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Root-knot nematode Meloidogyne incognita is among the biotic factors which has greatly affected both the yield and the quality of the tomato crop. The egg parasitic nematode, Purpureocillium lilacinum (Pl) is considered as one of the most promising agents in controlling and overcoming this plant pathogen. The nematicidal effect of the native isolate Pl AUMC 10149 on second stage juvenile’s survival and egg hatching of M. incognita at different times of exposure was tested in vitro. The obtained data showed that Pl gave a maximum percentage of J2 mortality (97.6%) and egg hatching inhibition (79.8%) after 72 hours of exposure. The potentiality of Pl as well as Bio-Nematon to control M. incognita infecting tomato was conducted using different times of application in vivo. Nine treatments with five replicates were used for such bioagents compared with the nematicide Oxamyl. Each seedling was inoculated with 1000 J2s of nematode/pot and 10 mL of Pl (1x1010 CFU/mL) or Bio-Nematon spore suspension (1x108 CFU/mL) 10mL/pot. The results indicated that the most effective treatments in reducing nematode population, number of galls and egg masses of M. incognita in plant roots was performed with treatment by Pl pre-planting and post-infection with Pl (Rf 1.9) giving a significant enhancement in plant length (64.9%), fresh weight (72.52%) and shoot dry weight (163.41%) without negatively impacting environment. Therefore, the present study confirmed that using P. lilacinum AUMC 10149 can be used as a practical supplement to environmentally friendly disease management of root-knot nematodes in Egypt. Resumo O nematoide-das-galhas Meloidogyne incognita está entre os fatores bióticos que afetaram enormemente a produção e a qualidade da cultura do tomate. O nematoide parasita de ovos, Purpureocillium lilacinum (Pl), é considerado um dos mais promissores agentes no controle e superação desse fitopatógeno. O efeito nematicida do isolado nativo Pl AUMC 10149 na sobrevivência de juvenis de segundo estágio e na eclosão dos ovos de M. incognita em diferentes momentos de exposição foi testado in vitro. Os dados obtidos mostraram que o Pl deu um percentual máximo de mortalidade de J2 (97.6%) e inibição da eclosão dos ovos (79.8%) após 72 horas de exposição. A potencialidade de Pl e de Bio-Nematon para controlar M. incognita infectando tomate foi conduzida em diferentes tempos de aplicação in vivo. Nove tratamentos com cinco repetições foram usados para tais bioagentes em comparação com o nematicida Oxamyl. Cada muda foi inoculada com 1.000 J2s de nematoide / vaso e 10 mL de Pl (1×1010 CFU/mL). Ou suspensão de esporos Bio-Nematon (1×108 CFU/mL) 10mL/pot. Os resultados indicaram que os tratamentos mais eficazes na redução da população de nematoides, número de galhas e desovas de M. incognita nas raízes das plantas foram realizados com Pl pré-plantio e pós-infecção com Pl (Rf 1.9), dando um aumento significativo no comprimento da planta (64.9%), massa fresca (72.52%) e massa seca da parte aérea (163.41%) sem impactar negativamente o meio ambiente. Portanto, o presente estudo confirmou que o uso de P. lilacinum AUMC 10149 pode ser usado como um suplemento prático para o manejo ecologicamente correto de nematoides-das-galhas no Egito.

Root-knot nematodes (Meloidogyne spp.) are obligate plant parasites that cause severe economic losses to agricultural crops worldwide. Because of serious health and environmental concerns related to the use of chemical nematicides, the development of efficient alternatives is of great importance. Biological control through exploiting the potential of rhizosphere microorganisms is currently accepted as an important approach for pest management in sustainable agriculture. In our research, during screening of rhizosphere bacteria against the root-knot nematodes Meloidogyne incognita, Ochrobactrum pseudogrignonense strain NC1 from the rhizosphere of healthy tomatoes showed strong nematode inhibition. A volatile nematicidal assay showed that the cell-free fermentation filtrate in the first-row wells of 12-well tissue culture plates caused M. incognita juvenile mortality in the second-row wells. Gas chromatography-mass spectrometry analysis revealed that dimethyl disulfide (DMDS) and benzaldehyde were the main volatile compounds produced by strain NC1. The nematicidal activity of these compounds indicated that the lethal concentration 50 against the M. incognita juveniles in the second-row wells and the fourth-row wells were 23.4 μmol/ml and 30.7 μmol/ml for DMDS and 4.7 μmol/ml and 15.2 μmol/ml for benzaldehyde, respectively. A greenhouse trial using O. pseudogrignonense strain NC1 provided management efficiencies of root-knot nematodes of 88 to 100% compared with the untreated control. This study demonstrated that nematode-induced root-gall suppression mediated by the bacterial volatiles DMDS and benzaldehyde presents a new opportunity for root-knot nematode management.

Meloidogyne incognita, the southern root-knot nematode (RKN), is the most predominant plant-parasitic nematode species of tomato and causes significant yield loss. The Mi-1.2 gene confers resistance in tomatoes to M. incognita; however, virulent RKN populations capable of parasitizing resistant tomato cultivars have been reported from different regions in the world. Four naturally occurring virulent populations of M. incognita were found in vegetable fields from four counties in Georgia with no history of tomato cultivation of the Mi gene. Two consecutive greenhouse trials showed that all four virulent RKN populations reproduced on tomato cultivars, including Amelia, Skyway, and Myrtle, with the Mi-1 gene, while an avirulent population of M. incognita race 3 was unable to overcome host resistance. Virulent RKN populations varied in reproduction among resistant cultivars, with Ma6 population having the greatest reproduction potential. No difference in penetration potential of the virulent (Ma6) and avirulent populations was found on susceptible and resistant tomato cultivars. However, virulent Ma6 population females were successful at egg-laying, whereas avirulent female development was arrested in the resistant cultivars. The virulent Ma6 population also induced feeding sites in the roots of resistant cultivars, whereas the avirulent population did not. To our knowledge, this is the first report of resistance-breaking populations of M. incognita in Georgia and the second state in the United States after California.

Various kinds of biotic and abiotic environmental stresses impose threat on growth and yield of crops. Amongst biotic stresses, Root knot nematode (RKN), especially Meloidogyne incognita act as one of the main constraints with wide range of hosts, that ultimately results in huge global losses in terms of yield and productivity. Nowadays, different soil micro biota has achieved importance as bio-control agents against RKNs. In this aspect, the present study was designed to assess the nematicidal potential of metabolites produced by Streptomyces sp. strain MR-14 against M. incognita in order to regulate its pathogenicity in plants. The current study revealed that metabolites present in crude extract showed 83% of mortality in juveniles of M. incognita. The work was further carried out in 7 days old M. incognita infested Solanum lycopersicum seedlings. The seedlings that were pre-treated with the metabolites in the form of crude extract and supernatant showed significant reduction in gall formation. Furthermore, treated seedlings showed enhanced photosynthetic activities as well as antioxidative defence mechanism. The microscopic studies were also assessed to screen the effect of microbial strain on the glutathione tagging and cell viability. The studies confirmed the potential of Streptomyces sp. strain MR-14 as biocontrol agent that not only promoted the plant growth but also improved the biochemical responses of the infected plants.

The impact of root infection by the nematode Meloidogyne incognita on leaf anti-herbivore defenses and plant resistance to the caterpillar Spodoptera exigua is modulated by the nematode infection cycle., Studies on plant-mediated interactions between root parasitic nematodes and aboveground herbivores are rapidly increasing. However, outcomes for the interacting organisms vary, and the mechanisms involved remain ambiguous. We hypothesized that the impact of root infection by the root-knot nematode Meloidogyne incognita on the performance of the aboveground caterpillar Spodoptera exigua is modulated by the nematode’s infection cycle. We challenged root-knot nematode-infected tomato plants with caterpillars when the nematode’s infection cycle was at the invasion, galling, and reproduction stages. We found that M. incognita root infection enhanced S. exigua performance during the galling stage, while it did not affect the caterpillar’s performance at the invasion and reproduction stages. Molecular and chemical analyses performed at the different stages of the nematode infection cycle revealed that M. incognita root infection systemically affected the jasmonic acid-, salicylic acid-, and abscisic acid-related responses, as well as the changes in the leaf metabolome triggered during S. exigua feeding. The M. incognita-induced leaf responses varied over the nematode’s root infection cycle. These findings suggest that specific leaf responses triggered systemically by the nematode at its different life-cycle stages underlie the differential impact of M. incognita on plant resistance against the caterpillar S. exigua.

