Morphological and morphometrical identification of Meloidogyne populations from various crop production areas in South Africa with emphasis on M. enterolobii

Zootaxa ◽  
2019 ◽  
Vol 4658 (2) ◽  
pp. 251-274
Author(s):  
MILAD RASHIDIFARD ◽  
HENDRIKA FOURIE ◽  
MIEKE STEFANIE DANEEL ◽  
MARIETTE MARAIS
Keyword(s):  
South Africa ◽  
Crop Production ◽  
Management Strategies ◽  
Morphological Characteristics ◽  
Molecular Techniques ◽  
Accurate Identification ◽  
Morphometric Characters ◽  
Geographical Regions ◽  
Meloidogyne Spp ◽  
Production Areas

Accurate identification of Meloidogyne spp. is crucial and the first step to apply suitable management strategies to combat these nematode pests. Perineal-pattern morphology of female specimens is one of the most common characteristics used for identification. However, for some species various morphological characteristics are similar which makes it challenging to correctly identify species. In this study different morphological and morphometrical characteristics were used to identify 37 populations of Meloidogyne obtained during 2015 and 2016 from various crop production areas situated across different geographical regions in South Africa. A comprehensive study of females, males and second-stage juveniles (J2) of the 37 Meloidogyne populations isolated was conducted, revealing the presence of Meloidogyne enterolobii, M. hapla, M. incognita and M. javanica. Although three perineal-pattern characteristics proved to be useful in discriminating particularly between M. enterolobii and M. incognita females, most of the morphometric characters used to identify female, male and J2 individuals overlapped among the different species. Substantial intraspecies variation was also evident among different populations. The use of classical identification approaches alone could therefore not clearly distinguish among the 37 Meloidogyne populations studied. Therefore, the use of molecular techniques in combination with morphological and morphometrical analyses is suggested to be more accurate and reliable in discriminating between Meloidogyne spp.

scholarly journals Diagnostic methods for identification of root-knot nematodes species from Brazil

2018 ◽  
Vol 48 (2) ◽  
Author(s):  
Tiago Garcia da Cunha ◽  
Liliane Evangelista Visôtto ◽  
Everaldo Antônio Lopes ◽  
Claúdio Marcelo Gonçalves Oliveira ◽  
Pedro Ivo Vieira Good God
Keyword(s):  
Dna Analysis ◽  
Management Strategies ◽  
Molecular Techniques ◽  
Diagnostic Methods ◽  
Root Knot Nematode ◽  
Accurate Identification ◽  
Root Knot Nematodes ◽  
Major Species ◽  
Meloidogyne Spp ◽  
Esterase Phenotypes

ABSTRACT: The accurate identification of root-knot nematode (RKN) species (Meloidogyne spp.) is essential for implementing management strategies. Methods based on the morphology of adults, isozymes phenotypes and DNA analysis can be used for the diagnosis of RKN. Traditionally, RKN species are identified by the analysis of the perineal patterns and esterase phenotypes. For both procedures, mature females are required. Over the last few decades, accurate and rapid molecular techniques have been validated for RKN diagnosis, including eggs, juveniles and adults as DNA sources. Here, we emphasized the methods used for diagnosis of RKN, including emerging molecular techniques, focusing on the major species reported in Brazil.

scholarly journals Relative Contribution of Seed Tuber- and Soilborne Inoculum to Potato Disease Development and Changes in the Population Genetic Structure of Rhizoctonia solani AG 3-PT under Field Conditions in South Africa

Plant Disease ◽  
2018 ◽  
Vol 102 (1) ◽  
pp. 60-66 ◽  
Author(s):  
Norman Muzhinji ◽  
James W. Woodhall ◽  
Mariette Truter ◽  
Jacquie E. van der Waals
Keyword(s):  
South Africa ◽  
Rhizoctonia Solani ◽  
Gene Diversity ◽  
Seed Tuber ◽  
Management Strategies ◽  
Stem Canker ◽  
Molecular Techniques ◽  
Tuber Initiation ◽  
Fixation Index ◽  
Potato Disease

