Plant-parasitic Nematode Populations Research Articles

Changes in the population and diversity of plant parasitic nematodes and their effects on sugarcane growth at Wonji‐Shoa Sugar Estate, Ethiopia

AbstractIn Wonji‐Shoa Sugar Estate (WSSE), sugarcane (Saccharum spp. hybrid) yields have declined by about 48% over the last 70 years. One of the causes for the decline is assumed to be the long‐term monoculture production system that results in the buildup of plant parasitic nematodes (PPNs). Therefore, the population and diversity of PPNs were investigated by conducting soil sampling using a biosequential method (simultaneous sampling of the soils of adjacent cultivated land [CL] and uncultivated land [UL]) and a chronosequential method (taking soil samples at different times from the same site). The samples were subjected to analysis using standard procedures to determine the change in the population, and identify the genera of PPNs. Additionally, a pot experiment that involved fumigation was conducted on top soils sampled from the CL and UL of the plantation. The results revealed that about 10 genera of PPNs (Meloidogyne, Helicotylenchus, Hoplolaimus, Rotylenchulus, Hemicycliophora, Discriconemella, Xhiphinema, Pratylenchus, Tylenchorhynchus, and Scutellonema) were detected, of which the first four were newly identified. The population density and the number of genera of PPNs found in the CL were 36‐fold and 4.5‐fold higher than those found in the UL, respectively. Furthermore, fumigation reduced the population of the PPNs by 61% and increased production of cane biomass by 63%. It is concluded that the soils of the WSSE are infested by PPNs, which consequently have detrimental effects on sugarcane growth. While amending soil fertility is crucial, reversing the decline in sugarcane yields also necessitates implementing an integrated soil management system that includes PPNs.

Prevalence and Characterization of Plant-Parasitic Nematodes Existing in RD41 Rice Fields in Pathum Thani Province, Thailand, with Emphasis on Hirschmanniella mucronata and Meloidogyne graminicola

Plant parasitic nematodes (PPNs) are one of the most destructive pests affecting rice growth worldwide. In this study, populations of PPNs associated with RD41 rice fields in Pathum Thani Province, Thailand, were surveyed and the dominant PPNs found in the fields were identified using a combination of morphological and molecular traits. A total of 105 soil or root samples were taken from 21 paddy fields in 7 districts of Pathum Thani, and nematode extraction was processed in a laboratory. In all sampled rice fields, 6 nematode genera, namely Hirschmanniella sp., Meloidogyne sp., Pratylenchus sp., Tylenchorhynchus sp., Helicotylenchus sp., and Tylenchus sp., were extracted. Of these 6 nematode genera, Hirschmanniella sp. was the most prevalent in both soil and root samples (66.7 - 100 % occurrence observed), followed by Meloidogyne sp., which was found in only 4 districts of the province (0.2 to 8.7 % occurrence observed). The species of these predominant PPNs were morphologically and molecularly characterized. The identification results remained consistent across morphological features and molecular techniques, confirming the presence of Hirschmanniella mucronata and Meloidogyne graminicola in the studied rice fields. The results of this study provide useful baseline data of the occurrence of PPNs in Thailand's rice fields. The incidence of some PPNs found in this study is likely to become a significant factor limiting rice production yields if they are not better managed. HIGHLIGHTS Plant-parasitic nematode (PPN) populations in RD41 rice fields located in Pathum Thani province, Thailand were examined Six PPN genera were extracted from soil and root samples The predominant PPNs were characterized using morphological and molecular traits The main PPNs were identified as mucronata and M. graminicola This study provides useful baseline data of PPNs found in Thailand's rice fields GRAPHICAL ABSTRACT

