Four studies were conducted to investigate plant-parasitic nematodes (PPN) of corn and soybean in ND. The first study investigated the incidence and abundance of vermiform PPN in ND corn fields in 2015 and 2016. Samples were collected from 300 corn fields across 20 counties. Seventy-two percent of the fields were positive for PPN. The major genera of PPN identified were Helicotylenchus, Tylenchorhynchus, Paratylenchus, Pratylenchus, Heterodera, Xiphinema, Hoplolaimus, and Paratrichodorus. The second study characterized SCN (SCN; Heterodera glycines) virulence phenotypes in ND. A total of 419 soybean fields across 22 counties were sampled during 2015, 2016, and 2017. Among these samples, 73 SCN field populations were successfully virulence phenotyped using the HG type tests. The HG types that were detected and confirmed in ND were HG type 0, 7, 2.5.7, 5.7, 1.2.5.7, and 2.7. The third study developed a new molecular method for detecting and identifying a new Pratylenchus sp. discovered in a soybean field in ND. A species-specific primer set, that can be used in both conventional and real-time polymerase chain reaction (PCR) assays, was designed from the internal transcribed spacer (ITS) region of ribosomal DNA. Laboratory experiments confirmed that the primers only amplified DNA of the target nematode species but not the non-target species used in the specificity tests. Practically, DNA from as little as a single nematode could be used to specifically identify the new Pratylenchus sp. using the molecular diagnostic methods developed in this study. The fourth study was conducted to ascertain resistance levels of 20 soybean cultivars to the new Pratylenchus sp. Combined results of four trials indicated that seven of the cultivars were moderately resistant, ten were moderately susceptible, four were susceptible, and none of the cultivars tested were resistant. Analysis of the habitat preference of the new Pratylenchus sp., revealed that above or close to 50% of the nematode population resided in roots at nine weeks after planting for a majority of the cultivars evaluated. Results from these studies will be helpful in improving nematode detection and developing management strategies to control plant-parasitic nematodes in ND corn and soybean fields.

No description available.

No description available.

Pratylenchus brachyurus é um dos nematóides mais disseminados na cultura do algodão nas áreas produtoras do Brasil. Sua patogenicidade ao algodoeiro, entretanto, é pouco estudada. Os objetivos deste trabalho foram: i) correlacionar níveis populacionais iniciais crescentes de P. brachyurus (0, 12.000, 30.000 e 75.000 exemplares/ planta) com os danos causados ao algodoeiro \'Delta Opal\'; ii) avaliar a patogenicidade de populações de P. brachyurus em algodoeiros \'Delta Opal\' e \'Fibermax 966\'; iii) testar cultivares de algodão em relação à reprodução de três populações de P. brachyurus ; iv) caracterizar a relação parasito-hospedeiro (em termos de suscetibilidade/resistência) de alguns adubos verdes, coberturas vegetais e pastagens a Pratylenchus brachyurus; v) caracterizar molecularmente populações de P. brachyurus, através de PCR-RFLP e seqüenciamento da região ITS-1 do rDNA. Os resultados sugerem que P. brachyurus é patógeno pouco agressivo da cultura do algodão, já que não se verificaram danos significativos às plantas em densidades populacionais do nematóide inferiores a 12.000 exemplares/ planta. Em relação às cultivares, todas foram suscetíveis a P. brachyurus . Entre as espécies vegetais testadas, as que se mostraram resistentes a P. brachyurus foram Crotalaria spectabilis, C. breviflora, amaranto \'BRS Alegria\', nabo forrageiro \'Comum\' e as cultivares de aveia preta Campeira Mor, IPFA 99006, Comum, CPAO 0010 e Garoa. As análises de PCRRFLP revelaram variabilidade genética entre as diferentes populações de P. brachyurus estudadas, em função dos diferentes padrões de bandas encontrados para as populações estudadas. O seqüenciamento da região ITS-1 do rDNA confirmou a variabilidade observada pela digestão enzimática, além de evidenciar heterogeneidade das regiões 18S e ITS-1 do rDNA de P. brachyurus / Although Pratylenchus brachyurus is widespread in Brazilian cotton fields, information about its importance as a cotton pathogen is scarce. The objectives of this work were: i) correlate crescent initial population densities (0; 12,000; 30,000; and 75,000 nematodes/ plant) with damage on cotton \'Delta Opal\'; ii) measure the pathogenic effect of P. brachyurus on cotton \'Delta Opal\' and \'Fibermax 966\'; iii) characterize the reaction of cotton cultivars to three populations of P. brachyurus ; iv) characterize the host reaction (in terms of susceptibility/ resistance) of some green manures, cover crops and pastures to two populations of P. brachyurus; v) characterize different populations of P. brachyurus by PCR-RFLP and sequencing of ITS-1 rDNA region. Results suggest that P. brachyurus is an eventual pathogen of cotton, since high population levels were necessary to reduce plant growth (< 12,000 nematodes/ plant). All cotton cultivars tested were rated as susceptible to P. brachyurus In relation to crop species tested, Crotalaria spectabilis, C. breviflora, amaranth \'BRS Alegria\', oil radish \'Comum\', and the black oat cultivars Campeira Mor, IPFA 99006, Comum, CPAO 0010, and Garoa were resistant to P. brachyurus PCR-RFLP showed intraspecific variability for different population of P. brachyurus studied. Sequencing of the ITS-1 rDNA region confirmed the results of the enzymatic digestion and demonstrated heterogeneity of 18S and ITS-1 rDNA regions of P. brachyurus.

