Assessing direct and residual effects of cover crops on the soybean cyst nematode, Heterodera glycines

Plant Disease ◽  
2021 ◽  
Author(s):  
Chelsea J. Harbach ◽  
Gregory L. Tylka
Keyword(s):  
Cover Crops ◽  
Cover Crop ◽  
Soybean Cyst Nematode ◽  
Heterodera Glycines ◽  
Cyst Nematode ◽  
Residual Effects ◽  
Infested Soil ◽  
Annual Ryegrass ◽  
Population Densities ◽  
Crimson Clover

Greenhouse experiments were conducted to determine if cover crops directly decrease population densities of the soybean cyst nematode (SCN), Heterodera glycines, and/or have residual effects on reproduction of the nematode on soybean (Glycine max). Population densities of SCN were not significantly decreased by nine cover crop plants or three cover crop mixes compared to a non-planted soil control in a repeated 60-day-long greenhouse experiment. When susceptible soybeans were grown in the soils after cover crop growth, fewer SCN females formed following three annual ryegrass (Lolium multiflorum) cultivars (Bounty, King, and RootMax), the Daikon radish (Raphanus sativus var. longipinnatus) cultivar CCS779, Kodiak mustard (Brassica juncea), and a mix containing cereal rye, crimson clover (Trifolium incarnatum), plus Daikon radish (cultivars not stated) compared to following the non-planted control. In another repeated experiment, cover crops were grown for 56 days in SCN-infested soil in the greenhouse then exposed to Iowa winter conditions for 28 days to simulate winter termination of the plants. One treatment, a cover crop mix containing Bounty annual ryegrass plus Enricher Daikon radish, had a decrease in SCN population density greater than the non-planted control at the end of the experiment. Significantly fewer SCN females formed on soybeans grown following several cover crops, including the three annual ryegrass cultivars that had the suppressive residual effects in the first experiment. In summary, there were no cover crop treatments that consistently decreased SCN population densities across experiments, and only one cover crop treatment in one experiment significantly reduced SCN population densities more than a non-planted soil control. However, there was a somewhat consistent, adverse, residual effect of cover crops on reproduction of SCN on susceptible soybeans following growth of multiple cover crops.

scholarly journals A mechanistic approach to assessing the potential for cover crops to serve as trap crops for the soybean cyst nematode

Plant Disease ◽  
2020 ◽  
Author(s):  
Chelsea J Harbach ◽  
Elizabeth Wlezien ◽  
Gregory L Tylka
Keyword(s):  
Cover Crops ◽  
Cover Crop ◽  
Soybean Cyst Nematode ◽  
Cyst Nematode ◽  
Crop Plants ◽  
Root Penetration ◽  
Annual Ryegrass ◽  
Trap Crops ◽  
Cereal Rye ◽  
Crimson Clover

The effects of cover crops on the biology of the soybean cyst nematode (SCN), Heterodera glycines, are not well established. It is possible that cover crops may reduce SCN population densities by acting as trap crops. Cover crops with potential to serve as trap crops may stimulate hatching and/or attract hatched SCN juveniles and also may be penetrated by large numbers of nematodes that cannot feed. Experiments were conducted to determine if root exudates and soil leachates (RE+SL) from various cover crop plants affected SCN hatching and chemotaxis and if there were significant differences in SCN juvenile root penetration among different cover crop plant types. In fourteen-day-long hatching experiments, there was greater SCN hatching in crimson clover (Trifolium incarnatum) RE+SL than in RE+SL from all other cover crop treatments in the experiments. No other cover crop RE+SL significantly affected hatching. In chemotaxis experiments, SCN juveniles were attracted to RE+SL from annual ryegrass (Lolium multiflorum) and cereal rye (Secale cereal) after 24 hours. In greenhouse experiments, significantly more SCN juveniles penetrated the roots of single cultivars of crimson clover, mustard (Brassica juncea), and rapeseed (Brassica napus) than 11 other cover crop species/cultivars evaluated in the experiment over the course of 20 days. Few SCN juveniles penetrated the roots of annual ryegrass and cereal rye. The results suggest crimson clover, grown as a cover crop, has the most potential to act as a trap crop for SCN. Cover crop plants may affect SCN biology in ways other than the mechanisms investigated in these experiments.

