Vermiwash: An agent of disease and pest control in soil, a review

Assessment of microbial flora and pesticidal effect of vermicast generated from Azadirachta indica (neem) for developing a biofertilizer-cum-pesticide as a single package

The soil comprising organic matter, nutrients, serve as substrate for plant growth and various organisms. In areas where there are large plantations, there is a huge leaf litter fall. The leaf litter upon decomposition releases nutrients and helps in nutrient recycling, for which the soil engineers such as earthworms, ants and termites are important key players. In this context, the present study was conducted to assess the characteristics of the vermicast obtained by vermicomposting neem leaf litter in terms of microbial flora, plant growth promoting properties and antagonistic activities of the vermicast against phytopathogens. Vermicomposting of neem leaf litter was done using two epigeic earthworm species Eisenia fetida and Eudrilus eugeniae. The vermicast exhibited antagonistic potential against plant pathogens. Out of the four vermiwash infusions studied, the 75 % formulation reduced the disease incidence against mealybug by 82 % in the tree Neolamarkia cadamba. The result of the study suggests that vermicast made from neem leaf litter may be a potent combination of a biofertilizer and a pesticide.

Effective combination of arugula vermicompost, chitin and inhibitory bacteria for suppression of the root-knot nematode Meloidogyne javanica and explanation of their beneficial properties based on microbial analysis

Root-knot nematodes (Meloidogyne spp.) are dangerous parasites of many crops worldwide. The threat of chemical nematicides has led to increasing interest in studying the inhibitory effects of organic amendments and bacteria on plant-parasitic nematodes, but their combination has been less studied. One laboratory and four glasshouse experiments were conducted to study the effect on M. javanica of animal manure, common vermicompost, shrimp shells, chitosan, compost and vermicompost from castor bean, chinaberry and arugula, and the combination of arugula vermicompost with some bacteria, isolated from vermicompost or earthworms. The extract of arugula compost and vermicompost, common vermicompost and composts from castor bean and chinaberry reduced nematode egg hatch by 12-32% and caused 13-40% mortality of second-stage juveniles in vitro. Soil amendments with the combination vermicompost of arugula + Pseudomonas. resinovorans + Sphingobacterium daejeonense + chitosan significantly increased the yield of infected tomato plants and reduced nematode reproduction factor by 63.1-76.6%. Comparison of chemical properties showed that arugula vermicompost had lower pH, EC, and C/N ratio than arugula compost. Metagenomics analysis showed that Bacillus, Geodermatophilus, Thermomonas, Lewinella, Pseudolabrys and Erythrobacter were the major bacterial genera in the vermicompost of arugula. Metagenomics analysis confirmed the presence of chitinolytic, detoxifying and PGPR bacteria in the vermicompost of arugula. The combination of arugula vermicompost + chitosan + P. resinovorans + S. daejeonense could be an environmentally friendly approach to control M. javanica.

Improved photocatalytic dye degradation and seed germination through enzyme-coupled titanium oxide nanopowder - A cost-effective approach

Enzyme-coupled titanium oxide nanopowder samples were prepared usingdifferent volumes of vermiwash using a cost-effective soft chemical method and their photocatalytic efficiency was studied against Methylene Blue (MB) dye decomposition. The volume of vermiwash used in the starting solution was varied from 50 to 200 mL in steps of 50 mL and the effect of enzymes prevalent in the vermiwash on the photocatalytic activity of titanium oxide (TiO₂) was studied. The resultant water obtained after the photocatalytic dye degradation was found to inherit the enzymes from the nanoproduct. This enzyme-activated treated water showed effective seed germination of black gram (Vigna mungo L.). The results suggested that the enzyme-coupled TiO₂ can be used as an effective and eco-friendly material for the treatment of contaminated water and consequently the treated water can also be utilized for enhanced seed germination.

Combined effects of vermicompost and vermicompost leachate on the early growth of Meloidogyne incognita stressed Withania somnifera (L.) Dunal

Roots of Withania somnifera, an important medicinal herb, are prone to the infection of Meloidogyne incognita (a root parasitic nematode). The infection lowers the quality and quantity of plant material and poses a challenge in crop cultivation and obtaining desirable yield. In the present study, in vitro inhibitory activity of vermicompost leachate (Vcom-L) was assessed against % hatch and survival of M. incognita in a 96 h assay. Then, Vcom-L was used as soil supplement in combination with vermicompost (Vcom) to evaluate their nematode inhibitory and stress alleviating effect in W. somnifera, in a pot experiment. Root galling intensity and growth performance of nematode-stressed W. somnifera raised from seeds pre-soaked in distilled water (DW), Vcom-L, vermicompost tea (Vcom-T) and different dilutions of Vcom-L were assessed. We observed 79% suppression of egg hatching and 89% juvenile (J2) mortality after 96 h compared to control, at 100% concentration of Vcom-L. Significant reduction in gall formation with increase in growth parameters of seedlings was observed after combined application of Vcom (60% or 100%) + Vcom-L and was evident as enhancement in seedling biomass and contents of chlorophyll and protein. However, proline, total phenolics and malondialdehyde (MDA) content declined significantly in these combinations compared to the control (0% Vcom). Activity of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidise (APX), guaiacol peroxidise (GPX) and glutathione reductase (GR) declined with Vcom as well as Vcom + Vcom-L and corresponded with decline in the accumulation of reactive oxygen species in leaves. Further, 1:5 and 1:10 dilutions of Vcom-L in combination with Vcom (60%) proved beneficial in mitigating the nematode-induced stress in W. somnifera. Present results showed the potential of Vcom and Vcom-L in standardised combination as an effective strategy in controlling the pathogenicity of M. incognita in medicinal plants such as W. somnifera.