Biochar is a vital carbon complex and can improve plant growth and suppress of soil-borne pathogens. Root-knot nematode, Meloidogyne incognita is identified as one of the most demoralizing pests blighting roots of many crops and lead to notable decrease in their productivities. So, the present study was carried out with a hypothesis that the application of biochar from various feed-stocks may cause significant enhancements in the tolerance of eggplant for M. incognita infection. Two types of biochars were manufactured by the slow pyrolysis process of rice straw and peanut residues. A pot experiment was conducted to explore the effects of rice straw biochar (RSB) and peanut residues biochar (PRB) on M. incognita and the growth and yield performances of eggplant in loamy soil. Eight treatments were achieved in the current experiment, resulted from the combination between RSB and PRB at four applied rates [zero =no addition, 5.25, 10.5 and 21 g/pot, which were equated to 0, 5, 10 and 20 t/ha, respectively]. Treatments were arranged in a randomized complete block design (RCBD) and with five replicates. The individual incorporation of RSB and PRB at rates of 5.25, 10.5, and 21 g/pot exhibited significant enhancements in growth parameters (length, fresh and dry weight of shoots and roots), and productivity of eggplant. Application of RSB or PRS at 21 g/pot caused superior impacts in enhancing the fresh fruit yield of eggplant (946 and 1012 g/pot). Soil pH increased after applications of RSB and PRB from 5.85 in the control treatment to 6.12-6.39 and 6.28-6.75, respectively. Both RSB and PRB revealed variable degrees in lessening numbers of egg masses and galls/root system and J2/250 g soil of M. incognita and this caused marked improvements in eggplant growth parameters in comparison to the control. The use of high doses of RSB and PRB was responsible for larger efficiency in declining the above-mentioned M. incognita parameters than their low rates. The largest declines in galls/ root system (80 and 93%), egg-masses/ root system (90 and 96%), egg/egg-mass (76 and 90%) and J2/250g soil (83 and 92%) at 50 and 90 days after transplanting (DAT) were shown after application of PRB at a rate of 21 g/pot. This study indicated that RSB and PRB can be used as effective materials in dropping the harmful effects of M. incognita and also can be recommended as eco-friendly alternatives to synthetic pesticides with marked nematicidal activity to control M. incognita infection.

Resistance of Several Hibiscus cannabinus genotypes Against Meloidogyne incognita Kenaf (Hibiscus cannabinus) is known as a source of natural fibers. Infection of Meloidogyne incognita (root-knot nematode) in kenaf plants causes stunting of plants, thereby reducing crop production. This study aimed to determine the resistance of seven kenaf genotypes against M. incognita. The experiment was conducted by infesting kenaf plants aged 15 days after planting (DAP) with M. incognita in a population of 40 juvenile nematodes 2 per 100 g of soil. The planting medium used was sandy soil with a composition of 55% sand, 36% dust, and 17% clay. The resistance variable consisted of root knot index and nematode reproduction factors. Analysis of salicylic acid, phenol, lignin and several plant growth variables were carried out at 75 DAP. Among the seven kenaf plant genotypes evaluated, there were 3 tolerant genotypes (KR4, KR15 and KR5) and 4 highly susceptible genotypes (KR1, KR6, Kin2, and DS028). Genotypes that had a tolerant response to M. incognita showed an increase in phenolic compounds, salicylic acid, and lignin in the roots compared to the control. The decrease in plant height, crown fresh weight, and root fresh weight varied due to M. incognita infection.

This study aims to use safety agents to control the root-knot nematode, Meloidogyne incognita infected gladiolus plants (Gladiolus grandiflorus) in pots under field conditions, directly by using two nematophagous fungi, Purpureocillium lilacinumwhich parasite on nematode eggs and Hirsutella rhossiliensis which parasite on second stage juvenile of nematode , and indirectly by using treatment of salicylic acid (SA). The applied agents applied either individually or in combination, reduced nematode numbers and improved gladiolus vegetative and flowering characteristics. Tri-treatment (SA + P. lilacinum + H. rhossiliensis) achieved the best results aptly, leading to increase reduction percentage of nematode juveniles to 80.2%, decreased egg masses production and root gall index to 91.3 and 83.3%, respectively, compared with bionematicide Tervigo (Abamectin) which gave reduction percentage of nematode juveniles as 78.9%, decreased egg masses production and root gall index (80.0, 66.7%, respectively). Also, the previous tri-treatment improved flowering traits as it led to an increment proportion of flowering stem length (58.6%); number of florets/spike (46.2%) and fresh weight of inflorescence (67.9%) compared with Tervigo (43.3, 41.8 and 54.2%, respectively). In addition, tri-treatment (SA + P. lilacinum + H. rhossiliensis) significantly improved chemical properties of N, P, K and total carbohydrate (76.8, 52.4, 47.4 and 31.4%, respectively) compared with Tervigo (42.7, 23.8, 6.3 and 4.5%, respectively). The obtained results can be concluded that, both nematophagous fungi complement each other, and adding SA led to their superiority in its effectiveness for M. incognita control over the nematicide Tervigo (Abamectin). Therefore, the use of chemical nematicide in which causes harmful effects to environment and humans should be reduced or substituted with clean biological control.

Chemical nematicides have potential for risks and pollution to the environment and human health. Hence, this promoted the needs to use alternatives from certain medical plants. This research was designated to evaluate certain moringa plant part residues with their aqueous extracts and seed oil suspension for controlling root-knot nematode, M. incognita on field dry pea (Pisum sativum L.) under screen house conditions. On the basis of mean of total percentages of nematode reduction for each parameter, it was found that dry root powder registered the highest mean of total percentages of reduction (81.6%) followed by those of mashed fresh leaves (80.8%), seeds powder (79.5%) and dry leaves (76.4%). When using extracts of moringa residues, it was noticed that aqueous extract of seeds powder achieved the highest percentage nematode reduction (81.1%) followed by extract of dry leaves powder (80.8%), extract of dry root powder (80.5%). The least reduction (74.2%) was caused by seed oil suspension Number of galls was reduced while number of nodules was increased according to the tested materials. Consequently, the different treatments improved plant growth and yield parameters.

Root-knot nematodes have been implicated in poor growth and death of trees in the nursery and newly established forest plantations. Cultivating resistant tree species is one of the viable methods in the management of nematode pests once they are identified. A pot experiment laid out in completely randomized design was conducted to screen fifteen selected tree seedlings for resistance to Meloidogyne incognita. Each tree seedling was replicated eight times and was grown on a steam-sterilized soil. The seedlings were inoculated each with 7,000 eggs of Meloidogyne incognita at four weeks after planting. Data were collected on plant height and stem girth at 12 weeks after inoculation. At termination, data were also collected on gall index (GI), final nematode population (Pf) and reproductive factor (RF). Data were analyzed using analysis of variance. Resistance or susceptibility status was assigned with Canto-Saenz host designation scheme. There was variability in the growth of the tree seedlings. Simphonia africana had the highest GI, Pf and RF of 3.3, 54,500 and 22.07, respectively and these values were significantly higher than values from other seedlings. Six tree seedlings; Simphonia africana, Theobroma cacao, Gmelina arborea, Piptadeniastrum africana, Chrysophyluum albidium and Parkia biglobosa were found to be susceptible to M. incognita, while six (Tetrapleura tetraptera, Anacardium occidentale, Annonas muricata, Dinium guinensis and Vitex doniana) were found to be resistant and three (Treculia africana, Mangifera indica and Dacryodes edulis) were tolerant. Resistant tree seedlings should be planted in M. incognita-infested plantation and susceptible species should be treated even in

Compatibility of Fictor composticola and Pasteuria penetrans was evaluated through two experiments against Meloidogyne incognita. In vitro assay conducted in 5 cm diameter Petri plates containing 1% water agar. Two males and two females of F. composticola were released alongwith 200 P. penetrans encumbered or healthy J2 of M. incognita. Observations on prey consumed were taken after 24 and 48 h of release. P. penetrans-encumbered J2 were consumed more by the predator than healthy J2. In a pot assay, cucumber plants grown in one kg pots were inoculated with 2000 P. penetrans encumbered or healthy J2 of M. incognita and 400 individuals of F. composticola. After 45 days; numbers of galls, egg masses and final J2 population in soil were significantly less in the treatment with F. composticola + P. penetrans-encumbered J2 than F. composticola with healthy J2. The root galls and the number of Pasteuria-infected females were more in the absence of predatory nematode.

