Effects of Nematodes on Crops

A special issue of Agronomy (ISSN 2073-4395). This special issue belongs to the section "Soil and Plant Nutrition".

Deadline for manuscript submissions: closed (20 July 2023) | Viewed by 46742

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Guest Editor
Graduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology, Tokyo 184-8588, Japan
Interests: soil science; soil; fertilizers; organic matter; carbon cycle; climate change; environmental impact assessment; nematodes
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Special Issue Information

Dear Colleagues,

Nematodes are an essential component in any global soil ecosystem and have key roles in completely contrasting two functions: beneficial and harmful to crop production. Free-living nematodes are beneficial in nutrient cycling in soil and consist of bacteriovores, fungivores, predators, and omnivores based on what they feed on. Natural nutrient supply capacity mediating by soil microbes and animals, including free-living nematodes, is important in sustainable crop production. By contrast, plant parasitic nematodes are harmful to plants and cause $US80 billion damage to global crop production. Thus, it is absolutely important to develop environmentally friendly control measures against plant pathogens. In this Special Issue, we expect to receive contributions in studies on any aspect on the effects of nematodes on crops. Research areas covering this Special Issue are, e.g., ecology of free-living or plant parasitic nematodes, molecular diagnosis of important nematodes, new nematode diseases, and novel or feasible biological, chemical, or physical control of plant parasitic nematodes.

Dr. Koki Toyota
Guest Editor

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Keywords

  • ecology
  • diagnosis
  • new control methods
  • new diseases
  • sustainable crop production
  • free-living nematodes
  • nutrient cycling

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Published Papers (12 papers)

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Research

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17 pages, 2611 KiB  
Article
Ecological Interaction in the Proliferation of Phytoparasitic Nematodes in Coffee var. Typica
by Luis Morales-Aranibar, Francisca Elena Yucra Yucra, Nivia Marisol Pilares Estrada, Eliseo Pumacallahui Salcedo, Carlos Morales-Aranibar, Nataniel Linares Gutiérrez, Oscar Mamani Aguilar, Richar Marlon Mollinedo Chura, Wilberth Caviedes Contreras, Jorge González Aguilera, Alan Mario Zuffo and Janaina Tauil Bernardo
Agronomy 2023, 13(6), 1653; https://doi.org/10.3390/agronomy13061653 - 20 Jun 2023
Cited by 1 | Viewed by 2087
Abstract
Phytoparasitic nematodes are a common problem in coffee production worldwide. In Peru, the proliferation of phytoparasitic nematodes in Coffea arabica L. var. Typica has negative impacts on coffee production and huge economic losses. The objective of this study was to determine the ecological [...] Read more.
Phytoparasitic nematodes are a common problem in coffee production worldwide. In Peru, the proliferation of phytoparasitic nematodes in Coffea arabica L. var. Typica has negative impacts on coffee production and huge economic losses. The objective of this study was to determine the ecological interactions that influence the proliferation of phytoparasitic nematodes in C. arabica var. Typica in Quillabamba, Cusco, Peru. The density of phytoparasitic nematodes in the soil and root was evaluated using the modified Baermann channel method. Identification of genera and species of phytoparasitic nematodes was carried out in the different samples, based on descriptions and taxonomic keys. Physical and chemical parameters of the soil were evaluated. Principal component analysis (PCA) and a correlation network were employed to distribute the different species of nematodes. The variables soil texture, organic matter, pH, altitude, temperature and humidity were used. During the sampling, several genera of plant-parasitic nematodes were identified in addition to various categories of nematodes. Meloidogyne exigua, Pratylenchus coffeae, Allotrichodorus longispiculis and Helicotylenchus longicaudatus are among the specific species of nematodes identified. The genus with the highest incidence was Meloidogyne spp. with 77.3% in soil and 96% in roots, reaching an average density of 340 nematodes in 100 g of soil and 368 nematodes in 1 g of roots. The PCA results show that 