Occurrence Of Plant-parasitic Nematodes Research Articles

Occurrence of Plant-Parasitic Nematodes on Ornamental Foliage Plants, Citrus Orchards, and Tea Plantations in Korea

This study was conducted to investigate the plant-parasitic nematodes of ornamental foliage plants, citrus orchards, and tea plantations from July to December 2022. As a result of the investigation of plant-parasitic nematodes in 415 foliage plants, root-lesion nematodes were detected most frequently, followed by rootknot nematodes, pin nematodes, and other nematodes. In tea plantations, spiral nematodes, cyst nematodes, and root-knot nematodes were detected. Citrus nematodes, ring nematodes, and root-knot nematodes were discovered in citrus orchards. In foliage plants, tea plantations, and citrus orchards, the detection rate of plantparasitic nematodes was not high, but root-lesion nematodes were detected. Therefore, it is necessary to apply appropriate control methods to manage root-lesion nematodes during the cultivation of foliage, tea, and citrus plants.

Population dynamics and damage threshold of Pratylenchus n. sp. and Meloidogyne javanica on finger millet

Summary Finger millet (Eleusine coracana) is a staple crop for subsistence farmers and is primarily cultivated in arid and semi-arid regions. Nevertheless, there are limited data available on the occurrence of plant-parasitic nematodes that specifically target finger millet, and the damage arising from such infections. In this study, we investigated the population dynamics, damage threshold and tolerance of the lesion nematode, Pratylenchus n. sp., and the root-knot nematode, Meloidogyne javanica, on finger millet ‘P-224’. We used 11 initial population densities (Pi) of second-stage juveniles (J2): 0, 0.125, 0.25, 0.5, 1, 2, 4, 8, 16, 32 and 64 J2 (g soil)−1 for M. javanica and the same densities of mixed life-stages for Pratylenchus n. sp. The logistic growth model, Seinhorst yield loss and population dynamic models were fitted to the shoot height, plant biomass and final nematode population density. Based on the population dynamics model parameters, maximum multiplication rates and maximum population densities for each nematode species were estimated. The maximum multiplication rates (a) were 32.39 and 17.46, whilst the maximum population densities (M) were 18.83 nematodes (g soil)−1 and 19.78 J2 (g soil)−1 for Pratylenchus n. sp. and M. javanica respectively. The maximum height reached (C) was negatively affected by increasing Pi for both nematode genera, while the rate of growth (B) and the time to reach was not affected based on the logistic model. A tolerance limit (T) of 1.70 nematodes (g soil)−1 and 0.65 J2 (g soil)−1; relative minimum grain yield (m) of 0.23 and 0.40 for Pratylenchus n. sp. and M. javanica was found, respectively. The results indicate that ‘P-224’ is a good host for both Pratylenchus n. sp. and M. javanica, which significantly reduce yield. These findings can be used as a base to develop effective nematode management strategies for finger millet.

Plant-parasitic nematode community and enzyme activities in soils under no-till soybean crops in Brazil

Soybean is Brazil's largest agricultural crop, grown across a variety of climates and soil conditions, and it is subjected to a large number of pests, including plant-parasitic nematodes. In general, the occurrence of plant-parasitic nematodes in soybean is influenced by various soil physicochemical properties, such as the pH, texture, and nutrient content. These soil properties may determine the nematodes community composition and affect soil quality and functioning, which can be monitored by analysing of soil enzyme activity. In this sense, the analysis of β-glucosidase and acid phosphatase enzymes can provide valuable information to assist decisions in the sustainable management of soybean cultivated soils in Brazil. In this study, we used 216 samples collected from no-till soybean fields across Brazil. The samples were used to investigate the influence of soil physical and chemical properties on the plant-parasitic nematode community and enzymatic activity. We identified seven genera of plant-parasitic nematodes including Meloidogyne, Pratylenchus, Heterodera, Rotylenchulus, Helicotylenchus, Scutellonema, and Xiphinema. Our results indicate that clay content and soil pH were the main properties modulating the plant-parasitic nematode community. We observed a higher abundance of plant-parasitic nematodes in highly acidic soils when compared to slightly acidic. In addition, soil organic matter content, available P, and pH were the main properties modulating microbial activity in the soil. No significant correlations were observed between enzymatic activity and nematode population density. This is the first study to provide insights into plant-parasitic nematode community composition and soil enzymes activity in soybean cultivated soils on a national scale in Brazil.