Les nématodes phytoparasites (NPP) sont des vers ronds microscopiques que l’on retrouve en communautés dans les sols agricoles. Les NPP les plus communs n’occasionnent pas de dégâts sur les cultures. Cependant M. chitwoodi, un NPP règlementé à l’échelle européenne, peut engendrer d’importantes baisses de rendement. Pour caractériser le risque de son implantation, nous nous sommes intéressés aux communautés indigènes en France afin d’identifier celles capables de le limiter suite à une introduction. Nous avons, dans un premier temps, décrit les communautés de NPP à l'échelle d'un paysage agricole, puis à l'échelle de neuf régions françaises. Ces investigations ont montré des communautés peu différenciées en termes de richesse spécifique mais variables en termes d’abondance. Si les variables environnementales expliquent le mieux la structure de ces communautés de NPP à une large échelle géographique, certaines pratiques culturales(labour, application de produits phytosanitaires) influencent fortement les communautés à l’échelle locale. Dans un second volet, nous avons étudié le potentiel de différentes communautés à limiter le développement de M. chitwoodi notamment par la compétition. Il semble que les communautés possédant les plus hauts niveaux d’abondance globale, indépendamment des taxa présents, permettent de diminuer la multiplication de M. chitwoodi. Cette thèse apporte donc des éléments de compréhension sur le fonctionnement des communautés de NPP dans les agrosystèmes français et leur potentiel à limiter le l’établissement de M. chitwoodi pour pouvoir prédire le r / Plant-parasitic nematodes (PPN) are microscopic worms that occur in communities in almost every agricultural soils. Commonly found PPN are usually harmless for the plants. However, M. chitwoodi, a PPN highly regulated in EU can induce important yield losses. In order to improve risk assessment of M. chitwoodi implantation, we studied French native PPN communities to identify those that can limit its establishment shortly after an introduction. We firstly described PPN communities in various agrosystems, at a landscape scale and then in nine French regions. Despite the quite homogeneous species richness observed across the fields sampled, we highlighted strong PPN taxa abundance variations. Environmental variables seemed to mainly drive the PPN communities structure at a large geographic scale but cultural practices(tillage and pesticides uses) seemed to explain the communities variation at the local scale. Secondly, we studied the capacity of different PPN communities to limit M. chitwoodi development through competition. It appeared that PPN communities with high global abundance, regardless of the taxa present, are able to decrease M. chitwoodi multiplication. The results of this PhD thesis bring some elements about the structure and functioning of PPN communities in French fields and their ability to reduce the M. chitwoodi establishment in order to predict its implantation risk.

