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Meloidogyne incognita(Kofoid and White) Chitwood a calamitous plant pathogen affects almost all the commercial crops, especially medicinal plants viz.Bacopa monnieriL. In this study, the efficacy of indigenous chitinolytic microbes againstM. incognitainB. monnieriwas 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) reducedM. incognitainfestation (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 asStreptomycessp., Microbacterium arabinogalactanolyticum, Cellulosimicrobium cellulans, Actinomycetales bacterium,Chitiniphilussp. andFlavobacterium 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 inB. monnieri. [ABSTRACT FROM PUBLISHER]

Ashwagandha (Withania somniferaL. 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, namelyCellulosimicrobium cellulansMTN13,Flavobacterium johnsoniaeMTN 20,Chitiniphilussp. MTN22 andStreptomycessp. MTN14, alone and in combination forM. incognitamanagement and enhancement of secondary metabolites inW. somniferacv. Poshita were evaluated. A significant enhancement in biomass yield (1.9-fold) and disease diminution (2.7-fold) was found in the dual microbial treatmentStreptomycessp. andChitiniphilussp. 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 2.1-fold in single- and dual-microbe treatments, respectively, than the untreated inoculated plants. The stimulation of the phenylpropanoid pathway and phenolics accumulation was the maximum at 5 days post inoculation (dpi), whereas antioxidant enzymes activities were the highest at 7 dpi. The results thus highlight a possible new function of chitinolytic microbes alone and in combinations that can effectively manageM. incognita-induced stress along with enhanced active molecules ofW. somnifera. [ABSTRACT FROM AUTHOR]

Despite the vast exploration of bioinoculants for disease resistance and crop yield enhancement, knowledge about their impact on quality and quantity of essential oil as well as induction of antioxidant is scarce, especially in medicinal and aromatic crops. In the present two-year field experimentation, a subset ofBacillusspp., namelyBacillus flexus, B. subtilis,B. megateriumandB. aryabhattai, was evaluated against the most devastating root-knot nematode,Meloidogyne incognita(Kofoid and White) Chitwood infestation and essential oil yield enhancement inOcimum basilicumvar. CIM-Soumya (Sweet basil). The plants treated withB. subtilisshowed significant (P< 0.05) enhancement in fresh biomass (42%), essential oil content (121%), nutrient uptake (83%) and reduced root-knot infestation (54%) as compared to untreated control. The defence afforded by bioinoculants was observed based on augmentation of the phenolic (97%), flavonoid (93%), free radical scavenging activity (34%) and total antioxidant (33%) inBacillus-treated infected plants as compared to untreated infected plants. The higher concentration of essential oil constituents, namely linalool (54%) and methyl chavicol (33%), was also recorded in same treatment. An increase in essential oil yield was reflected by induction of antioxidant machinery. The present study for the first time delineates nematicidal potentials ofB. flexusandB. aryabhattai. Altogether these findings suggest that exploitation of bioinoculants could be helpful for effective management of the root-knot nematode infestation along with higher qualitative and quantitative essential oil yield with augmented antioxidants in sweet basil. [ABSTRACT FROM AUTHOR]

The use of herbs in pharmaceutical preparation is ever increasing, and the demand for pesticides free material by the concern industries is on the rise. Consequently the need to grow disease-free plants using non-chemical fertilizers and pesticides is the need of the hour. Mentha arvensis cv. kosi is highly infested with Meloidogyne incognita (Kofoid and White) Chitwood, and severe oil yield loss occurs due to this nematode pest. Employing ecofriendly ways of nematode management, the mutualistic endophytes (Trichoderma harzianum strain Thu, Glomus intraradices) and plant growth promoting rhizobacteria (Bacillus megaterium and Pseudomonas fluorescens) were assessed individually and in combination on plant biomass, oil yield of menthol mint (M. arvensis cv. kosi), reproduction potential and population development of root knot nematode, M. incognita under glasshouse conditions. These microbes enhanced the plant biomass and percent oil yield both with and without M. incognita inoculation. Dual application of mutualistic fungal endophytes and Plant Growth Promoting Rhizobacteria (PGPRs) may be a wise option for enhancing the oil yield and tolerance of menthol mint against M. incognita infection. [ABSTRACT FROM PUBLISHER]

Nematode problems are increasing tremendously in arable soil due to the continuous cultivation of susceptible agricultural crops. Besides the scope of effective chemical armory to combat with, this pest is gradually decreasing. The major factor behind such a scenario is the adverse effect of chemical nematicides on human health, useful organisms, the environment as well as underground water. Therefore, effective chemical nematicides for field use may not be available in the future. Consequently, it has become inevitable to manage this pathogen through such non-chemical management tactics like fallow, flooding, changes in time of sowing/planting material, tillage practices, crop rotations, use of antagonistic crop, trap crop/cover crop, use of nematode free planting materials or seeds, solarization, organic amendment and biological control. Plant parasitic nematodes, if not checked, prove to be a major obstacle in the future prospects of medicinal and aromatic plants in India causing significant damage. Pogostemon cablin (Syn. P. patchouli) suffers greatly from infection of root-knot nematode, Meloidogyne incognita (Kofoid and White) Chitwood, resulting in a considerable reduction in oil yield. A glasshouse experiment was designed to evaluate the relative efficacy of bioagents (Glomus mosseae, Trichoderma harzianum), and a pesticide (Furadan) on reproduction and infection potential of M. incognita in P. cablin. Trichoderma harzianum enhanced the growth, biomass and oil yield of the test plant. Significant reduction in the severity of root-knot disease and population of M. incognita was recorded in the pots treated with T. harzianum when compared to the Furadan treated pots. G. mosseae also performed well but it was less effective than Furadan. It is therefore suggested that T. harzianum can be considered as a wise option instead of hazardous pesticides for reducing root-knot disease in P. cablin. [ABSTRACT FROM AUTHOR]