Understanding the contribution of seed tuber- and soilborne inocula of Rhizoctonia solani AG 3-PT in causing potato disease epidemics is an important step in implementing effective management strategies for the pathogen. A 2-year study was conducted to evaluate the contribution of each source of inoculum using an integrative experimental approach combining field trials and molecular techniques. Two distinct sets of genetically marked isolates were used as seed tuberborne and soilborne inocula in a mark-release-recapture experiment. Disease assessments were done during tuber initiation and at tuber harvest. Both inoculum sources were found to be equally important in causing black scurf disease, whereas soilborne inocula appeared to be more important for root and stolon infection, and seedborne inocula contributed more to stem canker. However, seed tuber-transmitted genotypes accounted for 60% of the total recovered isolates when genotyped using three polymerase chain reaction restriction fragment length polymorphism markers. The changes in population structure of the experimental R. solani population over the course of the growing season and across two growing seasons were investigated using eight microsatellite markers. The populations at different sampling times were somewhat genetically differentiated, as indicated by Nei’s gene diversity (0.24 to 0.27) and the fixation index (FST). The proportion of isolates with genotypes that differed from the inoculants ranged from 13 to 16% in 2013 and 2014, respectively, suggesting the possibility of emergence of new genotypes in the field. Because both soilborne and tuberborne inocula are critical, it is important to ensure the use of pathogen-free seed tubers to eliminate seed tuberborne inoculum and the introduction of new genotypes of R. solani for sustainable potato production in South Africa.

Root-knot nematodes (Meloidogyne spp.) in Europe

Nematology ◽  
2011 ◽  
Vol 13 (1) ◽  
pp. 3-16 ◽  
Author(s):  
Wim Wesemael ◽  
Nicole Viaene ◽  
Maurice Moens
Keyword(s):  
Management Strategies ◽  
Resistance Breeding ◽  
Common Species ◽  
Molecular Techniques ◽  
Morphological Identification ◽  
Meloidogyne Hapla ◽  
Root Knot Nematodes ◽  
Important Species ◽  
Meloidogyne Spp ◽  
Meloidogyne Species

AbstractIn Europe, root-knot nematodes are increasingly important. Out of more than 90 Meloidogyne species currently described, 23 have been found on the continent. In the cooler climates, Meloidogyne hapla, M. naasi, M. chitwoodi and M. fallax are prevalent. Meloidogyne arenaria, M. javanica and M. incognita are the most common species in warmer conditions of southern Europe, but also in glasshouses in northern Europe. Morphological identification of root-knot nematodes is difficult and time consuming; therefore, many research groups have been developing molecular techniques for identification of Meloidogyne species. Meloidogyne chitwoodi and M. fallax are quarantine organisms and subject to regulations, and the highly aggressive M. enterolobii has been added to the EPPO alert list. Differences between temperate and tropical Meloidogyne species and their prevalence in Europe imply the need for different management strategies in south and north Europe. Possible crop rotations for the control of root-knot nematodes are limited due to the wide host range of several important species. The banning of methyl bromide and restrictions on other fumigant pesticides in the EU have increased the application of biofumigation significantly in south Europe. The egg-parasitising fungus Paecilomyces lilacinus is commercialised in Germany and applied as dispersible granules for application in water. Intensive research is conducted on the egg-parasitising fungus Pochonia chlamydosporia, and the obligate parasitic bacterium Pasteuria penetrans. European research has paid much attention to resistance breeding and selection. The Mi gene of tomato is widely used but resistance-breaking populations of M. incognita and M. javanica have been reported in different countries.

Meloidogyne enterolobii, a threat to crop production with particular reference to sub-Saharan Africa: an extensive, critical and updated review

Nematology ◽  
2021 ◽  
pp. 1-39
Author(s):  
Raymond Lesley Collett ◽  
Mariette Marais ◽  
Mieke Daneel ◽  
Milad Rashidifard ◽  
Hendrika Fourie
Keyword(s):  
Crop Production ◽  
Management Strategies ◽  
Molecular Techniques ◽  
Sub Saharan Africa ◽  
Crop Damage ◽  
Future Research ◽  
Root Knot Nematode ◽  
Meloidogyne Enterolobii ◽  
Nematode Parasitism ◽  
Sub Saharan

