scholarly journals Soybean Cyst Nematode (Heterodera glycines) Distribution in North Carolina, U.S.A.

2017 ◽  
Vol 18 (4) ◽  
pp. 230-232 ◽  
Author(s):  
Weimin Ye

Soybean cyst nematode (SCN), Heterodera glycines Ichinohe, is an obligate, sedentary, and devastating parasite that is a major pathogen of soybean and accounts for an estimated $1.2 billion in production losses annually in the United States. SCN was first discovered in the United States in New Hanover County, North Carolina, in 1954. This report summarizes lab assay and survey results from July 1, 2014, to June 30, 2017. In this period, 100,118 grower samples were assayed for nematodes. SCN was detected in 21,922 of the soil samples (21.9%). The overall population level was 110 ± 266 (10 to 14,600) per 500 cm3 of soil. Based on the assay results from grower and survey soil samples, Anson, Catawba, Chatham, Dare, and Lincoln counties were added to the list of SCN-positive counties documented by June 30, 2014, bringing the total to 57. Johnston (3,462 SCN-positive samples), Wayne (3,274), Nash (2,960), Wilson (2,039), and Pasquotank (1,513) had the most SCN-positive samples. Montgomery (831 SCN/500 cm3 of soil on average), Bladen (790), Washington (610), Carteret (607), and Harnett (368) were found to have the highest SCN population levels.

2017 ◽  
Vol 18 (3) ◽  
pp. 167-168 ◽  
Author(s):  
Gregory L. Tylka ◽  
Christopher C. Marett

The soybean cyst nematode (SCN) is a major yield-reducing pathogen of soybeans in North America. The nematode is an introduced pest and, therefore, knowledge of the distribution of SCN can be helpful in identifying areas where scouting and management efforts should be focused. Such information is especially important because yield-reducing infestations of SCN can occur without obvious above-ground symptoms appearing. In late 2016, nematologists, plant pathologists, and state plant regulatory officials from the soybean-producing states in the United States and provinces in Canada were queried to obtain the latest information on where the nematode had been found. An updated map of the known distribution of SCN in North America was also created. There were 17 states in which SCN was newly found since 2014, when the map was last updated, including the first discovery of SCN in the state of New York. North Dakota was the state with the greatest number of counties, seven, in which SCN had been newly discovered since 2014. This updated information illustrates that the nematode continues to spread throughout the soybean-growing areas of the continent and emphasizes that continued efforts to scout for and manage SCN are warranted.


Author(s):  
Gregory L. Tylka ◽  
Christopher C. Marett

In the United States and Canada, the most damaging pathogen of soybean, Glycine max, is the soybean cyst nematode (SCN), Heterodera glycines. Plant health professionals working for universities and state and provincial departments of agriculture in the United States and Canada are queried periodically about counties and rural municipalities that are newly known to be infested with SCN in their states and provinces. Such a census was conducted in 2020, and the results were compared with results of the most recent survey, published in 2017. Between 2017 and 2020, 55 new SCN-infested counties were reported from 11 U.S. states. Also, 24 new SCN-infested counties and rural municipalities were identified in the Canadian provinces of Manitoba, Ontario, and Quebec. A map of the known distribution of SCN in these two countries was updated. The results reveal steady expansion of the distribution of SCN throughout the United States and Canada, and the pest almost certainly will continue to spread among and within soybean-producing areas of these countries in the future. Therefore, continued scouting and soil sampling for detection of new SCN infestations are warranted as the first step toward successfully managing the pathogen.


2014 ◽  
Vol 15 (2) ◽  
pp. 85-87 ◽  
Author(s):  
Gregory L. Tylka ◽  
Christopher C. Marett

The soybean cyst nematode (Heterodera glycines) is considered the most damaging pathogen of soybean in the USA and Canada, and causes considerable yield loss in many other soybean-producing countries. It is believed to have been introduced into North America from Asia. The map of the known distribution of H. glycines in the USA and Canada has been updated for 2014. Maps of its known distribution in past years illustrate the spread of the pathogen since its initial discovery in the United States in 1954. Accepted for publication 20 April 2014. Published 27 May 2014.


