scholarly journals Changes in the population density of root-knot nematodes in fall cropping of oat with different planting dates

2011 ◽  
Vol 41 (1) ◽  
pp. 19-22 ◽  
Author(s):  
Yasushi Tateishi ◽  
Masaaki Katsura ◽  
Hideaki Iwahori ◽  
Kenta Uesugi
Keyword(s):  
Population Density ◽  
Planting Dates ◽  
Root Knot Nematodes

Occurrence and distribution of root-knot nematodes, Meloidogyne spp., in cowpea growing areas of Nigeria

Nematology ◽  
2004 ◽  
Vol 6 (6) ◽  
pp. 811-817 ◽  
Author(s):  
Tayo Olowe
Keyword(s):  
Population Density ◽  
Mixed Population ◽  
The South ◽  
Root Knot Nematodes ◽  
Humid Forest ◽  
North West ◽  
Ecological Zones ◽  
The Core ◽  
North East ◽  
Meloidogyne Spp

AbstractA survey of root knot nematodes, Meloidogyne spp., was conducted in 248 major cowpea growing areas, spread over 31 States and the Federal Capital Territory in different ecological zones in Nigeria. The survey revealed the occurrence of Meloidogyne incognita, M. javanica and M. arenaria singly or in combination in all the cowpea farms sampled. In overall distribution, M. incognita (51.8%) was the most prevalent followed by M. javanica (44.1%) and M. arenaria (4.1%). The greatest abundance of M. javanica (65.6%) was concentrated in the Sudan savannah of the Core North (north-east and north-west) and that of M. incognita (82.1%) in the humid forest of the south (south-east, south-west and south-south). However, M. javanica (51.7%) and M. incognita (44.2%) tended to be common in the Guinea savannah of the middle belt (north-central). Mixed populations of the three species (4.0%), but more commonly of M. incognita and M. javanica (37.1%), were encountered. Meloidogyne arenaria never occurred as a pure population or mixed with M. javanica solely but was found mixed either with M. incognita alone or in combination with M. javanica and M. incognita, and more often in the south. In a mixed population of M. incognita and M. javanica in the Core North, where M. javanica was prevalent, M. incognita formed about one third (34.2%) of the mixed population density, whereas in the south where M. incognita was dominant, M. javanica formed a lower proportion of about one fifth (17%) of the mixed population density. These findings provide information and guidance for planning effective management strategies.

Evaluation of row spacing and population density effects on grain sorghum over a range of northern Australian environments

1981 ◽  
Vol 21 (109) ◽  
pp. 210 ◽  
Author(s):  
GA Thomas ◽  
RJK Myers ◽  
MA Foale ◽  
AV French ◽  
B Hall ◽  
...  
Keyword(s):  
Population Density ◽  
Full Range ◽  
Moisture Stress ◽  
Grain Sorghum ◽  
Row Spacing ◽  
Root Pruning ◽  
Population Densities ◽  
Planting Dates ◽  
Wide Range ◽  
Growing Conditions

Fifteen experiments were conducted between 1976 and 1978 to determine the response of grain sorghum to row spacing and population density over a range of soil types, planting dates and seasonal conditions. One experiment was at Kununurra, Western Australia, and the rest were in southern and central Queensland. The trials virtually covered the full range of growing conditions likely to be experienced in the sorghum growing area. Narrow and standard single rows (0.33 m to 1.07 m spacings) yielded as well as or better than more widely spaced (1.50 to 4.27 m) single or twin rows (0.33 or 0.36 m apart) at equivalent population densities over a wide range of yield levels. Only at yield levels below 900 kg ha-l was there a trend for 2.00 or 2.13 m twin rows to outyield the 0.33 or 0.36 m single row spacing. Significant yield reductions resulted in a number of trials, at yield levels above 1600 kg ha-l, from the use of wide row spacings. Where there was severe water stress, grain yields were also reduced by high population densities (>150,000 plants ha-l), particularly at the 0.33 or 0.36 m row spacing. There was no evidence that response to row spacing differed between cultivars. In the one experiment where it was studied, root pruning had no effect on grain yield under conditions of ample moisture supply, but yield was reduced by root pruning of wide row sorghum (1.8 m spacing) under conditions of moisture stress.

scholarly journals Suitable Hosts of Root Knot Nematode Attack: An Assessment on the Basis of Morphological Size Variations and Population Density under Field Conditions

2015 ◽  
Vol 4 (2) ◽  
pp. 87-92 ◽  
Author(s):  
Gamini Sahu ◽  
Surendra K. Gautam ◽  
Aditi N. Poddar
Keyword(s):  
Population Density ◽  
Crop Plants ◽  
The Body ◽  
Field Conditions ◽  
Vegetable Crops ◽  
Vegetable Crop ◽  
Root Knot Nematode ◽  
Root Knot Nematodes ◽  
Body Sizes ◽  
Meloidogyne Species

