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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.

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.

This study focused, for the first time, on the effect of ultrasonic features on the extraction efficiency of secondary metabolites in mustard seed cake (MSC). The nematostatic potential of sonicated seed cake was examined against the second-stage juveniles (J2s) of root-knot nematode, Meloidogyne javanica. The results show that a 35 ppm (parts per million) concentration of a sonicated extract (SE) sample of MSC caused 65% J2s mortality at 18 h exposure period in vitro. It also significantly suppressed the root-knot index (RKI=0.94) in tomato roots. The lethal concentration values for SE were 51.76, 29.79, and 13.34 ppm, respectively, at 6, 12, and 18 h of the exposure period, and the lethal concentration values for the non-sonicated extract (NSE) sample were 116.95, 76.38, and 55.59 ppm, respectively, at similar exposure time. Sinapine and gluconapin were identified as the major compounds in ultrasonic-assisted MSC. Because of the high extraction efficiency of metabolites in the SE, all treatments of SE were shown to be antagonistic to J2s. Thus, this study of ultrasonication activity-based profiling of MSC may help generate target-based compounds at a scale relevant to the control of disease caused by nematodes in economic crops.

To evaluate the 13 carrot cultivars against Meloidogyne incognita under green house conditions; different levels of susceptibility were observed in all the examined cultivars. Cultivar Golden Rosy was resistant to nematode attack with a low root gall index (1.2) while cultivar Kamini was found highly susceptible showing the highest root gall index (5.0). Similarly, the cultivars Rose Red, Noorie, Lali, Sindhuri, and Selection 80 were susceptible; the cultivars Pearl Red, Super Red, Surbhi, and Kamboj were moderately susceptible and the cultivars Desi Red and Red King were found moderately resistant against the nematode damage. A negative and significant correlation was found between root-knot nematode infestation and plant growth parameters.

In this study effort was made to manage the root-knot nematode, Meloidogyne incognita by the utilization of selected plants such as Coccinia grandis, Commelina benghalensis, Leucas cephalotes, Phyllanthus amarus and Trianthema portulacastrum. During the in vitro experiment, the second juveniles (J2s) of M. incognita directly treated with aqueous extracts of the plant leaves at 1000, 2000, 3000, 4000 and 5000 ppm concentrations. As a result, the 5000 ppm concentration was found most toxic against the survival of second stage juveniles of M. incognita compared to other concentrations. Maximum mortality of 91% was observed in 5000 ppm extract of P. amarus after 72 h of exposure with LC50 value 2084.49 ppm while minimum mortality of 6.2% was found in 1000 ppm extract of T. portulacastrum after 24 h with LC50 value 9484.18 ppm. The percent mortality of juveniles calculated the LC50 values of all the treatments after 24, 48 and 72 h. Similarly, the in vitro tests showed a gradual decrease in the rate of egg hatching of M. incognita with the increasing concentrations of aqueous leaves extracts of plants, i.e., 1000 ppm to 5000 ppm and exposure period. Maximum inhibition in egg hatching was found at 5000 ppm (86.5%) after seven days in the extract of P. amarus while least was observed in T. portulacastrum at 1000 ppm (10.6%). The findings indicate that the plant extracts were found lethal to J2s and also inhibit egg hatching. In pots under greenhouse conditions, the plants treated with both the doses (50 and 100 g/pot) of fresh chopped leaves of the selected botanicals significantly experienced the reduced infestations in relation to root gall index, egg masses/root system and nematode population/250 g soil. The P. amarus treated at 100 gm / pot showed highest nematicidal efficacy with the maximum reductions in all the pathological parameters as compared to the untreated uninoculated control simultaneously resulted in maximum increase of growth and physiological parameters of carrot such as shoot and root lengths, shoot and root fresh weights, shoot and root dry weights, chlorophyll and carotenoid contents and nitrate reductase activity (NRA). The information derived from this study suggests that the leaves of P. amarus plant can be used for the management of M. incognita and could be a possible replacement for synthetic nematicides. Keywords: Aqueous extract, Chopped leaves, Egg hatching, Mortality, LC50M.incognita

