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Brinjal (Solanum melongena L.) is an important vegetable worldwide and its production is hampered by the infestation of root-knot nematodes (Meloidogyne spp.). In an attempt to identify the Meloidogyne species involved in causing root-knot disease of brinjal by using molecular tools, plants showing knots/galls were collected from 22 brinjal growing locations that belong to different agro-ecological zones in Bangladesh. Nematode populations were maintained in a susceptible brinjal variety by inoculating with egg-masses developed on different varieties of brinjal roots collected from different locations. For molecular identification, DNA was extracted directly from galls developed in the roots of the inoculated plants. Randomly selected three galls from each location were crushed together in order to get DNA from mixed species of root-knot nematodes. Sequence Specific Amplified Region (SCAR) primers specific for Meloidogyne incognita, M. javanica or M. arenaria were used for PCR amplification. For 18 of the 22 locations, M. javanica was identified. At two locations M. incognita was found as a mixed population with M. javanica. M. arenaria was not found. PCR products were sequenced bi-directionally and their analysis revealed genetic variation among the populations. M. javanica was the predominant root-knot nematode species of brinjal in Bangladesh. Intra-specific variation of the SCAR suggested six phylogenetic groups of M. javanica. They showed significant differences in reproduction on brinjal and in their effect on root and shoot weight, while differences in hatching dynamics over five weeks were not significant. This population-dependent aggressiveness of the dominant root-knot nematode M. javanica on brinjal in Bangladesh should be considered for a more efficient management.

In this investigation, certain rosemary residues as powdered dry and mashed fresh leaves with their aqueous extracts were used for biocontrolling root-knot nematode, M. incognita on field pea cv. C...

Terrible though the global COVID-19 pandemic has undoubtedly been, and continues to be, its eruption has provided a stunningly stark new context to the many aspects of human life examined in this r...

Effects of SiO2 NPs and Rhizobium leguminosarum alone and in combination was observed on the Meloidogyne incognita and Pseudomonas syringae pv. pisi on pea. Inoculation of plants with M. incognita ...

Plant-parasitic nematodes, such as Meloidogyne incognita, cause serious damage to various agricultural crops worldwide, and their control necessitates environmentally safe measures. We have studied the effects of plant secondary metabolites on M. incognita locomotion, as it is an important factor affecting host inoculation inside the soil. We compared the effects to the respective behavioral responses of the model saprophytic nematode Caenorhabditis elegans. The tested botanical nematicides, all reported to be active against Meloidogyne sp. in our previous works, are small molecular weight molecules (acids, alcohols, aldehydes, and ketones). Here, we specifically report on the attractant or repellent properties of trans-anethole, (E,E)-2,4-decadienal, (E)-2-decenal, fosthiazate, and 2-undecanone. The treatments for both nematode species were made at sublethal concentration levels, namely, 1 mM (

Humic acid, a natural by-product from lignite coals, was evaluated for its potential to control root-knot nematode, Meloidogyne incogntia infecting banana. Hatching of M. incognita eggs was inhibited 50%–100% following incubation in 0.08%-2.0% humic acid in vitro. Exposure of juveniles (J2) of M. incognita to different humic acid concentrations significantly affected the mobility of J2 in vitro. The percent immobility of J2 increased with concentrations of humic acid up to 0.08%. In pot experiments, soil treatment with humic acid reduced the root galling in banana plantlets. All the humic acid tested concentrations (0.04%, 0.08%, 0.2% and 0.4%) significantly reduced the nematode soil density by 53.5%–56.7%, root infection by 61.9%–63.8%, egg population by 61.9%–63.8% and reproduction rate by 55.7%–56.6%. A significant improvement of growth of banana plantlets in terms of number of leaves, pseudostem height, girth, weight, root length and weight was noticed in humic acid treated pots. Humic acid di...

The manifest representation of space and place is essential to good archaeology. Our ability to document and relate these concepts, projected into the past and reflected in the present, has increas...

In this article, we outline the place of Russian criminology on the world criminological map during the pre-Soviet, Soviet, and post-Soviet eras. We examine the external institutional and economic ...

Nemarioc-AL and Nemafric-BL phytonematicides consistently reduced populations of plant-parasitic nematodes. The contribution of juvenile hatch inhibition to the overall reduction of the nematode numbers by the two phytonematicides, with cucurbitacin A and B as active ingredients, respectively, remains undocumented. The objectives of this study were to examine (i) the response of Meloidogyne incognita second-stage juveniles (J2) hatch to increasing concentration of cucurbitacins A and B, (ii) the potential saturation of J2 hatch when exposed to cucurbitacins for extended incubation periods, (iii) the minimum inhibition concentration for J2 hatch and (iv) the reversibility of J2 hatch inhibition.. Eggs of M. incognita were exposed to a series of purified cucurbitacin A and B concentrations over five incubation periods of 24, 48, 72 h and extended incubation periods of 7 and 10 days. Methanol-dissolved cucurbitacin A and B were each diluted and pipetted into well-plates making 11 concentrations, rang...