Root knot nematodes (Meloidogyne species) are major pests of vegetable crops causing serious losses in quantity and quality of crop yield. This study involves an assessment of their suitable hosts on the basis of variations in their population densities and body sizes in different vegetable crop plants under field conditions. A random survey of root knot nematode infestation in vegetable crops was conducted in 9 villages of Abhanpur block, Chhattisgarh state, Central India, from January 2012 to March 2012.  Diseased plants were identified on the basis of above ground symptoms and soil and root samples collected by digging. Extraction of nematodes was done by Cobb’s sieving and decantation method and Baerman’s funnel technique. Identification was done microscopically by morphological examination of perineal patterns of female nematodes. Body sizes were measured by using an eyepiece/ocular micrometer. Twenty nine percent of the total farm area surveyed suffered from root knot nematode attack. Among the several genera of vegetable crop plants surveyed, Lycopersicon esculentum, Dolichos lablab, Solanum melongena, Momordica charantia, Daucus carota,Capsicum annum,Cucumis sativus had root galls. Three species of root knot nematodes Meloidogyne incognita, M. javanica, M. areneria were identified from the above hosts and a comparative morphometric analysis of the body, head and neck size ratios of females were done. Non-significant body and head size variations existing between the females from D. lablab, S. melongena, C. annum, D. carota, L. esculentum showed that all the crops are equally susceptible to root knot nematode attack.  However, on the basis of nematode population density, D. carrota appears to be the best suitable host of the Meloidogyne species other than L. esculentum and S. melongena.

scholarly journals Occurrence and seasonal changes in the population of root-knot nematodes on honeybush (Cyclopia sp.)

2021 ◽  
Vol 58 (2) ◽  
pp. 202-212
Author(s):  
F. Y. Daramola ◽  
R. Malgas ◽  
A. P. Malan
Keyword(s):  
Population Density ◽  
Parasitic Nematodes ◽  
Western Cape ◽  
Meloidogyne Hapla ◽  
Plant Parasitic Nematodes ◽  
Severe Damage ◽  
Western Cape Province ◽  
Root Knot Nematodes ◽  
Second Stage ◽  
Important Group

Summary Root-knot nematodes in the genus Meloidogyne are an important group of plant-parasitic nematodes causing severe damage on agricultural crops worldwide. A study was conducted to identify the species of root-knot nematodes causing damage on honeybush monocultures and to assess the seasonal variations in the nematode population. Soil samples were collected from six experimental sites in Genadendal, Western Cape province of South Africa from 2016 to 2017. DNA was extracted from single-second stage juveniles and species identifi cation was done using species-specifi c sequence-characterised amplifi ed regions (SCAR) primers. Meloidogyne hapla and M. javanica were identifi ed from the sites. Mean population density of the nematodes varied significantly (p < 0.05) in the six sites, with the peak population being recorded in summer of 2017. The study suggests that seasonal variation in temperature and moisture could contribute to changes in the population density of root-knot nematodes in the soil.

Sampling procedures and damage thresholds for root-knot nematode (Meloidogyne javanica) on pineapple

2000 ◽  
Vol 40 (7) ◽  
pp. 1003 ◽  
Author(s):  
G. R. Stirling ◽  
R. Kopittke
Keyword(s):  
Population Density ◽  
Crop Yields ◽  
Meloidogyne Javanica ◽  
Root Knot Nematode ◽  
Ratoon Crop ◽  
Nematode Density ◽  
Root Knot Nematodes ◽  
Nematode Population Density ◽  
Sampling Procedures ◽  
Field Plots

The relationship between the population density of root-knot nematode (Meloidogyne javanica) and pineapple yield was studied by establishing different nematode densities in field plots at 3 sites. Differences in nematode populations between treatments were apparent 9–22 months after planting, but yields in the plant crop were similar, regardless of nematode density. In the ratoon crop, yields in treatments with less than 10 nematodes/200 mL soil at 9–22 months were reduced by about 10%. Yield reductions of more than 25% occurred when population densities were greater than 50 nematodes/200 mL soil. These results demonstrate that economically significant crop losses from root-knot nematodes can occur in pineapple when the population density at 12 months is greater than 1–5 nematodes/200 mL soil. The sampling procedures required to obtain reliable estimates of M. javanica in pineapple fields were determined by studying nematode distribution in 2 fields in south-east Queensland. Nematodes were extracted from more than 100 individual soil cores on a 5 by 5 m grid and populations were found to have a clumped rather than random distribution. A composite sample of 41 cores in 1 field and 72 cores in the other gave a relatively precise estimate of the population of root-knot nematodes (i.e. standard error : mean ratio of 0.3). These data suggest that a 50-core sampling unit is appropriate when nematode population density is being estimated for decision-making purposes.