Diversity and distribution of plant-parasitic nematodes associated with watermelon, in northwest Morocco

Watermelon (Citrullus lanatus) fields in northwest Morocco’s Molay Bousselham region were surveyed to study the distribution and occurrence of plant-parasitic nematodes. Eighteen nematode taxa were identified in soil and root samples collected from 24 watermelon plots. The most common plant-parasitic nematodes (PPN) identified were Meloidogyne (M. javanica, M. incognita, M. arenaria and M. hapla), Pratylenchus (P. penetrans, P. thornei, and P. fallax), Tylenchus, Helicotylenchus, Xiphinema and Ditylenchus genera. The diversity patterns of PPN were thoroughly assessed via calculating diversity indices. High species richness was recorded while significant differences were observed between the main locations based on the Shannon–Wiener index (H’) and the Evenness (J). This description of PPN assemblages associated with watermelon fields in northwest Morocco provides fundamental information to design suitable nematode management strategies to reduce yield loss and benefit our food security.

Occurrence of plant-parasitic nematodes in sugarbeet fields of North Dakota and Minnesota

Plant-parasitic nematodes (PPNs) are an important group of pathogens on sugarbeet. Surveys were conducted in the Red River Valley (RRV) area of North Dakota (ND) and Minnesota (MN) to determine the incidence, abundance, and distribution of PPNs in sugarbeet fields. A total of 217 soil samples were collected in 2016 and 2017 from fields with sugarbeet or a history of sugarbeet production. In addition, 48 samples were collected in 2016 from tare soils in sugarbeet piling stations, and two samples were collected in 2017 from sugarbeet production fields in eastern Montana (MT) and western ND border area. The incidence and abundance of major genera of PPNs identified from sugarbeet production fields in 2016 and 2017 were: Heterodera (incidence = 15%, abundance = 1,351/200 gm of soil); Helicotylenchus (38%, 157); Tylenchorhynchus (37%, 121); Paratylenchus (28%, 108); Pratylenchus (6%, 38); Paratrichodorus (7%, 37); Xiphinema (3%, 32); and Hoplolaimus (0.4%, 20). Helicotylenchus, Tylenchorhynchus, Paratylenchus, and Heterodera were the most frequent and widely distributed nematode genera whereas, Paratrichodorus and Pratylenchus were found less frequently and at low densities. Xiphinema and Hoplolaimus were rarely detected at lower densities. Paratylenchus and Tylenchorhynchus were widely distributed in most of the sampled counties (n = 11), followed by Helicotylenchus (10), Heterodera (8), Pratylenchus (8), Xiphinema (4), Paratrichodorus (3), and Hoplolaimus (1). Species-specific PCR assays and direct sequencing of ribosomal DNA were conducted to identify species. Species identification revealed that the cyst nematodes from one of the counties in eastern MT were Heterodera schachtii and the cyst nematodes analyzed from 31 samples in 12 counties in ND and MN were H. glycines. We have not identified any H. schachtii thus far from surveyed samples in eastern ND and western MN. Other nematode species identified include Paratrichodorus allius, Pratylenchus neglectus, Tylenchorhynchus sp., Paratylenchus nanus, Helicotylenchus microlobus, and H. pseudorobustus. Accurate identification of these nematodes and awareness of their occurrence across the region is essential for developing effective pest management strategies for improved sugarbeet production.

Occurrence of plant-parasitic nematodes on enset (Ensete ventricosum) in Ethiopia with focus on Pratylenchus goodeyi as a key species of the crop

Summary Enset (Ensete ventricosum) is an important starch staple crop, cultivated primarily in south and southwestern Ethiopia. Enset is the main crop of a sustainable indigenous African system that ensures food security in a country that is food deficient. Related to the banana family, enset is similarly affected by plant-parasitic nematodes. Plant-parasitic nematodes impose a huge constraint on agriculture. The distribution, population density and incidence of plant-parasitic nematodes of enset was determined during August 2018. A total of 308 fields were sampled from major enset-growing zones of Ethiopia. Eleven plant-parasitic nematode taxa were identified, with Pratylenchus (lesion nematode) being the most prominent genus present with a prominence value of 1460. It was present in each sample, with a highest mean population density per growing zone of 16 050 (10 g root)−1, although densities as high as 25 000 were observed in fields at higher altitudes in Guraghe (2200-3000 m a.s.l.). This lesion nematode is found in abundance in the cooler mountainous regions. Visible damage on the roots and corms was manifested as dark purple lesions. Using a combination of morphometric and molecular data, all populations were identified as P. goodeyi and similar to populations from Kenya, Uganda and Spain (Tenerife). Differences in population densities amongst cultivars indicate possible resistance of enset to P. goodeyi.

