Presence Of Plant Parasitic Nematodes Research Articles

THE POTENTIAL OF TEQUIL, A PLANT EXTRACT BASED ON QUILLAJA SAPONARIA, IN SUSTAINABLE AGRICULTURE

More attention is being given to researches of eco-sustainable solutions to be implemented in agriculture, particularly in the presence of plant parasitic nematodes, whose damages have significant global importance. Unsustainable practices, such as fumigation and monoculture, have led to depletion of biodiversity, allowing harmful trophic groups (bacteria, fungi, and nematodes) to prevail, and their negative synergistic action further exacerbating yield losses. Considering the notable and progressive restriction of usable molecules, nematode control strategies must necessarily consider the appropriate integration of methods. The main objective of control is to limit pathogen populations below the damage threshold, rather than aiming at their eradication as mistakenly pursued in the past. This goal can be achieved with the help of solutions that promote plant development through biostimulation of root systems, which are often affected by various organisms in the biosphere. Tequil, through its well-documented synergy of saponins, tannins, and polyphenols, produces invigorating, biostimulating, and strengthening effects on the root system. Indeed, in vitro tests and field trials have highlighted Tequil’s appreciable activity in containing trophic groups, particularly root-knot nematodes of the Meloidogyne genus. Therefore, its use could indirectly contribute to nematode control and limit yield losses. Key Words: Quillaja saponaria, nematodes, bio stimulation, biocontrol, abiotic stresses resistance.

New Records of Ditylenchus Species from Southern Alberta, Canada.

The presence of plant-parasitic nematodes (PPNs) in cultivated areas is a limiting factor in achieving marketable crop yield. To control and alleviate the effects of these nematodes and determine appropriate management strategies, species-level identification is crucial. Therefore, we conducted a nematode diversity survey, which resulted in the detection of four Ditylenchus species in cultivated areas of southern Alberta, Canada. The recovered species had six lines in the lateral field, delicate stylets (>10 µm long), distinct postvulval uterine sacs, and pointed to rounded tail tips. The morphological and molecular characterization of these nematodes revealed their identity as D. anchilisposomus, D. clarus, D. tenuidens and D. valveus, all of which are members of the D. triformis group. All of the identified species were found to be new records in Canada except for D. valveus. Accurate Ditylenchus species identification is crucial because false-positive identification can result in the implementation of quarantine measures over the detected area. Our current study not only documented the presence of Ditylenchus species from southern Alberta, but also described their morpho-molecular characteristics and subsequent phylogenetic relationships with related species. The results of our study will aid in the decision on whether these species should become a part of nematode management programs since nontarget species can become pests due to changes in cropping patterns or climate.

Six Genera of Plant-Parasitic Nematodes From Bangladesh

The presence of plant-parasitic nematodes causing crop loss every year had been overlooked in the existing fruits, vegetables and flowers cultivation system in Bangladesh. Therefore, the study was conducted to isolate and identify plantparasitic nematodes from soil and infected plant-parts of fruits (banana, orange), vegetables (pointed gourd, tomato and brinjal) and flower (gerbera) from the districts of Jashore, Jhenaidah, Gazipur and Sylhet during 2017-18 and 2018-19 cropping seasons. A total of 68 samples of which 20 fruit samples, 45 vegetables samples and 3 flower samples were collected and observed for nematode infestation. Baermann funnel method was used to extract the active nematodes from plant parts and Cobb’s method was used for the isolation of nematodes from soil samples. Different morphological structures of the nematodes viz. esophagus, median bulb, basal bulb, intestine, reproductive structures (vulba, bursa), etc. were used to identify the nematodes. To identify Meloidogyne spp. from root knot of tomato, brinjal and gerbera, juvenile larvae J2 and perineal pattern of female nematodes were used. A total of six genera of nematodes were identified and all of them were under the order Tylenchida. The nematode genera were Tylenchorhynchus sp., Tylenchus sp., Hoplolaimus sp., Helicotylenchus sp., Pratylenchus sp. and Meloidogyne spp. The root-knot nematode, Meloidogyne incognita was recorded for the first time in flower crop gerbera in Bangladesh.
 Bangladesh J. Agril. Res. 46(3): 275-284, September 2021