Meloidogyne incognita (Kofoid and White) Chitwood a calamitous plant pathogen affects almost all the commercial crops, especially medicinal plants viz. Bacopa monnieri L. In this study, the efficacy of indigenous chitinolytic microbes against M. incognita in B. monnieri was evaluated under sterilised and natural soil conditions. The plant growth was observed for various parameters viz. nutrient uptake, phytochemical activities and secondary metabolites (bacoside). In the natural soil under green house conditions, the isolates significantly (P ≤ 0.05) reduced M. incognita infestation (1.38–2.78-folds) with significant increase in secondary metabolites (1.28–1.88-fold) over the untreated control. The potential strains were identified through 16S-rRNA as Streptomyces sp., Microbacterium arabinogalactanolyticum, Cellulosimicrobium cellulans, Actinomycetales bacterium, Chitiniphilus sp. and Flavobacterium johnsoniae. These findings thus highlight the potential of indigenous chitinolytic microbes that can be utilised for overall fitness of the plant along with the reduced root-knot nematode infestation in B. monnieri.

Ashwagandha (Withania somnifera L. Dunal), a therapeutically imperative herb is known for its useful steroidal lactones (withanolide and withaferin) and acyl steryl glycosides. The plant is a highly susceptible host for the plant parasitic nematode, Meloidogyne incognita. Selected chitinolytic microbes, namely Cellulosimicrobium cellulans MTN13, Flavobacterium johnsoniae MTN 20, Chitiniphilus sp. MTN22 and Streptomyces sp. MTN14, alone and in combination for M. incognita management and enhancement of secondary metabolites in W. somnifera cv. Poshita were evaluated. A significant enhancement in biomass yield (1.9-fold) and disease diminution (2.7-fold) was found in the dual microbial treatment Streptomyces sp. and Chitiniphilus sp. with respect to the untreated inoculated control plants. A significant augmentation (2.7- and 2.0-fold, respectively) in withanolide A and withaferin A was also found in the same treatment. The studies revealed increment of defence variables 1.1- to 1.3-fold and 1.6- to ...

Most beetroot (Beta vulgaris) cultivars in South Africa are exotic and were specifically bred for root-knot (Meloidogyne species) nematode populations in their countries of origin. Due to the widespread distribution of different Meloidogyne species and races, exotic cultivars should be matched with nematode populations in importing countries. The objective of this study was to determine the interrelations between exotic beetroot cultivars ‘Detroit Red Dark’ and ‘Crimson Globe’ with Meloidogyne species in the predominant beetroot-producing regions in South Africa. Different inoculum series of M. incognita and M. javanica were used on the two beetroot cultivars. At 56 days after initiating the treatments, roots of both cultivars had small undeveloped root galls, with the reproductive factor values of M. incognita on ‘Detroit Dark Red’ being above and below unity at low (≤125 inoculation) and high (≥250 inoculation) nematode levels, respectively. Growth of ‘Detroit Dark Red’ was significantly stimula...

Globally, most of the crop-related developmental projects collapsed due to the existence of aggressive plant-parasitic nematodes. Intensive South African biofortification efforts using exotic and local sweet potato (Ipomoea batatas) cultivars have hardly considered the inclusion of nematode resistance in plant breeding, despite the withdrawal of most nematicides from agrochemical markets. The objective of this study was to screen 12 selected biofortification sweet potato cultivars for host-status to South Africa tropical root-knot (Meloidogyne species) nematodes. Three exotic orange-fleshed, three local orange-fleshed and six cream-fleshed cultivars were used in three separate experiments of M. javanica and races 2 and 4 of M. incognita. In each experiment, 6000 eggs and second-stage juveniles/plant were used for inoculation, with nematode assessment performed at 56 days after inoculation. All tested biofortification exotic (except for cv. ‘W-119’) and local cultivars were hosts to Meloidogyne spe...

The root-knot nematode, Meloidogyne incognita, and the Phytophthora blight pathogen, Phytophthora capsici, cause root diseases in bell pepper under field conditions. However, limited information is available about the interactions between these two pathogens on different bell pepper cultivars. Greenhouse experiments were conducted on cultivars of bell pepper with different levels of resistance to P. capsici (‘Aristotle’, ‘Paladin’ and ‘Intruder’), by concomitant and sequential inoculation of both pathogens. The treatments included inoculating both pathogens simultaneously into the root zone, inoculating M. incognita 7 days before P. capsici, inoculating P. capsici 7 days before M. incognita, inoculating M. incognita or P. capsici alone, and an untreated control without any pathogens. In ‘Aristotle’ and ‘Intruder’, P. capsici inoculation with M. incognita simultaneously or 7 days before or after M. incognita reduced gall index significantly as compared with M. incognita alone. In ‘Paladin’, P. caps...