63.7% of the variability of the data is retained in the first two components. PCA shows that the sampled areas were differentiated and grouped with the evaluated characteristics, while the nematodes overlap in the representation of the analysis, thus making it difficult to select them. Pearson’s correlation showed a negative correlation between altitude and soil nematode density (−0.22), suggesting that conditions at higher altitudes may be more unfavorable for nematode growth. In addition, a positive correlation was found between soil pH and organic matter (0.93, p < 0.001) and may influence nematode density. The factors that influence the density of nematodes in the soil and plant roots are multiple and complex, and their understanding is essential for the success of coffee production. The finding of the current study may be useful in the development of sustainable strategies for managing nematodes in coffee network production. Full article
(This article belongs to the Special Issue Effects of Nematodes on Crops)
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15 pages, 2480 KiB  
Article
Transmissible Effects of a Biochar Amendment to an Upper Soil Zone Upon an Associated Lower Zone, Including Attenuation of Soybean Cyst Nematode (Heterodera glycines)
by Nguyen Van Sinh, Doan Thi Truc Linh, Nguyen Thi Kim Phuong, Karl Ritz and Koki Toyota
Agronomy 2023, 13(1), 53; https://doi.org/10.3390/agronomy13010053 - 23 Dec 2022
Cited by 2 | Viewed by 1813
Abstract
Mung bean residues stimulate the hatching of soybean cyst nematode (SCN). In our previous study, combined incorporation of mung bean residues and biochar into soil can be effective in suppression of the soybean cyst nematode (SCN), Heterodera glycines, in the upper layer soil. [...] Read more.
Mung bean residues stimulate the hatching of soybean cyst nematode (SCN). In our previous study, combined incorporation of mung bean residues and biochar into soil can be effective in suppression of the soybean cyst nematode (SCN), Heterodera glycines, in the upper layer soil. However, there are no data available as to whether such effects are transmissible, and could for example be manifest in subsoil zones where such incorporation is confined to topsoils, via water-based pathways. We evaluated the effects of leachate passage from a biochar-amended soil in an upper soil zone to a lower zone in a microcosm-based system, upon a range of physicochemical properties and density of SCN. Disturbed soil was filled in a total of 9 cylindrical cores with two layers. The upper layer (0–15 cm) was amended with biochar at rates equivalent to 0, 0.3% or 1.8%, with bulk density set at of 1.1 g cm−3. The lower layer (15–25 cm) without biochar amendment was compacted to 1.2 g cm−3. Mung beans were grown for two weeks and incorporated into the upper layer. Water was surface-applied to the cores 4, 6, and 8 weeks after mung bean incorporation. After 16 weeks, the upper and lower layer soils were separately collected and assayed. The presence of biochar in the upper layer reduced the abundance of free-living nematodes, mainly bacterivorous, but increased that of a predator genus Ecumenicus in this zone. In the lower layer of soil under a biochar-amended upper layer, available P and soluble cations were increased as were abundances of total nematodes including Ecumenicus, resulting in greater maturity index, basal and structure indices. Notably, SCN density was decreased in lower zones by more than 90% compared to zero-biochar controls. This demonstrates that the effects of biochar upon soil properties, including impacts on biota and plant pathogens, are transmissible. Full article
(This article belongs to the Special Issue Effects of Nematodes on Crops)
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15 pages, 1435 KiB  
Article
Early Season Growth Responses of Resistant and Susceptible Cotton Genotypes to Reniform Nematode and Soil Potassium Application
by Bhupinder Singh, Daryl R. Chastain, Salliana R. Stetina, Emile S. Gardiner and John L. Snider
Agronomy 2022, 12(11), 2895; https://doi.org/10.3390/agronomy12112895 - 19 Nov 2022
Cited by 1 | Viewed by 2510
Abstract
A greenhouse study was conducted to investigate the roles that host plant resistance and soil potassium (K) levels play in affecting Rotylenchulus reniformis Linford and Oliveira (Tylenchida: Hoplolaimidae) (RN) populations and early season cotton (Gossypium hirsutum L.) growth. Two upland, RN-resistant cotton [...] Read more.