A Primary Study for Checking the Occurrence of Plant Parasitic Nematodes with the Crop Banana at Agricultural Areas of Palakkad Taluk, India

The reviews on production of banana during the recent years were not a satisfying one with respect to fourth position of Kerala in area of cultivation in India. Among so many factors for this declination, plant parasitic nematodes also found as a major negative factor. Thus the present study tried to prove this predict and conducted a survey in the unexplored rhizosphere region of an important crop banana (Nendran) in Palakkad taluk of Kerala, India during the post monsoon season of 2017. A total of twenty seven samples each were collected from banana rhizosphere soil and roots and processed for this study. The analysis revealed that the most abundant nematode population was Radopholus spp. and most frequently occurred genus was Meloidogyne spp. in the studied banana fields. The major diversity showing area were Elappully panchayath for rhizosphere soil samples and Kannadi panchayath for root samples. Different plant parasitic nematodes such as Aphelenchus spp., Criconemoides spp., Dory laimoides spp., Helicotylenchus spp., Hoplolaimus spp., Meloidogyne sp p., Pratylenchus spp., Radopholus spp., Rotylenchulus spp., Tylenchoryn chus spp. and Tylenchus spp. were observed in both soil and root samples examined.

Occurrence of plant parasitic nematodes associated with Noni (Morinda citrifolia L.) intercrop with Coconut

Occurrence of plant parasitic nematodes associated with Noni (<i>Morinda citrifolia</i> L.) intercrop with Coconut

Comparative study on the host susceptibility of different banana cultivars to plant parasitic nematodes in Malappuram district of Kerala, India

Six cultivars of banana grown widely in Malappuram district of Kerala were evaluated for the diversity of plant parasitic nematodes in their respective rhizosphere. The genotypes evaluated include Nendran, Poovan (Mysore), Njali poovan, Mysore poovan, Chenkadali and Ponnan. The study aims on a comparative analysis of rhizosphere of different banana varieties for the occurrence of plant parasitic nematodes, diversity, frequency of occurrence and to determine the most vulnerable type of banana variety. Cobb’s decanting and sieving method was used to isolate nematodes from soil. Thirty three samples randomly collected from different blocks of Malappuram district are subjected to analysis and a ten species of nematodes were reported. Among the six varieties analysed both Nendran and Mysore Poovan variety seems to be more susceptible to phytoparasitic nematodes. With respect to eight blocks of Malappuram district, Helicotylenchus sp. shows highest prominence value followed by Radopholus similis, reniform nematode and Meloidogyne incognita.

Diversity of arbuscular mycorrhizal fungi and nematodes in a 14 years no-tillage chronosequence

We evaluated the effects of the conversion of native areas of the Cerrado to no-tillage on the population of arbuscular mycorrhizal fungi and nematodes. Three areas under no-tillage (7, 11 and 14 years of cultivation) were evaluated and compared to adjacent areas of the Cerrado not impacted by agriculture. Results indicated that although no-tillage is a conservation system, it has either slightly reduced, slightly improved, or maintained the taxonomic and functional diversity of arbuscular mycorrhizal fungi and nematodes, even after 14 years of cultivation. In addition, cultivated areas presented reduced diversity of arbuscular mycorrhizal fungi, and increased occurrence of plant parasitic nematodes. The observed differences could be a result of both disturbance to the soil structure through agriculture and reduced plant diversity in the soybean-corn rotation, as compared to the adjacent uncultivated Cerrado.

Occurrence of Plant Parasitic Nematodes in Yamagata Prefecture

Occurrence of Plant Parasitic Nematodes in Yamagata Prefecture

Challenges in Tropical Plant Nematology

A major challenge facing agricultural scientists today is the need to secure food for an increasing world population. This growth occurs predominantly in developing, mostly tropical countries, where the majority of hungry people live. Reducing yield losses caused by pathogens of tropical agricultural crops is one measure that can contribute to increased food production. Although plant-parasitic nematodes are often not as important as some other biotic and nonbiotic constraints on crop production in the tropics, they can nevertheless cause extensive damage and substantial yield losses. The effects of agricultural, environmental, socioeconomic, and policy changes on the occurrence of plant-parasitic nematodes in the tropics and the losses these pathogens cause are largely undocumented. Recent developments pose new challenges to tropical nematology. The increased application of molecular diagnostics may widen the knowledge gap between nematologists working in developed countries and in the tropics. Uncertainties concerning the validity of nematode species will lead to practical problems related to quarantine measures and nematode management. The study of interactions between nematodes and other pathogens in disease complexes provide opportunities for multidisciplinary research with scientists from other disciplines but remain underexploited. Difficulties in recognizing emerging nematode threats prevent the timely implementation of management strategies, thus increasing yield losses. Research is needed to address these challenges. Examples are presented mainly but not exclusively from banana, peanut, and rice nematology.