Interference of nematode infection with mineral malnutrition (MMN) elements in biofortificated cultigens could devalue the health potential of such crops for humans. A pot trial was conducted to determine the response of selected MMN elements in African ginger (Siphonochilus aethiopicus) pseudo-stems to the southern root-knot (Meloidogyne incognita) nematode. Fifty-six days after inoculation, the sensitivity of the pseudo-stems to nematode infection was confirmed, with 23–45% reduced potassium in pseudo-stem tissues, but had no effect on other MMN elements. In conclusion, population densities of M. incognita race 2 should be managed to enhance the potential uses of S. aethiopicus as a biofortification crop.

In March 1855, Alexandre Dumas published the story of a young French woman who had spent 10 years traveling through Australia, New Zealand, the South Pacific, California, and Mexico. He assured his readers that the story was true but could not reveal her identity for personal and family reasons. Since 1855, scholars have puzzled over the true identity of Madame Giovanni, but none have come to a satisfactory conclusion. In fact, Madame Giovanni was a real person who actually did most of the things described in her journal. In 2015, after four years of research, Douglas Wilkie published The Journal of Madame Callegari: The True Story Behind Alexandre Dumas’s Journal de Madame Giovanni” (Melbourne: Historia Incognita, 2015). This article is a much abbreviated account highlighting her connections with the United States and Mexico. Madame Giovanni was an extraordinary traveler and adventurer and yet she has remained a mystery — a femina incognita.

Experiments in Glycine max (soybean) identified the expression of the salicylic acid signaling and defense gene NONEXPRESSOR OF PR1 (NPR1) in root cells (i.e., syncytium) parasitized by the plant parasitic nematode Heterodera glycines undergoing the process of resistance. Gm-NPR1-2 overexpression in G. max effectively suppresses parasitism by H. glycines. The heterologous expression of Gm-NPR1-2 in Gossypium hirsutum impairs the ability of the parasitic nematode Meloidogyne incognita to form root galls, egg sacs, eggs and second-stage juvenile (J2) nematodes. In related experiments, a G. max β-glycosidase (Gm-βg-4) related to Lotus japonicus secreted defense gene α-hydroxynitrile glucosidase LjBGD7 suppresses M. incognita parasitism. The results identify a cumulative negative effect that the transgenes have on M. incognita parasitism and demonstrate that the G. max–H. glycines pathosystem is a useful tool to identify defense genes that function in other agriculturally relevant plant species to pla...

The root knot nematode, Meloidogyne incognita (Kofoid and White) Chitwood, is an important pest of okra [Abelmoschus esculentus (L) Moench], causing root galling and yield losses in commercial and local consumption cultivars. Use of expensive, toxic nematicides needs to be replaced with genetic improvement of plants for resistance to nematodes. A study was conducted to determine pathogenicity of root knot nematode on okra accessions and their degree of resistance to the nematode. Okra accessions obtained form the National Centre for Genetic Resources and Biotechnology, Ibadan, Oyo State, Nigeria, were exposed to 0 or 5000 eggs of M. incognita per plant. Two seeds from each accession were sown in pots containing a sterilized sandy loam soil and thinned to one plant per pot before inoculation with nematodes. Data were collected on plant height, shoot weight, fruit weight, numbers of galls, and nematode population in roots and soil. Reductions in plant height due to M. incognita infection ranged from...

Since weeds serve as hosts for nematode pests, the host status of 20 weed species (commonly occurring in fields of developing farmers) to Meloidogyne incognita and M. javanica, respectively, were investigated. Greenhouse studies showed that seven weed species had Rf values >1 for both nematode species indicating susceptibility, while 13 had Rf values ≤ 1 indicating resistance. Greenhouse results showed that Hibiscus trionum and Amaranthus tricolor were identified as the most susceptible and Chenopodium carinatum and Datura ferox the poorest hosts for M. incognita and M. javanica. For field experiments at Kuruman, Solanum retroflexum was the most susceptible weed to a M. javanica population, while the same was evident for H. trionum at Nelspruit, where a mixed population of M. incognita and M. javanica occurred and at Potchefstroom, where a population of M. incognita was present. Results from this study indicated that certain weed species are highly susceptible to root-knot nematodes and should be removed ...

It requires courage to depict the complexities and conundrums of the Arabian Peninsula's recent history in general, and Yemeni history in particular, in a single anthology, and we must congratulate...

Contribution of egg hatch inhibition in the overall reduction of Meloidogyne incognita numbers by Nemafric-BL phytonematicide was determined in vitro using a series of water-diluted phytonematicide solutions. Hatched juveniles were assessed at four different incubation periods. Thereafter, each phytonematicide solution was water-diluted 5 times and incubated for 5 days to evaluate the reversibility of egg hatch inhibition. At all exposure periods, except the shortest (24 h), concentration effects on egg hatch were highly significant with juvenile numbers versus increasing concentrations exhibiting quadratic relations. The models for the three consecutive exposure periods explain the quadratic relations by 95%, 94% and 98%, respectively. Results suggested that egg hatch inhibition was one of the mechanisms involved in reducing M. incognita population densities by Nemafric-BL phytonematicide.