A greenhouse study was conducted to investigate the roles that host plant resistance and soil potassium (K) levels play in affecting Rotylenchulus reniformis Linford and Oliveira (Tylenchida: Hoplolaimidae) (RN) populations and early season cotton (Gossypium hirsutum L.) growth. Two upland, RN-resistant cotton lines (G. barbadense introgressions: 08SS110-NE06.OP and 08SS100), a genetic standard (Deltapine 16) and a commercially available susceptible cultivar (PHY 490 W3FE) were evaluated at four different levels of K [100% of recommended rate, 150% of recommended, 50% of recommended, and a base level] from seeding until harvesting, 60 days after sowing (DAS). Quadratic functions (r2 = 0.82 to 0.95) best described the early season growth response of cotton genotypes to soil K. The base K level was associated with the lowest values for most morphological variables, including plant height (PH), mainstem nodes (MSN), leaf area, and dry weight at 30 DAS and 60 DAS. However, soil K did not affect RN population counts (RC). Additionally, soil K did not influence the rate of change in growth variables among genotypes. The resistant genotype 08SS110-NE06.OP showed greater growth in terms of time to first true leaf, PH, MSN, and above-ground dry weights compared to the commercially available susceptible genotype. No interaction between K and RN or genotype and RN was found in early season cotton growth. However, RC in pots of resistant genotypes was less than in pots of susceptible genotypes. Our research on the early season growth response to soil K by novel, RN-resistant genotypes and susceptible genotypes contributes to the development of improved RN resistance and fertilization management in cotton. Full article
(This article belongs to the Special Issue Effects of Nematodes on Crops)
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8 pages, 1461 KiB  
Article
Brevibacillus laterosporus as a Natural Biological Control Agent of Soil-Dwelling Nematodes
by Rim Hamze and Luca Ruiu
Agronomy 2022, 12(11), 2686; https://doi.org/10.3390/agronomy12112686 - 29 Oct 2022
Cited by 4 | Viewed by 2350
Abstract
The nematocidal potential of an entomopathogenic strain of Brevibacillus laterosporus previously known for its antimicrobial properties was assessed on the free-living nematode microworm Panagrellus redivivus and the root-knot nematode Meloidogyne incognita. Laboratory bioassays showed significant nematocidal properties of the culture supernatant of [...] Read more.
The nematocidal potential of an entomopathogenic strain of Brevibacillus laterosporus previously known for its antimicrobial properties was assessed on the free-living nematode microworm Panagrellus redivivus and the root-knot nematode Meloidogyne incognita. Laboratory bioassays showed significant nematocidal properties of the culture supernatant of the bacterium, achieving over 90% mortality of both microworms and M. incognita juveniles when the supernatant was collected at the sporulation phase, which related to the progressive production and release of virulence factors and toxins in the culture medium at this stage of bacterial growth. A protein fraction obtained by precipitation from the bacterial culture supernatant was found to be very active against nematodes with a concentration-dependent effect and an LC50 value of 0.4 µg/µL on M. incognita. Bacterial preparations based on either spores or a culture supernatant proved to be effective in reducing M. incognita density in treated compared with untreated soil, which makes the use of B. laterosporus as a biological control agent of soil-dwelling nematode pests particularly promising. Full article
(This article belongs to the Special Issue Effects of Nematodes on Crops)
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8 pages, 1884 KiB  
Communication
Occurrence and Identification of Root-Knot Nematodes on Red Dragon Fruit (Hylocereus polyrhizus) in Hainan, China
by Haibo Long, Yuan Chen, Yueling Pei, Huadong Li, Yanfang Sun and Tuizi Feng
Agronomy 2022, 12(5), 1064; https://doi.org/10.3390/agronomy12051064 - 28 Apr 2022
Cited by 9 | Viewed by 3656
Abstract
The genus Meloidogyne is one of the most economically damaging plant parasitic nematodes on a worldwide basis. To date, only the dragon fruits in Brazil were reported infected by M. javanica or M. incognita in previous surveys. From 2019–2021, we conducted our investigation [...] Read more.