Effects of Cover Crops on Population Reduction of Soybean Cyst Nematode (Heterodera glycines)

Plant Disease ◽  
2020 ◽  
Author(s):  
Krishna Acharya ◽  
Guiping Yan ◽  
Addison Plaisance
Keyword(s):  
Cover Crops ◽  
Soybean Cyst Nematode ◽  
Heterodera Glycines ◽  
Foxtail Millet ◽  
Cyst Nematode ◽  
Natural Soil ◽  
Initial Population ◽  
Annual Ryegrass ◽  
Initial Population Density ◽  
Population Reduction

Microplot experiments were conducted to evaluate the effects of cover crops on population reduction of a major soybean pest, soybean cyst nematode (SCN; Heterodera glycines Ichinohe) in 2016 and 2017. Ten crop species, including annual ryegrass (Lolium multiflorum L), Austrian winter pea (Pisum sativum L. subsp. arvense), carinata (Brassica carinata A. Braun), faba bean (Vicia faba Roth), foxtail millet [Setaria italica (L) P. Beauvois], daikon radish (Raphanus sativus L.), red clover (Trifolium pratense L.), sweetclover (Melilotus officinalis L.), turnip (Brassica rapa subsp. rapa L.), and winter rye (Secale cereale L.) were planted along with susceptible soybean [Glycine max (L.) Merr., cv. Barnes] in soil naturally infested with each of two SCN populations (SCN103 and SCN2W) from two North Dakota soybean fields. Crops were grown in large plastic pots for 75 days in an outdoor environment (Microplot). Soil samples were collected from each pot for nematode extraction and SCN eggs were counted to determine the final SCN egg density. The population reduction was determined for each crop, and non-planted natural soil (fallow). All the tested crops and non-planted natural soil had significantly (P < 0.0001) lower final population densities compared to susceptible soybean (Barnes). Also, a significant difference (P < 0.0001) was observed between the SCN population suppressions caused by cover crops versus the fallow treatment. All cover crops except Austrian winter pea, carinata, faba bean, and foxtail millet had consistently lower SCN egg numbers than in fallow in both years of the experiments. The average population reductions of SCN by the cover crops ranged from 44 to 67% in comparison with the initial population density, while the fallow had natural reductions from 4 to 24%. Annual ryegrass and daikon radish reduced SCN egg numbers to a greater extent than the other cover crops, with an average of 65 and 67% reduction of initial population density, respectively from two years. The results suggested that cover crops reduced the SCN populations in external microplot conditions, and their use has great potential for improving SCN management in infested fields.

Potential for Soybean Cyst Nematode Reproduction on Winter Weeds and Cover Crops in Tennessee

2007 ◽  
Vol 8 (1) ◽  
pp. 25 ◽  
Author(s):  
P. A. Donald ◽  
Robert Hayes ◽  
Eric Walker
Keyword(s):  
Population Density ◽  
Cover Crops ◽  
Cover Crop ◽  
Soybean Cyst Nematode ◽  
Management Strategies ◽  
Cyst Nematode ◽  
No Tillage ◽  
Nematode Reproduction ◽  
Tillage Practices ◽  
Crimson Clover

The soybean cyst nematode (SCN), Heterodera glycines, is a major yield limiting pest of soybean (Glycine max). Current SCN management strategies include resistant soybean varieties and rotation with non-host crops. Increased adoption of the early soybean production system (ESPS) combined with a greater incidence of winter weeds from no-tillage practices may increase the population density of SCN during the noncrop period since several winter weeds and cover crops are hosts for SCN. A field experiment with a split-strip design was conducted over three years to evaluate whether SCN reproduced on weeds and cover crops during the noncrop period. Winter weeds and crimson clover roots were examined for females and cysts with eggs. The soil was sampled to determine if an increase in SCN egg population density occurred. We found no indication of SCN reproduction on winter weeds during the noncrop period or on the cover crop crimson clover. Accepted for publication 2 November 2006. Published 26 February 2007.

Plant Growth and Soybean Cyst Nematode Response to Purple Deadnettle (Lamium purpureum), Annual Ryegrass, and Soybean Combinations

Weed Science ◽  
2009 ◽  
Vol 57 (5) ◽  
pp. 489-493 ◽  
Author(s):  
Valerie A. Mock ◽  
J. Earl Creech ◽  
Vince M. Davis ◽  
William G. Johnson
Keyword(s):  
Population Density ◽  
Plant Growth ◽  
Cover Crop ◽  
Soybean Cyst Nematode ◽  
Cyst Nematode ◽  
Annual Ryegrass ◽  
Population Densities ◽  
Resistant Plant ◽  
Greenhouse Study