Impact of Soybean Planting Date on Soil Population Density of Macrophomina phaseolina

2007 ◽  
Vol 8 (1) ◽  
pp. 13 ◽  
Author(s):  
J. A. Wrather ◽  
J. G. Shannon ◽  
A. Mengistu
Keyword(s):  
Population Density ◽  
Soil Layer ◽  
Macrophomina Phaseolina ◽  
Planting Date ◽  
Soil Samples ◽  
Population Densities ◽  
Maturity Group ◽  
Planting Dates ◽  
Soil Population ◽  
Group 3

A field experiment was conducted during 2000-2003 near Portageville, MO to determine the affects of soybean planting date on the soil population density of Macrophomina phaseolina. The site was planted to cotton the previous 10 years. The planting dates were mid-April, mid-May, and mid-June during 2000-2003, and the cultivars FFR3975 and Asgrow 3834, maturity group 3, were very susceptible to M. phaseolina. Plots were in the same location each year. Soil samples from the top 15-cm soil layer were collected from plots during May 2000-2004 and analyzed for the population density of M. phaseolina. Planting date did not affect the soil population density of M. phaseolina, but the differences in soil population density among years were significant. These results suggest that soybean producers should not be concerned about planting date directly affecting M. phaseolina soil population densities. Accepted for publication 22 May 2007. Published 17 September 2007.

scholarly journals Green Manure Crops for Management of Meloidogyne javanica and Pythium aphanidermatum

HortScience ◽  
2015 ◽  
Vol 50 (1) ◽  
pp. 90-98 ◽  
Author(s):  
Anthony M. Ortiz ◽  
Brent S. Sipes ◽  
Susan C. Miyasaka ◽  
Alton S. Arakaki
Keyword(s):  
Population Density ◽  
Green Manure ◽  
Field Trial ◽  
Meloidogyne Javanica ◽  
Pythium Aphanidermatum ◽  
Root Knot Nematodes ◽  
Yellow Mustard ◽  
Sunn Hemp ◽  
Sorghum Sudangrass ◽  
Green Manure Crops

To determine the potential to suppress root-knot nematode Meloidogyne javanica, 10 genotypes of seven green manure species were evaluated in a greenhouse study. These species were: black hollyhock (Alcea rosea L.); canola (Brassica napus L.); cabbage (B. oleracea L.); French marigold (Tagetes patula L.), sorghum–sudangrass [Sorghum bicolor (L.) Moench nothosubsp. drummondii (Steud.) de Wet ex Davidse]; sunn hemp (Crotalaria juncea L.); and yellow mustard (Sinapis alba L.). Plants were inoculated with eggs of M. javanica and after 6 weeks, nematode eggs and reproduction factor (Rf = final egg population density/initial egg population density) were determined. Marigolds were non-hosts to M. javanica; other crop species that were poor hosts to M. javanica included canola cv. Dwarf Essex, sorghum–sudangrass cvs. Piper and Sordan 79, black hollyhock cv. Nigra, and sunn hemp. Based on low Rf, four groups of species were selected for further evaluation in the greenhouse to determine the response to both M. javanica and another crop pathogen, Pythium aphanidermatum. These four groups of green manure crops were: 1) seven marigold genotypes; 2) four Brassicaceae genotypes; 3) seven sorghum–sudangrass hybrids; and 4) four other species [black hollyhock, sunn hemp, elecampane (Inula helenium L.), and black-eyed Susan (Rudbeckia hirta L.)]. Plants were inoculated with a factorial combination of M. javanica and P. aphanidermatum (none, each alone, and in combination) and repeated four times in a split-plot experimental design (whole plots were factorial treatments and subplots were green manure crop genotypes). Six weeks after inoculation, plants were harvested and measured for fresh and dry weights of shoots and roots and Rf of M. javanica. Adverse effects of P. aphanidermatum were characterized by dead or dying roots and measured by reduced plant biomass. Negative synergistic effects were observed in several marigold and Brassicaceae genotypes, in which the combined effects of M. javanica and P. aphanidermatum reduced shoot and root growth more severely than either treatment alone. Marigold T. erecta cv. Orangeade, sorghum–sudangrass cvs. Graze-All, Piper, and Sordan 79, and sunn hemp appeared to be resistant to M. javanica and P. aphanidermatum, either alone or in combination. Based on results of greenhouse trials, eight green manure crops (yellow mustard cv. Ida Gold, French marigolds cvs. Nema-gone and Golden Guardian, sorghum–sudangrass cvs. Sordan 79 and Tastemaker, sunn hemp, unplanted plot, and a control plot with weed mat) were selected and grown for 3 months in a field trial in Pepeekeo, HI. Each treatment was replicated four times in a randomized complete block design. Shoot biomass was sampled at 1, 2, and 3 months after planting. Plant–parasitic nematodes were counted before planting and at 4 months after planting. Dry weight biomass averaged across three sampling dates was greatest for the two sorghum–sudangrass hybrids followed by those of two marigold cultivars that did not differ from them. No significant differences in populations of root-knot nematodes were found. Based on this field trial as well as greenhouse trials, marigold cultivars, sorghum–sudangrass hybrids, and sunn hemp appeared to be non-hosts or poor hosts to reniform (Rotylenchulus reniformis) as well as root-knot nematodes and well adapted to the environmental conditions found along the Hamakua Coast of the Hawaii Island.

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