The genus Meloidogyne is one of the most economically damaging plant parasitic nematodes on a worldwide basis. To date, only the dragon fruits in Brazil were reported infected by M. javanica or M. incognita in previous surveys. From 2019–2021, we conducted our investigation in 62 orchards from 10 counties of Hainan, which are the main producing areas of dragon fruits in China. The collected roots were visually scored by gall index to evaluate the distribution and severity of diseases caused by Meloidogyne. Then, the isolated nematodes were further confirmed by a combination of morphological and molecular analysis. This survey revealed that the root-knot nematodes were widely distributed in red dragon fruit planting areas in Hainan and caused severe symptoms including stunting, wilting, and yellowing of the stems. The nematode populations were identified as M. enterolobii and M. javanica, among which, M. enterolobii accounted for a larger proportion, 93.9%. To our knowledge, this is the first report of M. enterolobii causing diseases on red dragon fruit. The results obtained from this survey will provide an insight into the presence of root-knot nematodes in dragon fruit plants. Also, these results will raise attention for developing effective management strategies to prevent further spread of root-knot nematodes on dragon fruit in Hainan. Full article
(This article belongs to the Special Issue Effects of Nematodes on Crops)
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20 pages, 3668 KiB  
Article
Description of Filenchus Species from Agroecosystem of Southern Alberta, Canada
by Maria Munawar, Pablo Castillo and Dmytro P. Yevtushenko
Agronomy 2022, 12(3), 690; https://doi.org/10.3390/agronomy12030690 - 12 Mar 2022
Cited by 7 | Viewed by 3666
Abstract
Understanding the existing nematode biodiversity is of significant concern because nematodes may divert nutrients from plants and use them for their own development and reproduction. The presence and diagnostics of Filenchus species occurring in southern Alberta have not been addressed in previous studies. [...] Read more.
Understanding the existing nematode biodiversity is of significant concern because nematodes may divert nutrients from plants and use them for their own development and reproduction. The presence and diagnostics of Filenchus species occurring in southern Alberta have not been addressed in previous studies. Herein, we provide a comprehensive characterization of adult females of four known Filenchus species (F. cylindricus, F. hazenensis, F. sheri, and F. thornei) recovered from cultivated fields in southern Alberta. Three of the species are new records in Canada, while one is a native species that was previously described from the Canadian high arctic area. These organisms are mild parasitic species; we describe them here to enhance the visibility of soil nematodes and facilitate accurate species identification. The diagnostic resolution within Filenchus is low, because many species are described without adequate consideration of intra-specific variation. The species descriptions and molecular data obtained during the present study will reduce the confusion in examining the existing lineages among Filenchus species and will aid in improving phylogenetic resolution. Our results suggest that the known diversity of Canadian nemato-fauna has increased. However, more research is needed to further identify other genera and species of phytoparasitic nematodes that may occur in grasses, weeds, and wild plants present in cultivated areas. Moreover, the molecular characterization of these species from Canada, in comparison to a reference dataset (NCBI) of Tylenchidae nematodes, provides insight into the biogeography of nematodes. Full article
(This article belongs to the Special Issue Effects of Nematodes on Crops)
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17 pages, 2208 KiB  
Article
Influence of Rice Husk Biochar on Soil Nematode Community under Upland and Flooded Conditions: A Microcosm Experiment
by Nguyen Van Sinh, Risako Kato, Doan Thi Truc Linh, Nguyen Thi Kim Phuong and Koki Toyota
Agronomy 2022, 12(2), 378; https://doi.org/10.3390/agronomy12020378 - 2 Feb 2022
Cited by 6 | Viewed by 3115
Abstract
Biochar has the potential for improving soil properties and supporting ecological functions, but it has negative impacts on soil organisms in some cases. This study aimed to assess the effect of biochar application at rates of 0 (B0), 5 Mg ha−1 (B5), [...] Read more.