The role of some Iranian strains of Pseudomonas spp. as biocontrol agents against Meloidogyne incognita and their ability to colonise pistachio roots was investigated. The results of in vitro experiments indicated that all tested bacteria produced significant suppression of M. incognita and showed that all strains were able to kill M. incognita juveniles with strain VUPf428 achieving about 99% mortality at 72 h. The results of in vivo treatments indicated that the best strains that could build high populations in soil infested with nematodes were VUPf5, VUPf52 and VUPf205. These isolates also caused highest reduction in galling and nematode multiplication in a greenhouse test although all strains native to Iran could colonise pistachio roots in pots. Some strains could produce secondary metabolites such as siderophores, proteases and volatile metabolites at high population levels.

Specific endophytes with biocontrol potential might occur in diseased plant tissues. We isolated an endophytic fungus from tomato root galls infected with Meloidogyne incognita and identified it as Acremonium implicatum based on morphology and internal transcribed spacer sequences. Its biocontrol potential was tested in vitro and in pot and field experiments. In the in vitro test, 96.0% of second-stage juveniles of M. incognita were killed by a culture filtrate of A. implicatum after 48 h. The fungus also suppressed egg hatching, with only 36.3% of treated eggs hatching compared with 87.3% of control eggs. Pot experiments showed that A. implicatum inhibited the formation of root galls, with 40.6 galls per treated plant compared with 121.6 on control plants. A. implicatum reduced the nematode population in soil, with 151.1 nematodes per 100 g treated soil and 375.1 in control soil. Field experiments demonstrated that the root gall index of treated plants (25) was markedly lower than that of control plants ...

Culture of Steinernema sp. was maintained on Corcyra cephalonica larvae. Steinernema sp. (at 50, 500, 1000, 2500, 5000, 10,000 and 20,000 ij’s /500 g soil) was concomitantly inoculated with 500 J2 of Meloidogyne incognita/500 g soil to the eggplant seedlings in the pots filled with 4 kg sterilised soil. The simultaneous inoculation of M. incognita with either of the inoculum levels (1000, 2500, 5000 and 10,000 J3/500 g soil) of Steinernema sp. significantly reduced the damage caused by M. incognita in terms of plant growth parameters, viz. plant length, dry weight, number of flowers and weight of fruits. Moreover, the highest improvement in plant growth parameters, viz. plant length, dry weight, number of flowers and weight of fruits, was recorded in plants inoculated with 5000 J3 of Steinernema sp./500 g soil followed by 2500, 1000 and 10,000 J3/500 g soil. The highest reduction in the reproduction factor and number of galls/root system was recorded in the plants treated with 5000 J3 Steinernema sp./500 ...

There are several practices in the management of root-knot nematode (Meloidogyne incognita) in crop fields such as chemical pesticides, nematicides, crop rotation etc. But due to the environmental problems caused by the nematicides or pesticides, alternative tactics such as natural products are getting attention. Among the natural products, plant essential oils provide an important role in the protection of plants from insects, nematodes and microorganisms. In the present experiment in a split-root trial with okra (Abelmoschus esculentus) cv. Purbani Kranti as a host plant and M. incognita as challenging parasite, citral and menthol induced the increase of Phenylalanine ammonia lyase activity in okra plants. Citral and menthol at a rate of 2 mg/plant reduced M. incognita infection without adversely affecting plant growth or yield. This is an important finding with the application of these two essential oils for nematode control and also the reduction of chemical nematicides for environmental benefits.

Biopesticides are being tested in control parasitic nematodes as a replacement for synthetic chemicals. This study was undertaken to investigate effects of the biopesticides abamectin, emamectin, and biosal on egg hatch and mortality of second instar juveniles (J2) of Meloidogyne incognita (Kofoid and White) Chitwood under laboratory and field conditions on tomato (Solanum lycopersicum L). Treatments consisted of the biopesticides and water (control). Numbers of J2 hatched was determined at 1, 3, and 6 days and mortality of J2 at 12, 24, and 48 h after inoculation. Evaluation of biopesticides under field conditions was for yield, number of flowers, numbers of fruit per plant, average fruit weight, shoot and root length, numbers of galls and egg masses per root system, and nematode rate of reproduction. Abamectin was more effective than emamectin and biosal against M. incognita under laboratory and field conditions. Application of abamectin produced the highest juvenile mortality and increased fruit weight...

The author proposes scientific recognition of an existing, previously undefined and unnamed global feature. Aquaterra is suggested as the new name for the lands that were alternately exposed and in...