A greenhouse study was conducted to determine the influence of soybean cyst nematode (SCN) –susceptible and –resistant plant combinations on SCN population densities and plant growth. Purple deadnettle, annual ryegrass, SCN-resistant and -susceptible soybean were planted in pots alone or in combination at one plant pot−1. Annual ryegrass and purple deadnettle reduced soybean growth. Pots with SCN-resistant plants had lower numbers of SCN cysts and eggs than pots with SCN-susceptible plants. However, an SCN-susceptible species grown with any of the SCN-resistant plants resulted in higher cyst counts than pots with only SCN-resistant plants. From an SCN management standpoint, this research suggests that there may be no incentive to using annual ryegrass as a cover crop over planting other SCN-resistant crops to reduce SCN population density.

Nematicidal activity of ethanol solutions on soybean cyst nematode Heterodera glycines

Nematology ◽  
2019 ◽  
Vol 22 (1) ◽  
pp. 111-121
Author(s):  
Luma A. Pedroso ◽  
Vicente P. Campos ◽  
Aline F. Barros ◽  
Julio C.P. Silva ◽  
Gustavo M. Assis ◽  
...  
Keyword(s):  
Lipid Content ◽  
Sustainable Management ◽  
Soybean Cyst Nematode ◽  
Management Practices ◽  
Heterodera Glycines ◽  
Cyst Nematode ◽  
Infested Soil ◽  
Tropical Regions ◽  
Second Stage ◽  
Low Concentrations

Summary The cyst nematode, Heterodera glycines, is a major pathogen of soybean in tropical regions, which demands novel sustainable management practices. In this work, the use of ethanol against H. glycines was evaluated as both a solution and a fumigant. On second-stage juveniles (J2) of H. glycines, ethanol at low concentration was more effective by direct dipping than by only fumigating the J2. Hatching was significantly reduced by direct dipping in ethanol solutions. Fumigation of H. glycines-infested soil with ethanol reduced infectivity by almost 100% and the number of eggs by about 67% at ethanol concentrations of 48% and 72%, respectively. Only the ethanol at 48% concentration significantly reduced the J2 lipid content, while J2 infectivity and the number of eggs were reduced by dipping at 6% ethanol. The J2 were internally altered by the ethanol solutions. Therefore, ethanol is toxic to H. glycines at low concentrations and affects its pathogenic behaviour rather than simply reducing the lipids.

Herbicide Programs for the Termination of Various Cover Crop Species

2017 ◽  
Vol 31 (4) ◽  
pp. 514-522 ◽  
Author(s):  
Cody D. Cornelius ◽  
Kevin W. Bradley
Keyword(s):  
Cover Crops ◽  
Cover Crop ◽  
Field Experiments ◽  
Crop Yields ◽  
Production Systems ◽  
Annual Ryegrass ◽  
Crop Species ◽  
Cereal Rye ◽  
Crimson Clover ◽  
Herbicide Treatments

The recent interest in cover crops as a component of Midwest corn and soybean production systems has led to a greater need to understand the most effective herbicide treatments for cover crop termination prior to planting corn or soybean. Previous research has shown that certain cover crop species can significantly reduce subsequent cash crop yields if not completely terminated. Two field experiments were conducted in 2013, 2014, and 2015 to determine the most effective herbicide program for the termination of winter wheat, cereal rye, crimson clover, Austrian winter pea, annual ryegrass, and hairy vetch; and cover crops were terminated in early April or early May. Visual control and above ground biomass reduction was determined 28 d after application (DAA). Control of grass cover crop species was often best with glyphosate alone or combined with 2,4-D, dicamba, or saflufenacil. The most consistent control of broadleaf cover crops occurred following treatment with glyphosate +2,4-D, dicamba, or saflufenacil. In general, control of cover crops was higher with early April applications compared to early May. In a separate study, control of 15-, 25-, and 75-cm tall annual ryegrass was highest with glyphosate at 2.8 kg ha−1or glyphosate at 1.4 kg ha−1plus clethodim at 0.136 kgha−1. Paraquat- or glufosinate-containing treatments did not provide adequate annual ryegrass control. For practitioners who desire higher levels of cover crop biomass, these results indicate that adequate levels of cover crop control can still be achieved in the late spring with certain herbicide treatments. But it is important to consider cover crop termination well in advance to ensure the most effective herbicide or herbicide combinations are used and the products are applied at the appropriate stage.