Fresh leaves of Calotropis procera , Wedelia chinensis , Lantana camara, Jatropha pandurifolia, Parthenium hysterophorus and Nerium indicum were evaluated for their hatching and mortality of Meloidogyne incognita. After that tested plants were used as an organic amendment for the management of M. incognita affecting Tomato. Four concentrations S, S/10, S/100 and S/1000 of leaf extracts of tested plants were prepared. All the plant extracts showed varied and significant results over control. The “S” concentration of leaf extracts of C. procera, P. hysterophorus, L. camara and W. chinensis exhibited 100% mortality over J. Pandurifolia, N. indicum after 48 h exposure period. Similarly, larval hatching was completely inhibited by “S” concentration of extracts of tested plants except for N. indicum after five days of the exposure period. Increased dilution showed a direct effect on hatching but a contrary effect on mortality. The juvenile mortality increased with increase in exposure period. In pot condition, soil amended with chopped leaves of tested plants 50 g and100 g alone and in combination with 50 g leaves plus carbofuran significantly enhanced the plant growth and decreased host infestation caused by M. incognita over control. Among treatments, C. procera leaves plus carbofuran were found to be the best in increasing plant growth and chlorophyll content.

Summary The root-knot nematode Meloidogyne incognita is a major soil parasite of lentil crops. Increasing restrictions of chemical nematicides have triggered a growing attention and interest in alternate root-knot nematode management. The present study was conducted to examine the level of resistance and/or susceptibility of five lentil cultivars (PL-456, KLS-218, Desi, DPL-62, Malika), grown in pots, against the root-knot nematode M. incognita. Root-knot nematode reproduction and host damage were assessed by recording the nematode infestation levels and reduction percentage of plant growth parameters. Nematode response and plant growth differentiated amongst the lentil cultivars. None of the cultivars was found immune or highly resistant. The cultivar Malika was found moderately resistant as it showed the lowest number of galls and egg masses/root as well as the lowest reduction of plant fresh weight (10.4%) and dry weight (6.9%). On the other hand, the cultivar Desi manifested the highest susceptibility exhibiting the highest number of galls and egg masses. There was a significantly negative correlation between the number of galls and plant growth parameters (plant fresh and dry weight and plant height).

Plants are the one of the glorious and fascinating source of natural biopesticides. The present investigation was carried out for pytochemical analysis and to assess the nematicidal and nematostatic potential of aqueous extract of some plant parts viz., Ageratum conyzoides and Coccinia grandis against hatching and nematicidal behavior of root-knot nematode, Meloidogyne incognita in vitro conditions. The second stage juveniles (J2) were exposed at 24, 48 and 72 hours in different concentration (S, S/2, S/10, and S/100) of plant extracts. During in vitro condition inhibition of egg hatchability and J2 juveniles’ mortality varied according to the concentration of plant extract. The extract of Ageratum conyzoides leaves and stem exhibited highly promising mortality (98-100%) after 72 hours of exposure periods while the plant extract of C. grandis leaves and fruit showed minimum mortality (56-60%) after 24 hours of exposure periods. There was a gradual decrease in egghatching with an increase in the concentration of aqueous extract of plants. A. conyzoides leaves and stem extract elucidating most effectiveness in reducing egghatching and increase in mortality of J2 juveniles of M. incognita. Concentration of the extract was directly proportional to the mortality of second stage juveniles and inversely proportional to the egghatching. Phytochemical analysis in various solvent of different polarity such as ethanol, methanol, acetone, chloroform, petroleum and water marked the impressive outcome of alkaloids, saponins, tannins, flavonoids, protein, amines, glycosides, carbohydrate, steroids, mucilage, gums, terpenoids and phlobatannins in the plant extracts. The aqueous extract of Ageratum conyzoides showed maximum egg inhibition and J2 juvenile mortality due to the presence of phytoconstituents such as alkaloid, tannins, phenol, saponins, glycosides, flavonoids, carbohydrate, protein, mucilage/gum and phlobatannins while Coccinia grandis showed minimum egg inhibition and juvenile mortality.