Nanonematicides: production, mechanisms, efficacy, opportunities and challenges

Summary Classical methods of using many toxic chemical pesticides for managing plant-parasitic nematodes (PPN) on key crops are inappropriate and have unfavourable consequences on human health and the environment. By contrast, nanotechnology can provide a wide range of alternative applications with additional merits based on nanoparticle (NP) pesticides. Three major categories, i.e., physical, chemical and biological methods, have been generally used for synthesis of nanonematicides. The merits and demerits of these methods are highlighted. The biological method generally involves easy, fast, scalable, cheap and environmentally safe techniques. As nanonematicides can reduce the non-selective use of classical nematicides with their high pollution and unhealthy levels, mechanisms underlying PPN population suppression by these nanonematicides are presented to help in their further optimisation. Nanonematicides are guiding a radical change in their efficacy against PPN, but more attention should be given to secure their clean production and application with cost-effective methods.

Influence of Cropping Sequence and Tillage System on Plant-Parasitic Nematodes and Peanut (Arachis hypogaea) Response to Fluopyram Applied at Planting

Crop sequence and tillage can affect the yield of peanut (Arachis hypogaea L.) and other crops. Research was conducted from 2006 through 2022 to determine the response of peanut to previous crop sequences including corn (Zea mays L.) and cotton (Gossypium hirsutum L.) planted in continuous conventional tillage (e.g., disking, field cultivating, and bedding with in-row sub-soiling) or strip tillage (e.g., tilling a 45 cm section on rows spaced 91 cm apart using fluted coulters, rolling baskets, and in-row sub-soiling). In 2013, 2019, and 2022, the entire test area was planted with peanut. In 2019 and 2022, peanut was planted without or with fluopyram applied in the seed furrow at planting. Decreasing the number of years between peanut planting resulted in lower peanut yields compared with fewer years of peanut planting in the rotation sequence. Continuous conventional tillage and strip tillage resulted in similar peanut yields at one location, while the yield was lower at a second location when peanut was planted in continuous strip tillage. Fluopyram did not affect peanut yield regardless of previous crop rotation sequence, the number of years separating peanut plantings, or the tillage system. However, minor differences in the populations of plant-parasitic nematodes in soil were noted when comparing fluopyram treatment. The results from these experiments indicate that while fluopyram can reduce the populations of some plant-parasitic nematodes in soil, the magnitude of reduction does not translate into increases in peanut yield.

Plant-parasite nematodes in soils cultivated with pecans in Rio Grande do Sul, Brazil

ABSTRACT Rio Grande do Sul State produces 70% of pecans in Brazil. There is a high density of phytopathogenic nematodes in orchards. This study characterises the populations of plant-parasitic nematodes and investigates their association with soil properties in pecan-cultivated areas. The genera Mesocriconema, Criconemoides, Discocriconemella, Xiphinema, Tylenchus, Pratylenchus, Helicotylenchus, and Aphelenchoides were all identified. Discocriconemella and Xiphinema were positively associated with soil organic matter, cation exchange capacity, clay content, copper, zinc, calcium, magnesium, and potassium. Conversely, Pratylenchus, Helicotylenchus, Tylenchus, Criconemoides, and Aphelenchoides were positively correlated with aluminium. Mesocriconema, the most commonly found nematode, negatively correlated with most soil chemical attributes. A significant correlation was observed between the genera Criconemoides, Mesocriconema, Aphelenchoides, and Tylenchus. Parasitic nematodes in pecan orchards have not previously been documented in this region of Brazil.

Depth distribution of plant-parasitic nematodes on bentgrass golf greens in Missouri and Indiana.