The soil food web exhibits complex interactions between organisms including those between soil nematodes and bacteria. In the present study, 26 bacterial genera were obtained from the intestines of 11 species of bacteriophagous and predatory nematodes. A minimum number of two bacterial genera, namely Escherichia (species coli) and Staphylococcus, were isolated from Dorylaimoides micoletzkyi whereas a maximum number of nine bacterial genera were obtained from Butlerius butleri. Burkholderia was the most attractive bacterial strain for Meloidogyne incognita with the maximum number of nematode aggregations. Caenorhabditis elegans aggregated around Proteus colonies in greater numbers than any other colony whereas the maximum aggregation of Acrobeloides maximus was recorded around Pseudomonas. Three common bacterial strains were found to attract both M. incognita and A. maximus, five bacterial strains elicited response both from A. maximus and C. elegans whereas three common strains were found attractive to M....

Keeping in view the staid health and ecological apprehensions coupled with the use of pesticides, entomopathogenic nematodes have the potential to supersede pesticides for the management of various pests. Brinjal plants are the most seriously affected by Meloidogyne incognita. The main objective of this study was to evaluate the persistence effectiveness of bacterial cell suspensions (Xenorhabdus and Photorhabdus spp.) and their culture filtrates in soil up to 7, 14 and 21 days and their response against M. incognita as a source of biological control for nematode management. In a life cycle study, Xenorhabdus and Photorhabdus spp., isolated from Steinernema asiaticum and Heterorhabditis bacteriophora, were proved more effective in influencing the life cycle of RKNs. It was found that all the treatments of bacterial cell suspensions and their culture filtrates at all persistent times proved effective in reducing the number of females and egg masses as compared to control. It delayed penetration of nematode...

The Antarctic has come to be considered a place of climate change, both in parallel to broader global understandings of anthropogenic climate change and in response to previous conceptions of the Antarctic as blank, empty, scientific or peaceful. This article shows how a place becomes irresistibly linked to a global discourse through concerted effort as well as technoscientific ways of thinking about nature. Further, this paper demonstrates how the apparently blank Antarctic becomes inscribed with and saturated by popular imaginations, as well as the ways Antarctic actors trouble, confound and are made to fall into line with the tropes of global climate catastrophe. To do this, the article reviews recent scientific research in the Antarctic as ways in which nature – including penguins, ice and flowering plants – inscribe their response to climate change on the continent, as well as some data that “confounds” the narrative of Antarctic warming, melting and collapsing. The article concludes with an analysis...

Damaging threshold levels of root-knot nematode Meloidogyne incognita and root-rot fungus Fusarium solani on plant growth parameters, viz., plant length, fresh and dry weight of chilli were determined by conducting their pathogenicity trials in pot experiments. The results revealed a significant reduction in the plant growth parameters at and above the inoculum level of about 1000 J2 per plant of M. incognita and the highest reduction was recorded at 8000 J2 per plant. Significant reduction in plant growth parameters was recorded at 1.00 g mycelial mat of F. solani per plant, while the highest reduction was observed at 8.00 g mycelial mat per plant. The damaging threshold level was 1000 J2 per plant of M. incognita and 1.00 g mycelial mat of F. solani.

The potential of 24 indigenous isolates of Purpureocillium lilacinum (Paecilomyces lilacinus) (Thom) Samson collected from different agro-climatic zones of India was investigated against the root-knot nematode, Meloidogyne incognita. The studies were conducted in vitro (larvicidal, ovicidal and egg-parasitising capacity) and under naturally infested field conditions with selected strains. Repeated field trials were conducted with talc-based preparations of fungal strains at 10 kg ha−1, which were applied mixed in farm yard manure (FYM) at 1.5 t ha−1. Results (in vitro) showed that all tested isolates were capable to parasitise eggs, inhibit egg hatching and cause juvenile mortality of M. incognita at various levels. Based on the performance under in vitro studies, eight isolates (NDPL-01, ANDPL-02, SHGPL-03, HYBPL-04, AHDPL-05, PTNPL-06, SNGPL-07 and VNSPL-08) were re-tested to confirm the results. HYBDPL-04 was found causing highest mortality (80%), inhibition of egg hatching (90%) as well as parasitisat...

Nematicidal activities of extracts from plants were assayed against Meloidogyne incognita in vitro. Leaves of six different plants were collected in and around Aligarh Muslim University Campus. Aqueous extracts of six plants were screened for egg hatchability and nematicidal activity against second stage juveniles of M. incognita in the plant pathology and nematology laboratory, AMU Aligarh. The nematode egg and juveniles were exposed 12, 24 and 48 h in (S, S/2, S/10, S/100) concentrations of plant extracts. The plant extracts of leaves of six plants species viz. Jatropha pandurifolia, Polyalthia longifolia, Wedelia chinensis, Nerium indicum, Duranta repens and Cassia fistula exhibited highly promising mortality of 99.00–72.00% after 48 h of exposure. Aqueous extracts of leaves of J. pandurifolia, P. longifolia, W. chinensis were recorded to be highly effective for inhibition of egg hatching and increasing juvenile mortality of M. incognita. There was a gradual decrease in egg hatching and increase in mor...

