Measuring yield loss in cereals caused by root lesion nematodes (Pratylenchus neglectus and P. thornei) with and without nematicide

1999 ◽  
Vol 50 (4) ◽  
pp. 617 ◽  
Author(s):  
S. P. Taylor ◽  
V. A. Vanstone ◽  
A. H. Ware ◽  
A. C. McKay ◽  
D. Szot ◽  
...  
Keyword(s):  
Negative Correlation ◽  
Yield Loss ◽  
Wheat Variety ◽  
Significant Negative Correlation ◽  
Multiplication Rate ◽  
Nematode Density ◽  
Wheat Varieties ◽  
Pratylenchus Neglectus ◽  
Lesion Nematodes ◽  
Root Lesion Nematodes

Yield loss caused by root lesion nematodes (Pratylenchus neglectus and P. thornei) was measured using the nematicide aldicarb (Temik 150GTM) or by correlating yield with initial or final nematode densities. In 1996, rotation trials (1 P. neglectus and 1 P. thornei) were established with susceptible and moderately resistant wheat varieties and resistant barley and triticale varieties. An intolerant oat variety (cv. Echidna) was planted over all plots in 1997. Nematode densities were 90% (P. neglectus) or 95% (P. thornei) lower in oat plots following the resistant triticale (cv. Tahara) relative to the susceptible wheat (cv. Machete). In 1997, a significant, negative correlation between both initial and final nematode density and yield was obtained. In wheat variety trials (3 sites) in 1997, a significant, negative correlation was also obtained between mean variety yield and mean final P. neglectus density or mean P. neglectus multiplication rate. Yield loss of up to 20% was calculated from the regression. In all trials, cereal varieties that were more resistant were also more tolerant. In 1996, aldicarb rate trials (1 P. neglectus and 1 P. thornei) were established to assess the affect of rate and timing of aldicarb application on yield of 2 susceptible/intolerant wheat varieties (cvv. Machete and Janz). Lower rates of aldicarb (≤1.5 kg a.i./ha) gave inconsistent nematode control and did not significantly increase yield. Rates ≥2.5 kg a.i./ha reduced nematode densities by 70–90%, resulting in up to 23% greater yield for Machete. The magnitude of yield loss caused by P. neglectus or P. thornei determined with or without nematicide was similar between trials.

Relationship between root lesion nematodes (Pratylenchus neglectus and P. thornei) and performance of wheat varieties

1998 ◽  
Vol 38 (2) ◽  
pp. 181 ◽  
Author(s):  
V. A. Vanstone ◽  
A. J. Rathjen ◽  
A. H. Ware ◽  
R. D. Wheeler
Keyword(s):  
Wheat Yield ◽  
South Australia ◽  
Nematode Species ◽  
Significant Negative Correlation ◽  
Limiting Factors ◽  
Wheat Varieties ◽  
Pratylenchus Neglectus ◽  
Lesion Nematodes ◽  
Root Lesion Nematodes ◽  
The Relationship

Summary. The root lesion nematodes Pratylenchus neglectus andP. thornei occur throughout the cereal cropping areas of South Australia. In 1996, field trials on the Eyre Peninsula of South Australia were assessed to determine the relationship between density of nematodes within field plots in early October and harvested grain yield of 9 wheat varieties. The Pratylenchus species present was either P. neglectus (at Streaky Bay, Minnipa and Kalanbi) or P. thornei (at Nunjikompita). Absence of other major yield limiting factors at these sites in 1996 enabled determination of the relationship between nematode population and wheat yield. There was a significant, negative correlation between mean yield and nematode populations for the 9 varieties at 3 of the sites (P<0.01 for Streaky Bay and Nunjikompita; P<0.05 for Minnipa). Root lesion nematodes were responsible for 56–74% of the observed varietal differences in yield at these sites. The tolerant variety Excalibur yielded 19% (Streaky Bay), 23% (Minnipa) or 33% (Nunjikompita) more than the intolerant variety Spear, and Excalibur resulted in 69, 63 or 66% fewer nematodes, respectively, than in plots of Spear. Although nematode populations could not be assessed at the Kalanbi site, varietal yield relations were similar to the other sites, with Excalibur yielding 18% more than Spear. The 9 varieties were ranked for both resistance and tolerance to the 2 nematode species.

Pratylenchus penetrans and P. neglectus in tubers of potato (Solanum tuberosum) in Ontario

1991 ◽  
Vol 71 (4) ◽  
pp. 1251-1256 ◽  
Author(s):  
Th. H. A. Olthof ◽  
M. S. Wolynetz
Keyword(s):  
Solanum Tuberosum ◽  
Inner Core ◽  
Pratylenchus Penetrans ◽  
Potato Tubers ◽  
Population Densities ◽  
Pratylenchus Neglectus ◽  
Lesion Nematodes ◽  
Cold Room ◽  
Mist Chamber ◽  
Root Lesion Nematodes

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

Genetic variation in resistance to Pratylenchus neglectus in wheat and triticales

1995 ◽  
Vol 35 (5) ◽  
pp. 597 ◽  
Author(s):  
M Farsi ◽  
VA Vanstone ◽  
JM Fisher ◽  
AJ Rathjen
Keyword(s):  
Yield Loss ◽  
Genetic Material ◽  
Whole Genome ◽  
Root Lesion Nematode ◽  
Substitution Lines ◽  
Wheat Varieties ◽  
Pratylenchus Neglectus ◽  
Significant Difference ◽  
Genetic Mechanisms ◽  
Lesion Nematode