Cucumber (Cucumis sativus L.) is a high nutritious and mineral-rich vegetable, which occupies a prominent place as a salad and vegeta-ble. It is being used in many ways in the daily diet of humans and widely cultivated worldwide. The decrease of agricultural land, ad-verse environmental conditions and continuous increase of popula-tion, the demand of nutritious food is a matter of great concern to the world. Protected cultivation is a very effective tool to solve this problem because in this cultivation the productivity of crops is very high as compared to open field conditions. High value crops suc-cessfully grown in protected cultivation, specially vegetables (cu-cumber, tomato, Capsicum etc.) which are highly susceptible to the numerous pests and pathogens, including phyto-parasitic nema-todes (specially root-knot nematode, Meloidogyne spp.). With this view, present trial was taken to estimate the avoidable losses caused by Meloidogyne incognita infecting cucumber in poly-house situated on farmer’s field with the application of phorate at 2 kg a.i. ha-1 over check. Results exhibited that application of chemical treatment significantly reduced number of galls per 5 g roots, egg masses per 5 g roots, eggs & juveniles per egg mass and final nema-tode population 79.03, 81.10, 30.91 and 56.54%, respectively. Avoidable yield losses were recorded to the tune of 66.84% on cu-cumber by M. incognita in poly-house.

Pests bring about significant decrease in carrot production which often cause to huge financial loss. A major constraint facing carrot production worldwide is infestation with root knot nematode Meloidogyne incognita. Different management strategies have been utilised in the control of M. incognita with various degrees of favourable outcome. Synthetic nematicides, though globally perceived as the most effective is largely negated by their toxicity and adverse effects on humans and the environment. A sizeable recognition has been redirected to the application of nanoparticles in agriculture. In order to achieve progress in the burgeoning of environmentally safe bio-nematicide, the green synthesis of silver nanoparticles with Cnidoscolus aconitifolius extracts was evaluated on carrot plants inoculated with M. incognita juveniles on the field. Extract from C. aconitifolius was taken as the reducing agent, while silver nitrate is the metal precursor. Colour change by the extracts confirms the formation of AgNP. The AgNPs produced were characterised with UV–Vis absorption spectroscopy, FTIR and SEM. Results revealed the formation of AgNPs with surface plasmon resonance absorption at 410, 423 and 428 nm, SEM confirmed the formation of AgNP as mainly spherical ranging between 2 and 20 nm. AgNPs were applied at 25, 50 and 75 ml which is equivalent to 50, 100 and 150 mol, respectively on the field. AgNPs treated carrots plants had significantly (p

The adjuvants involved in pesticide formulation have a vital role in enhancing the physical properties of active ingredient delivered to the target site in plant-parasitic nematodes. The present study elucidates the potential effect of combinations of the nematicide oxamyl (Vaydate® 24 % SL) and surfactants on the root-knot nematode Meloidogyne incognita infecting tomato plants. Three surfactants namely, Agrimax-3H®, Silwet L-77®, and Sylgard 309® were used at their recommended rats (15 ml/100 L, 5 ml /100 L, and 250 ml/100 L, respectively) as well as the combinations of their respective ¼ R, ½ R, ¾ R with oxamyl at three rates i.e. the recommended (R, 48 mg a.i /plant); ¾ R, 36 mg a.i./plant and ½ R, 24 mg a.i./plant. The results revealed that surfactants caused approximately 50 and 25% hatching inhibition in egg masses and eggs, respectively while oxamyl exhibited the highest egg hatching inhibition by 90% throughout the trial period. The combination of oxamyl and Agrimax-3H showed significantly (P ≤ 0.01) more effectiveness against egg masses (71.17%) or free eggs (55.45% ) hatching as exposure time increase. Moreover, oxamyl potency increased to kill 95% of IJ2 whereas, other surfactants caused a 30% reduction. The mixtures of all tested adjuvants with oxamyl at the recommended rate raised oxamyl potency to kill 100 % IJ2 accompanied by a shortage of oxamyl latent period (LP). Whereas, Agrimax-3H surpassed other surfactants and shorted the LT50 of oxamyl to 0.82 days increasing its nematicidal effect. The addition of surfactants to oxamyl as protective treatment displayed a significant increase in tomato plant growth and suppressed galling of M. incognita while the combination between oxamyl and surfactants as curative treatments showed a vigor control efficacy within oxamyl and Agrimax-3H only and surpassed oxamyl formulation without significant difference.

Summary Alkaloids and alkaloid-producing plants have the potential to reduce crop damage by plant-parasitic nematodes. In a series of in vitro experiments, the nematicidal activity of the tropane alkaloids, hyoscyamine and scopolamine, and a mixture of both on the root-knot nematode, Meloidogyne incognita, was tested. Solutions of 16 mg of compound per ml of solvent were used in concentrations of 80-1280 μg ml−1 of water. Inactivity of second-stage juveniles of M. incognita increased with increasing concentration and exposure time. Lethal concentrations (LC50) after 120 min of exposure ranged from 182.4 μg ml−1 for scopolamine to 318.4 μg ml−1 for hyoscyamine and 332.8 μg ml−1 for the combination of both alkaloids. Similarly, the same concentrations of scopolamine inhibited hatching of M. incognita to a greater extent than hyoscyamine. In a glasshouse experiment, M. incognita was not able to penetrate the roots, induce galls and reproduce on Datura stramonium, D. innoxia and D. tatula. Results indicate that the tropane alkaloids hyoscyamine and scopolamine contained in Datura plants express a strong nematicidal activity against M. incognita and could possibly be used for an alternative and sustainable nematode management.

Induced resistance techniques for plant disease management are one of the robust and constructive approaches against plant pests. The present study conducted to trigger the plant-mediated resistance in tomato cv. “K-21” against Meloidogyne incognita by the involvement of dl-β aminobutyric acid (BABA) under salt stress conditions. Results indicate that seedlings elicitors (dl-β aminobutyric acid) strongly suppressed multiplication of nematode population. At the same time, we could not observe this effect in an inoculated control. Additionally, treated tomato roots with BABA and BABA, coupled with NaCl, showed significant improvement in growth parameters and phenolic compounds. Application of BABA (1.21 mM) + NaCl (100 mM) in combination significantly reduced the root-knot index by 48%. Whereas the same combination significantly improved the phenolic compounds and dry weight content up to 75% and 64% respectively. The minute amount of BABA, in combination with salt stress, resulted in greater efficacy as compared to the higher quantity of BABA (2.42 mM) that might be the cause of synergistic interaction. However, the lowest % increase in phenolic compounds by 60% and decrease of the root-knot index by 40% as we observed in the highest dose of BABA (4.84 mM). Findings of our study suggest that the application of BABA alone and in combination with salt is a promising tactic to inflate the tomato resistance against M. incognita that might be associated with the enhanced defence response in tomato. Moreover, the stress modulation reaction of BABA under salt stress would be linked with resistance in plants.

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...

Nematicidal activity of heat-sterilizing filtrate culture of Myrothecium verrucaria was evaluated against Meloidogyne incognita in Vitro and the metabolites formulated as granules of M. verrucaria were prepared and tested on sugar beet plants infested with M. incognita comparison with DiTera™ and Rugby 10%G, under greenhouse conditions. Laboratory results showed that sterilized culture filtrate of the fungus M. verrucaria either by syringe or by autoclaving significantly reduced the percentages of egg hatching and increased the percentage of 2nd stage juveniles (J2) mortality of M. incognita. The most effective reductions of hatching were obtained at 50% concentration with the sterilized filtrate by autoclaving (94.23%), while the most effective reached 96.70% increasing in the percentage of mortality of J2 after 3 days from treating by 50% concentration in case the sterilized filtrate by syringe. Results of greenhouse experiment showed that, all treatments by the prepared fungal formulae of M. verrucaria or DiTerawith different rats significantly reduced the number of galls on sugar beet roots and final nematode population (J2) in soil compared with control (nematode only). The higher rate (0.2 g /pot) was achieved the highest reduction in root-galling (86%) with DiTera treatment and the highest reduction in (J2) with fungal formulae treatment (92.2%). Improvement in plant growth parameters were noticed by treatments. Analysis by GC-MS of the fungus metabolites was identified compounds to have antimicrobial and nematicidal activities. The prepared formulae from the Egyptian isolate of M. verrucaria can be used as safety bio-nematicide against M. incognita on sugar beet.