Meloidogyne incognita infestation on maize results in heavy yield loss in farmers’ field. Most of the varieties adopted by subsistence farmers in Nigeria are susceptible to M. incognita. Beside these, the cost of control exceeding the profit from the crop using nematicides and the pollution risk they pose to the environment has necessitated the need for alternatives. Pot and field experiments were, therefore, conducted to investigate the effects of Chromolaena odorata powder and Glomus mosseae (a mycorrhizal fungus) on M. incognita pathogenicity on maize. Hybrid Oba super II improved maize variety adopted by local farmers was selected for the study. Maize plants were grown with G. mosseae (5 spores/g of soil) and soil amended with C. odorata powder (1% w/w) singly and in combination. Two weeks after emergence, Test plants were inoculated with 5000 M. incognita eggs. Sixty days after planting, destructive samples were assessed for root gall symptom and severity, and nematode population. Results show that G...

Effect of interactions of Meloidogyne incognita with Ralstonia solanacearum and interaction of M. incognita with Pectobacterium carotovorum were studied in sequential and simultaneous inoculations on potato (Solanum tuberosum). Inoculation of M. incognita caused a lesser reduction in plant growth than caused by R. solanacearum. Inoculation of M. incognita plus R. solanacearum caused a greater reduction in plant growth than the damage caused by either pathogen. Inoculation of M. incognita prior to R. solanacearum resulted in a greater reduction in plant growth than R. solanacearum was inoculated prior to M. incognita. However, inoculation of M. incognita or P. carotovorum caused similar reduction in plant growth. Inoculation of P. carotovorum prior to M. incognita caused lesser reduction in plant growth than simultaneous inoculation of both pathogens. Inoculation of M. incognita caused galling in potato roots but the size of galls was small. Inoculation of P. carotovorum or R. solanacearum with M. incognit...

Meloidoyne incognita (root-knot nematode) and Fusarium solani (root-rot pathogen) were the common soil-borne pathogens and cause severe damage to bean plants in newly reclaimed sandy soil in Nubaryia district, Behera Governorate, Egypt. The antagonistic effects of Trichoderma album and Trichoderma viride as well as three commercial products namely Rhizo-N® (Bacillus subtilis), Bio-Arc® 6% (Bacillus megaterium) and Bio-Zeid® 2.5% (T. album) were tested against M. incognita and F. solani under naturally infected field conditions. T. album and T. viride highly reduced the frequency (%) population of pathogenic fungi such as Fusarium spp., F. solani and Rhizoctonia spp., than the commercial products. Results indicated that all the tested bio-control agents reduced, significantly, the nematode criteria as evidenced by the number of juvenile (J2) in soil and number of galls and egg masses on roots of common bean and Fusarium root-rot incidence (%). Rhizo-N® highly reduced the number of J2 in soil, while T. albu...

A microplot experiment was conducted to determine application interval of fermented crude extracts of wild watermelon (Cucumis africanus) fruit for optimum growth of tomato (Solanum lycopersicum) plants and suppression of the southern root-knot (Meloidogyne incognita) nematode. Four-week-old tomato cultivar ‘Floradade’ seedlings were each inoculated with 5000 second-stage juveniles of M. incognita race 2 with 3% dilution of fermented crude extracts applied through drip irrigation at 1, 2, 3 and 4 times per 30-day month. At 56 days after the treatment, plant variables and increasing application frequencies had quadratic relationships, with the model explaining 63–99% total treatment variation in variables. Mean integrated optimum application frequency was 2.4 weeks, which translated to an optimum 17-day application interval. At this interval, final nematode population densities were low. In conclusion, at 3% dilution fermented crude extracts from C. africanus fruit could be applied at 17-day inter...

Early modern European knowledge about California was informed by the impressions of the first explorers as well as by more empirical information collected over the centuries that followed, and from which the shape and extent of that territory slowly grew out of the shadows of terra incognita and Spanish possession of it became consolidated. National claims on its periphery, however, provoked continued debate about the geographical scope of California, and the desire to possess it led both English and Spanish authors and cartographers to represent these national claims, and by extension, to fill in and occupy the otherwise blank space with information that demonstrated possession. By the eighteenth century, contemporaneous textual and cartographical configurations of the American west fused empirical knowledge of that territory with an imagined landscape, sustaining an international competition for territory. This article explores early endeavours to claim California within the New World territories of England and Spain from the sixteenth century to the reception of Miguel de Venegas’ Noticia de la California, published in 1757.