Pratylenchus brachyurus é um dos nematóides mais disseminados na cultura do algodão nas áreas produtoras do Brasil. Sua patogenicidade ao algodoeiro, entretanto, é pouco estudada. Os objetivos deste trabalho foram: i) correlacionar níveis populacionais iniciais crescentes de P. brachyurus (0, 12.000, 30.000 e 75.000 exemplares/ planta) com os danos causados ao algodoeiro \'Delta Opal\'; ii) avaliar a patogenicidade de populações de P. brachyurus em algodoeiros \'Delta Opal\' e \'Fibermax 966\'; iii) testar cultivares de algodão em relação à reprodução de três populações de P. brachyurus ; iv) caracterizar a relação parasito-hospedeiro (em termos de suscetibilidade/resistência) de alguns adubos verdes, coberturas vegetais e pastagens a Pratylenchus brachyurus; v) caracterizar molecularmente populações de P. brachyurus, através de PCR-RFLP e seqüenciamento da região ITS-1 do rDNA. Os resultados sugerem que P. brachyurus é patógeno pouco agressivo da cultura do algodão, já que não se verificaram danos significativos às plantas em densidades populacionais do nematóide inferiores a 12.000 exemplares/ planta. Em relação às cultivares, todas foram suscetíveis a P. brachyurus . Entre as espécies vegetais testadas, as que se mostraram resistentes a P. brachyurus foram Crotalaria spectabilis, C. breviflora, amaranto \'BRS Alegria\', nabo forrageiro \'Comum\' e as cultivares de aveia preta Campeira Mor, IPFA 99006, Comum, CPAO 0010 e Garoa. As análises de PCRRFLP revelaram variabilidade genética entre as diferentes populações de P. brachyurus estudadas, em função dos diferentes padrões de bandas encontrados para as populações estudadas. O seqüenciamento da região ITS-1 do rDNA confirmou a variabilidade observada pela digestão enzimática, além de evidenciar heterogeneidade das regiões 18S e ITS-1 do rDNA de P. brachyurus / Although Pratylenchus brachyurus is widespread in Brazilian cotton fields, information about its importance as a cotton pathogen is scarce. The objectives of this work were: i) correlate crescent initial population densities (0; 12,000; 30,000; and 75,000 nematodes/ plant) with damage on cotton \'Delta Opal\'; ii) measure the pathogenic effect of P. brachyurus on cotton \'Delta Opal\' and \'Fibermax 966\'; iii) characterize the reaction of cotton cultivars to three populations of P. brachyurus ; iv) characterize the host reaction (in terms of susceptibility/ resistance) of some green manures, cover crops and pastures to two populations of P. brachyurus; v) characterize different populations of P. brachyurus by PCR-RFLP and sequencing of ITS-1 rDNA region. Results suggest that P. brachyurus is an eventual pathogen of cotton, since high population levels were necessary to reduce plant growth (< 12,000 nematodes/ plant). All cotton cultivars tested were rated as susceptible to P. brachyurus In relation to crop species tested, Crotalaria spectabilis, C. breviflora, amaranth \'BRS Alegria\', oil radish \'Comum\', and the black oat cultivars Campeira Mor, IPFA 99006, Comum, CPAO 0010, and Garoa were resistant to P. brachyurus PCR-RFLP showed intraspecific variability for different population of P. brachyurus studied. Sequencing of the ITS-1 rDNA region confirmed the results of the enzymatic digestion and demonstrated heterogeneity of 18S and ITS-1 rDNA regions of P. brachyurus.

Na região dos cerrados, as principais culturas de cobertura utilizadas para a produção de palha no sistema de plantio direto são o milheto (Pennisetum glaucum R. BR.) e as aveias (Avenas spp.). No entanto, a resposta dessas espécies vegetais frente ao nematóide das lesões (Pratylenchus brachyurus) e o das galhas (Meloidogyne incognita) são escassas. O objetivo do presente trabalho é de verificar a resposta de genótipos de milhetos, aveias e outras coberturas vegetais a Pratylenchus brachyurus e de aveias a Meloidogyne incognita sob condições controladas. Desenvolveram-se quatro experimentos no total, no experimento 1, os cultivares de milhetos testados foram resistentes ao nematóide (FR<1,0) com exceção da cultivar ADR 500 (população BA). No experimento 2, as aveias pretas contribuíram para a redução populacional (resistentes) de P. brachyurus, fato oposto, pode ser verificado para as aveias branca e amarela (suscetíveis). No terceiro experimento, diferentemente do verificado no experimento 1, os milhetos se mostraram suscetíveis a P. brachyurus, e, o sorgo BRS-800 foi a cobertura que mais incrementou a densidade do nematóide, equiparando-se estatisticamente com a soja BRS 133. No quarto experimento, verificou-se aumento da densidade das três populações de M. incognita nas aveias pretas testadas, em contraposição à redução verificada na aveia branca UFRGS 17 e amarela São Carlos. / In Cerrado region, the main cover crop used in no tillage system are the pearl millet (Pennisetum glaucum) and the oats (Avena spp.). However, the response of these vegetable species to lesion nematode (Pratylenchus brachyurus) and to root-knot nematode (Meloidogyne incognita) is scarce. The aim of the present work was verify the response of the pearl millet genotypes, oats and other cover crops to P. brachyurus and of oats to M. incognita under greenhouse conditions. Four experiments were done; in experiment 1, the pearl millet cultivars tested were resistant to nematode (FR<1.0) with exception of the cultivar ADR 500 (population BA). In experiment 2, the black oats reduced the P. brachyurus population (resistant); contrarily, white and yellow oats were susceptible. In third experiment, the pearl millets showed as susceptible to P. brachyurus, and the sorghum BRS-800 was the cover crop more susceptible to nematode, statistically closed to soybean BRS 133. In experiment 4, black oats increased the three populations of M. incognita tested, instead the reduction verified in white oat UFRGS 17 and yellow São Carlos.