Plant-parasitic nematodes are a major pest of turfgrass in the United States, yet there are few options for successful management. Most current management strategies rely on the use of a limited number of chemical nematicides, so finding a new management option for nematode suppression would be extremely valuable for turfgrass managers. The aim of this study is to evaluate a new nematicide, fluazaindolizine (Reklemel™ active), for its ability to reduce plant-parasitic nematode population density and improve turfgrass quality. Separate research trials were conducted on bermudagrass infested with Belonolaimus longicaudatus and Meloidogyne incognita in greenhouse, microplot, and field settings over 2018 and 2019. Both greenhouse evaluations demonstrated multiple rates of fluazaindolizine reduced B. longicaudatus population density, and one of the two M. incognita trials showed multiple rates of fluazaindolizine reduced nematode population density. Fluazaindolizine was also effective at reducing population density of both B. longicaudatus and M. incognita in microplot settings for both 2018 and 2019, and a significant improvement in turf quality was observed for both visual turfgrass ratings and NDVI. Field trials demonstrated a significant reduction for both B. longicaudatus and M. incognita population density by multiple rates of fluazaindolizine, but no significant differences in turf quality ratings were observed. Overall, fluazaindolizine shows promise as a chemical nematicide for plant-parasitic nematode management on turfgrass.

Cluster bean is a cash crop growing in all parts of Rajasthan and root-not nematode, Meloidogyne incognita is one of constraint and hidden foe of this crop. It does much loss to crop than other pests. A management trial was conducted in two Kharif seasons on farmer’s field naturally infested with root-knot nematode, M. incognita to find out the efficacy of bio-agents viz., Paecilomyces lilacinus, Pochonia chlamydosporia, and Pseudomonas fluorescens at 0.5, 1 and 2 per cent w/w as seed treatment against root-knot nematode, M. incognita infecting cluster bean. Results exhibited that T. harzianum at 2 per cent w/w was most effective followed by P. lilacinus at 2 per cent w/w and P. chlamydosporia at 2 per cent w/w in terms of reducing the infection of root-knot nematode, M. incognita and increasing the yield of cluster bean.

Weeds can be hosting and alternative multipliers of root-knot nematodes (Meloidogyne spp.). Among the main weeds, species of the genus Ipomoea stands out for their cosmopolitan presence and the negative impact on crops. In addition, they can behave as hosts and promote the reproduction of pests, diseases, and nematodes. However, the ability of Meloidogyne nematodes to infect morning-glory (Ipomoea spp.) is little understood. In this context, the objective was to evaluate the reproduction of M. arenaria, M. enterolobii, M. ethiopica, M. hapla, M. incognita, M. javanica, M. luci, and M. morocciensis in I. grandifolia, I. hederifolia, I. nil, I. purpurea, and I. quamoclit. Plants were individually inoculated with 5,000 eggs and second-stage juveniles and kept in a greenhouse for 60 days. The design was completely randomized with six repetitions. After this period, the root system of each plant was evaluated to gall index (IG) and reproduction factor (RF). It was verified that the eight species of Melodoigyne have the capacity to parasitize I. grandifolia, I. hederifolia, I. nil, I. purpurea, and I. quamoclit, showing the susceptibility of these weeds to the plant-parasitic nematodes. The highest RF were observed for M. enterolobii with values of 12.5 and 12.9 for I. quamoclit and I. hederifolia, respectively. While M. arenaria obtained the lowest values, with RF ≤ 4.0 for all species of Ipomoea. Thus, weed species of the Ipomoea genus are potential hosts and multipliers of root-knot nematodes, making it important to be considered in integrated management strategies for these plant-parasitic nematodes.

Meloidogyne incognita is an obligate plant-parasitic nematode causing serious damage to agricultural crops. Major constraints in nematode management arose due to the limited availability of non-fumigant nematicides in conjunction with the considerable ill effects of fumigants on human and non-target organisms. Recently, fluensulfone has been reported to be an effective non-fumigant nematicide against plant-parasitic nematodes and the model nematode Caenorhabditis elegans. The nematicidal efficacy varies according to its concentration at the time of application, exposure timing, nematode species variability, and even across subpopulations within the same species. It interferes with the key physiological processes of nematodes, like motility, behavior, chemosensation, stylet thrusting, infectivity, metabolism, lipid consumption, tissue integrity, oviposition, egg hatching, and survival. However, the molecular basis of these multivariate physiological anomalies is still largely unknown. Quantitative real-time PCR was carried out to understand the acute transcriptional perturbation of 30 functional genes associated with key physiological and life processes in a M. incognita population, following exposure of 10, 50, and 100 ppm of fluensulfone for 5 and 10 hr. The chemical treatment resulted in significant downregulation of all the neuropeptidergic genes, with concomitant repression of majority of genes related to chemosensation, esophageal gland secretion, parasitism, fatty acid metabolism, and G-protein coupled receptors. Collectively, the parasitism genes were found to be perturbed at highest magnitude, followed by the GPCRs and neuropeptidergic genes. These results establish the wide ranging effect of fluensulfone on various metabolic and physiological pathways of nematode.

Pot culture experiment was carried out under glass house condition to evaluate the resistance/tolerance of seven varieties of vegetable cowpea against Meloidogyne incognita. The variety Kadakkal local found as resistant with gall index 1 and all other varieties were highly susceptible to M. incognita. A field experiment was carried out to study the comparative effect of bio agents (Purpureocillium lilacinum and Stenotrophomonas maltophilia) and organic amendment (neem cake) in comparison with chemicals fluopyram and carbosulfan for the management of M. incognita in cowpea. All the treatments increased yield and reduced nematode population compared to untreated. Among the treatments, P. lilacinum cfu 2x106 @ 10 g/m2 in combination with neem cake @ 50 g/m2 and fluopyram 400 SC @ 250 g a.i./ha were statistically on par in increasing yield (53.70-54.63 %) and reducing nematode population in soil (93.03-94.27 %) and root (86.94-88.31 %).

Root-knot nematodes (RKNs; Meloidogyne spp.) are becoming a serious problem in legume production. This study identified Vigna genotypes exhibiting resistance to M. incognita (RKN) and characterized the modes of the resistance to M. incognita. In total, 279 accessions from 21 Vigna species were screened for resistance based on a galling index (GI) and an egg mass index (EI). Seven accessions were highly resistant to RKN with GI≤25, namely JP74716 (V. mungo var. mungo; cultivated black gram), JP107881 (V. nepalensis), JP229392 (V. radiata var. sublobata; wild mungbean), AusTRCF118141 (V. unguiculata subsp. unguiculata; cultivated cowpea), AusTRCF306385 (V. unguiculata subsp. unguiculata), AusTRCF322090 (V. vexillata var. vexillata; wild zombi pea) and JP235929 (V. vexillata var. vexillata). JP229392 and AusTRCF322090 were the most resistant accessions having EI values of 18.74 and 1.88, respectively. Continuous culture of M. incognita on both JP229392 and AusTRCF322090 resulted in a weakness in pathogenic ability for this RKN. The resistance in JP229392 and AusTRCF322090 to RKN appeared to be antibiosis that was associated with reduced nematode penetration, retardation of nematode development and impeding giant cell formation. The Vigna germplasm resistance to RKN identified in this study could be utilized as gene sources for the development of RKN-resistant Vigna cultivars.

