Root-knot Nematode Species Research Articles

Pasteuria nishizawae sp. nov., a mycelial and endospore-forming bacterium parasitic on cyst nematodes of genera Heterodera and Globodera

This study describes Pasteuria nishizawae sp. nov., a fourth species of the genus Pasteuria. This mycelial and endospere-forming bacterium parasitizes the adult females of cyst-forming nematodes in the genera Heterodera and Globodera. The distinct ultrastructural features and unique host range found for this bacterium separate it from two closely related species, Pasteuria penetrans, which parasitizes several species of rootknot nematodes of the genus Meloidogyne, and Pasteuria thomei, which appears to parasitize only one species of the root-lesion nematode, Pratylenchus brachyurus. Because these obligate bacterial parasites of nematodes have not been cultured axenically, the taxonomic relationships described here for each species are based mainly on developmental morphology, fine structure of the respective sporangia and endospores, and their pathogenicity on nematode species.

Resistance of maize to Meloidogyne arenaria and Meloidogyne javanica

A diallel cross of eight maize, Zea mays L., inbred lines was analyzed for reaction to two species of root-knot nematodes, Meloidogyne arenaria (Neal) Chitwood and M. javanica (Treub) Chitwood. Egg production following inoculation of F1 hybrid seedlings with nematode eggs was determined in a greenhouse experiment. Data were analyzed using Griffing's Method 4, Model I. General combining ability was a significant source of variation in egg production of both M. arenaria and M. javanica; specific combining ability was not a significant source of variation for either. The correlation between egg production of the two nematode species on the 28 F1 hybrids was highly significant. Hybrids with Mp313 or SC213 as one parent were the most resistant to both species. This indicates that germ plasm is available for developing inbred lines and hybrids with resistance to both M. arenaria race 2 and M. javanica.

SCREENING CULTIGENS OF CUCUMBER AND HORNED CUCUMBER FOR RESISTANCE TO ROOT KNOT NEMATODES

Root knot, caused by Meloidogyne spp. is the most important disease of cucumber (Cucumis sativus L.) in North Carolina, causing an average annual yield loss of 12 %. A greenhouse study was conducted 10 screen 924 cultigens (728 accessions, 136 cultivars and 36 breeding lines of C. sativus, and 24 accessions of C. metuliferus Naud.] for resistance to 3 species of root knot nematodes, M. incognita r. 3, M. arenaria r. 2 and M. hapla, Plants were grown from seed in 150-mm diameter clay pots. Two-week-old seedlings were inoculated with 5000 nematode eggs per plant, then evaluated for resistance 9 weeks later. All cultigens evaluated were resistant to M. hapla. Little resistance was found in the cultigens of C. sativus to M. incognita r. 3 and M. arenaria r. 2. Most of the cultigens evaluated were susceptible to both. `Southern Pickler' was resistant to both nematodes (1 % average galls). `Green Thumb and LJ 90430 were resistant to M. arenaria r. 2, Two check cultigens, `Sumter' and Wis. SMR 18, had an average of more than 50% galls. All C. metuliferus cultigens evaluated were resistant to all root knot nematodes tested. PI 482452 was most resistant (1 % average galls), and PI 482443 was least resistant (5% average galls) of the C. metuliferus cultigens tested.

Elimination of nematodes from ginger (Zingiber officinaleRoscoe) by tissue culture

The rootknot nematode species Meloidogyne incognita and M. javanica pose a serious threat to the cultivation of ginger in South Africa. Tissue culture was investigated as a method of obtaining prop...

浅間山麓・八ケ岳山麓等の高冷地におけるネコブセンチュウ, ネグサレセンチュウの検出種

浅間山麓・八ケ岳山麓等の高冷地におけるネコブセンチュウ, ネグサレセンチュウの検出種

Inheritance of the resistance toMeloidogyne incognita, M. javanica, andM. arenaria in potatoes

The objectives of this research were: 1) to try to determine the inheritance of the resistance toMeloidogyne incognita, M. javanica, andM. arenaria and 2) to study genetic relationships among the three species of root-knot nematodes in potatoes. The source of resistance used wasSolanum sparsipilum. The progenies analyzed in this study may be grouped into a few discrete segregation patterns, three forM. incognita andM. javanica and two forM. arenaria. More than one dominant locus, but not many loci are needed to explain the segregation obtained in the three species. Susceptible clones ofS. sparsipilum possess recessive or epistatic genes which affect the pattern of segregation for resistance, when these clones are crossed to resistant clones. Maternal effects were expressed in reciprocal crosses between susceptible and resistant clones when they were tested for resistance toM. arenaria. Clones in this study which are resistant toM. arenaria are also resistant toM. incognita andM. javanica

Influence of temperature on penetration and development of 2 species of root-knot nematodes to and in susceptible and resistant tomato varieties

Influence of temperature on penetration and development of 2 species of root-knot nematodes to and in susceptible and resistant tomato varieties

A Preliminary Note on Nematode Pests in Brunei

Abstract Soil samples including plant roots, were taken from areas with plants suspected of being damaged by nematodes. Analysis and identification was carried out. The most common and widespread nematode was Rotylenchulus reniformis which had fifteen hosts. There was a consistently high build-up of this nematode in experimental plantings of passion fruit and chemicals have to be used for control. Two species of root-knot nematode, Meloidogyne incognita and M. javanica, were widely found although infestation seemed to be confined to a few plants in a crop. Only Meloidogyne spp. and Rotylenchulus reniformis are of economic importance. The main crops, i.e. rice and citrus, have no nematode problems under current practices. However, nematodes may become a problem as larger intensive farming schemes are developed.