Diese Arbeit untersucht die Reaktion der Stieleiche auf pflanzenparasitären Nematoden mittels RNA-Sequenzierung und Analyse von stabilen Isotopen und Fettsäuren. Einblicke in Rhizosphäreninteraktionen wurden über mutualistische Partner (Ektomykorrhizapilze, Rhizosphärenhelferbakterien), fungivore Collembolen und multitrophische Gemeinschaften gewonnen. Die Struktur und Biomasse der Mikroorganismen sowie die Fitness der Eichen wurden erfasst. Die Effekte wurzelfressender Nematoden auf die Eiche wurden durch das endogene rhythmische Wachstum des Baumes reguliert. Die Nematoden lösten eine stärkere Reaktion während des Sprosswachstumsschubs aus, u.a. Aktivierung von Abwehrmechanismen und Hemmung der Photosynthese, wohingegen beim Wurzelwachstumsschub pathogen bezogene Signale unterdrückt waren. Die Anwesenheit des Pilzsymbionten schwächte die Pflanzenabwehr und verbesserte die Stresstoleranz, was indirekt das Wachstum der Mikroorganismen förderte. Die Helferbakterien begünstigten den Mykorrhizapilz, was wiederum das Pflanzenwachstum stimulierte und dem negativen Effekt der Nematoden entgegenwirkte. Parasitäre Nematoden und fungivore Collembolen beeinflussten die Verteilung des pflanzlichen Kohlenstoffes unabhängig voneinander; Nematoden verringerten und Collembolen verbesserten die Allokation von Photoassimilaten in Gram-postiven Bakterien. Zudem war steigende trophische Diversität der Bodenfauna in der Rhizosphäre entscheidend für die Balance innerhalb der mikrobiellen Gemeinschaft, welche das Pflanzenwachstum fördert. Diese Arbeit stellt die Bedeutung der endogenen Ressourcenzuteilung von Pflanzen für unterirdische biotische Wechselbeziehungen heraus. Diese Pflanzenstrategie als bedeutender Faktor für Rhizosphärenprozesse sollte in zukünftige Studien Berücksichtigung finden. Die Einbeziehung der Hauptakteure in der Rhizosphäre ermöglicht zudem ein realistischeres Bild von Nematoden-Pflanzen Interaktionen und damit ein effektiveres Management. / This thesis investigated the response of Pedunculate oak to the plant-parasitic nematode Pratylenchus penetrans, using RNA-sequencing, stable isotope labelling and fatty acid analyses. Insight into rhizosphere interactions was gained by employing beneficial biotic partners (ectomycorrhizal fungi, rhizosphere helper bacteria), fungal grazers (Collembola) and multitrophic environments. Microbial biomass and community structure as well as oak fitness were assessed. The effects of root-feeding nematodes on oak were largely governed by the endogenous rhythmic growth of the tree. The nematodes triggered a stronger response during shoot flush, e.g. activation of multi-layered defence mechanisms and repression of photosynthesis, as compared to root flush where pathogen-related signalling was repressed. With the presence of the mycorrhizal symbiont plant defence was attenuated and stress tolerance enhanced, indirectly promoting the growth of rhizosphere microorganisms. The helper bacteria fostered the ectomycorrhizal fungus, which in turn stimulated plant growth, counteracting the negative effects of nematodes. Plant-parasitic nematodes and Collembola grazers had independent roles in plant carbon allocation patterns, with nematodes hampering whilst Collembola enhancing the flux of recent photoassimilates to Gram-positive bacteria. Lastly, increasing trophic diversity of the soil fauna in the rhizosphere of oaks was crucial for the maintenances of a microbial community equilibrium that promotes plant growth. In sum, this study highlights the importance of endogenous resource allocation pattern of plants in determining the outcome of belowground biotic interactions. Therefore such plant traits should be considered as important drivers for rhizosphere processes in future studies. Moreover, taking into account the rhizosphere main players in studies on parasitic nematode-plant interactions will result in a more realistic picture and thus more effective nematode management.