Summary Crop damage inflicted by Meloidogyne enterolobii justifies an updated literature review focusing on recent discoveries about its identification, biology and management. Since its description in 1983, M. enterolobii has become a pest of great concern, particularly due to its virulence, which renders controlling this nematode pest a challenge. The global distribution of M. enteroblii is summarised, with emphasis placed on limited research done for the species in sub-Saharan Africa where food production and security is threatened by root-knot nematode parasitism. Novel advances in methods used to detect M. enterolobii are touched upon, especially the improvement in advanced molecular techniques that complements shortcomings in morphology and morphometic approaches. Despite these exciting developments, the employment of effective management strategies to combat the species remains problematic. Future research on various aspects of M. enterolobii is crucial, with focus to be placed on the use of available resources to contain damage caused by this species.

scholarly journals The hunt for plant viruses in South Africa: The early days

2020 ◽  
Vol 116 (11/12) ◽  
Author(s):  
Chrissie Rey
Keyword(s):  
South Africa ◽  
Management Strategies ◽  
Plant Viruses ◽  
Diagnostic Methods ◽  
Plant Diseases ◽  
Viral Diseases ◽  
Small Scale ◽  
Indigenous Plants ◽  
Accurate Identification ◽  
Potential Yield

Plant viruses cause widespread disease in agriculturally important crops, resulting in a reduction in both quality and quantity of produce. The introduction of intensive crop monoculture has resulted in an exponential increase in viral diseases which can cross over from wild indigenous plants. Viral pathogens also can occur in mixed infections, and rapid, sensitive and reliable diagnostic methods are required to identify and characterise the viruses responsible for the field diseases. In comparison to bacterial and fungal diseases, viral diseases are more difficult to diagnose. This review covers a period (1985–2011) in the history of virus discovery in South Africa during which several plant viruses from commercial and smallscale farms were identified and characterised. Interestingly, novel viruses were discovered in three crops, namely guar and cassava grown by small-scale farmers in Mpumalanga, and in commercial tobacco. The implication of these plant diseases is potential yield loss to farmers which can affect their livelihoods, and result in severe economic loss for the food and agriculture industries. Accurate identification of the causal viral agents of these viral diseases is a prerequisite for development of effective management strategies.

scholarly journals Trunk Disease Fungi Associated With Diospyros kaki in South Africa

Plant Disease ◽  
2016 ◽  
Vol 100 (12) ◽  
pp. 2383-2393 ◽  
Author(s):  
P. Moyo ◽  
L. Mostert ◽  
M. Bester ◽  
F. Halleen
Keyword(s):  
South Africa ◽  
Morphological Characteristics ◽  
Diospyros Kaki ◽  
Western Cape ◽  
Eutypa Lata ◽  
Trunk Disease ◽  
Pathogenicity Tests ◽  
Production Areas ◽  
The Impact ◽  
First Time

Persimmon trees with dieback symptoms and cankers were observed in three production areas in Western Cape Province in South Africa. Isolations were made from diseased branches, cankers, and pruning wounds as well as fungal fruiting bodies on dead branches and old pruning wounds. Several trunk disease pathogens were identified based on morphological characteristics and by molecular methods, including Diaporthe eres, D. infecunda, Eutypella citricola, E. microtheca, Phaeoacremonium parasiticum, P. scolyti, P. australiense, P. minimum, Fomitiporia capensis, Fomitiporia sp., Fomitiporella sp., and Inocutis sp., which were isolated from persimmon for the first time in the world. Other first reports from persimmon in South Africa include D. foeniculina, D. ambigua, D. mutila, Diaporthe sp., Neofusicoccum australe, N. parvum, Diplodia seriata, and Eutypa lata. Pathogenicity tests conducted with all species, except the basidiomycetes, confirmed their status as possible persimmon pathogens. This is the first study to determine and identify fungi associated with diseased persimmon in South Africa. The knowledge gained in this study forms the basis for further research to determine the impact of these fungi on persimmon productivity.

scholarly journals 677 Phosphorus Soil Transformations and Management for Vegetables