Biochar has the potential for improving soil properties and supporting ecological functions, but it has negative impacts on soil organisms in some cases. This study aimed to assess the effect of biochar application at rates of 0 (B0), 5 Mg ha−1 (B5), 20 Mg−1 (B20), and 40 Mg ha−1 (B40) on soil nematode community under upland and flooded conditions in a short-term microcosm experiment. After biochar application, soil was incubated for 2 to 8 weeks and nematodes were identified for community composition, trophic structures, functional guilds, maturity index and metabolic footprints. The chemical properties of the soils were also analyzed. General linear model revealed that biochar increased soil pH, EC, NO3-N, available phosphorus, total C, and C/N ratio, particularly in the highest application rate and shifted the composition of nematodes. The greatest abundances of omnivores (Mesodorylaimus, Thornenema), predator (Nygolaimus) and functional guilds of cp5 were observed in B5, resulting in greatest structure footprint and composite footprint, (omnivorous + predator) footprint and total biomass in B5. While abundances of nematodes tended to decrease with the biochar applicate rates, the abundance of Prismatolaimus was the highest in B40. During the 8-week incubation period, the abundances of Achromadora, Alaimus, Aporcelaimellus, Cryptonchus, Mononchus, and Tobrilus remained stable in upland conditions. Under flooded conditions, the abundances of almost all taxa were markedly lower than those under upland conditions irrespective of biochar application, except for Acrobeloides, Alaimus, Aphelenchoides, and Ditylenchus. We highlighted that 5 Mg ha−1 of rice husk biochar can be the optimum in shaping the nematode community. Full article
(This article belongs to the Special Issue Effects of Nematodes on Crops)
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21 pages, 2120 KiB  
Article
Impacts of Fallow Conditions, Compost and Silicate Fertilizer on Soil Nematode Community in Salt–Affected Paddy Rice Fields in Acid Sulfate and Alluvial Soils in the Mekong Delta, Vietnam
by Nguyen Van Sinh, Chau Minh Khoi, Nguyen Thi Kim Phuong, Tran Ba Linh, Dang Duy Minh, Roland N. Perry and Koki Toyota
Agronomy 2021, 11(3), 425; https://doi.org/10.3390/agronomy11030425 - 26 Feb 2021
Cited by 5 | Viewed by 3353
Abstract
Avoidance of intensive rice cultivation (IRC) and soil amendments are potential practices to enhance soil properties. There is only limited information on the effects of reduced IRC and its mixture with compost or silicate fertilizer (Si) on the soil nematode community in salt–affected [...] Read more.
Avoidance of intensive rice cultivation (IRC) and soil amendments are potential practices to enhance soil properties. There is only limited information on the effects of reduced IRC and its mixture with compost or silicate fertilizer (Si) on the soil nematode community in salt–affected soils. This study aimed to assess the shifts of soil nematode community by reducing a rice crop from triple rice system (RRR) to a double rice system and mixed with compost or Si in paddy fields in acid sulfate soil (ASS) and alluvial soil (AL) in the Mekong Delta, Vietnam. Field experiments were designed with four treatments in four replicates, including RRR and a proposed system of double–rice followed by a fallow (FRR) and with 3 Mg ha–1 crop−1 compost or 100 kg ha–1 crop−1 Si. Soils were collected at harvest after the 2 year experiment, reflecting the fifth and third consecutive rice crop in RRR and FRR system, respectively. Results showed that reduced IRC gave a significant reduction in abundance of plant–parasitic nematodes (PPN), dominated by Hirschmanniella and increased abundance bacterivorous nematodes when mixed to compost and silicate fertilizer in ASS. In addition, reduced IRC increased nematode biodiversity Hill’s indices and reduced herbivorous footprint in ASS. Proposed system having compost or Si had strongly increased in bacterivorous and omnivorous footprints. Particularly, reduced IRC mixture with Si increased abundance of Rhabdolaimus, Mesodorylaimus and Aquatides, metabolic footprints (structure footprint, bacterivorous, omnivorous and predator) and diversity Hill’s N1 index in ASS. Our results highlighted that reduced IRC was a beneficial practice for decreasing abundance of PPN in salt-affected soils and increasing abundance of FLN in ASS. IRC mixture with compost or Si had potential in structuring the nematode communities with increasing biodiversity, trophic structure, and metabolic footprints. Full article
(This article belongs to the Special Issue Effects of Nematodes on Crops)
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9 pages, 1991 KiB  
Article
Distribution of Pigeon Pea Cyst Nematode and Root-Knot Nematodes in Major Sesame Growing Areas in Myanmar
by Yu Yu Min, Thu Htet Naing, Nwe Nwe Htun, Aung Kyaw Myint, Yuri Ichinose, Roland N. Perry, Atsushi Yoshimura and Koki Toyota
Agronomy 2020, 10(10), 1457; https://doi.org/10.3390/agronomy10101457 - 23 Sep 2020
Cited by 3 | Viewed by 3122
Abstract
The pigeon pea cyst nematode, Heterodera cajani, is an economically important plant-parasitic nematode in sesame production. The objective of the study was to investigate distribution of H. cajani in the major sesame producing areas in Myanmar. Before cultivation, soil samples were collected [...] Read more.