Distribution, population density, race and type determination of soybean cyst nematode, Heterodera glycines, in Iran

Nematology ◽  
2008 ◽  
Vol 10 (6) ◽  
pp. 919-924 ◽  
Author(s):  
Mansour Salati ◽  
Robert Riggs ◽  
Zahra Tanha Maafi
Keyword(s):  
Soybean Cyst Nematode ◽  
Heterodera Glycines ◽  
Growing Season ◽  
Cyst Nematode ◽  
Soil Samples ◽  
Population Densities ◽  
Northern Iran ◽  
Second Stage ◽  
The World

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.

scholarly journals Soybean Stem Colonization by Genotypes A and B of Cadophora gregata Increases with Increasing Population Densities of Heterodera glycines

Plant Disease ◽  
2006 ◽  
Vol 90 (10) ◽  
pp. 1297-1301 ◽  
Author(s):  
G. M. Tabor ◽  
G. L. Tylka ◽  
C. R. Bronson
Keyword(s):  
Population Density ◽  
Soybean Cyst Nematode ◽  
Heterodera Glycines ◽  
Cyst Nematode ◽  
Stem Rot ◽  
Population Densities ◽  
Brown Stem Rot ◽  
Phialophora Gregata ◽  
Soybean Genotypes ◽  
Genotype A

Growth chamber experiments were conducted to investigate whether parasitism by increasing population densities of Heterodera glycines, the soybean cyst nematode, increases the incidence and severity of stem colonization by the aggressive genotype A and the mild genotype B of Cadophora gregata (Phialophora gregata), causal agents of brown stem rot of soybeans. Soybean genotypes with three combinations of resistance and susceptibility to H. glycines and genotype A of C. gregata were inoculated with each genotype of C. gregata alone or each genotype with two population densities of H. glycines eggs, 1,500 or 10,000 per 100 cm3 of soil. Stems of two H. glycines-susceptible soybeans were more colonized by both aggressive and mild genotypes of C. gregata in the presence of high than in the presence of low H. glycines population density.

scholarly journals Distribution and Virulence Phenotypes of Heterodera glycines in Missouri

Plant Disease ◽  
2003 ◽  
Vol 87 (8) ◽  
pp. 929-932 ◽  
Author(s):  
T. L. Niblack ◽  
J. A. Wrather ◽  
R. D. Heinz ◽  
P. A. Donald
Keyword(s):  
Soybean Cyst Nematode ◽  
Heterodera Glycines ◽  
Phenotypic Diversity ◽  
Research Priorities ◽  
Plant Introduction ◽  
Cyst Nematode ◽  
Population Densities ◽  
Sources Of Resistance ◽  
Resistant Varieties ◽  
Two Samples

The soybean cyst nematode, Heterodera glycines, is the most economically important pathogen of soybean in Missouri. Knowledge of the nematode's distribution and ability to adapt to resistant varieties is important for determining crop losses and establishing research priorities. No previous surveys of Missouri have provided reliable population density and phenotypic diversity data; therefore, we conducted a random survey to obtain both. Two samples from each of 200 fields were collected; 392 samples were processed for extractions of cysts and eggs. Two hundred and forty seven (63%) of the samples had detectable cyst nematode populations, which ranged from 15 to 149,700 eggs per 250 cm3 of soil. The lowest average population densities were observed in the east-central region of Missouri (2,260 eggs per 250 cm3 of soil), and the highest were observed in the northeast (9,238 eggs per 250 cm3 of soil), but among the eight regions sampled, mean population densities did not differ significantly. These population densities were potentially responsible for losses worth over $58 million in 1999 in Missouri. Race tests were conducted on populations from 183 samples. In order of frequency, races 3, 1, and 2 accounted for 86% of H. glycines populations. Nearly 60% of the populations were virulent (able to produce females) on plant introduction (PI) 88788, which is the source of resistance for most H. glycines-resistant cultivars. More than a third of the populations were virulent on cv. Peking, another common resistance source. Very few populations were virulent on PI 90763 or PI 437654, suggesting that these sources of resistance should be exploited more frequently.

scholarly journals Distribution and Virulence Phenotypes of Soybean Cyst Nematode (Heterodera glycines) based upon Host Differentials in Jilin Province

2021 ◽  
Vol 25 (03) ◽  
pp. 735-741
Author(s):  
Xiujuan Yan
Keyword(s):  
Soybean Cyst Nematode ◽  
Heterodera Glycines ◽  
Plant Introduction ◽  
Cyst Nematode ◽  
Soil Samples ◽  
Jilin Province ◽  
Limiting Factors ◽  
Population Densities ◽  
Soybean Production ◽  
First Time

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

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