Some notes on the occurrence of plant parasitic nematodes of fruit trees in Slovakia

Forty plant parasitic nematode species were identified in soil of fruit orchards in the southeastern and southwestern areas of the Danubian Lowlands and East Slovak Lowland, characterised by light sandy soil of riverine origin, locally combined with drift sand landscape. They were &lt;i&gt;Ditylenchus dipsaci&lt;/i&gt;, &lt;i&gt;Helicotylenchus canadensis&lt;/i&gt;, &lt;i&gt;H. digonicus&lt;/i&gt;, &lt;i&gt;H. dihystera&lt;/i&gt;, &lt;i&gt;H. multicinctus&lt;/i&gt;, &lt;i&gt;Rotylenchus agnetis&lt;/i&gt;, &lt;i&gt;R. fallorobustus&lt;/i&gt;, &lt;i&gt;R. goodeyi&lt;/i&gt;, &lt;i&gt;Rotylenchulus borealis&lt;/i&gt;, &lt;i&gt;Pratylenchus crenatus&lt;/i&gt;, &lt;i&gt;P. penetrans&lt;/i&gt;, &lt;i&gt;P. pratensis&lt;/i&gt;, &lt;i&gt;P. thornei&lt;/i&gt;, &lt;i&gt;Zygotylenchus guevarai&lt;/i&gt;, &lt;i&gt;Pratylenchoides laticauda&lt;/i&gt;, &lt;i&gt;Meloidogyne hapla&lt;/i&gt;, &lt;i&gt;Bitylenchus dubius&lt;/i&gt;, &lt;i&gt;Tylenchorhynchus cylindricus&lt;/i&gt;, &lt;i&gt;Merlinius nanus&lt;/i&gt;, &lt;i&gt;Macroposthonia antipolitana&lt;/i&gt;, &lt;i&gt;M. rustica&lt;/i&gt;, &lt;i&gt;M. xenoplax&lt;/i&gt;, &lt;i&gt;Paratylenchus bukowinensis&lt;/i&gt;, &lt;i&gt;P. elachistus&lt;/i&gt;, &lt;i&gt;P. nanus&lt;/i&gt;, &lt;i&gt;P. projectus&lt;/i&gt;, &lt;i&gt;Longidorus elongatus&lt;/i&gt;, &lt;i&gt;L. euonymus&lt;/i&gt;, &lt;i&gt;L. juvenilis&lt;/i&gt;, unidentified &lt;i&gt;Longidorus&lt;/i&gt; sp., &lt;i&gt;Xiphinema diversicaudatum&lt;/i&gt;, &lt;i&gt;X. italiae&lt;/i&gt;, &lt;i&gt;X. pachtaicum&lt;/i&gt;, &lt;i&gt;X. taylori&lt;/i&gt;, &lt;i&gt;X. vuittenezi&lt;/i&gt;, &lt;i&gt;Trichodorus primitivus&lt;/i&gt;, &lt;i&gt;T. sparsus&lt;/i&gt;, &lt;i&gt;T. viruliferus&lt;/i&gt;, &lt;i&gt;Paratrichodorus macrostylus&lt;/i&gt; and &lt;i&gt;P. pachydermus&lt;/i&gt;. Many of the observed species are phytopathologically important parasites of fruit trees and some are also vectors of plant viruses. The frequency of occurrence, dominance and abundance of individual species were determined.

Fitonematoides associados a bananais 'Pacovan' sob condição de cultivo irrigado: relação com a produção