The pigeon pea cyst nematode, Heterodera cajani, is an economically important plant-parasitic nematode in sesame production. The objective of the study was to investigate distribution of H. cajani in the major sesame producing areas in Myanmar. Before cultivation, soil samples were collected in 96 local farmer’s fields: (19 fields in Magway, 20 fields in Mandalay, 14 fields in Sagaing and 43 in Nay Pyi Taw), and nematode density was quantified by real-time PCR. The cyst nematode was detected in 63.2% of the fields in Magway and the mean density was 22.6 eggs equivalent (20 g soil)−1. In Mandalay and Nay Pyi Taw, the cyst nematode was detected in 40.0% and 18.6% of the fields with the mean densities of 9.9 and 21.0 eggs equivalent (20 g soil)−1, respectively. By contrast, the cyst nematode was not detected in Sagaing fields, in which sesame is rotated with paddy rice. Infestation of root-knot nematodes (RKN, Meloidogyne spp.) was also evaluated, because sesame is generally rotated with rice and pulses, which are attacked by RKN. The results showed 25.6% infestation of RKN with a mean density of 34.3 eggs equivalent (20 g soil)−1 only in Nay Pyi Taw, while there was no infestation in Magway, Mandalay, and Sagaing. The relationships between the nematode infestation level and the cropping patterns in each sesame growing area in Myanmar were discussed. Full article
(This article belongs to the Special Issue Effects of Nematodes on Crops)
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15 pages, 2979 KiB  
Article
Distribution of Root-Lesion and Stunt Nematodes, and Their Relationship with Soil Properties and Nematode Fauna in Sugarcane Fields in Okinawa, Japan
by Masanori Kawanobe, Soh Sugihara, Naoko Miyamaru, Koichi Yoshida, Eito Nonomura, Hiroaki Oshiro and Koki Toyota
Agronomy 2020, 10(6), 762; https://doi.org/10.3390/agronomy10060762 - 27 May 2020
Cited by 9 | Viewed by 3072
Abstract
Sugarcane cultivation in Japan has not yet focused on suppressing plant-parasitic nematodes. For proper nematode management, it is essential to know the spatial distribution of economically important plant-parasitic nematodes and free-living nematodes that play important roles in terrestrial ecosystems. We aimed to reveal [...] Read more.