Plant Immunity and Potential of Plant Extracts in Management of Parasitic Nematodes

One major challenge that agricultural production faces is the presence of plant-parasitic nematodes in crop fields. Plant-parasitic nematodes cause serious plant physical injuries, the inability of plants to acquire nutrients from the soil, and weaken the plant immune system. However, plants respond in several ways by producing hormones, anti-nematocidal proteins, repellents, nemastatic compounds, or inhibiting the feeding cell formation and development that minimize attack and injuries by the nematodes. Sometimes these mechanisms fail and therefore plant growers have to use plant management practices to prevent and suppress the presence of parasitic nematodes. The development and use of synthetic nematicides have limitations associated with costs and environmental pollution. Therefore, the use of plant extracts that contains anthelmintic compounds has proved to be successful in suppressing parasitic nematodes while maintaining environmental safety for living organisms. However, the relationship between plant immunity and the applications of plant extracts has not been well documented. It is against this background that this minireview explains the mechanism of plant immunity and the potential of plant extracts in enhancing plants to resist and suppress parasitic nematodes. The research progress and challenges of using the plant extracts have also been discussed thus creating potential areas of future research on applications of plant extracts in parasitic nematodes management. Furthermore, this minireview has recommended the use of sustainable integrated management of plant-parasitic nematodes approach.

Root knot nematode infections promoted by agricultural practice modifications in Vietnam and the impacts on rice production

A survey conducted on newly cultivated lowland rice fields by direct seeding method in Hai Duong Province, Viet Nam, in March 2017 revealed high devastation of the field. In these fields, farmers used an annual crop rotation cycle of rice-scallion-rice. Investigations on the devastated fields revealed that the chemical and physical soil properties were appropriate for rice cultivation. On the other hand, observations done on the root systems showed that the dead plants have symptomatic root galls suggesting the presence of plant parasitic nematodes. Sequencing of the internal transcribed spacer (ITS) region of the rDNA genes of the nematodes showed that the root nematodes extracted from the infested fields belonged to Meloidogyne graminicola. The reproductive factor of the isolated M. graminicola population on the IR64 rice variety (Oryza sativa indica) was normal, suggesting that the impact of this plant pest was not due to the emergence of an unusual virulent population. The combination of the three factors (wrong cropping choice for rotation, using rice variety susceptible to M. graminicola and direct seeding) were obviously promoting the nematode infection and its high proliferation in the surveyed fields. Meloidogyne graminicola could parasitize and propagate in scallions of Vietnam. Since this plant is annually cultivated on a paddy field for crop rotation, preventive measures or alternative plant for crop rottion is necessary.

Plant health evaluations of Belonolaimus longicaudatus and Meloidogyne incognita colonized bermudagrass using remote sensing

The objective of this study was to evaluate the ability of an unmanned aerial system (UAS) equipped with a multispectral sensor to track plant health in the presence of plant-parasitic nematodes in conjunction with nematicide applications. Four nematicides were evaluated for their ability to suppress Belonolaimus longicaudatus and Meloidogyne incognita in microplots, and three nematicides were evaluated on a golf course for their ability to suppress multiple plant-parasitic nematode genera. Visual ratings, Normalized Difference Vegetation Index (NDVI), and Normalized Difference RedEdge Index (NDRE) were reported throughout the trial to assess plant health. B. longicaudatus and M. incognita population density was significantly lowered by nematicide treatments in microplots and correlated with visual ratings, NDVI, and NDRE plant health ratings. On the golf course, all nematicides reduced total plant-parasitic nematode population density at 28, 56, and 84 days after treatment (DAT). Visual turf quality ratings, NDVI, and NDRE were positively correlated with lower nematode population density in the majority of evaluation dates. In the microplot and golf course settings, the parameters evaluated for plant health were correlated with plant-parasitic nematode population density: visual ratings, NDVI, and NDRE improved as nematode population density declined. These results show that remote sensing has the potential to be a beneficial tool for assessing plant-parasitic nematode infected bermudagrass.