Control of plant-parasitic nematodes (PPNs) on golf putting greens with nematicides is dependent on the seasonal occurrence and depth distribution of target PPN populations. This study aimed to determine if plant-parasitic nematode populations on golf course putting greens in Missouri and Indiana peaked at a targetable depth at a specific time in the year, focusing primarily on lance (Hoplolaimus spp.) and root-knot (Meloidogyne spp.) nematodes. To elucidate species diversity in the region, rDNA from a subset of lance and root-knot nematodes was sequenced and analyzed, with additional micromorphology of a lance nematode assessed in scanning electron micrographs (SEM). Soil samples were taken to a depth of 25 cm and stratified into 5 cm increments during April, June, August and October at seven sites across Missouri, three in the Kansas City metro of Kansas in 2021 and in ten sites across Indiana in 2022. Samples were stratified in five-centimeter increments and aggregated for a total of 100 cm3 of soil at each depth for each sampling. Samples were processed using a semi-automatic elutriator followed by the sucrose-flotation method, and populations were counted using a hemocytometer and recorded. For molecular characterization, rDNA was extracted and analyzed from 31 individual lance nematodes from one site in Missouri and eight sites in Indiana, and 13 root-knot nematodes from nine sites across Indiana. A significant interaction occurred between sampling month and depth for lance and ring nematodes Missouri/KS, with both PPN populations peaking at the 0-5 cm depth during October, which is well after most targeted nematicide applications are applied. Ring nematodes in Indiana did not follow this trend and were most abundant in August at a depth of 0-5 cm. No significant interaction between depth and month occurred for lance or root-knot nematodes in Indiana, or root-knot nematodes in Missouri/KS. Hoplolaimus stephanus and H. magnistylus were the lance species identified on golf greens, and Meloidogyne naasi, M. graminicola and M. marylandi were the root-knot species identified. Scanning-electron micrographs confirmed morphological characteristics unique to H. stephanus.

Characterization and Effect of a Nematophagous Fungus Talaromyces cystophila sp. nov. for the Biological Control of Corn Cyst Nematode.

The dynamic of plant-parasitic nematode populations in soil is closely related to soil microorganisms. Fungi from Heterodera zeae cysts were isolated to explore the phenomenon of decline in the H. zeae population in the soil. Phylogenetic study of partial ITS, BenA, CaM, and RPB2 gene sequences, in addition to morphological investigations, was utilized to identify a nematode-destroyingfungus. The nematicidal activity of a novel strain GX1 against H. zeae was assessed in vitro and in the greenhouse. Our findings revealed that strain GX1 is a new species of Talaromyces, named Talaromyces cystophila. It has a strong parasitic and lethal effect on H. zeae cysts, with 91.11% parasitism on cysts at 3 days after treatment. The contents of second-stage juveniles (J2s) and eggs inside the cysts were degraded and formed dense vacuoles, and the damaged eggs could not hatch normally. The spore suspension exhibited high nematophagous activity against nematodes, and fermentation filtrate exhibited marked inhibition of egg hatching and nematicidal activities on J2s. The hatching inhibition rates of eggs exposed to 1 × 108 CFU/ml spore suspensions or 20% 1-week fermentation filtrate (1-WF) for 15 days were 98.56 and 100%, respectively. The mortality of J2s exposed to 1 × 108 CFU/ml spore suspension reached 100% at 24 h; exposure to 50% 2-WF was 98.65 and 100% at 24 and 48 h, respectively. Greenhouse experiments revealed that the spore suspension and fermentation broth considerably decreased H. zeae reproduction by 56.17 to 78.76%. T. cystophila is a potential biocontrol strain with nematophagous and nematicidal activity that deserves attention and application.

Influence of Seasonal Variations on Population Dynamics of Phyto-Parasitic Nematodes in Soil and Roots of Bell Pepper (Capsicum annuum L.) in Otari, Rivers State, Nigeria