Dentre os fatores que afetam a produtividade da bananeira, destacam-se as pragas, doenças e tratos culturais fitossanitários inadequados. Nesse contexto, os fitonematóides possuem grande importância devido à diminuição da eficiência na absorção de água e nutrientes pelas raízes, causando também o tombamento das plantas à medida que os cachos se aproximam da colheita. Cerca de 146 espécies de nematóides já foram relatadas associados à rizosfera da bananeira. Contudo, apenas Radopholus similis, diversas espécies dos gêneros Meloidogyne, Helicotylenchus, Pratylenchus e Rotylenchulus causam perdas significativas em bananais. Em bananais situados em perímetros irrigados nos municípios de Petrolina-PE e Juazeiro-BA, do Distrito de Irrigação Senador Nilo Coelho foram aplicados questionários para se obterem informações do histórico da área, incluindo nutrição das plantas, fertilidade, tratos culturais, ocorrência de pragas e pós-colheita. Observou-se que 90% da área era locada com pequenos produtores. Os maiores problemas levantados foram: manejo inadequado, colheita e pós-colheita, nematóides e ventos fortes. Na presente pesquisa, realizou-se um levantamento de fitonematóides. Objetivou-se identificar os gêneros dos fitonematóides presentes, e estudar a relação entre a produção de bananeiras dos diversos núcleos selecionados com as populações de fitonematóides presentes no solo e nas raízes. Em cada área selecionada, foram marcadas 20 bananeiras e amostrados solo e raízes, sendo uma amostra composta constituída de quatro subamostras de cada planta para representar a população de fitonematóides. Os gêneros de nematóides mais abundantes foram Helicotylenchus, Meloidogyne e Rotylenchulus. A produção de banana não esteve relacionada ao número de propriedades dentro de cada núcleo, nem à densidade dos fitonematóides (Helicotylenchus sp., Meloidogyne sp., Rotylenchulus sp., Pratylenchus sp. e Radopholus similis). Pôde-se inferir que o manejo adotado em cada núcleo de produção de banana irrigada influenciou na produção (peso de cachos) sob diferentes populações de fitonematóides.

Plant-parasitic nematodes in soil-less culture systems

Abstract The development from growing plants in field soil to soil-less culture systems has not resulted in the elimination of problems caused by plant-parasitic nematodes. Species of Meloidogyne and Radopholus have been reported to occur in soil-less culture systems, such as flower crops. The reasons for initial nematode infestation are numerous but the primary reason is likely to be infested plant material. Since nematodes are not expected in soil-less systems, they are often overlooked. However, extension specialists report an increasing occurrence of plant-parasitic nematodes in soil-less culture systems and nematodes seem to be more prevalent than is often thought likely. In an attempt to increase the awareness of the prevalence of plant-parasitic nematodes in soil-less culture systems, this short paper summarises incidences of nematode detections and reviews methods for their detection and strategies for their control.

Occurrence of plant parasitic nematodes and non‐pathogenic species ofFusariumin tomato plants in Kenya and their role as mutualistic synergists for biological control of root‐knot nematodes

Abstract The occurrence of plant parasitic nematodes and endophytic fungi in tomato plants was determined from different regions in Kenya. In areas with regular cultivation of tomatoes, the population densities of all species of nematodes, regardless of trophic group, were high. Meloidogyne incognita was the predominant plant parasitic nematode in the regions investigated. Apparently endophytic fungi were frequently isolated from tomato roots, with Fusarium oxysporum being the most common endophyte detected. In contrast, irregular cultivation of tomato resulted in lower overall nematode densities and the absence of Meloidogyne infestation. F. oxysporum occurred only sporadically. Four isolates of F. oxysporum which were tested in subsequent greenhouse experiments, reduced M. incognita populations without adversely affecting plant health. Non‐pathogenic isolates of F. oxysporum with mutualistic symbiotic behaviour are potential biological control agents for plant parasitic nematodes.

Occurrence of Plant Parasitic Nematodes in Punjab, India

Abstract Forty-seven plant nematode species were found associated with 33 crops, bringing the total number of plant nematode species reported from the state to 68. Meloidogyne incognita, M. arenaria, Pratylenchus zeae, Tylenchorhynchus brassicae, Tylenchulus semipenetrans, Rotylenchulus reniformis, Xiphincma americanum, Heterodera avenae and H. zeae cause extensive damage. Vegetables were the most adversely affected of all the crops investigated.

Olpidium brassicae and Polymyxa graminis in Roots of Creeping Bent in Golf Putting Greens

During an investigation to determine the occurrence of plant-parasitic nematodes associated with creeping bent (Agrostis palustris Huds.) in golf putting greens (9) microscopic examination of the roots revealed the presence of numerous cystosori of Polymyxa graminis Led. and resting spores of Olpidium brassicae (Wor.) Dang. Examination of other samples obtained from a putting green on the Harrison Park Golf Course, Danville, Illinois, in September revealed that the roots of 89 percent of the plants examined were infected with P. graminis. Stellate resting spores of 0. brassicae were present in the roots of all plants. The high incidence of these obligate parasites in adventitious roots, both primary and lateral, suggested that they might be instrumental in causing the annual killing of most of the root system of creeping bent in putting greens during midsummer in the midwest. Consequently, studies were begun to determine whether these fungi occurred commonly in Illinois putting greens, and if they were causing significant damage.