The sedentary endoparasitic root-knot nematode [RKN], Meloidogyne incognita (Kofoid and White) Chitwood, is worldwide an economically important agri-pest, reducing the yield and quality of crops. The traditional method of RKN control is based mainly on chemical nematicides, which will not be frequently available from 2005 onwards; their use is highly objectionable due to their major contribution to ground water contamination, and dangers to the environment and to human and animal health. Consequently, new and environmentally safe tools for RKN management are urgently needed. The objective of the present investigation was to evaluate different bio-organic wastes on RKN infestation and the growth / oil yield of Artemisia pallens Wall. The tested wastes were: 1. Distillation waste of Mentha arvensis (menthol mint); 2. Murraya koengii (meethi neem / curry leaf); 3. Cymbopogon flexuosus (lemongrass); 4. C. martinii (palmarosa); 5. C. winterianus (citronella); 6. Pelargonium graveolens (geranium); 7. Pogostemon patchouli (patchouli); 8. Tagetes minuta (marigold); 9. Vermicompost of M. arvensis, Chrysanthemum cinerariaefolium (pyrethrum), Tagetes minuta and C. winterianus; 10. Trichoderma harzianum isolate U; 11. VA fungi Glomus aggregatum; G. fasciculatum. The results obtained with these different bio-organics were compared with three controls: untreated — uninoculated, untreated — inoculated and the chemical pesticide carbofuran. Results revealed a considerable enhancement of herbage biomass, flower bud and oil yields when plants were treated with the distillation waste of C. martinii, C. winterianus, M. koengii, M. arvensis, vermicompost of C. cinerariaefolium, T. minuta, M. arvensis and bio-agent T. harzianum. Least nematode infections were recorded with the distillation waste of M. koengii, C. martinii, C. flexuosus, and vermicompost of T. minuta, C. cinerariaefolium and M. arvensis. The results revealed that these environmentally sound bio-organics could be used for replacement of chemical nematicides. [ABSTRACT FROM AUTHOR]

Sweet basil (Ocimum basilicum), a highly valuable medicinal crop, is extremely susceptible to Meloidogyne incognita infestation, leading to severe losses in yield and chemo-pharmaceutical quality. Currently, chemical nematicides are the only effective option for the disease management. However, high toxicity to non-target organisms and adverse impact on soil health motivated the look for ecofriendly alternatives. Here, bioinoculants (Bacillus megatarium ("BM"), B. subtilis ("BS")) were isolated from the rhizosphere of various medicinal and aromatic plants growing in Lucknow region, India. Their biocontrol effects were studied in O. basilicum plants that were invaded by M. incognita either in single or in consortium with Trichoderma harzianum ("TH") and their efficiency compared to chemical nematicide (carbofuran) and a microbial reference strain (Pseudomonas fluorescens). The results show that all bioinoculants enhanced the growth and oil yield production and increased the nutrient content of O. basilicum by significantly reducing M. incognita infestation by 46 to 72%. Among the strains, a consortium of BM and TH was the most potent treatment. The efficiency of these bioinoculants was not restricted to sterile soil condition but remained high also in natural soil conditions, indicating that enriching soils with rhizospheric microbes can be an effective alternative to chemical nematicides. [ABSTRACT FROM AUTHOR]

Abstract: Withania somnifera L. (Family Solanaceae) is an angiospermic medicinal herb, well recognized for the immense therapeutic potentials of its roots containing several withanolides. W. somnifera is also a susceptible host for southern root knot nematode, Meloidogyne incognita. The nematode infestation in roots causes serious crop losses in terms of yield and chemo-pharmaceutical quality of this medicinal herb. In the present study, influence of five rhizospheric microbes, namely Bacillus megaterium (ATCC No. 14581), Pseudomonas fluorescens (ATCC No. 13525), Trichoderma viride (MTCC No. 167), Paecilomyces lilacinus (PDBC PL55) and Glomus intraradices was studied for the management of M. incognita in W. somnifera cv. Poshita under greenhouse conditions. All rhizospheric microbes, except G. intraradices, displayed nematicidal potentials via ovicidal and larvicidal actions in vitro and, resulted in significant improvement in plant growth parameters. The rate of nematode damage to W. somnifera was directly proportional to M. incognita (number of J2) population. [Copyright &y& Elsevier]