Bahasa Indonesia

Plant parasitic nematodes can cause crop losses in celery. Parasitic nematodes that infect celery are Helicotylenchus spp., Trichodorus , Longidorus , Xiphinema and Meloidogyne spp Cropping pattern becomes part of the factors that influence the presence of plant parasitic nematodes in celery. Field obervation was conducted in celery growing areas to study the diversity and abundance of parasitic nematodes from monoculture and polyculture cropping system. Seven genus of nematodes, i.e. Meloidogyne, Pratylenchus, Tylenchorhinchus, Tylenchulus, Xiphinema, and two nonparasitic nematode were identified from polyculture cropping system, whereas 4 genus were found from monoculture cropping system i.e. Meloidogyne , Pratylenchus , Tylenchulus and Trichodorus. Genus with high abundance in polyculture cropping pattern was Xiphinema and Meloidogyne however Trichodorus was not found . Genus with a high abundance in monoculture was Meloidogyen and Xiphinema was not found. The genus most frequently found was Meloidogyne in polyculture and Xiphinema in monoculture.

In Vitro Evaluation of Some Bacterial Isolates as Biofertilizers and Biocontrol Agents Against The Second Stage Juveniles of Meloidogyne incognita

Representative soil samples were collected from soil apart and the rhizosphere of different plant varieties grown in five Egyptian Governorates. The presence of plant parasitic nematodes (PPN) and free living nematodes (FLN) in the collected samples were estimated. In addition, one hundred and 65 bacterial cultures which well known as biofertilizers (some are able to fix nitrogen and the others solubilize either phosphate or potassium) were isolated. The isolated bacteria were screened depending on their rate of growth. Thirty-five cultures of fast growing nitrogen fixing bacteria (NFB), phosphate solubilizing bacteria (PSB) and potassium solubilizing bacteria (KSB) and their cultural filtrates were tested in vitro as biocontrol agents against the second stage juvenile (J2s) of the Meloidogyne incognita. In general, higher mortality percentages of nematodes were recorded by bacterial cultures than their comparative cultural filtrates. The highest mortality percentages were recorded by cultures of NFB7, PSB2 and KSB2 (100% at dilution 1/10), while it was 99.3, 99 and 97.8% at dilution 1/100, respectively. NFB7 exhibited a high nitrogen fixation rate (4.2 μmole N2/mL/h), while PSB2 and KSB2 effectively solubilized phosphate and potassium comparing with the control treatments (1.94 fold of available phosphate and 2.0 fold of available potassium, respectively). NFB7, PSB2 and KSB2 isolates showed the highest protease, gelatinase and chitinase activities which were thought responsible for their nematicidal effect. The three bacterial isolates were identified as Paenibacillus polymyxa, Bacillus megaterium and Bacillus circulans, respectively.

In vitro evaluation of some bacterial isolates as biofertilizers and biocontrol agents against the second stage juveniles of Meloidogyne incognita

Representative soil samples were collected from soil apart and the rhizosphere of different plant varieties grown in five Egyptian Governorates. The presence of plant parasitic nematodes (PPN) and free living nematodes (FLN) in the collected samples were estimated. In addition, one hundred and 65 bacterial cultures which well known as biofertilizers (some are able to fix nitrogen and the others solubilize either phosphate or potassium) were isolated. The isolated bacteria were screened depending on their rate of growth. Thirty-five cultures of fast growing nitrogen fixing bacteria (NFB), phosphate solubilizing bacteria (PSB) and potassium solubilizing bacteria (KSB) and their cultural filtrates were tested in vitro as biocontrol agents against the second stage juvenile (J2s) of the Meloidogyne incognita. In general, higher mortality percentages of nematodes were recorded by bacterial cultures than their comparative cultural filtrates. The highest mortality percentages were recorded by cultures of NFB7, PSB2 and KSB2 (100% at dilution 1/10), while it was 99.3, 99 and 97.8% at dilution 1/100, respectively. NFB7 exhibited a high nitrogen fixation rate (4.2 μmole N2/mL/h), while PSB2 and KSB2 effectively solubilized phosphate and potassium comparing with the control treatments (1.94 fold of available phosphate and 2.0 fold of available potassium, respectively). NFB7, PSB2 and KSB2 isolates showed the highest protease, gelatinase and chitinase activities which were thought responsible for their nematicidal effect. The three bacterial isolates were identified as Paenibacillus polymyxa, Bacillus megaterium and Bacillus circulans, respectively.