The root lesion nematode Pratylenchus neglectus occurs throughout the South Australian cereal belt, where it potentially contributes to yield loss. Genetic material was examined for resistance to P. neglectus, and included 2 susceptible local commercial wheat varieties (Spear, Molineux), 2 derivatives from Spear (RAC 613-27, RAC 613-47), wheat varieties varying in reaction to I? thornei, rye and rye derivatives, triticales, and 1R substitution lines in Chinese Spring. Seeds were surface-sterilised and germinated, and 3-day-old seedlings were inoculated with about 250 larvae and 150 eggs. Plants were grown in pots containing pasteurised soil and transferred to a controlled temperature waterbath at 22 � 1�C. After 7 weeks, nematodes were extracted and counted. A significant difference for the number of nematodes per plant and per gram dry root was found between the 3 main groups of genetic material: the wheat varieties, the substitution lines, and lines with the whole genome of rye (including triticales). The triticales Abacus and Muir showed the lowest number of nematodes (per gram root and per plant). None of the wheat varieties was resistant, so genetic mechanisms conferring resistance or tolerance to P. thornei are not effective against P. neglectus.

scholarly journals Survey of Plant-Parasitic Nematodes in Kansas and Eastern Colorado Wheat Fields

2014 ◽  
Vol 15 (3) ◽  
pp. 112-117 ◽  
Author(s):  
T. C. Todd ◽  
J. A. Appel ◽  
J. Vogel ◽  
N. A. Tisserat
Keyword(s):  
Great Plains ◽  
Yield Loss ◽  
Parasitic Nematodes ◽  
Plant Parasitic Nematodes ◽  
Population Densities ◽  
Economic Thresholds ◽  
Lesion Nematodes ◽  
Maximum Root ◽  
Root Lesion Nematodes ◽  
Plant Parasitic

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.

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
Keyword(s):  
Population Density ◽  
Avena Sativa ◽  
Pratylenchus Penetrans ◽  
Population Densities ◽  
Pratylenchus Neglectus ◽  
Lesion Nematodes ◽  
Oat Cultivars ◽  
Root Lesion Nematodes

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

Root-lesion nematode (Pratylenchus thornei) limits response of wheat but not barley to stored soil moisture in the Hermitage long-term tillage experiment

1995 ◽  
Vol 35 (7) ◽  
pp. 1049 ◽  
Author(s):  
JP Thompson ◽  
J Mackenzie ◽  
R Amos
Keyword(s):  
Maximum Yield ◽  
No Tillage ◽  
Root Lesion Nematode ◽  
Wheat Varieties ◽  
Stubble Retention ◽  
Pratylenchus Thornei ◽  
Lesion Nematodes ◽  
Lesion Nematode ◽  
Root Lesion Nematodes

The cumulative effects of factorial treatments of tillage (no tillage, conventional), stubble retention (burnt, retained), and nitrogen fertiliser (0, 23, 69 kg N/ha) on yield of continuous winter cereals and on soil properties have been tested in the Hermitage fallow management experiment since 1969. Despite increased soil water stored from the combination of no tillage and stubble retention, wheat responses to the extra water were disappointing in the first 11 years of the experiment. Soil samples from the experiment were shown to be heavily infested with the root-lesion nematode (Pratylenchus thornei Sher and Allen), and therefore in 1980, the main plots were split for crop (wheat cv. Timgalen, barley cv. Clipper) and nematicide treatment (nil, aldicarb). Barley (maximum yield 3.2 t/ha) tolerated the nematodes and responded in this dry year to the extra stored water accumulated with no tillage and stubble retention, but wheat (maximum yield 1.22 t/ha) did not. Nematicide increased wheat yields by 42%. The results from the changes to the Hermitage experiment in 1980 show the importance of considering root-lesion nematodes in interpreting results from long-term experiments involving wheat and in applying those results to farms. Control of root-lesion nematodes on farms by crop rotation and by growing tolerant and resistant wheat varieties is needed to obtain full yield benefits from improved tillage practices.

scholarly journals Cover Crops Resistant to Root-lesion Nematodes in Raspberry

HortScience ◽  
1996 ◽  
Vol 31 (7) ◽  
pp. 1195-1198 ◽  
Author(s):  
Thierry Vrain ◽  
Robyn DeYoung ◽  
John Hall ◽  
Stan Freyman
Keyword(s):  
White Clover ◽  
Cover Crops ◽  
Cover Crop ◽  
Rubus Idaeus ◽  
Pratylenchus Penetrans ◽  
Nematode Density ◽  
Red Fescue ◽  
Lesion Nematodes ◽  
Lesion Nematode ◽  
Root Lesion Nematodes

Cover crops used in red raspberry plantings (Rubus idaeus L.) are often good hosts of the root-lesion nematode (Pratylenchus penetrans Filipjev & Sch. Stekoven), a major soilborne pathogen of raspberry. The effects of two susceptible cover crops, white clover (Trifolium repens L.) and barley (Hordeum vulgare L.), planted in between rows, on nematode density and growth of raspberry plants were compared to those of three cover crops resistant to the nematode: redtop (Agrostis alba L.), creeping red fescue (Festuca rubra L.), and `Saia' oat (Avena sativa L.). Nematode multiplication in raspberry roots and in cover crop roots was assessed over 4 years. Growth and vigor of plants were estimated at the end of the experiment by counting primocanes and determining height and biomass. Nematode multiplication was suppressed in roots of `Saia' oat, fescue, and redtop compared to barley or white clover. Nematode density in roots and rhizosphere soil of raspberry was not affected by the choice of cover crops. Nematode suppression in the three resistant cover crops did not translate into increased vigor of raspberry plants.

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