Sugarcane cultivation in Japan has not yet focused on suppressing plant-parasitic nematodes. For proper nematode management, it is essential to know the spatial distribution of economically important plant-parasitic nematodes and free-living nematodes that play important roles in terrestrial ecosystems. We aimed to reveal nematode fauna and soil properties in 85 sugarcane fields of three major sugarcane producing islands in Japan, and to examine their relationship by using the mixed-effect model and by visualizing the spatial distributions using the inverse distance weighting (IDW) approach. The nematode community structures were analyzed by non-metric multidimensional scaling (NMDS). Among plant-parasitic nematodes in sugarcane, the root-lesion nematodes (Pratylenchus sp.) and the stunt nematodes (Tylenchorhynchus sp.) were widely distributed in these islands, yet the abundance and the species varied geospatially. Soil pH was significantly correlated with the abundance of Pratylenchus and Tylenchorhynchus species. The abundance of Pratylenchus and Tylenchorhynchus species were significantly correlated with soil pH. The abundance of Pratylenchus was significantly correlated with the abundance of free-living nematodes, the number of free-living nematode species, and exchangeable cation K+, as were the abundance of Tylenchorhynchus to the clay content and that of non-Tylenchorhynchus. This study also revealed that the three islands had different nematode faunas, which were explained especially by soil pH, texture, and exchangeable basic cations. Full article
(This article belongs to the Special Issue Effects of Nematodes on Crops)
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13 pages, 1029 KiB  
Article
Screening of Nematicides against the Lotus Root Nematode, Hirschmanniella diversa Sher (Tylenchida: Pratylenchidae) and the Efficacy of a Selected Nematicide under Lotus Micro-Field Conditions
by Motonori Takagi, Maki Goto, David Wari, Mina Saito, Roland N. Perry and Koki Toyota
Agronomy 2020, 10(3), 373; https://doi.org/10.3390/agronomy10030373 - 8 Mar 2020
Cited by 8 | Viewed by 4496
Abstract
In Japan, Hirschmanniella diversa is an important pest in lotus cultivation in paddy fields and only lime nitrogen is registered for its control. Therefore, additional nematicides are required to control the nematode. The objective of this study was to screen for an effective [...] Read more.
In Japan, Hirschmanniella diversa is an important pest in lotus cultivation in paddy fields and only lime nitrogen is registered for its control. Therefore, additional nematicides are required to control the nematode. The objective of this study was to screen for an effective nematicide. Fourth-stage juveniles and adults of H. diversa sampled from a lotus field were tested in in vitro solution experiments against 37 pesticides that are registered for the pest control of crops in Japan. Carbamate-based benfuracarb, organophosphate-based fenthion, nereistoxin-based cartap hydrochloride and cyanamide showed nematicidal effects against H. diversa. Benfuracarb at 1 μg/mL showed a nematostatic effect on H. diversa in an agar plate assay. Further, H. diversa treated with benfuracarb did not resume activity 7 days post nematicide treatment when transferred to distilled water. Benfuracarb was tested in micro-field experiments, in which H. diversa density and lotus tuber damage levels were monitored. Results showed that benfuracarb reduced H. diversa densities in the roots during the cultivation period in 2012 and consistently reduced damage levels during a five year study period. Thus, benfuracarb is recommended as an effective nematicide to be used for H. diversa control in lotus cultivation. Full article
(This article belongs to the Special Issue Effects of Nematodes on Crops)
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Review

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16 pages, 483 KiB  
Review
From Old-Generation to Next-Generation Nematicides
by Yuji Oka
Agronomy 2020, 10(9), 1387; https://doi.org/10.3390/agronomy10091387 - 14 Sep 2020
Cited by 83 | Viewed by 10726
Abstract
The phaseout of methyl bromide and the ban on, or withdrawal of, other toxic soil fumigants and non-fumigant nematicides belonging to the organophosphate and carbamate groups are leading to changes in nematode-control strategies. Sustainable nematode-control methods are available and preferred, but not always [...] Read more.
The phaseout of methyl bromide and the ban on, or withdrawal of, other toxic soil fumigants and non-fumigant nematicides belonging to the organophosphate and carbamate groups are leading to changes in nematode-control strategies. Sustainable nematode-control methods are available and preferred, but not always effective enough, especially for cash crops in intensive agriculture. A few non-fumigant nematicides, which have a relatively high control efficacy with a low toxicity to non-target organisms, have been released to the market or are in the process of being registered for use. Fluensulfone, fluopyram, and fluazaindolizine are the three main and most promising next-generation nematicides. In this paper, several aspects of these non-fumigant nematicides are reviewed, along with a brief history and problems of old-generation nematicides. Full article
(This article belongs to the Special Issue Effects of Nematodes on Crops)
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