Weather instability affects nematode proliferation in soil, affecting plant growth. Identifying endemic species and favourable seasons can guide farmers in cultivating crops during specific seasons, minimizing infections and improving yield. A survey to evaluate the influence of seasonal disparity on plant parasitic nematodes population in soil and roots of bell pepper (Capsicum annuum L.) was carried out during dry and rainy seasons in Otari, Abua/Odual Local Government Area of Rivers State, Nigeria. Five bell pepper cultivated fields were randomly selected and a total of 300 soil samples were collected and assayed for soil nematodes. The soil samples were collected using a soil auger at 0-15 cm depth, and roots were collected by the use of sterilized kitchen knife simultaneously for the isolation of nematode. The modified sieve plate method was employed for the extraction of nematodes. Nematode identification was carried out using a pictorial key. A total of 2,220 nematodes from 11 genera were reported in this study, among which 1,290 (58.1%) were recovered during the rainy season while the dry season showed 930 (41.9%) nematodes. Nematode population vary significantly between seasons in soil (P = .13) and roots of bell pepper (P = 3.90), with Heterodera species having higher density (1.44 and 1.03) during the rainy and dry seasons respectively in the soil. High density of Meloidogyne (0.97) was recorded during the rainy season and Radopholus spp (1.40) during the dry season in the root of bell pepper plant. The study showed that seasonal variations impacted on nematode population abundance in fields, establishing that nematodes are responsive to every unsteady condition of the soil environment resulting from seasonal disparity, and only species who adapt rapidly survive. Farmers should increase crop cultivation during the rainy season to boost yield, as nematodes population decline as rainfall increases.

Prevalence, Spatial Distribution, and Population Density of Plant-Parasitic Nematodes in Vegetable Fields of North Carolina, South Carolina, and Tennessee Counties

Plant-parasitic nematodes are a diverse group of soilborne plant pathogens that limit the yield of numerous vegetable crops globally. Few studies have investigated nematode populations affecting vegetable crops in Tennessee and North and South Carolina. Between December 2020 and October 2022, vegetable fields in selected counties of these states were sampled for plant-parasitic nematodes. Data on the prevalence, spatial distribution, and population density of seven genera of plant-parasitic nematodes, identified via morphology, were collected. Root-knot nematodes were identified in 60% of the fields sampled, with population densities ranging from 10 to 10,400 nematodes per 500 cm3 of soil. Detection rates of other genera as percentages of total fields sampled were: spiral (42%), stubby root (32%), stunt (21%), ring (13%), and lesion (8%) nematodes. Out of eight crops sampled, fields either currently or formerly planted to tomato or pepper were the most frequently sampled in the survey (77% of total fields). This is the first survey to collect data on populations of plant-parasitic nematodes in this region, and the results highlight the need for continued surveillance and study of their impact in vegetable production.

Nematode population dynamics and plant steaming effects on strawberry cultivars under organic field conditions in Florida

Summary Demand for Florida organic strawberries has significantly increased in recent years, yet this industry is threatened by pests and pathogens that often come with transplants from out-of-state nurseries. Plant steaming has been explored as an alternative to reduce those threats in transplants. This study evaluated the yield performance of seven strawberry cultivars and their impact on nematode densities and plant vigour after steaming was applied to transplants imported from California during two growing seasons (2020-2021 and 2021-2022). The cultivars used were ‘Sensation® Florida127’, ‘Florida Brilliance’, ‘Florida Radiance’, ‘Winterstar™ FL 05-107’, ‘Florida Elyana’, ‘Strawberry Festival’ and ‘Florida Beauty’. Plant steaming reduced plant vigour only 4 weeks after transplanting. Nevertheless, no negative effect was observed in total fruit yield. Differences among cultivars were observed for plant vigour, total fruit yield and abundance of root-knot nematodes. The plant vigour of each cultivar depended on the time of the year, which varied significantly throughout the season. Cultivars ‘Sensation® Florida127’ and ‘Florida Radiance’ attained the highest total yield in both seasons. There was an effect of the cropping system in the nematode community, which increased the bacterivores but drastically reduced omnivores and ring nematodes over time. No effect of cultivar was observed in plant-parasitic nematode populations. The cultivar ‘Winterstar™ FL 05-107’ was an exception since Meloidogyne javanica population densities were significantly higher in ‘Winterstar™ FL 05-107’s experimental plots. Overall, transplant steaming shows the potential to be a component of an integrated pest and disease management programme for the success of sustainable and profitable yields