A trial was conducted under green house condition to study the efficacy of some chemicals as soil fumigation and soil application on plant growth characters and reproduction of M. incognita infecting bell pepper. In this study, chemicals viz. metham sodium at 20 ml/m2, 30 ml/m2, 40 ml/m2, fluensulfone at 5 g/m2, 10 g/m2, 15 g/m2 and carbofuran at 20 g/m2 were applied and suitable control was also maintained for comparison. Observations on plant growth characters (shoot and root length, shoot and root weight) and nematode reproduction factors (number of galls per 5g root, number of egg masses per 5g root, nematode population/200 cc soil) and yield kg/plant were recorded. Results showed that metham sodium @ 40ml/m2 was best treatment to improve the plant growth characters, yield and reducing nematode reproduction on bell pepper.

Root-knot nematode, Meloidogyne incognita is considered as one of the major non-insect pests of crops. The management of these root feeders becomes highly challenging due to a strong host-parasitic relationship. Pochonia chlamydosporia is a nematophagus fungus that colonizes eggs of nematodes. This study aimed to test the efficacy of P. chlamydosporia (NAIMCC-SF0039) against M. incognita. An oil dispersion formulation of P. chlamydosporia was prepared using emulsifiers and vegetable oil. This formulation had a shelf-life of 90 days (3.3 × 108 CFU/mL) at room temperature (28 ± 1 °C). The inhibitory effect of oil formulation was tested against M. incognita by inoculating it on the egg mass. We found that colonization of the gelatinous matrix occurred on the third day of inoculation followed by complete egg parasitization on the seventh day. A greenhouse trial was laid out to evaluate the biocontrol potential of P. chlamydosporia in cucumber (Cucumis sativus). The results showed that the application of talc formulation of P. chlamydosporia at the rate of 1 kg per acre during planting, followed by delivery of 1 L of oil dispersion formulation through drip lines at 30-day intervals caused the highest reduction of nematode infestation. This treatment recorded 67.9 and 57.5% reduction in egg masses and soil nematode population respectively than that of control.

Root-knot nematodes (Meloidogyne ssp.) are one of the most damaging phytoparasites in various agricultural crops along the southern coast of Peru. The aim of the present study was to characterise the root-knot nematode and determine the frequency of the nematodes associated with artichoke crop in the “Irrigacion Majes”. Samples of roots and soil were collected in artichoke crops. The nematode genera associated with the crops were determined and quantified by morphological characteristics. Meloidogyne spp. populations extracted from the roots were characterised using esterase phenotypes (Est). Seven phytoparasitic nematode genera were found in the soil samples: Meloidogyne, Helicotylenchus, Mesocriconema, Aphelenchus, Tylenchorrynchus, Pratylenchus, Hemicyclophora and free-living nematodes. In the roots sampled, 32 populations of Meloidogyne spp. were found, distributed into four species: (1) M. hapla Est H2, Rm: 0.92, 1.18, with 47.37% frequency in the samples; (2) two phenotypes for M. incognita Est I1, Rm: 1.0 (47.37%), Est I2, Rm: 1.03, 1.08 (31.58%); (3) one phenotype for M. arenaria Est A1 Rm: 1.19 (21.05%); and an atypical species named Meloidogyne sp. Rm: 0.84 (21.05%).

Summary Soil treatments with formulated plant biomasses or waste materials can be an effective alternative to green manure crops for a sustainable management of root-knot nematode infestations. The suppressive performance of soil amendments with three commercial formulations of defatted seed meal from Brassica carinata, dry biomass of Medicago sativa and pressed pulp from Beta vulgaris was comparatively evaluated on the root knot nematode Meloidogyne incognita both on potted and field tomato (cv. Regina) trials. Products were applied at rates of 10, 20, 30 or 40 g/kg and 20 and 40 T/ ha soil in pots and field, respectively. Soil non treated or treated with the nematicide Oxamyl were used as controls in both experiments. Amendments in potted soil significantly reduced M. incognita infestation on tomato roots compared to both the untreated control and treatment with Oxamyl, also increasing tomato plant growth up to the 30 g/kg soil rate. At the end of the field tomato crop, soil population density of M. incognita resulted significantly reduced by all the tested treatments, whereas tomato yield was significantly higher than the untreated control only at the lowest amendment rate. Soil amendments with the materials tested in this study demonstrated to be a potential additional tool for a satisfactory and safe management of root-knot nematodes.

Biological control would be a prospective alternative to the existing chemical nematicides to keep the root knot nematode, Meloidogyne incognita regimented. Macrofungi are fungal species that produce fruiting bodies visible to the naked eye. Many of the macro basidiomycetous fungi produce several compounds which recorded with nematicidal and insecticidal properties. In this study, eleven macro basidiomycetes were screened in vitro against M. incognita. The crude culture filtrates were extracted and evaluated for their antagonistic effect on egg hatching and juvenile mortality of M. incognita. Crude culture filtrates of Ganoderma lucidum and Lentinus edodes were found to be toxic to egg masses and exhibit the highest mortality rate. The results revealed that the crude culture filtrates of G. lucidum reduced the M. incognita egg hatching 89.8% and increased the juvenile mortality by 93.5% which was followed by L. edodes which inhibited the egg hatching by 85% and caused juvenile mortality by 90.83%.

Background Root-knot nematode is one of the most significant diseases of vegetable crops in the world. Biological control with microbial antagonists has been emerged as a promising and eco-friendly treatment to control pathogens. The aim of this study was to screen and identify novel biocontrol agents against root-knot nematode, Meloidogyne incognita. Results A total of 890 fungal isolates were obtained from rhizosphere soil of different crops and screened by nematicidal activity assays. Snef1910 strain showed high virulence against second stage juveniles (J2s) of M. incognita and identified as Trichoderma citrinoviride by morphology analysis and biomolecular assay. Furthermore, T. citrinoviride Snef1910 significantly inhibited egg hatching with the hatching inhibition percentages of 90.27, 77.50, and 67.06% at 48, 72, and 96 h after the treatment, respectively. The results of pot experiment showed that the metabolites of T. citrinoviride Snef1910 significantly decreased the number of root galls, J2s, and nematode egg masses and J2s population density in soil and significantly promoted the growth of tomato plants. In the field experiment, the biocontrol application showed that the control efficacy of T. citrinoviride Snef1910 against root-knot nematode was more than 50%. Meanwhile, T. citrinoviride Snef1910 increased the tomato plant biomass. Conclusions T. citrinoviride strain Snef1910 could be used as a potential biological control agent against root-knot nematode, M. incognita.

Root-knot nematode (RKN) Meloidogyne incognita stands out among the most harmful polyphagous endoparasite causing serious harm to plants, and distributed all over the globe. RKN causes reduced growth, quality and yield along with reduced resistance of the host against biotic and abiotic stresses. Infective second stage juvenile enters host roots with the help of the stylet and becomes sedentary getting into the vascular cylinder. Dramatic changes occur in host cells, making a specialized feeding site, induced by the secretion of effector protein by RKN. M. incognita can be controlled by nematicides, biocontrol agents, botanicals essential oils and growing resistant cultivars. Nematicides are no longer allowed to use in many parts of the world because of environmental hazards and toxicity to humans and other organisms. Researchers are concentrating on searching suitable alternatives to nematicides for effective management of M. incognita. This review mainly tries to explain the biology of M. incognita and different management options recommended in recent years. However, an effective and economical management of M. incognita remains an immense challenge.

The root-knot nematode (RKN) Meloidogyne incognita is one of the most economically damaging plant-parasitic nematodes. Molecular studies of the plant–RKN interaction have been vigorously carried out in dicotyledonous model plants, while the host range of M. incognita is wide including monocotyledonous plants. As M. incognita causes quality and yield losses in rice (Oryza sativa L.) cultivated in both upland and irrigated systems, we developed a method to examine the plant–RKN interaction in this model monocotyledonous crop plant. Here, we show that a transparent paper pouch could be used to evaluate nematode infection rates in rice with similar results to that of the traditional soil method. The system using a transparent paper pouch can be used to observe the spatial and temporal distribution of developing galls and can save the space of growth chamber.