During a survey of nurseries and plantations of black pepper plants in Quang Tri province in Vietnam during the rainy season of 2007, nine fungal taxa were isolated from the roots of the black pepper plants. Fusarium solani was found in about one out of four black pepper root samples examined but not in the nurseries and also not from black pepper plants younger than five years growing in plantations. Since in these nurseries about one out of two black pepper plants examined had yellow leaves, this observation suggests that another pathogen must be the initial cause of the yellowing of the leaves. A likely pathogenic candidate is M. incognita which was extracted from every single black pepper plant examined in the nurseries. During the same survey, we also observed that F. solani was not isolated from the roots of black pepper plants that did not had yellow leaves and that the percentage of black pepper plants with yellow leaves increased with increased frequency of occurrence of F. solani. This observati...

Biocontrol of wilt disease complex of pea caused by the root-knot nematode Meloidogyne incognita and Fusarium oxysporum f. sp. pisi was studied on pea (Pisum sativum L.) using plant growth-promoting rhizobacterium Pseudomonas fluorescens and root nodule bacterium Rhizobium sp. Inoculation of M. incognita and F.oxysporum alone caused significant reductions in plant growth over un-inoculated control. Reduction in plant growth caused by M. incognita was statistically equal to that caused by F. oxysporum. Inoculation of M. incognita plus F. oxysporum together caused a greater reduction in plant growth than the sum of damage caused by these pathogens singly. Inoculation of P. fluorescens and Rhizobium sp. individually or both together increased plant growth in pathogen inoculated and un-inoculated plants. Inoculation of P. fluorescens to pathogen-inoculated plants caused a greater increase in plant growth than caused by Rhizobium sp. Application of Rhizobium plus P. fluorescens caused a greater increase in pla...

A survey of Poi crop in Ghaziabad (UP) exhibited a disease complex incidence by Meloidogyne incognita and Fusarium solani causing synergistic effect on the host. Paecilomyces lilacinus was found from the egg masses of M. incognita and Aspergillus niger and Aspergillus terreus from the rhizosphere of root-knot infected Poi crop. Paecilomyces lilacinus parasitised the eggs to a greater extent. The level of parasitism was highest (65%) by P. lilacinus while Aspergillus spp. did not colonise the eggs. Fusarium solani which in the present investigation has been established to be pathogenic to Poi plant.

Host resistance in managing the southern root-knot nematode (Meloidogyne incognita) is limited by the existence of races of this nematode species. Pepper (Capistrano frutens) cultivar ‘Capistrano’ released for resistance against M. incognita races 3 and 4 in Central and South America, was evaluated for host-status and host-sensitivity to M. incognita race 2 in Limpopo Province, South Africa. Plants in pots uninoculated or inoculated with nematodes were arranged in a completely randomized design, with 15 replications. At 120 days after inoculation, the reproductive factor was less than unity, while nematode infection had no effect on plant growth. Thus, the cultivar is resistant to M. incognita race 2 and could be included in crop rotation systems intended to suppress population densities of M. incognita race 2.

The objective of our study was to examine the effect of local environmental conditions, especially air temperature and rainfall, in two agro-ecological regions in Vietnam on the population dynamics of Meloidogyne incognita on black pepper plants and on percentage root galling. The two study sites were situated in Cam Lo, Quang Tri province (North Central Coast) and Buon Ma Thuot, Dac Lac province (Central Highlands). At the study sites, 13 plant-parasitic nematode taxa belonging to 12 genera were identified. Ten of these taxa were present in both study sites. Helicotylenchus certus, Hemicriconemoides cocophilus and Pratylenchus coffeae were only found in Buon Ma Thuot. Based on nematode population densities, M. incognita was the most abundant taxon present. Rainfall and air temperature differed significantly between the two study sites. The most important climatic difference was rainfall: in Buon Ma Thuot, the rainy season lasted 2 months longer and the monthly rainfall during the rainy season was much hi...

Under greenhouse conditions, a pot experiment was conducted to clarify the potential of using some legumes as intercropped plants for reducing the root-knot nematode Meloidogyne incognita infecting sugar beet (Beta vulgaris L.) cv. DS-9004 compared to non-legume plant, garlic and non-intercropped plants. The obtained results revealed that all legumes including chickpea, Egyptian clover, faba bean, fenugreek, lentil and lupin significantly (p ≤ 0.05) reduced nematode criteria on the roots of sugar beet at different degrees. Chickpea and Egyptian clover reduced the number of galls on the roots of sugar beet as the percentage of reductions were 54 and 50%, respectively, followed by lupin and fenugreek, while garlic achieved 72% reduction compared to non-intercropped plants. Lupin reduced the number of egg masses by 59% followed by Egyptian clover and fenugreek (32%), three months after the treatment. On the other hand, six months after the treatment, chickpea reduced the number of galls by 55.7% followed by ...