HortScience ◽  
1999 ◽  
Vol 34 (3) ◽  
pp. 565B-565
Author(s):  
C.A. Sanchez
Keyword(s):  
Crop Production ◽  
Environmental Concern ◽  
Abiotic Factors ◽  
Management Strategies ◽  
P Uptake ◽  
Utilization Efficiency ◽  
Vegetable Crops ◽  
Wetland Ecosystems ◽  
P Fertilizer ◽  
Production Areas

The amount of phosphorus (P) accumulated by vegetable crops is relatively small compared to nitrogen and potassium. However, large amounts of P fertilizer are often required for optimal yield and quality. Typically P added to soils is quickly converted to unavailable forms resulting in low crop utilization efficiencies. These low P uptake efficiencies have long been of economic concern and a major focus of agronomic and horticultural research. Additionally, in certain regions where crop production areas are hydrologically linked to wetland ecosystems, P fertilization is also of environmental concern. This presentation will summarize important P soil transformations, biotic and abiotic factors influencing the availability of P to crops, and P fertilizer management strategies for improved crop utilization efficiency and reduced environmental impact.

scholarly journals Current and Future Pathotyping Platforms for Plasmodiophora brassicae in Canada

Plants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1446
Author(s):  
Heather H. Tso ◽  
Leonardo Galindo-González ◽  
Stephen E. Strelkov
Keyword(s):  
Crop Production ◽  
Plasmodiophora Brassicae ◽  
Cost Effective ◽  
Turnaround Time ◽  
Molecular Techniques ◽  
Differential Set ◽  
Management Plans ◽  
Increased Sensitivity ◽  
Phenotypic Methods ◽  
Important Disease

Clubroot, caused by Plasmodiophora brassicae, is one of the most detrimental threats to crucifers worldwide and has emerged as an important disease of canola (Brassica napus) in Canada. At present, pathotypes are distinguished phenotypically by their virulence patterns on host differential sets, including the systems of Williams, Somé et al., the European Clubroot Differential set, and most recently the Canadian Clubroot Differential set and the Sinitic Clubroot Differential set. Although these are frequently used because of their simplicity of application, they are time-consuming, labor-intensive, and can lack sensitivity. Early, preventative pathotype detection is imperative to maximize productivity and promote sustainable crop production. The decreased turnaround time and increased sensitivity and specificity of genotypic pathotyping will be valuable for the development of integrated clubroot management plans, and interest in molecular techniques to complement phenotypic methods is increasing. This review provides a synopsis of current and future molecular pathotyping platforms for P. brassicae and aims to provide information on techniques that may be most suitable for the development of rapid, reliable, and cost-effective pathotyping assays.

Fatigue-management strategies among women with endometriosis in South Africa: a qualitative study

2021 ◽  
pp. 008124632110201
Author(s):  
Zamafiso Nombulelo Sibande ◽  
Rizwana Roomaney
Keyword(s):  
South Africa ◽  
South African ◽  
Psychosocial Intervention ◽  
Public Hospital ◽  
Management Strategies ◽  
Cognitive Strategies ◽  
Secondary Symptom ◽  
Face To Face ◽  
Fatigue Management ◽  
Insight Into

Fatigue is a common, secondary symptom of endometriosis that has not been qualitatively explored. We conducted individual, face-to-face interviews with 25 women in South Africa about their experiences of endometriosis-related fatigue. Participants were recruited at a public hospital in Cape Town and through several South African endometriosis organizations. Interviews were conducted in English and Afrikaans and ranged from 30 min to 1 hr 16 min in duration. All interviews were audio recorded and transcribed. Interviews were analyzed using thematic analysis. We found that both the experience of fatigue and fatigue-management strategies were highly personalized. Participants reported using a variety of cognitive strategies, such as planning, pacing, and pushing through their fatigue to reduce the levels of fatigue. Participants also employed physical strategies such as rest, dietary changes, using supplements, and exercise. We found that while participants often tried fatigue-management strategies suggested to them by others, they struggled to maintain these strategies even when they were successful. There are currently no interventions aimed at reducing endometriosis-related fatigue. The findings of this study provide insight into the management of fatigue in women with endometriosis and may be used to develop a psychosocial intervention for fatigue among women with the disease.

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