The root knot nematode, Meloidogyne incognita, is a sedentary endoparasitic plant pathogen with broad host range. It infects variety of crops and causes drastic annual crop yield losses worldwide. Its management is a major concern for sustainable crop production. In the present study, bio-formulations viz.., Purpureocillium lilacinum WP (1 × 108 CFU/g), P. lilacinum Liquid (1 × 109 CFU/ml), Trichoderma harzianum (WP) (2 × 106 CFU/g) and T. viride (WP) (2 × 106 CFU/g) along with chemical control Furadan 3G were evaluated for their comparative efficacy in suppressing egg hatching and causing juvenile mortality of M. incognita. All the bio-formulations showed certain degree of egg hatch suppression as well as juvenile mortality of M. incognita over untreated control when exposed to different concentrations over a period of time and their efficacy increased with increase in concentration and exposure period. Among all the bio-formulations, P. lilacinum (Liquid) formulation showed overall significantly more egg hatch inhibition (64.0%) and all other formulations were at par with each other. For juvenile mortality all the bio-formulations behaved significantly at par with each other however, P. lilacinum (Liquid) formulation showed comparatively more juvenile mortality.

The present study reports on the powerful nematicidal activity of a series of electron-deficient alkynes against the root-knot nematode Meloidogyne incognita (Kofoid and White) Chitwood. Interestingly, we found that the conjugation of electron-withdrawing carbonyl groups to an alkyne triple bond was extremely proficient in inducing nematode paralysis and death. In particular, dimethylacetylenedicarboxylate (10), 3-butyn-2-one (1), and methyl propiolate (4), with EC50/48 h of 1.54 ± 0.16, 2.38 ± 0.31, and 2.83 ± 0.28 mg/L, respectively, were shown to be the best tested compounds. Earlier studies reported on the ability of alkynoic esters and alkynones to induce a chemoselective cysteine modification of unprotected peptides. Thus, also following our previous findings on the impairment of vacuolar-type proton translocating ATPase functionality by activated carbonyl derivatives, we speculate that the formation of a vinyl sulfide linkage might be responsible for the nematicidal activity of the presented electron-deficient alkynes.

Echinacea species are reported for a large content of bioactive compounds, but their effects on phytoparasitic nematodes are still unknown. This study comparatively investigated the in vitro activity of chemically characterized extracts from E. angustifolia, E. pallida and E. purpurea on juveniles and eggs of the root-knot nematode Meloidogyne incognita. Suppressiveness of soil amendments with Echinacea plant biomasses was also investigated against M. incognita on tomato in potting mixes. More than 50% juvenile mortality occurred after a 48-h exposure to a 500 mu g mL(-1) solution of all Echinacea extracts, as well as more than 50% of M. incognita eggs did not hatch after a 1-week exposure to the same concentration of E. angustifolia extracts. Nematode multiplication on tomato roots was always significantly reduced in soil amended with all Echinacea biomasses, as well as almost all treatments also resulted in a significant tomato growth increase. Polar compounds such as echinacoside and chicoric acid were the main components of the extracts from Echinacea aerial parts, whereas apolar components as alkamides prevailed in root extracts. Data confirmed the potential of the three Echinacea species, mainly E. angustifolia, for the formulation of new formulates for a sustainable nematode management.

Root-knot nematode (Meloidogyne incognita) is chief plant parasitic nematode of various crops globally. Meanwhile, the negative side effects on human health and environmental concerns associated with haphazard uses of chemical nematicides. Hence, the search for a safe and effective approach is more relevant. The present study was aimed to evaluate the nematicidal potential of Snef1216 (Penicillium chrysogenum) against M. incognita at different concentrations (5%, 10%, 25%, 50%, 75% and 100%) and with the nutritious medium. The egg hatching inhibition and mortality of second stage juveniles of M. incognita were assessed after 6, 12, 24, 48 and 72 h exposure. Results revealed that egg hatching inhibition and percent mortality of M. incognita increased with increasing concentration and exposure time. The highest mortality of juveniles was recorded at 100% conc. i.e., 24.20%, 36%, 66%, 78% and 97.8% at 6, 12, 24, 48 and 72 h, respectively. The highest ovicidal activity was recorded at 100% concentration with 5.20% of eggs hatching. The outcome suggested that Snef1216 (P. chrysogenum) resulted in the lowest LC50 value was recorded as 3718.496 at 6 h exposure period followed by 10479.87, 11186.682, 14838.58 and 24001.430 at 72, 12, 48 and 24 h respectively via ovicidal assay. Whereas, in the larvicidal assay, the lowest LC50 value demonstrated at 72 h being 17.628% exposure period followed by 28.345, 50.490, 215.710 and 482.595% at 48, 24, 12 and 6 h respectively. It is concluded that Snef1216 has potential being used as a biocontrol agent against M. incognita and can serve as a source of a novel nematicidal agent of fungal origin.

Summary The host response to Meloidogyne javanica infection of selected Oryza sativa and NERICA (New Rice for Africa) genotypes that are commonly grown in Tanzania and East Africa was examined. The O. sativa genotypes ‘Komboka’ and ‘Supa’ appeared to be partially resistant. A further experiment showed that both genotypes are also partially resistant to M. graminicola infection. The host response of ‘Komboka’ and ‘Supa’ to M. javanica and M. graminicola was further examined and compared in indoor growth chamber conditions. The genotypes ‘TOG5674’, ‘TOG5675’, ‘CG11’ and ‘CG14’ (both O. glaberrima) were included as the resistant reference genotypes for M. graminicola and the genotype ‘UPLRi-5’ (O. sativa) was included as the susceptible reference genotype for both species of root-knot nematodes. Meloidogyne graminicola was more aggressive on ‘Komboka’ and ‘Supa’ than M. javanica. Significantly less root galling was observed on ‘Komboka’ and ‘Supa’ than on ‘UPLRi-5’. In ‘Komboka’ and ‘Supa’ significantly fewer second-stage juveniles (J2) were able to penetrate the roots, to develop into adult females and to reproduce compared with ‘UPLRi-5’. Differential emigration of J2 from the roots of ‘Komboka’ and ‘Supa’ compared with ‘UPLRi-5’ contributed to the observed partial resistance in these genotypes to M. graminicola and M. javanica. Nematodes that successfully penetrated and developed in ‘Komboka’ and ‘Supa’ showed aberrant phenotypes. ‘Supa’ and ‘Komboka’ may be recommended for use by farmers in M. javanica and M. graminicola-infested fields.

Thirty seven pepper genotypes, Capsicum chinense, C. annuum and C. frutescens, were characterized for resistance to three root-knot nematode species (Meloidogyne javanica, M. incognita race 1 and M. enterolobii) aiming to find potential resistance sources to be used in breeding programs. Three experiments were carried out, in 2013, 2014 and 2016, in a greenhouse, in randomized block design and six replicates, one plant/pot. Data were submitted to analysis of variance and average clustering. All evaluated pepper genotypes were resistant or immune to M. javanica. For M. incognita race 1, all accessions of C. frutescens, evaluated in the first experiment, were resistant, whereas the six accessions of C. chinense were susceptible. For M. incognita, all genotypes of C. chinense and C. annuum, evaluated in the second experiment, were resistant. In the third experiment, evaluating C. annuum genotypes, we verified that most were susceptible to M. incognita race 1; genotypes CNPH 30118 and CNPH 6144 were resistant, though. M. enterolobii, which is the most aggressive species, with few resistance sources described, showed a tendency of greater degree of resistance in C. chinense and C. frutescens. Although most of the evaluated genotypes were susceptible, significant differences were observed regarding the degree of susceptibility. The main contribution of this study was the identification of a genotype resistant to M. enterolobii, cultivar BRS Nandaia, which can be used in breeding programs. RESUMO Este trabalho teve como objetivo a caracterização de 37 genótipos de pimenta das espécies Capsicum chinense, C. annuum e C. frutescens, quanto à resistência a três espécies de nematoides-das-galhas Meloidogyne javanica, M. incognita raça 1 e M. enterolobii, visando prospectar potenciais fontes de resistência para serem utilizadas no melhoramento. Para isso, foram realizados três experimentos em 2013, 2014 e 2016, em casa de vegetação, com delineamento em blocos casualizados com seis repetições em parcelas constituídas por uma planta/vaso. Os dados foram submetidos a análises de variância e de agrupamento de médias. Todos genótipos de pimenta avaliados foram resistentes ou imunes a M. javanica. Para M. incognita raça 1, todos genótipos de C. frutescens avaliados no primeiro experimento foram resistentes, enquanto que os seis genótipos de C. chinense foram suscetíveis. Ainda, para M. incognita, todos genótipos de C. chinense e C. annuum avaliados no segundo experimento, foram resistentes. No terceiro experimento, com genótipos de C. annuum, a maioria foi suscetível a M. incognita raça 1, mas os genótipos CNPH 30118 e CNPH 6144 foram resistentes. Quanto a M. enterolobii, que é a espécie mais agressiva, com poucas fontes de resistência descritas, houve uma tendência de maior grau de resistência em C. chinense e C. frutescens. Mas, apesar de a maioria dos genótipos avaliados serem suscetíveis, foram observadas diferenças significativas quanto ao grau de suscetibilidade. A principal contribuição deste trabalho foi a identificação de um genótipo resistente a M. enterolobii, a cultivar BRS Nandaia, sendo possível explorar esta fonte de resistência no melhoramento genético.