This paper introduces ‘Terra Incognita’, a contemporary photographic practice located in the relationship between photography, seismology and the visual representation of landscape in Southern California. Photography and geological science have been used together since the late nineteenth century to document this region, and Terra Incognita can be situated within this visual culture of using photography in the representation of scientific knowledge, in particular to extend the threshold of visual perception. Concepts borrowed from archaeology provided a framework for the Terra Incognita practice, and also (together with discourses on Southern California, photography itself and seismology) for constructing meaning in the photographs. The seismic activity caused by the extensive fault zone which exists in this region is immense, with the topography moving at a rate of about five centimetres every year. Southern California, through sitting precariously on the edge of the North American continent, cha...

Meloidogyne species remain one of the major constraints to production of soybeans (Glycine max (L.) Merrill) in Nigeria. Ecologically minded management approaches are being promoted in order to reduce environmental and human health hazards associated with overdependence on synthetic nematicides. Composted manure provides one of the most acceptable nematode control methods in an organic soybean production system. The comparative efficacy of six composts in the management of Meloidogyne spp. of soybean was evaluated. The composts were prepared using fresh plant leaves of Chromolaena odorata, Tithonia diversifolia, or Carica papaya, stacked with poultry manure or cattle manure, in ratio 3:1 and applied at the rate of 5 t ha-1 in a field planted with Meloidogyne incognita (Mi)-susceptible soybean variety, TGx 1019-2EN, inoculated with M. incognita eggs, laid out in a Randomized Complete Block Design with six replications. All treatments significantly reduced Mi populations by 76.6–94.9% with attendant signifi...

The nematicidal activity of dried ground seeds of Ammi majus, Matricaria chamomilla, Ricinus communis, Brassica alba, B. oleracea, Peganum harmala, Solanum nigrum, Raphanus sativus and Eucalyptus sp. was assessed against the root-knot nematode, Meloidogyne incognita, infecting tomato in a glasshouse. The powdered seeds of the tested plants were incorporated into the soil at the rate of 5 g/kg and their nematicidal activity was compared with that of the synthetic nematicide carbofuran at the rate of 0.01 g a.i./kg. The effects of the treatments on the growth of tomato were also examined. The populations of M. incognita in the soil and root galling of tomato were significantly suppressed by the powdered seeds of all the plant species tested, with the greatest reduction occurring in soil amended with M. chamomilla, followed by soil treated with powdered seeds of A. majus, S. nigrum, R. communis and Eucalyptus sp. The efficacy of B. oleracea, B. alba, M. chamomilla and R. communis in reducing the number of J2...

Thirty-five nematode species belonging to 19 genera were extracted from 432 soil and root samples collected in 19 districts in six provinces in the North Central Coast, Central Highlands and Phu Quoc Island. Based on our study, the predominant nematode species associated with black pepper plants in Vietnam is Meloidogyne incognita: almost every soil and root sample examined during our study was infected with this root-knot nematode species. No difference in frequency of occurrence of M. incognita among the three agro-ecological regions surveyed was observed. However, the root population density of M. incognita in black pepper plants was on average about five times higher in the North Central Coast and Central Highlands than in Phu Quoc Island. Large differences in root population density of M. incognita on black pepper plants were observed in different districts within the same agro-ecological region. Black pepper roots infected with M. incognita showed the same type of galls as described in the literatur...

Culture filtrates of selected soil fungi, namely Aspergillus flavus, Aspergillus fumigatus, Aspergillus niger, Fusarium oxysporum, Penicillium vermiculatum and Rhizopus nigricans exhibited variable response to egg hatching and mortality of the root-knot nematode, Meloidogyne incognita. Higher concentrations of the culture filtrates of all the fungi inhibited egg hatching and proved to be toxic to the juveniles of M. incognita. In addition, development of the gall and multiplication of M. incognita were also found adversely affected in varying degrees on all the plants of Vigna radiata treated with the filtrates. The culture filtrate of A. niger showed highest toxicity to the nematode than those of any other fungus tested. Soil drench application of the culture filtrates gave better seedling growth and least nematode multiplication in comparison to seed soaking treatment.

Wild watermelon (Cucumis africanus) and wild cucumber (Cucumis myriocarpus), which are highly resistant to the southern root-knot nematode (Meloidogyne incognita) race 2, have the potential for serving as seedling rootstocks for the highly nematode-susceptible watermelon (Citrullus lanatus) cultivars. In South Africa, due to high labour costs, most cotton farmers are turning to watermelon production. In these regions, there is high incidence of M. incognita race 4. A pot experiment in the greenhouse was, therefore, initiated to investigate the host-status and host-sensitivity of Cucumis africanus and Cucumis myriocarpus to M. incognita race 4, when inoculated with 0, 200, 600, 100, 1400, 1800 and 2200 eggs and second-stage juveniles (J2s). At harvest, 56 days after inoculation, the reproductive factor values at all levels of inoculation were less than one. Penetration indices on both plant species were greater than one, suggesting that the resistance was post-infectional and therefore, introgress...