Phytonematodes are known to cause substantial losses in crop yields across the world. Since the middle of the last century, these pests have been adequately controlled by chemical nematicides. However, due to increasing public health concern, strict regulations in the EU and elsewhere have significantly reduced the usage of these environmentally not-so-safe chemicals. This has led us to look for reliable biological alternatives. The Pasteuria group of Gram-positive endospore-forming bacteria (phylum: Firmicutes) often associated with nematode-suppressive soils are potentially reliable nematode biocontrol agents. However, the highly specific interaction of Pasteuria to their nematode hosts poses a challenge to the management of heterogeneous populations of nematodes in the field; the mechanism behind this specificity remains unclear. One of the fundamental basis of host specificity is the attachment of Pasteuria endospores to the cuticle of their host nematodes which is the first and essential step in the infection process. Thus, understanding the molecular mechanisms that govern the attachment process is important in identifying suitable populations of Pasteuria for effective broad-range management of plant parasitic nematodes in soil. Previous studies suggest the presence of immunogenic collagen-like fibres and carbohydrates on the endospore coat of Pasteuria that may have a role in the initial interaction of the endospores with their nematode hosts. Published work on phylogeny relates Pasteuria to Bacillus spp. most of which have well annotated and characterized genomes while the genome of Pasteuria remains to be sequenced completely. In this thesis, I attempt to explore the endospore biology of obligate and fastidious Pasteuria spp. using the wide knowledgebase of well studied Bacillus endospores. The primary aim was to characterize the immunogeneic determinants that are possibly responsible for the attachment of Pasteuria endospores to the host nematode cuticle by a combination of computational and lab-based approaches. To approve the suggested phylogenetic closeness of Pasteuria to Bacillus, the first part of the study focused on phylogeny reconstruction of Pasteuria spp. amongst Bacillus spp. and other members of the phylum Firmicutes. This was followed by in silico studies to identify candidate collagen-like genes in P. penetrans; the putative functional proteins encoded by these candidate genes were then comparatively characterized with collagens from other organisms including the members of the genus Bacillus. The surface associated collagen-like proteins and other possible immunogens on the endospores of Pasteuria were characterized by protein immunoblotting, lectin blotting and immunofluorescence microscopy and comparisons were made with B. thuringiensis endospores. Lastly, endospore attachment assays were done to test the hypothesis that collagens and carbohydrates play a role in Pasteuria endospore attachment. The results of the computational analyses suggest a family of collagen coding putative genes in the Pasteuria genome, all of which are predicted to have varied biochemical properties and are seemingly of diverse evolutionary origin. The Western blot and microscopic analyses show that the endospores of P. penetrans and B. thuringiensis share some common immunodominant surface epitopes. The attachment assays confirm the involvement of collagens and at least one carbohydrate (N-acetylglucosamine) in the endospore attachment. However, the results also indicate possible involvement of other adhesins in the process; to support this, at the end of the thesis, I propose a new 'Multitype Adhesin Model' for initial interaction of Pasteuria endospores with the cuticle of their host nematodes. The outcomes of this project will help in identifying the molecular basis of the complex Pasteuria-nematode interaction. This will provide a basis to develop environmentally benign nematode bio-management strategies.