Relationship between plant parasitic nematodes population and soil moisture and temperature

Relationship between plant parasitic nematodes population and soil moisture and temperature

Effect of soil factors on plant-parasitic nematode associated with tomato (Solanum lycopersicum), case study in Limpopo Province, South Africa

Plant-parasitic nematodes are some of the most important plant pathogens in tomato farms. Tomato is an acritical and high-demand vegetable in the world. The plant-parasitic nematodes are highly adapted and can cause severe damage to tomato farms. Therefore, understanding the population of nematodes on the tomato field assists the farmer in managing them and having better yields. This study was conducted to identify nematode species from the soil and root samples during a survey of plant-parasitic nematodes in four tomato farms in 2021. The samples were collected across the farms in Limpopo province, South Africa. Analyzing the soil and identifying the nematodes has been done at the Aquaculture Research Unit, University of Limpopo. Seven nematode species were identified from the soil and root samples out of the 40 soil samples collected. The nematodes encountered were Meloidogyne (700), Pratylenchus (430), Xiphinema (380), Helicotylenchus (260), Ditylenchus (180), Rotylenchus (110), Tylenchorhynchus (90). The CCA results indicated the contribution of PPN species and soil variables in tomato farms to the analysis indicated that Meloidogyne and Rotylenchus were dominant in substrates characterized by soil structure (Clay, Silt%), and high-level of Ca (%), Carbon (%), and K (%) found in Polokwane and Tzaneen tomato farms. At the same time, Helicotylenchus, Pratylenchus, and Xiphinema were dominant in substrates characterized by sand (%), Na (%), and Mg (%) found in Giyani and Louis Trichardt tomato farms. In conclusion, soil factors can directly affect soil biology. In this study, the results showed unsustainable soil factor was the reason for the high plant-parasitic nematode population in the tomato field.

Plant-Parasitic Nematodes Associated with Cannabis sativa in Florida.

The subtropical climate of Florida allows for a wide range of crops to be grown. With the classification of hemp (Cannabis sativa L., <0.3% delta-9-tetrahydrocannabinol) as an agricultural commodity, hemp has become a potential alternative crop in Florida. Hemp cultivars of different geographies (Europe, China, and North America), and uses (fiber, oil and CBD), were evaluated in three field experiments. The field experiments evaluated a total of 26 cultivars and were conducted for two consecutive seasons at three different locations (soil types) in North (sandy loam), Central (fine sand), and South Florida (gravelly loam). Nematode soil populations were measured at the end of each season. A diverse population of plant-parasitic nematodes was found, with reniform nematodes (RN, Rotylenchulus reniformis) the dominant species in North and South Florida (up to 27.5 nematodes/cc soil), and RKN (Meloidogne javanica) the main species in central Florida (up to 4.7 nematodes/cc soil). Other nematodes that were commonly found in south Florida (and to a lesser extent north Florida) were spiral (Helicotylenchus spp.), stunt (Tylenchorhynchus spp.) and ring nematodes (Criconemoids), while in central Florida, stubby root (Nanidorus minor) and sting nematodes (Belonolaimus longicaduatus) were found. No significant difference among hemp cultivars was noted at any of the locations. RKN were found in all three regions and soils, while RN were only found in North and South Florida. This is the first report on plant-parasitic nematodes associated with hemp in Florida fields. Natural nematode populations varied greatly, depending on where in Florida hemp was grown. Growers who wish to include hemp in their crop rotation need to be aware of potential pest pressure from nematodes. More research is needed to determine to what extent nematodes, especially RKN and RN, can reduce hemp growth and yield.