Root-knot nematode (Meloidogyne incognita) is a catastrophicphytonematodeparasite causing enormous losses to wild as well as cultivated crops worldwide. Despitethe fact that synthetic nematicides have most significant effect, limiting these phytonematodes but theinherent toxic nature of these chemicals to the environment and human beings have compelled the researchers to think for safe, alternative and eco-friendly substitutes for these chemicals. A pot trial was conducted under the greenhouse conditions to evaluate the efficacy of different doses of plant oil cakes against root knot nematode infecting Black gram, Vigna mungo. Root knot nematode, Meloidogyne incognita was found to reduce plant growth and pollen fertility and yield in pulse crop. Among various treatments the Neem cake @ 100g/pot was found most effective in limiting root gall index and enhancing plant growth parameters followed by Mustard cake @ 100g. Neem cake @ 50g/pot, Castor cake @ 100g/pot and Linseed cake @ 100g/pot were statistically at par. Above studies as surean effective and commercially cheap source of controlling root knot nematode in favour sustainable agriculture and food security.

An investigation was carried out to study the pathogenicity of root knot nematode Meloidogyne incognita on okra and its management through various organic amendments. The inoculum level of 1000 juveniles per plant showed significant reduction in various plant growth parameters, which reveals that M. incognita is a potential pathogen of okra. With the increase in inoculums level of M. incognita (J2), there was a progressive decrease in various plant growth parameters. The maximum reduction in plant growth parameters was observed at an inoculum level of 4000 juveniles per plant. The efficacy of five organic amendments viz. groundnut cake, castor cake, sunflower cake, linseed cake and sawdust was tested against root knot nematode M. incognita. Amending the soil with different oil cakes was found to be effective in reducing the nematode soil population, number of females, number of egg masses as well as root gall formation in okra. The highest increase in plant growth (13%) and maximum reduction in number of ...

Glasshouse experiment was conducted to assess the impact of green chopped leaves of four test plants (Lantana camara, Ficus virens, Kigelia pinnata and Ficus bengalensis) and two nematicides (Phorate and Carbofuran) on the plant growth parameters of tomato cv. K25 and on the root-knot development. Results revealed that all the tested treatments significantly (p = 0.05) improved plant growth parameters and reduced root-knot development compared to control. Among the tested organic additives, chopped green leaves of Lantana camara added to soil gave the highest enhancement in plant growth parameters, including plant height, fresh and dry weight, number of fruits and fruit weight with the values of 94.2 cm, 106.8 g, 31.6 g, 7.2 and 153.3 g respectively, as well as a greater reduction of Meloidogyne javanica reproduction and development but exhibiting a lower response compared to nematicides. There was also significant reduction in root-knot development in tomato plants growing in other organic additive amend...

Various concentrations of aqueous leaf extract of Lantana camara were assessed in vitro conditions against second stage juveniles (J2) of Meloidogyne incognita. The standard concentration 'S' of leaf extract was found to be highly nematostatic, where nematodes were completely paralyzed after 12 h and after 48 h of exposure, 96% of juveniles were killed at same concentration. However, the mortality of juveniles was 75% in S/2 dilution at 48 h. The degree of effectiveness and dilutions of extract were directly proportional. The percentage of paralyzed juveniles was decreased, when J2 transferred in distilled water after 48 h incubation in standard aqueous leaf extract. Addition of freeze-dried aqueous extract to sterile sandy substrate at S/2 dilution significantly decreased the root-knot infection to susceptible eggplants whereas second stage juveniles (J2) that penetrated roots of eggplant were able to complete development in sterile sandy substrate without treatment of freeze-dried aqueous extract.