIRST REPORT ,Botany ,Root-knot nematode ,Ciencias Naturales ,lcsh:QH301-705.5 ,Meloidogyne javanica ,FLORIDA ,biology ,Arts & Humanities ,Life Sciences ,HUMULUS LUPULUS ,biology.organism_classification ,purl.org/becyt/ford/4.5 [https] ,lcsh:Biology (General) ,CIENCIAS AGRÍCOLAS ,Florida ,Otras Ciencias Agrícolas ,purl.org/becyt/ford/4 [https] ,010606 plant biology & botany - Abstract
Humulus lupulus (Cannabaceae), commonly referred to as hops, are perennial, herbaceous climbing plants, native to temperate northern climates. Hops are cultivated for their strobiles or cones, which are often used for flavoring and aroma in food, tea, and beer (Almaguer et al. 2014; Burgess 1964). Because of the high demand for hops from the micro-brewing industry in the Tampa-St. Petersburg area, it has recently been introduced in Florida. The crop grows rapidly in the early spring to late summer. Plants reach a mature height of 18-25 feet in one year and produce cones from mid-summer to early fall (Pearson, 2016). Hop rhizomes were planted in April 2016 at the Gulf Coast Research Station, Wimauma, Hillsborough Co., Florida, USA. In October 2016, several hop plants that exhibited yellowing leaves and stunted growth were uprooted and showed severe root galling (Figs.1;2). Rhizosphere soil samples were collected for nematode extraction and showed high numbers of root-knot nematode second-stage juveniles (J2) (up to 1500 J2/ 200cm3 soil). Heavily galled root samples were sent to the Florida Department of Agriculture and Consumer Services, Division of Plant Industry Nematology Laboratory in Gainesville, FL. Species identification was performed using morphological analyses of females perenal patterns (n=22), selected characters of second-stage juveniles (n=17), and isozyme phenotypes (esterase and malate dehydrogenase) of egg- laying females (n=26) extracted from the roots. Configuration of the perineal patterns, morphometrics of body, stylet and tail length of J2 and the esterase phenotype (EST= J3), which is species-specific and malate phenotype (MDH=N1), are consistente with those reported in the original descrition of M. javanica and many other populations of this nematode species collected in Florida and other countries (Brito et al., 2008; Cofcewick et al., 2005; Carneiro et al., 2004; Jepson, 1987; Esbenshade and Triantaphyllou, 1985). For molecular analyses, DNA was extracted from individual females and mitochondrial DNA was amplified with MORF (5?- ATC GGG GTT TAA TAA TGG G - 3?) and MTHIS (5? - AAA TTC AAT TGA AAT TAA TAG C -3?) primer set (Pagan et al., 2015; Stanton et al., 1997). A fragment of approximately 740 bp was produced, which has been reported for M. incognita and M. javanica found in Florida (Baidoo et al., 2016). To further confirm the species identification we use the speices-specific SCAR primer set Fjav (5 ?- GGT GCG CGA TTG AAC TGA GC - 3?) and Rjav (5? - CAG GCC CTT CAG TGG AAC TAT AC - 3?) (Zijlstra et al., 2000). This primer set yield a fragment of of approximately 670bp, which is identical to that previously reported for M. javanica (Humphreys-Pereira et al., 2017; Baidoo et al., 2016; Zijlstra et al., 2000). Additionally, NADH dehydrogenase subunit 5 gene was amplified using NAD5F2 (5?- TAT TTT TTG TTT GAG ATA TAT TAG - 3?) and NAD5R1 (5?- CGTGAATCTTGATTTTCCATTTTT-3?) primers as described by Janssen et al. (2016). The GenBank accession number of the nad5 gene sequence is MH230176. The obtained the nad5 gene sequence was identical to the reference sequence of M. javanica provided by Janssen et al. (2016). To our knowledge, this is the first report of H. lupulus as a host of the Javanese root-knot nematode (M. javanica) in Florida., Centro de Estudios Parasitológicos y de Vectores more...
- Published
- 2018
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