Heritabilities of Sweet Potato Resistances to Root Knot Caused by Meloidogyne incognita and M. javanica1

Abstract Three greenhouse tests to determine the reactions of sweet potato (Ipomoea batatas (L.) Lam.) breeding lines and their respective open-pollinated offspring to 2 species of root-knot nematodes were conducted. Resistances occurred in high frequency to both the southern root knot nematode (Meloidogyne incognita (Kofoid & White) Chitwood) and the Javanese (tropical) root knot nematode (M. javanica (Treub) Chitwood). Reaction to M. incognita was studied in 2 consecutive years with different sets of parental lines using an egg mass index. Estimated heritability (h2) in 1976 was 0.75 ± 0.23 and in 1977 was 0.57 ± 0.37. Three indices of reaction to M. javanica and respective h2 estimates were: Egg mass index, 0.69 ± 0.18; galling index, 0.78 ± 0.19; and necrosis index, 0.72 ± 0.20. Resistances to the 2 species were not correlated, indicating independent inheritance. Development of cultivars with high levels of resistance to each or to both of the above diseases is possible.

Effect of some species of root-knot and lesion nematodes on the growth of garden pea seedling

Effect of some species of root-knot and lesion nematodes on the growth of garden pea seedling

A case of intra-uterine egg development in a species of root-knot nematode

A case of intra-uterine egg development in a species of root-knot nematode

Reactions of lines of Phaseolus atropurpureus to four species of root-knot nematode

In each of two years the reactions of 36 lines of Phaseolus atropurpureus to the four root-knot nematodes Meloidogyne arenaria, M. hapla, M. incognita, and M. javanica were studied. Seven of the experimental lines were common to the two years. Two known susceptible species, Phaseolus lathyroides and Lycopersicon esculentum (tomato cv. Grosse Lisse), were used as controls. Four macroscopic and four microscopic reactions were recorded on each occasion, and the results analysed. Resistance to the four nematodes was present in all lines of P. atropurpureus. There was also evidence of differential resistance between lines; some showed increased resistance to all nematodes except M. hapla, and others showed both increased susceptibility to M. hapla and increased resistance to M. javanica. The severity of attack on thc controls was significantly less in the second ycar. Several explanations for this are advanced.

Breeding Peaches for Root-knot Nematode Resistance1

Abstract Five peach rootstock selections show immunity to root-knot nematode disease caused by Meloidogyne incognita (Kofoid and White) Chitwood and M. javanica (Treub) Chitwood. These are the first peach rootstocks which remain free from galls when exposed to both these root-knot nematode species. They are derived from a 1949 cross in Chico, California, of Prunus davidiana Franch with a Chinese Peach. Resistance to the species M. incognita and M. javanica depends on different genes. Resistance to the former was inherited as a monofactorial dominant. Resistance to M. javanica appeared dependent on 2 or more dominant genes in both ‘Okinawa’ and P. davidiana, but P. davidiana progenies were completely free from visible galls. A third type of root-knot nematode was discovered in Florida in 1966. It reproduces readily on ‘Okinawa’, ‘Nemaguard’ and the other lines which have been selected for resistance or immunity to M. incognita and M. javanica.

Cold-Hardiness of Nematodes. I. Effects of Rapid Freezing On the Eggs and Larvae of Meloidogyne Incognita and M. Hapla 1 )

Meloidogyne hapla, a species of root-knot nematode that can survive freezing temperatures, and M. incognita a species that cannot, were observed while being frozen on a microscope stage where temperatures could be lowered to -40° ± 0.1° C at a maximum rate of 10° C/min. Eggs and larvae survived for short periods in supercooled water and in ice, but formation of internal ice was lethal to both species. At a lower rate of cooling, 1° C/min., there was no difference in the ability of the two species to survive subzero temperatures. However, when larvae were frozen in physiological salt solution or egg-masses were stored for long periods at temperatures slightly above freezing and then frozen, significantly more M. hapla survived than did M. incognita.

A PRELIMINARY REPORT ON THE OCCURRENCE OF ROOT-KNOT NEMATODES (Meloidogyne spp.) ON SOME IMPORTANT CROP PLANTS IN MADRAS STATE

Root-knot is one of the oldest and most widely known nematode diseases of plants and occurs on the roots of numerous plants belonging to all families. Root-knot nematodes belonging to three species and one subspecies viz., Meloidogyne javanica, M. incognita, M. incognita acrita and M. arenaria have been recorded from different parts of India so far on a number of cultivated crops. The present paper summarizes the result of one year's preliminary survey on the occurrence and distribution of different species of root-knot nematodes on some important crop plants in Madras State. Five different species of Meloidogyne and one subspecies viz., M. incognita incognita, M. incognita acrita, M. javanica, M. arenaria, M. hapla and M. brevicauda are recorded from various cultivated crops. M. arenaria is reported for the first time in South India and M. hapla and M. brevicauda are new records in India. The survey has given clear indication that the root-knot nematodes constitute one of the most common nematode problems in Madras State.

Species and distribution of root-knot nematodes in fig farm

Species and distribution of root-knot nematodes in fig farm