2021 ◽  
Author(s):  
Intiaz Amin Chowdhury ◽  
Guiping Yan ◽  
Addison Plaisance ◽  
sam markell

Soybean cyst nematode (SCN; Heterodera glycines) continues to be the greatest threat to soybean production in the United States. Since host resistance is the primary strategy used to control SCN, knowledge of SCN virulence phenotypes (HG types) is necessary for choosing sources of resistance for SCN management. To characterize SCN virulence phenotypes in North Dakota (ND), a total of 419 soybean fields across 22 counties were sampled during 2015, 2016, and 2017. SCN was detected in 42% of the fields sampled and population densities in these samples ranged from 30 to 92,800 eggs and juveniles per 100 cm3 of soil. The SCN populations from some of the infested fields were virulence phenotyped with seven soybean indicator lines and a susceptible check (Barnes) using the HG type tests. Overall, 73 SCN field populations were successfully virulence phenotyped. The HG types detected in ND were HG type 0 (frequency rate: 36%), 7 (27%), 2.5.7 (19%), 5.7 (11%), 1.2.5.7 (4%), and 2.7 (2%). However, prior to this study only HG type 0 was detected in ND. The designation of each of the HG types detected was then validated in this study by repeating the HG type tests for thirty-three arbitrarily selected samples. This research for the first time reports several new HG types detected in ND and confirms that the virulence of SCN populations is shifting and overcoming resistance, highlighting the necessity of utilization of different resistance sources, rotation of resistance sources, and identification of novel resistance sources for SCN management in ND.


2021 ◽  
pp. 117-124
Author(s):  
Gregory L. Tylka

Abstract This chapter focuses on the economic importance, host range, geographical distribution, damage symptoms and biology and life cycle of the soyabean cyst nematode, Heterodera glycines, a pervasive and destructive pest to soyabean production in the mid-western USA. Some information on its interaction with other plant pathogens, the efficacy and optimization of some recommended integrated nematode management practices and future outlook and research requirements are also presented.


Nematology ◽  
2008 ◽  
Vol 10 (6) ◽  
pp. 919-924 ◽  
Author(s):  
Mansour Salati ◽  
Robert Riggs ◽  
Zahra Tanha Maafi

AbstractThe soybean cyst nematode (SCN), Heterodera glycines, found in most soybean growing regions in the world, is considered the most economically damaging pathogen of soybean worldwide. A survey conducted in the northern provinces of Mazandaran and Golestan, the main soybean-producing areas in Iran, revealed SCN was widespread in different localities of these regions. Of the 55 and 88 soil samples collected from soybean fields in Mazandaran and Golestan provinces, respectively, ten (18.8%) and 23 (26%) samples were infested with H. glycines; the population densities of second-stage juveniles (J2) and eggs ranged from 500 to 60 000 and 500 to ≥100 000 per 250 cm3 soil, respectively. These population densities of H. glycines are indicative of reductions in soybean yield. HG Type tests were conducted on 16 field populations. HG Type 0 (race 3) was the most common with 94% frequency, whereas HG Type 7 (race 6) was found in 6% of tested populations. Most populations of H. glycines parasitised PI88788 and PI548316. Eight of the most commonly used soybean cultivars were tested against H. glycines HG Type 0; seven of them, Sepideh, Sahar (Pershing), Gorgan 3, Williams 82, JK (Sari), BP (Telar) and Hill, had high female indices and were considered susceptible to HG Type 0. Only the cultivar DPX showed low female indices and was resistant to race 3. The initial observations showed that the first life cycle of SCN required 30-34 days in early-planted fields (late May and early June), whereas in late-planted fields (early July), white females were visible 20 days after planting. Several generations could be expected in a single growing season under field conditions in northern Iran.


2021 ◽  
Vol 25 (03) ◽  
pp. 735-741
Author(s):  
Xiujuan Yan

Jilin is the dominant soybean production province in China. Soybean cyst nematode [Heterodera glycines] (SCN) is one of the most important yield-limiting factors in soybean production. Information about the distribution and virulence phenotypes of SCN in soybean fields are essential for optimizing varieties choice in the region. The distribution and virulence phenotypes of SCN in 141 soil samples from 38 cites (cities, counties and towns) across Jilin province were investigated. One hundred and four (73.76%) of the samples from all 38 cities (counties, towns) tested positive for SCN and SCN population densities were more than 5 cysts/100 mL soil in 53 samples from 27 cities (counties, towns). In those 53 samples, we identified 7 races and 12 Heterodera glycines (HG) types, with Race 3 and HG Type 7 being the most dominant genotypes. Of all the genotypes identified, Race10 and HG Type 1.7 were found for the first time in China, and HG Type 3.4.5.7 was the first reported worldwide. Thirty-eight SCN populations (34.5%) were virulent on plant introduction (PI) 548316 (#7) and 15 of them had female indices (FI) ≥ 10% on Pickett. PI 548316 and Pickett were not recommended as parents of breeding against cyst nematode in Jilin province. Peking-type resistance sources were preferred to pi88788-type in Jilin province. In addition, it was found neither the race nor HG scheme is sufficient for differentiating SCN populations in Jilin province, nor the combination of the two methods is recommended for studying the genetic diversity of SCN in Jilin province. That is, Pickett which was removed in HG scheme should be included not as an indicator line but just to separate different races from the same HG type. © 2021 Friends Science Publishers


