POPULATION DENSITIES OF FOUR SPECIES OF ROOT-LESION NEMATODES (Pratylenchus) IN THE OAT CULTIVARS, SAIA AND OAC WOODSTOCK

1989 ◽  
Vol 69 (3) ◽  
pp. 903-905 ◽  
Author(s):  
J. L. TOWNSHEND

The population densities of four species of root-lesion nematodes (Pratylenchus) were examined in two cultivars of oat (Avena sativa L.) grown in greenhouse pots. The cultivar Saia harbored fewer P. neglectus and P. penetrans than the cultivar OAC Woodstock, while both cultivars were similar hosts for P. sensillatus. Pratylenchus crenatus did not develop in either cultivar.Key words: Oat, population density, Pratylenchus crenatus, Pratylenchus neglectus, Pratylenchus penetrans, Pratylenchus sensillatus

1991 ◽  
Vol 71 (4) ◽  
pp. 1251-1256 ◽  
Author(s):  
Th. H. A. Olthof ◽  
M. S. Wolynetz

Root-lesion nematodes (Pratylenchus penetrans) were extracted from peels of potato tubers (Solanum tuberosum 'Russet Burbank'). The average number of P. penetrans recovered over a 2-wk period in a mist chamber from four batches of tubers, stored for 3–18 wk at 7 °C in a cold room, ranged from 11 to 1925 nematodes tuber−1. An average of 374 Pratylenchus neglectus tuber−1 were recovered from the peels of potato Norchip, grown in soil containing on average 4370 nematodes kg−1 of soil at harvest, and stored for 19 wk at 7 °C. P. penetrans and P. neglectus were recovered only from the outer layer of potato tubers; none was found in the inner core. Planting halves of tubers containing an average of 1925 P. penetrans tuber−1 into nematode-free soil resulted in soil population densities of 2225 P. penetrans kg−1 of soil and root population densities of 884 nematodes root system−1 after 8 wk in the greenhouse. Although many, if not most, potato fields in southern Ontario are already infested by P. penetrans, these studies have shown that stored, infested tubers can initiate a new infestation. Key words: Peel, potato tuber, Pratylenchus neglectus, Pratylenchus penetrans, root-lesion nematode, Solanum tuberosum


2005 ◽  
Vol 80 (3) ◽  
pp. 179-184 ◽  
Author(s):  
J. Kimpinski ◽  
Y.A. Papadopoulos ◽  
B.R. Christie ◽  
K.B. McRae ◽  
C.E. Gallant

Greenhouse trials were conducted to determine the levels of invasion of birdsfoot trefoil(Lotus corniculatus) cultivars and lines by the root-lesion nematode (Pratylenchuspenetrans). Numbersof nematodesin roots grown in 50-cm3 polystyrene starter pots were determined 6 weeks after planting. Nematodes were detected in the roots of all cultivars and lines, though the degree of invasion varied significantly. In the first screening trial, carried out in 1994 on 23 cultivars and lines, NB90-104, Upstart, and Viking harbored the lowest population densities of nematodes with levels below 1 000 g-1 of dry root, while Fergus and EPF had population densities over 30 000 g-1 of dry root. In the second screening trial conducted in 1995, all nine cultivars and lines tested, including NB90-104, Upstart, and Viking, had nematode levels greater than 7 900 g-1 of dry root. The results indicated that the cultivars and lines tested in this study exhibited wide genetic variability for invasion by root-lesion nematodes.


2012 ◽  
Vol 13 (1) ◽  
pp. 4 ◽  
Author(s):  
Ann E. MacGuidwin ◽  
Breann E. Bender

Root lesion nematodes are versatile parasites that move freely between root and soil habitats. Most laboratories conduct separate assays for soil or root tissue, using time-of-year as the selecting factor. We used a dual assay that simultaneously extracts nematodes from soil and root fragments in soil samples to identify the value of soil versus root tests using 920 research samples collected 1 April to 15 May, and 853 clinic samples collected year round. Nematodes were recovered from both soil and root fragments regardless of the time of year or origin of the sample. When the data were summarized by cohort, the mean percentage of nematodes recovered from root fragments was 65% for the research samples, 59% for clinic samples submitted 1 March to 15 June, 56% for clinic samples submitted 16 June to 31 July, and 49% for clinic samples submitted after 1 August. Both the incidence and population density of root lesion nematodes was underestimated if only the soil or only the root fraction was considered, indicating the need for testing methods that consider both habitats. The variability among samples for the distribution of nematodes between root and soil habitats was high, negating the option of running one assay and using a constant scaling factor to account for the other. Accepted for publication 30 October 2012. Published 20 November 2012.


HortScience ◽  
1990 ◽  
Vol 25 (3) ◽  
pp. 318-320
Author(s):  
J.L. Townshend

The effects of temperature and root-lesion nematodes [Pratylenchus penetrans (Cobb)] on the growth of newly germinated `Bartlett' pear seedlings (Pyrus communis L.) were examined. At five temperatures from 10 to 30C, P. penetrans (five per gram of soil) did not purple the leaves. After 8 weeks, leaf number, trunk height, and top and root weights were reduced only at 25C. The number of P. penetrans in the roots were greatest at 15 and 20C. At 20C, P. penetrans (16 per gram of soil) caused the leaves of seedlings to turn purple, and, by 6 weeks after treatment, the nematodes had reduced leaf production, trunk elongation, and top and root growth.


