• The Plant Pathology Journal
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• v.31 no.4
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• pp.441-445
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• 2015

Carrot (Dacus carota var. sativus) is one of the top-ten most economically important vegetable crops produced worldwide, and the root-knot nematodes, Meloidogyne spp., are one of the most important pests in the carrot. In Korea, M. hapla and M. incognita are presumed to be the major root-knot nematodes distributing mostly in open carrot fields and greenhouses, respectively. In our study, currently-developed and commercial carrot cultivars and the parental lines were examined for their pathological responses to M. incognita and M. hapla 7 weeks after inoculation with about 1,000 second-stage juveniles (J2) of the nematodes. All the carrot cultivars and lines showed susceptible responses to both nematodes with the gall index (GI) of 2.4-4.4, which were always higher on the carrot plants infected with M. incognita than M. hapla. Gall sizes were remarkably larger with more serious reduction of the root growths in the plants infected with M. incognita than M. hapla, suggesting the carrot lines examined in our study were more susceptible to the former than the latter. In the infection sites of the root tissues, giant cells were more extensively formed, occupying larger stellar regions with the prominent destruction of adjacent xylem vessels by M. incognita than M. hapla. All of these results suggest M. incognita affect more seriously on the carrot plants that are grown in greenhouses, compared to M. hapla that has a major distribution in open carrot fields, which would be used for determining cropping systems based on target nematode species, their damage and pathological characteristics.

• Proceedings of the Korean Society of Soil Zoology Conference
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• 2003.06a
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• pp.11-11
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• 2003

• Research in Plant Disease
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• v.29 no.4
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• pp.459-463
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• 2023

This study was conducted to investigate the plant-parasitic nematodes of ornamental foliage plants, citrus orchards, and tea plantations from July to December 2022. As a result of the investigation of plant-parasitic nematodes in 415 foliage plants, root-lesion nematodes were detected most frequently, followed by root-knot nematodes, pin nematodes, and other nematodes. In tea plantations, spiral nematodes, cyst nematodes, and root-knot nematodes were detected. Citrus nematodes, ring nematodes, and root-knot nematodes were discovered in citrus orchards. In foliage plants, tea plantations, and citrus orchards, the detection rate of plant-parasitic nematodes was not high, but root-lesion nematodes were detected. Therefore, it is necessary to apply appropriate control methods to manage root-lesion nematodes during the cultivation of foliage, tea, and citrus plants.

• The Plant Pathology Journal
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• v.29 no.3
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• pp.242-248
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• 2013

In the Northeast of Brazil, expansion of guava crops has been impaired by Meloidogyne enterolobii that causes root galls, leaf fall and plant death. Considering the fact that arbuscular mycorrhizal Fungi (AMF) improve plant growth giving protection against damages by plant pathogens, this work was carried out to select AMF efficient to increase production of guava seedlings and their tolerance to M. enterolobii. Seedlings of guava were inoculated with 200 spores of Gigaspora albida, Glomus etunicatum or Acaulospora longula and 55 days later with 4,000 eggs of M. enterolobii. The interactions between the AMF and M. enterolobii were assessed by measuring leaf number, aerial dry biomass, $CO_2$ evolution and arbuscular and total mycorrhizal colonization. In general, plant growth was improved by the treatments with A. longula or with G. albida. The presence of the nematode decreased arbuscular colonization and increased general enzymatic activity. Higher dehydrogenase activity occurred with the A. longula treatment and $CO_2$ evolution was higher in the control with the nematode. More spores and higher production of glomalin-related soil proteins were observed in the treatment with G. albida. The numbers of galls, egg masses and eggs were reduced in the presence of A. longula. Inoculation with this fungus benefitted plant growth and decreased nematode reproduction.

• The Plant Pathology Journal
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• v.19 no.3
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• pp.138-142
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• 2003

Soil amendments with oriental herbal medicines such as fruit of Anethum graveolens, flower buds of Syzygium aromaticum, rhizome of Cnidium officinale, rhizome of Coptis chinensis, root bark of Paeonia suffructicosa, stem bark of phellodendron amurense, and stem bark of Cinnamomum cassia at the rate of 0.2％ (weight by volume of soil) significantly reduced Meloidogyne incognita infection (root gall formation) of tomato seedlings compared with the control. The most effective treatments were root bark of p. suffructicosa and stem bark of C. cassia as they gave minimum numbers of galls on tomato roots (4.7% and 8.9%, respectively, relative to control) as compared to other treatments. Another study with root bark of p. suffructicosa and C. cassia at different application doses also showed consistent results in reducing gall number. The control efficacy decreased as the application doses were lower-ed, indicating their dose-dependent control activities. These treatments significantly enhanced aboveground plant growths (total masses).