Author(s):  
Krishna Acharya ◽  
Guiping Yan

Soybean cyst nematode (SCN; Heterodera glycines) is one of the devastating soybean pests worldwide, including the United States. Resistant cultivars combined with crop rotation are the primary methods for managing this nematode. SCN is known to have genetically diverse populations and can develop new virulent forms over time due to the continuous planting of cultivars derived from same source of resistance. Thus, identifying novel SCN resistant sources is of paramount importance for soybean breeding for nematode resistance. In this study, we screened 149 early maturity soybean [Glycine max (L.)] accessions for resistance to SCN HG type 2.5.7, which is one of the prevalent virulent SCN populations in North Dakota. SCN white females were extracted from individual plants of each accession after 35 days of growth in greenhouse conditions. The females were counted to determine a female index [FI = (average number of females on a tested accession/average number of females in Barnes, a susceptible soybean check) x 100]. The resistance response of each soybean accession was categorized as resistant, moderately resistant, moderately susceptible, and susceptible. Out of the soybean 149 accessions tested, only 13 were resistant in both runs of the experiments. The majority of screened soybean accessions were susceptible or moderately susceptible to the SCN HG type 2.5.7. The resistant soybean accessions identified in this study have the potential to be used in breeding SCN-resistant cultivars after further elucidation of the resistance genes or loci.


Plant Disease ◽  
2016 ◽  
Vol 100 (11) ◽  
pp. 2281-2286 ◽  
Author(s):  
K. Acharya ◽  
C. Tande ◽  
E. Byamukama

The soybean cyst nematode (SCN), Heterodera glycines, is the most important yield-limiting pathogen of soybean in the United States. In South Dakota, SCN has been found in 29 counties, as of 2016, and continues to spread. Determining the virulence phenotypes (HG types) of the SCN populations can reveal the diversity of the SCN populations and the sources of resistance that would be most effective for SCN management. To determine the HG types prevalent in South Dakota, 250 soil samples were collected from at least three arbitrarily selected fields in each of the 28 counties with fields previously found to be infested with SCN. SCN was detected in 82 fields (33%), and combined egg and juvenile counts ranged from 200 to 65,200 per 100 cm3 of soil. Eggs and juveniles were extracted from each soil sample and were used to infest seven SCN HG type test indicator soybean lines and ‘Williams 82’ as the susceptible check. A female index (FI) was calculated based on the number of females found on each indicator line relative to those on the susceptible check. A FI equal to or greater than 10% in any line was assigned as that HG type. Out of 73 SCN populations for which HG type tests were done, 63% had FI ≥10% on PI 548316 (indicator line #7), 25% on PI 88788 (#2), 19% on PI 209332 (#5), 7% on PI 548402 (#1), 4% on PI 90736 (#3), and 4% on PI 89722 (#6). None of the SCN populations had FI ≥10% on PI 437654 (indicator line #4). The most prevalent HG types were 0, 2.5.7, and 7. These accounted for 81% of all the HG types determined for the samples tested. HG types with ≥10% reproduction on indicator lines PI 88788, PI 209332, and PI 548317 were most prevalent in the soil samples tested, suggesting that the use of these sources of resistance for developing SCN resistant cultivars should be avoided. For sustainable SCN management, use of resistant cultivars should be rotated with nonhost crops and cultivars with different sources of resistance.


Author(s):  
Tom Maier ◽  
Rick E. Masonbrink ◽  
Paramasivan Vijayapalani ◽  
Michael Gardner ◽  
Amanda D. Howland ◽  
...  

The soybean cyst nematode, Heterodera glycines, is the most economically devastating pathogen of soybean in the United States and threatens to become even more damaging through the selection of virulent nematode populations in the field that can overcome natural resistance mechanisms in soybean cultivars. This pathogen, therefore, demands intense transcriptomic/genomic research inquiries into the biology of its parasitic mechanisms. H. glycines delivers effector proteins that are produced in specialized gland cells into the soybean root to enable infection. The study of effector proteins, thus, is particularly promising when exploring novel management options against this pathogen. Here we announce the availability of a gland cell-specific RNA-seq resource. These data represent an expression snapshot of gland cell activity during early soybean infection of a virulent and an avirulent H. glycines population, which provides a unique and highly valuable resource for scientists examining effector biology and nematode virulence.


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