2021 ◽  
pp. 362-367
Author(s):  
Ann E. MacGuidwin

Abstract Pratylenchus penetrans is a cosmopolitan species reported from 69 countries representing every continent except Antarctica. P. penetrans has a wide host range including potato and is found throughout the potato growing region of the northern USA. Most potato fields are infested with the fungus Verticillium dahliae as well as root lesion nematodes, and a disease interaction between the two has been demonstrated for multiple soil types, potato cultivars and production regions. The significance of the interaction between P. penetrans and V. dahliae is that it is synergistic rather than additive. This chapter discusses the economic importance, distribution, symptoms of damage, biology and life cycle, recommended integrated nematode management and management optimization of P. penetrans. Future research requirements are also mentioned.


1964 ◽  
Vol 44 (3) ◽  
pp. 272-275 ◽  
Author(s):  
G. T. Morgan ◽  
W. B. Collins

As a source of organic material in strawberry culture, composted timothy hay resulted in the greatest depression of soil populations of root lesion nematodes, Pratylenchus penetrans (Cobb. 1917) Filip & Stek., 1941. In contrast, actively growing timothy sod caused the largest increase in soil nematodes.In a crop rotation, timothy also resulted in high populations of P. penetrans while beans lowered the numbers appreciably.


HortScience ◽  
1994 ◽  
Vol 29 (9) ◽  
pp. 1074-1077 ◽  
Author(s):  
John W. Potter ◽  
Adam Dale

Intraspecific crossing of `Guardian' and `Midway' cultivated strawberry (Fragaria ×ananassa Duch.) produced a family of genotypes, some of which suppressed root-lesion nematode [Pratylenchus penetrans (Cobb)] population counts and produced large berries and high yield. Unlike `Midway', `Guardian' also suppressed P. penetrans. Among several beach strawberry [Fragaria chiloensis (L.) Duch.] and woodland strawberry (Fragaria virginiana Duch.) genotypes, variation was found in resistance and tolerance to root-lesion nematodes. Three F. chiloensis genotypes showed tolerance, and at least two genotypes may be somewhat resistant. Three F. virginiana genotypes also were tolerant, and three were resistant. Also, one (`Little Cataraqui 4') combined root growth vigor with nematode resistance. We concluded that exploitable genetic diversity in vigor and reaction to root-lesion nematodes exists in wild Fragaria and in F. ×ananassa.


2014 ◽  
Vol 15 (3) ◽  
pp. 112-117 ◽  
Author(s):  
T. C. Todd ◽  
J. A. Appel ◽  
J. Vogel ◽  
N. A. Tisserat

Observations on the prevalence and abundance of plant-parasitic nematodes were made from soil and root samples collected from 2,640 wheat fields in Kansas and Colorado during 2007-2010. Stunt nematodes (predominately Merlinius brevidens and Quinisulcius acutus), root-lesion nematodes (predominately Pratylenchus neglectus), and pin nematodes (Paratylenchus projectus) were the most commonly encountered taxa. Maximum soil population densities of 6,520 and 1,880 nematodes/100 cm3 soil were observed for pin and stunt nematodes, respectively, while a maximum root population density of 90,309 nematodes/g dry root was observed for root-lesion nematodes. Lower nematode densities were associated with wheat following corn, grain sorghum, or soybean for pin and stunt nematodes, and with wheat following fallow for root-lesion nematodes. Based on the results of this survey, 6% and 8% of wheat acreage in the central Great Plains are estimated to be at risk for significant (>5%) yield loss due to stunt nematodes and root-lesion nematodes, respectively. The number of fields with high population densities of both stunt and root-lesion nematodes was negligible (1%); therefore, the total wheat acreage with nematode populations above provisional economic thresholds is estimated to be ∼13%. Damage relationships with greater accuracy, precision, and relevance are necessary to establish reliable yield loss estimates for this region. 3 June 2014. 11 August 2014.


1989 ◽  
Vol 69 (1) ◽  
pp. 285-295 ◽  
Author(s):  
Th. H. A. OLTHOF ◽  
J. W. POTTER ◽  
P. W. JOHNSON

Redhaven peach (Prunus persica (L.) Batsch) trees, grafted on the rootstocks Bailey, Siberian C, or Harrow Blood, with roots free of, or infested by, root-lesion nematodes (Pratylenchus penetrans) were planted in fumigated or P. penetrans-infested Vineland fine sandy loam at Jordan Station, Ontario. Tree growth and soil nematode population densities were monitored for 6 yr. In general, fumigation suppressed soil populations of P. penetrans during the first 4 yr, whereas no consistent nematode control was obtained through the use of nematode-free rootstock. The rootstock Siberian C supported larger numbers of P. penetrans than the other two rootstocks throughout the experiment, whereas Bailey favored the build-up of the pin nematode (Paratylenchus projectus). Tree diameter of nematode-free rootstock was greatest in the first 3 yr only; soil fumigation alone increased growth during the first year only. Tree mortality tended to be lowest in fumigated soil planted to clean rootstocks. Harrow Blood showed the highest mortality; Siberian C the lowest. The data suggest that only nematode-free peach trees should be planted. Orchards should be fumigated if P. penetrans exceeds 800 kg−1 of soil and/or when there is a history of replant failure on a light-textured soil.Key words: Prunus persica, pin nematode, Paratylenchus projectus, replant problem, rootstocks, fumigation


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