Root-knot nematodes (Meloidogyne spp.) are important contributors to yield reduction in tomato. Though resistant cultivars to common species (Meloidogyne arenaria, M. incognita, and M. javanica) are available, they are not effective against other major species of root-knot nematodes. Cultivars or lines of Solanum sisymbriifolium were examined to assess the presence and level of resistance to five major species: M. arenaria race 1, M. incognita race 3, M. haplanaria, M. javanica, and M. enterolobii. Differences in S. sisymbriifolium response to the nematode infection were apparent when susceptibility or resistance was classified by the egg counts per gram fresh weight of root and the multiplication rate of the nematodes. The cultivar Diamond was highly susceptible, Quattro and White Star were susceptible, while Sis Syn II was resistant to M. arenaria. Quattro, White Star, and Sis Syn II exhibited a moderate to high level of resistance to M. incognita but the nematode increased 2.5-fold from the initial population of the M. incognita on Diamond. All S. sisymbriifolium cultivars were highly resistant to both M. haplanaria and M. enterolobii, while highly susceptible to M. javanica. A microplot study under field conditions using Sis Syn II confirmed that M. arenaria, M. incognita, and M. haplanaria were not pathogenic on the plant. Likewise, an examination on cross-sections of galled root tissues confirmed the susceptibility and resistance of S. sisymbriifolium lines to Meloidogyne spp. Using S. sisymbriifolium as a resistant rootstock or a new source of resistance may result in the development of nonchemical and sustainable management strategies to protect the tomato crop.

A field experiment was conducted in the field of Plant Pathology Division, Bangladesh Agricultural Research Institute to find out the efficacy of organic amendments viz. poultry refuse, rice bran , fresh saw dust, dry saw dust, tea waste and a nematicide Furadan 5G against root-knot disease (Meloidogyne incognita) of tomato during three consecutive years viz. 2012-13, 2013-14 and 2014-15. Soil was treated with different organic amendments 10 days before seedling transplanting and Furadan 5G was applied on the day of seedling transplanting of tomato. The soils of the experimental plots were inoculated with chopped severely galled (M. incognita) roots of tomato at the time of treatment application. In all the years, considerable reduction in root-knot disease and increase in plant growth and fruit yield were achieved with different treatments and Furadan 5G. The most effective treatment was poultry refuse followed by rice bran and Furadan 5G. In 1st year, 2nd year and 3rd year, gall index values were 5.16, 4.94 and 6.27 under control, respectively. The severity was reduced to 59.11-64.53% in 1st year, 50.60-60.72% in 2nd year and 48.96-55.34% in the 3rd year compared to control due to application of the rice bran, Furadan 5G and poultry refuse. On the other hand, fruit yield under control was 44.82 t/ha at 1st year 49.73 t/ha in 2nd year and 36.95 t/ha at 3rd year. The highly effective three treatments increased fruit yield to 11.02-29.90% in 1st year, 17.17-30.56% in 2nd year and 23.39-35.02% in the 3rd year compared to control. The fruit yield of tomato was directly and linearly correlated with gall indices in tomato gall. Based on the findings of present the study poultry refuse and rice bran noted as an effective treatment to manage root-knot disease of tomato.

Background Root-knot nematodes (Meloidogyne spp.) are soilborne pathogens that can cause great damage to and economic loss of crops globally. Owing to the high toxicity of chemicals toward humans and the environment, the use of biocontrol bacteria, a promising method for controlling root-knot nematodes, has gained attention. Results To screen novel bacterial strains for their ability to control root-knot nematodes, 106 bacterial strains were isolated from soil. Eight of the obtained isolates exhibited satisfactory nematicidal activity against Meloidogyne incognita at 2-fold dilutions (approximately 3 × 1012 CFU mL-1 ) after 12 h of exposure. Based on their physiological, biochemical and molecular (16S rRNA and gyrB gene sequences) characteristics, the eight strains were identified as Bacillus halotolerans, B. kochii, B. oceanisediminis, B. pumilus, B. toyonensis, B. cereus, Pseudomonas aeruginosa and B. pseudomycoides. In greenhouse and field experiments, the eight isolates suppressed M. incognita up to 69.96% compared to the control. Additionally, the yield of tomato increased 1.4-26.1% over that of the control. Conclusion The strains of B. halotolerans DDWA, B. kochii DDWB, B. oceanisediminis DDWC and B. pseudomycoides JNC have potential to control M. incognita, which has not been previously reported. © 2020 Society of Chemical Industry.

Soil amendment with biochar is widely used to improve soil fertility and crop productivity. However, its effect on plant nematodes has not been examined properly. The present study investigates the effects of biochar on root knot nematode, Meloidogyne incognita under in planta conditions. In pots experiment, biochar (45 g) when paired with oil cakes (15 g) suppressed the M. incognita and improved the plant growth of tested plant. Significant suppression in nematode infestation in terms of egg masses and eggs by (56.0 and 52.7%) and maximum improvement in plant growth in plant length and dry weight by 74.1 and 63.8%, respectively was observed when combined soil application of biochar and mustard cake was applied in the soil. The effect was least when biochar was applied alone. The study has suggested that biochar amendment along with mustard oil cake can control root knot nematode infestation in lentil.

Multi-drug resistance in nematodes is a serious problem as lately several resistant phenotypes have emerged following the intermittent usage of synthetic nematicides. Contemporary research continues to focus on developing and/or repurposing small molecule inhibitors that are eco-friendly. Here, we describe the repurposing of the indole derivative, 5-iodoindole, as a nematicide for the root-knot nematode, Meloidogyne incognita. 5-Iodoindole effectively killed juveniles and freshly hatched juveniles by inducing multiple vacuole formation. Notably, at higher dosage (50 μg/mL), 5-iodoindole induced rapid juvenile death within 6 h. Microscopic analysis confirmed that the rapid death was due to the generation of reactive oxygen species (ROS). Computational docking attributed this ROS production to the antagonistic effect of 5-iodoindole on glutathione S-transferase (GST), which is known to play a critical role in the suppression of ROS in nematode models. Furthermore, 5-iodoindole also effectively reduced the gall formations and eggs masses of M. incognita on Solanum lycopersicum roots in pot experiments, and importantly it did not harm the physiological properties of the plant. Overall, the study provides valuable insights on the use of 5-iodoindole as an alternate measure to control root-knot nematodes. Overall, our findings suggest the efficacy of 5-iodoindole should be studied under field conditions.