Thesis (M. Agricultural Management (Animal Production)) -- University of Limpopo, 2016 / Cultivated potato (Solanum tuberosum L.) cultigens do not have resistant genotypes to root-knot (Meloidogyne species) nematodes. Currently, efforts are underway to introgress nematode resistance in potato breeding programmes, whereas other environment-friendly nematode management strategies are being assessed in various cultigens. Nemafric-BL and Nemarioc-AL phytonematicides have being researched and developed for managing the root-knot nematode whereas Biocult Mycorrhizae are intended to enhance crop productivity through improved absorption of P, which is inherently low in most South African soils. The objectives of the study, therefore, were: (1) to determine the interactive effects of Nemacur (N), Biocult Mycorrhizae (B) and Nemarioc-AL or Nemafric-BL phytonematicide (P) on population densities of M. javanica and growth of potato plants, (2) to investigate the effects of Nemacur (N), Velum (V), Biocult Mycorhizae (B) and Nemarioc-AL or Nemafric-BL phytonematicide (P) on population densities of M. javanica and growth of potato plants. For the microplot experiment, potato cv. ‘Mondial G3’ seeds were sown in 25 cm-diameter plastic pots with 5 000 ml steam-pasteurised river sand and Hygromix-T at 3:1 (v/v) growing mixture in autumn (March-May) 2015. Pots were buried 80% deep into the soil in with 0.5 m inter-row and 0.5 m intra-row spacing. Potato cv. ‘Mondial G3’ seeds were dipped in a mixture of Mancozeb with a wettener for disease management prior to sowing. Appropriate treatments were applied soon after emergence of leaves. Each plant was inoculated by dispensing a mixture of 5 000 eggs and M. javanica J2. Eight treatments, control (N0B0P0), Nemacur (N1B0P0), Biocult (N0B1P0), phytonematicide (N0B0P1), Nemacur × Biocult (N1B1P0), Nemacur × phytonematicide (N1B0P1), Biocult × phytonematicide (N0B1P1) and Nemacur × Biocult × phytonematicide (N1B1P1), were arranged in a randomised complete block xxvi design (RCBD) with 8 replications (n= 64). Under field conditions the study was conducted in summer (October 2015 - January 2016), with 30-cm furrows dug and potato seeds placed in the soil with 30 cm inter-row and 40 cm intra-row spacing. The four treatments, namely, (1) untreated control, (2) Nemacur or Velum (3) Biocult Mycorrhizae and (4) Nemarioc-AL or Nemafric-BL phytonematicide, were arranged in RCBD, replicated three times for the Velum experiment and five times for the Nemacur experiment. At 56 days after inoculation, the second order interaction (N1B1P1) was highly significant (P ≤ 0.01) for eggs in root and total nematodes, contributing 13 and 12% to total treatment variation (TTV) of the two variables, respectively, in the Nemarioc-AL phytonematicide study. Relative to untreated control, the second order interaction (N1B1P1) reduced eggs in root and total nematodes by 42 and 36%, respectively. In both Nemarioc-AL and Nemafric-BL phytonematicide experiments, the combination of phytonematicide and Biocult Mycorrhizae reduced gall rating. Nemacur, Biocult and Nemarioc-AL phytonematicide, the treatment effects were highly significant on eggs, J2 in root and total nematodes, contributing 53, 68 and 57% to TTV of the three variables, respectively. Nemacur, Biocult and Nemafric-BL phytonematicide treatments each was not significant (P ≤ 0.05) for nematodes variables. Both treatments for Nemacur, Biocult and Nemarioc-AL or Nemafric-BL phytonematicides were significant for gall rating, contributing 92 and 70% to TTV of the variable, respectively. In Nemarioc-AL phytonematicide, relative to the untreated control, gall rating was reduced by 48 to 56%, whereas in Nemafric-BL phytonematicide the variable was reduced by 33 to 56%. In the Velum study, Biocult and Nemarioc-AL or Nemafric-BL phytonematicide, the treatment effects in both experiments were highly significant (P ≤ 0.01) on eggs in root, contributing 88% to TTV of the variable. Both treatments from Nemarioc-AL xxvii and Nemafric-BL phytonematicides had no significant effects on all plant variables measured. In microplot, the second order interaction (Nemacur × Biocult × Nemarioc-AL phytonematicide) was highly significant for nematode eggs in root and total nematode. In a three-way matrix, the N1B1P1 interaction had the highest effects on eggs, followed by Biocult alone, then Nemacur alone and then the phytonematicide. The same trend was observed in the three-way matrix for total nematodes. However, in two-way matrix for eggs, Biocult outperformed Nemacur, as was the phytonematicide on J2. In another microplot study, the second order interaction (Nemacur × Biocult × Nemafric-BL phytonematicide) was significant for J2 in soil and roots, with the three-way matrix showing, that Biocult alone had higher effects than the N1B1P1 interaction on J2 in root. A three-way matrix also showed that Nemacur was outperformed by the phytonematicide alone, Biocult alone and the interactions on J2 in soil. In conclusion, Nemarioc-AL and Nemafric-BL phytonematicides could each be used with Biocult Mycorrhizae in the management of population densities of M. javanica in potato production since the impact from Nemacur which is a synthetic nematicide does not have that much difference from that of phytonematicides interacted with Biocult Mycorrhizae. / Agricultural Research Council