• Korean journal of applied entomology
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• v.41 no.4
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• pp.293-298
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• 2002

Cadusafos and fosthiazate were applied at the rate of 1.8 g a.i./6$\m^2$ as pre-plant or pre-plant＋post-plant treatments on winter-grown oriental melon in a greenhouse soil infested with Meloidogyne arenaria. Nematicides reduced root-knot nematode population from 35 to 90% compared with control； fosthiazate was better than cadusafos (P ＝ 0.003) and fosthiazate pre-plant＋post-plant application reduced nematode population densities as much as 90%. Nematicides increased yield in an average of 23% (11-38%) in May, 39% (2-65%) in June, and 31% (12-46%) for the total (P ＝ 0.085). The residue in the fruit of oriental melon by post-plant treatment of fosthiazate exceeded maximum residue limit of 0.2ppm, while the Cadusafos residue was below the limit. It is concluded that fosthiazate cannot be used as a post-plant treatment in winer-grown oriental melon with overall consideration, i. e., danger of residue, value of melon, costs of nematicide, consumer demand on safer agricultural products, and effects of fallow.

• Microbiology and Biotechnology Letters
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• v.35 no.3
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• pp.250-254
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• 2007

Bacillus thringiensis strain 108 was isolated from soil and had nematicidal activity against second stage juvenile of plant root-knot nematode, Meloidogyne incognita. The strain 108, a rod shape, spore forming and Gram positive bacterium, produced lecithinase, catalase, and ${\delta}$-endotoxin. The strain 108 belongs to H serotype 3, Bacillus thuringiensis var. kurstaki. A nematicidal substance of the strain 108 was partially purified on Sephadex G-25 gel filtration, activated carbon adsorption, silica gel adsorption, and Sephadex G-10 gel filtration. $LC_{90}$ of the partially purified substance against M incognita was $1.2\;{\mu}g/ml$. The nematicidal substance was stable by heat treatment at $100^{\circ}C$ for 1hr, but was perfectly lost nematicidal activity after autoclave ($110^{\circ}C$, 30 min).

• The Plant Pathology Journal
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• v.19 no.3
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• pp.177-180
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• 2003

Pasteuria penetrans KW1 (PP), parasitic bacterium of nematode, was isolated from oriental melon greenhouse soil in Korea and evaluated for the suppression effect on the reproduction of southern root-knot nematode, Meloidogyne incognita (MI), in lettuce (Lactuca sativa L. var. Chungchima) and oriental melon (Cucumis melo L. var. Eunchun). Pot experiments were conducted by planting the lettuce seedlings in medium inoculated with 5,000 MI juveniles/pot (J), J +100,000 PP endospores/l g medium, and J +200,000 PP endospores/1 g medium. After 11 weeks of plantation, number of root galls in J +200,000 PP endospores/1 g medium was decreased to 92/root (38.9%, control effect), compared to the J of 150/root. In the second plantation of lettuce in the same pots, the numbers of root gall were significantly decreased in PP treated pots with 75 (77.2%, control effect) and 150/root (54.4%, control effect) in J +200,000 and J +100,000 PP endospores/1 g medium, respectively, compared to the J of 330/root when harvested at 10 weeks after planting. In oriental melon, root gall percentages were 32.1 (60.2%, control effect) and 52.9％ (34.5%, control effect) in J +200,000 and J + 1(10,000 endospores/l g medium which were significantly lower than that of 80.7％ in J.

• The Plant Pathology Journal
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• v.30 no.3
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• pp.288-298
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• 2014

We examined the efficacy of a bacterium for biocontrol of the root-knot nematode (RKN) Meloidogyne hapla in carrot (Daucus carota subsp. sativus) and tomato (Solanum lycopersicum). Among 542 bacterial isolates from various soils and plants, the highest nematode mortality was observed for treatments with isolate C1-7, which was identified as Bacillus cereus based on cultural and morphological characteristics, the Biolog program, and 16S rRNA sequencing analyses. The population density and the nematicidal activity of B. cereus C1-7 remained high until the end of culture in brain heart infusion broth, suggesting that it may have sustainable biocontrol potential. In pot experiments, the biocontrol efficacy of B. cereus C1-7 was high, showing complete inhibition of root gall or egg mass formation by RKN in carrot and tomato plants, and subsequently reducing RKN damage and suppressing nematode population growth, respectively. Light microscopy of RKN-infected carrot root tissues treated with C1-7 showed reduced formation of gall cells and fully developed giant cells, while extensive gall cells and fully mature giant cells with prominent cell wall ingrowths formed in the untreated control plants infected with RKNs. These histopathological characteristics may be the result of residual or systemic biocontrol activity of the bacterium, which may coincide with the biocontrol efficacies of nematodes in pots. These results suggest that B. cereus C1-7 can be used as a biocontrol agent for M. hapla.

• Korean journal of applied entomology
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• v.39 no.2
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• pp.111-115
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• 2000

Fifty-two nematode predatory fungi were isolated from 37 soil samples collected from eight provinces in Korea. Isolated fungi were tested their predacity against Rhabditis sp. and Meloidogyne incognita in petri dish, and against M. incognita in greenhouse pot experiments. Fifty isolates had trapping organ of adhesive networks and two isolates had adhesive column or adhesive knob. In petri dish experiments, 5 1 isolates against Rhubditis sp. and 26 isolates against M. incognita showed over 91 % of predacity; in greenhouse experiments, however, only three isolates showed over 81% of predacity. These results imply that the results from the laboratory experiments are not consistent with those from the greenhouse experiments. Therefore, to select a promising biocontrol predatory fungi for plant-parasitic nematodes, the screening experiment should be conducted in conditions close to nature.