Soil biodisinfestation is the process generated after the incorporation of organic amendments followed by a plastic cover to control soilborne diseases. Among organic amendments, the use of agricultural by-products could be an interesting alternative as it promotes circular economy. In this study, beer bagasse and defatted rapeseed cake together with fresh cow manure were incorporated into the soil (1.5, 0.5, and 20 kg/m2, fresh weight, respectively) to assess their capacity to reduce disease incidence caused by the root-knot nematode Meloidogyne incognita in protected lettuce crops and develop suppressive soils. The trial was conducted in a commercial greenhouse for 7 weeks during which temperature was continuously recorded at three different soil depths (15, 30, and 45 cm). Short- and long-term effects were assessed: before treatment, after treatment, after first crop post-treatment and one year post-treatment. Disease incidence and changes in nematode community structure were analyzed along with microbiological properties and general physicochemical parameters. After biodisinfestation, microbiological activity significantly increased in the treated soils and changes in the nematode community structure were detected in detriment of M. incognita and other plant-parasitic nematodes. These effects were more apparent after the first crop post-treatment than right after biodisinfestation. In the first crop after biodisinfestation, lettuce yield increased in the treated plots and root galling indices were significantly lower. One year after treatment, differences between treatments could be observed in the incidence of the damage caused by M. incognita that remained lower in the treated plots. In this trial, the addition of beer bagasse and rapeseed cake along with fresh manure in biodisinfestation treatment demonstrated nematicidal effects against M. incognita. Moreover, we suggest that the compounds released during the degradation of these by-products and the sub-lethal temperatures achieved in this trial during biodisinfestation (

Root-knot nematodes are one of serious pathogens which cause economically losses to their host plants. Nanotechnology is a fast-growing technology in nematode and other pathogens management to avoid the hazard effects of chemical pesticides and nematicides on human health, non-target organisms and ecosystems. The effects of Ag engineered nanoparticles (AgENPs) synthesized by green method using plants with nematicidal properties or reductive potential such as Curcuma comosa (N1), Cycas circinalis (N2), Chitosan (N3) and Crotalaria juncea (N4) were tested. This study was done to investigate the genotoxic evaluation of the four AgENPs and the analysis of its effects through the assessment of pathogenicity and reproductivity of Meloidogyne incognita, plant growth parameters, silver residue, activity of antioxidative enzymes and assessment of DNA damage. The experiment was conducted using three old tomato seedlings which transplanted, treated with three concentrations of four AgENPs and infected with 1000 IJs M. incognita under screen house condition. The data demonstrated that, all nematode parameters were suppressed using the different concentrations of AgENPs. The suppressive effect was increased proportionally with the Ag concentrations. Moreover, the damage in DNA parameters was increased proportionally with concentration of AgENPs. Silver residue in tomato fruits after application is relatively very low.

Among 200 fungal strains isolated from the soil, only one culture filtrate of Aspergillus flavus JCK-4087 showed strong nematicidal activity against Meloidogyne incognita. The nematicidal metabolite isolated from the culture filtrate of JCK-4087 was identified as cyclopiazonic acid (CPA). Because JCK-4087 also produced aflatoxins, six strains of Penicillium commune, which have been reported to be CPA producers, were obtained from the bank and then tested for their CPA productivity. CPA was isolated from the culture filtrate of P. commune KACC 45973. CPA killed the second-stage juveniles of M. incognita, M. hapla, and M. arearia with EC50–3 days 4.50, 18.82, and 60.51 μg mL–1, respectively. CPA also significantly inhibited egg hatch of M. incognita and M. hapla after a total of 28 days of treatment with the concentrations > 25 μg mL–1. The enhancement of CPA production by P. commune KACC 45973 was explored using an optimized medium based on Plackett–Burman design (PBD) and central composite design (CCD). The highest CPA production (381.48 μg mL–1) was obtained from the optimized medium, exhibiting an increase of 7.88 times when compared with that from potato dextrose broth culture. Application of the wettable power-type formulation of the ethyl acetate extract of the culture filtrate of KACC 45973 reduced gall formation and nematode populations in tomato roots and soils under greenhouse conditions. These results suggest that CPA produced by P. commune KACC 45973 can be used as either a biochemical nematicide or a lead molecule for developing chemical nematicides to control root-knot nematodes.

Identifikasi nematoda berdasarkan karakter morfologi memerluan ketelitian tinggi dan perlu didukung hasil identifikasi secara molekuler. Salah satu metode identifikasi molekuler ialah dengan DNA barcode. DNA barcode merupakan identifikasi molekuler dengan menggunakan gen cytochrome oksidase sub unit 1 (CO1). Penelitian ini bertujuan untuk mengidentifikasi NPA yang berasosiasi pada tanaman bit berdasarkan PCR dan perunutan nukleotida gen CO1 Meloidogyne. Sampel umbi bit diperoleh dari lahan pertanian yang terletak di Kecamatan Cipanas, Kabupaten Cianjur, Jawa Barat. Pengambilan sampel dilakukan dengan metode purposive sampling. Identifikasi morfologi dengan mengamati pola perineal NPA betina. Identifikasi molekuler meliputi ekstraksi, amplifikasi, visualisasi DNA, analisis peruntutan nukleotida dan filogenetika. Hasil pengamatan pola perineal secara morfologi didapatkan spesies M. incognita dan M. arenaria. Amplifikasi DNA yang dilakukan menggunakan primer spesifik CO1SIF (5’-GCCTGCATTTGGTTAG-‘3) dan CO1SIR (5’-TCAAACCAGTCCT-‘3), CO1SAF (5’-GGGTACTGGATGAACATTA-‘3) dan CO1SAR (5’-ACTTCAGGATGACCAAA-‘3)berhasil mendapatkan pita DNA berukuran ± 360 untuk M. arenaria dan ± 326 untuk M. incognita. Hasil sekuensing menunjukkan bahwa isolat M. incognita asal Indonesia berkerabat dekat dengan isolat M. incognita asal Cina, Amerika Serikat, Vietnam, dan Inggris dengan tingkat homologi 100%. Hasil analisis filogenetika menunjukkan bahwa M. incognita Indonesia masih satu kelompok dengan M. incognita asal Cina, Amerika Serikat, Vietnam dan Inggris. Adapun isolat M. arenaria berkerabat dekat dengan isolat M. arenaria asal Argentina dan Amerika Serikat dengan tingkat homologi 100%. Hasil analisis filogenetika menunjukkan bahwa M. arenaria asal Indonesia masih satu kelompok dengan M. arenaria asal Argentina dan Amerika Serikat.

The root-knot nematodes of the genus Meloidogyne are important and damaging parasites capable of infecting most flowering plants. Within this genus, several species of the Meloidogyne incognita group show evidence of paleopolyploidy in their genomes. We used our software tool POInT, the Polyploidy Orthology Inference Tool, to phylogenetically model the gene losses that followed that polyploidy. These models, and simulations based on them, show that three of these species (M. incognita, M. arenaria and M. javanica) descend from a single common hybridization event that yielded triplicated genomes with three distinguishable subgenomes. While one of the three subgenomes shows elevated gene loss rates relative to the other two, this subgenome does not show elevated sequence divergence. In all three species, ancestral loci where two of the three gene copies have been lost are less likely to have orthologs in Caenorhabditis elegans that are lethal when knocked down than are ancestral loci with surviving duplicate copies.

Root-knot disease is among the main diseases affecting coffee crop. The plant selection to the development new resistant cultivars is among one the most efficient methods of control. The present work aimed to quantify the resistance responses of Coffea canephora clones to root-knot nematode Meloidogyne incognita in the Western Amazon. For this, 17 previously selected clones were evaluated in three experimental trials, carried out in the municipalities of Ji-Paraná and Porto Velho, Rondônia. The resistance to root-knot nematodes M. incognita were evaluated by the numbers of gall in the roots (NG) and by the reproductive factor (RF). The resistance response was also interpreted according the genetic diversity of the clones based in their morphological traits. The clones BRS3210, C12, BRS2314, BRS3137 and BRS1216 are resistant to M. incognita with RF of 0.34, 0.62, 0.79, 0.86 and 0.98, respectively. BRS3213, C125, C15, BRS2336, BRS3220 and C09 clones were classified as susceptible, with RF of 1.93, 1.95, 2.00, 2.31, 2.32 and 2.35. The BRS3193, C160 and BRS2357 clones were classified as very susceptible, with RF values of 3.03, 4.41 and 5.82, respectively. The clustering based on the genetic diversity of morphological traits indicated that genotypes more similar to the Robusta botanic variety had lower RF. The hybrid plants showed intermediate degrees of resistance indicating the segregation for the character of the M. incognita resistance. The clones BRS3210, C12, BRS2299, BRS2314, BRS3137 and BRS1216 expressed resistance responses to M. incognita with potential for growing resistant genotypes in the Western Amazon. Made available in DSpace on 2020-09-10T04:39:21Z (GMT). No. of bitstreams: 1 ART20076.pdf: 627359 bytes, checksum: 575abca4a6b9678f2ba13c0f95bdfd84 (MD5) Previous issue date: 2020