Vermicompost and Its Derivatives against Phytopathogenic Fungi in the Soil: A Review

Synthetic chemicals, such as fertilizers and pesticides, are abundantly used in agriculture to enhance soil fertility and prevent the occurrence of diseases, respectively. Many studies have reported a negative influence of these chemicals on the soil environment. Natural sources from earthworms and their products, as a result of vermicomposting, may be considered better alternatives. The aim of this review was to reveal the source of antifungal efficiency of vermicompost and its derivatives, such as vermiwash, coelomic fluid, skin secretion of earthworms, and metabolites from decomposer bacteria in vermicompost, in order to highlight their application in agriculture. The synergistic activity of bioactive compounds present in coelomic fluid, mucus, skin secretion, and metabolites from associated bacteria (decomposer) assisted crop plants for effective action against various soil pathogenic fungi, such as Rhizoctoniasolani, Alternaria solani, Aspergillus niger, A.flavus, Fusariumoxysporum, and F. graminearum. Thus, these bioactive metabolites can be recommended to suppress plant fungal diseases. Vermicompost and its derivatives should be considered for use in agricultural fields to control harmful soil fungi and increase crop productivity.

Composted Municipal Green Waste Infused with Biocontrol Agents to Control Plant Parasitic Nematodes-A Review

The last few years have witnessed the emergence of alternative measures to control plant parasitic nematodes (PPNs). We briefly reviewed the potential of compost and the direct or indirect roles of soil-dwelling organisms against PPNs. We compiled and assessed the most intensively researched factors of suppressivity. Municipal green waste (MGW) was identified and profiled. We found that compost, with or without beneficial microorganisms as biocontrol agents (BCAs) against PPNs, were shown to have mechanisms for the control of plant parasitic nematodes. Compost supports a diverse microbiome, introduces and enhances populations of antagonistic microorganisms, releases nematicidal compounds, increases the tolerance and resistance of plants, and encourages the establishment of a "soil environment" that is unsuitable for PPNs. Our compilation of recent papers reveals that while the scope of research on compost and BCAs is extensive, the role of MGW-based compost (MGWC) in the control of PPNs has been given less attention. We conclude that the most environmentally friendly and long-term, sustainable form of PPN control is to encourage and enhance the soil microbiome. MGW is a valuable resource material produced in significant amounts worldwide. More studies are suggested on the use of MGWC, because it has a considerable potential to create and maintain soil suppressivity against PPNs. To expand knowledge, future research directions shall include trials investigating MGWC, inoculated with BCAs.

Documentation of Commonly Used Ethnoveterinary Medicines from Wild Plants of the High Mountains in Shimla District, Himachal Pradesh, India

The aim of current study is to provide a significant traditional knowledge on wild medicines used for ethnoveterinary purposes in the rural area of Maraog region in district Shimla. The medicinal plants have played a significant role in the treatment of human as well as animal’s diseases. The rural people of the Maraog region were interviewed through a questionnaire and extensive field surveys were conducted from June 2020 to July 2021. The discussion, observations and interviews were conducted in study site and included 96 informants. The information gathered from the residents is presented in a table format and includes scientific and local names, different parts used, diseases treated and mode administration. The most commonly used taxa are calculated with used value. The study revealed 100 plants in which trees (7), shrubs (26), herbs (56), ferns (5), grasses (3) and climbers (3) were identified. The most commonly documented livestock diseases were found to be hoof infections, eyes infections, poisoning and skin infections. In the current study, the Rosaceae family was reported as being the highest number (11), followed by Asteraceae (10) and then Lamiaceae (6). It was found that leaves, roots, flowers and fruits are the commonly used parts for ethnoveterinary medications. The phytochemicals present in the plant, such as alkaloids, sterols, glycosides, flavonoids, lignin, coumarins and terpenoids, etc., may be responsible for their medicinal properties. In this documentation, it was observed that the younger generation does not have good knowledge of medicinal plants as compared to the older ones. Therefore, it is necessary to preserve the traditional knowledge of these medicinal plants before their permanent loss. The documentation and conservation of medicinal plants can be a good start for novel phytopharmacological research in the veterinary field.