Prevalence and farmers' perceptions of parasitic nematodes in yam rhizosphere soils from some yam producing areas of Ghana

Rhizosphere soil samples of yam from Adidwan, Ejura, Kintampo, Mampong, Nkoranza and Techiman, in the transitional agro-ecological zone of Ghana, and yam tubers from Techiman market were analysed for the presence of plant parasitic nematodes in August and September, 2002. Yam farmers from the areas were also surveyed using questionnaire to determine their perceptions of nematodes. Thirteen genera of nematodes were identified in the yam rhizosphere soil samples. These were Aphelenchoides, Criconemella, Helicotylenchus, Hoplolaimus, Longidorus, Meloidogyne, Paratylenchus, Pratylenchus, Rotylenchulus, Scutellonema, Trichodorus, Tylenchus and Xiphinema . Of these, Aphelenchoides, Meloidogyne, Paratylenchus, Pratylenchus and Rotylenchulus were found in all the six yam- growing areas. The most frequently detected genus was Pratylenchus (21.8% relative abundance) and the least was Longidorus (0.4%). All yam tubers purchased from the market were infected by parasitic nematodes such as Meloidogyne, Pratylenchus and Scutellonema with Pratylenchus being the most frequently recovered. Farmers had poor perceptions of yam nematodes. Apart from Techiman and Ejura where 40 and 10%, respectively, of yam farmers knew about nematodes, farmers from the remaining areas did not know about the pest. Planting materials were not treated for control of nematodes. Keywords : yam, dioscorea, plant parasitic nematodes, rhizosphere soil, transitional agro- ecological zone Agricultural and Food Science Journal of Ghana Vol. 3 2004: 217-226

Plant-parasitic nematodes associated with turfgrass in golf courses in southern Ontario

One hundred thirty-five soil samples, collected from 15 golfcourses throughout southern Ontario in 1995, 1997, and 1998 were analysed for the presence of plant-parasitic nematodes. Criconemoides spp., Helicotylenchus spp., Heterodera spp., Hoplolaimus spp., Meloidogyne spp., Paratylenchus spp., Pratylenchus spp., Tylenchorhynchus spp., and Xiphinema spp. were recorded. The ring nematodes, Criconemoides spp., and the pin nematodes, Paratylenchus spp., were present in all 15 golf courses. The lesion nematodes, Pratylenchus spp., and the spiral nematodes, Helicotylenchus spp., were present in 14 courses. The lance nematodes, Hoplolaimus spp., were present in 13 courses. The stunt nematodes, Tylenchorhynchus spp., were present in 12 golf courses. Four species of the lesion nematode were recorded: Pratylenchus crenatus, P. neglectus, P. fallax, and P. thornei. This is the first report of P. fallax in Ontario, and the first detection of P. thornei on turf in the province.

Microcosm experiments on the development of different plant parasitic nematode fauna in two soils from the Soudanese-Sahelian zone of West Africa

To test the hypothesis that the structure of plant parasitic nematode communities is affected by soil characteristics, experiments were conducted in a greenhouse with two soils with different physical and chemical characteristics and land management histories (fallow and a cultivated field) from adjacent plots. The cultivated soil was more sandy and had lower organic matter and nutrient contents than the fallow soil. Four nematode assemblages of Scutellonema cavenessi, Helicotylenchus dihystera and Tylenchorhynchus gladiolatus were inoculated in the soils. The pot experiment was conducted on millet during 2 months. Multiplication rates of H. dihystera were not significantly different in the two soils. T. gladiolatus had a lower multiplication rate in the fine-textured soil. S. cavenessi seemed to reproduce better in the coarse-textured soil when inoculated in low density with H. dihystera. The presence of plant parasitic nematodes in the cultivated soil caused a significant decrease of millet biomass, whereas plants in the fallow soil were less sensitive to nematode damage and were only affected when the soil was inoculated with T. gladiolatus alone. This experiment did not explain the distribution of plant parasitic species observed in the field. However, parameters other than the presence of a favourable host plant and micro-climatic conditions were found to induce differences in the reproductive rates of several species of plant parasitic nematodes.