Plant-parasitic nematodes in soils of agricultural lands in Crimea

During 2017-2023, about 150 soil samples were collected from vineyards and lands planned for planting grapevines located in the Central, South-western and South-eastern areas of Crimea. As a result of this work, 29 species of plant-parasitic nematodes from 9 families were found. The study of the relative abundance of populations of plant-parasitic nematodes in the soils in abandoned fruit and grape agroecosystems and in fields with the cultivation of cereals was also carried out.

The Fight against Plant-Parasitic Nematodes: Current Status of Bacterial and Fungal Biocontrol Agents.

Plant-parasitic nematodes (PPNs) are among the most notorious and underrated threats to food security and plant health worldwide, compromising crop yields and causing billions of dollars of losses annually. Chemical control strategies rely heavily on synthetic chemical nematicides to reduce PPN population densities, but their use is being progressively restricted due to environmental and human health concerns, so alternative control methods are urgently needed. Here, we review the potential of bacterial and fungal agents to suppress the most important PPNs, namely Aphelenchoides besseyi, Bursaphelenchus xylophilus, Ditylenchus dipsaci, Globodera spp., Heterodera spp., Meloidogyne spp., Nacobbus aberrans, Pratylenchus spp., Radopholus similis, Rotylenchulus reniformis, and Xiphinema index.

Plant Parasitic Nematodes on Paulownia tomentosa in Poland

Abstract Short-rotation woody plants of the genus Paulownia are attracting more and more attention as trees that produce biomass and reduce the concentration of carbon dioxide in the atmosphere. However, plants growing in monoculture affect the properties and condition of the soil. One of the effects of changes in the soil environment is the growing population of plant parasitic nematodes (PPN). The article presents information about the PPN inhabiting the root zone of the Paulownia tomentosa plantation in Poland. In this study, the frequency and density of nematode populations in samples from seven plantations in Poland were determined. The extracted nematodes were identified at the species level on the basis of the male and female morphological characteristics according to several available identification resources. A total of 20 nematode species were identified, of which 9 were classified as accessory and 11 as occasional. Among them, Trichodorus viruliferus and Longidorus attenuatus belonging to the group of viral messengers were identified.

Plant-parasitic nematodes in Nova Scotia vineyards

Plant-parasitic nematode populations were analyzed from composite soil samples collected from 62 vineyard blocks throughout Nova Scotia in 2018 and 2019. Nematode groups of potential concern that were found included ring nematodes (family Criconematidae), dagger nematodes (Xiphinema spp.), and root-knot nematodes (Meloidogyne spp.). Ring nematodes were overall the most widespread and abundant group of plant-parasitic nematodes, recovered from 79% of blocks with an overall average population density of 114 nematodes per 100 cm3 soil. Ring nematodes tended to be more abundant in older blocks. DNA sequence analyses of a subset of the ring nematode populations confirmed the presence of Mesocriconema xenoplax, which is the species known to be damaging to and most widely associated with grapevine globally. The analyses indicated that Criconema permistum was also present, notably in samples with the greatest ring nematode population densities. The results indicate that ring nematodes could be affecting the health of Nova Scotia vineyards, particularly in the future as populations continue to develop in relatively young vineyards and as older blocks are replanted. Additional research is needed to delineate the distribution of M. xenoplax vis-à-vis other species and to experimentally assess the host-parasite relationship between C. permistum and grapevine.

Factors Associated with Plant Parasitic Nematode (PPN) Population: A Review

<i>Meloidogyne</i> spp., root-knot nematodes (RKNs), are sedentary endoparasites that harm practically every crop on the planet. The root knot nematode attacks a variety of vegetable crops, causing delayed maturity, lower yields and quality, high production costs, and, as a result, a loss of income. The number of Root Knot Nematodes fluctuates from time to time, which can be caused by changes in temperature, soil type, and soil moisture. However, because the damage displays indications of drought and nutrient stress, it is frequently disregarded and goes unrecognized by most farmers. They degrade product quality in addition to reducing crop output owing to disruption in the host plant's physiology. The lack of awareness among farmers about the issues caused by root knot nematodes, as well as poor management strategies to combat the threat is a serious impediment to the protection of vegetable crops. To increase farmer acceptance, management techniques should be implemented in accordance with integrated pest management (IPM) practices. Vegetable growers should also be informed about the dangers of root-knot nematodes. In general, the paper summarizes elements that influence root knot nematode population dynamics, the significance of root knot nematodes and their development, as well as the pathogen life cycle and control methods.

Deciphering bacteria associated with a pre-parasitic stage of the root-knot nematode Meloidogyne hapla in nemato-suppressive and nemato-conducive soils

Nematode-suppressive soils are characterized by the ability of soil microbial communities to reduce populations of plant-parasitic nematodes (PPN) either directly or by inducing systemic resistance in plants. Various microorganisms have been recognized as antagonists of PPN in suppressive soils using culture-dependent and culture-independent methods. However, the associations that PPN form with microorganisms in nematode-conducive soils have been poorly studied. Here we drenched tomato rhizospheres with microbial suspensions from nine different soils and followed their effects on plant growth and root invasion of the infective second-stage juveniles (J2) of the northern root-knot nematode species Meloidogyne hapla. Based on the number of invaded J2, four soils were determined as nematode-suppressive, while five soils were categorized as nematode-conducive. To reveal bacteria attached to the J2 cuticle in soils with varying suppressiveness, we incubated J2 in suspensions from three suppressive and three conducive soils, and analyzed J2-attached bacteria using amplicon sequencing of the V3-V4 region of 16S rRNA gene. Our results suggest that the soil origin had a major effect on the composition of J2-attached bacteria, while the highest bacterial abundance and richness were observed on J2 from two suppressive soils. In addition, the highest number of indicator amplicon sequence variants (ASVs) was associated with J2 in two suppressive soils, but they had a very distinct bacterial profile. Further studies are needed to resolve the complexity of nemato-microbial interactions in soil and to determine the exact function of nematode-attached microorganisms in suppressive and conducive soils and their role in nematode suppression and protection.

Occurrence, Diversity and Abundance of Nematode Pests of Pineapple (Ananas comosus) in Two Local Government Areas of Rivers State, Nigeria

Plant-parasitic nematodes (PPNs) contribute to yield losses in pineapple production. Limited studies have been conducted on plant-parasitic nematodes on pineapple despite reports of PPNs infecting it. A survey was conducted in Obio-Akpor and Ikwerre Local Government Areas (LGAs) of Rivers State to determine the occurrence, abundance and diversity of PPNs associated with pineapple. A total of 60 composite samples were collected from the two LGAs. Nematodes were extracted from soil and root samples using the modified Baermann technique and identified using standard procedures. Data were processed using relative frequency of occurrence (RFOC), relative importance values (RIVs), diversity indices, nematode population was calculated and analysis of variance. The most occurring plant-parasitic nematodes were Pratylenchus, Helicotylenchus, Meloidogyne, Scutellonema and Tylenchulus. In Obio Akpor LGA, Helicotylenchus with RFOC 33.3% was the most occurring nematode pests, while Pratylenchus was the most important plant-parasitic nematode (RIV 33.8%). In Ikwerre LGA, both Helicotylenchus and Pratylenchus have the same occurrence (RFOC 33.3%) with Pratylenchus being the most important nematode pest. Pratylenchus species with RIV of 52.4% were the most important PPNs associated with pineapple in both Obio-Akpor and Ikwerre LGAs. Dominance and Shannon- Weiner indices among the PPNs are 0.58 and 0.86, respectively. In Ikwerre and Obio-Akpor LGAs, Aluu (1530) and Rumuekini (630) pineapple farms have the highest population of PPNs, respectively. Ikwerre LGA (2,150) pineapple farms had more PPNs than Obio-Akpor LGA (660). Nematode pests are associated with pineapple in the two LGAs and could be contributing to yield losses.