The distribution of Tylenchulus semipenetrans and other parasitic nematodes associated with citrus in northern Victoria

Citrus orchards in the Cobram district of northern Victoria were surveyed in 1976 for the presence of plant parasitic nematodes; in particular for the citrus nematode Tylenchulus semipenetrans. One hundred and forty-six soil samples were collected from 38 orchards. Nine genera were recorded, the most prevalant being Tylenchulus and Paratrichodorus (95 per cent and 37 per cent respectively, of all samples). T. semipenetrans was present in all orchards sampled. Population levels of T. semipenetrans larvae exceeded 1000 per 500 g of soil in 60 per cent of samples.

The distribution of Xiphinema index and other parasitic nematodes associated with grapevines in north-eastern Victoria

Twenty-four vineyards in north-eastern Victoria were surveyed in 1969 for the presence of plant parasitic nematodes; in particular for Xiphinema index the vector of grape fanleaf virus (GFV). Eight genera were recorded, the most prevalent being Paratylenchus and Xiphinema (37 per cent and 32 per cent respectively, of all samples). X. index was present in nine vineyards, and 10 per cent of all samples. A more detailed survey was made in 1970 of those vineyards in which X. index was known to be present. X. index was found in 50 per cent of samples, and 74 per cent of all samples contained Xiphinema species. Ninety vines from X. index-positive samples on two vineyards were tested for presence of virus. Although no symptoms of virus infection were evident in the field, 52 per cent of vines were shown to be infected with latent strains of GFV. All X. index-infested vineyards are within a radius of 10 km of Rutherglen. It is not known how long X. index has been present, but its introduction was probably from southern France in the 1890s together with Phylloxera resistant rootstocks.

Nematodes and Forest Trees--Types of Damage to Tree Roots

The presence of plant-parasitic nematodes and their importance as pests of agricultural and ornamental crops have long been rccognized in the devel­ oped nations of the world. The injury and crop losses caused by the root-knot nematode, the sugarbeet nematode, and the golden nematode have been obvi­ ous for many years because these parasites are limiting factors in economic crop production in certain areas. It is now becoming obvious, particularly in perennial ornamentals and fruit and nut crops, that still greater injury may be caused by nematodes whose presence and damage is less easily measured. Since nematodes cause serious damage to citrus, peaches, walnuts, cherries, almonds, and many other horticulturally important trees, it is not surprising that they also damage forest trees, yet nematode diseases of forest trees re­ main virtually unknown. Disregard of rhizosphere ecology by forest scientists probably accounts for past failures to recognize nematodes as important soil and site factors in forestry. Root losses due to nematodes on forest trees have generally gone unnoticed. In fact, forest soils are probably the least known portion of the forest environment. Plant-parasitic nematode� are found in practically all regions of the world in which forest trees grow (48). And yet to the present day, nursery seed­ lings not withstanding, few records implicate these parasites as causes of growth loss. This is due in large measure to difficulties encountered in accu­ rately measuring growth loss in trees resulting from damage to feeder roots. Approaches to soil-borne diseases of any perennial crop are limited by the complexity of the problems. The fact that the research is laborious and time consuming has probably caused many investigators to avoid this area. Never­ theless, information concerning host-parasite relations of nematodes and tree roots is essential to provide a basis for recognition and diagnosis of diseases. Until such information is available, accurate estimates of yield losses of trees due to nematodes will be lacking. Recently, plant-parasitic nematodes have been recognized as causal agents