Evaluation Of Bioagents Research Articles

Evaluation of Bioagents against Stemphylium vesicarium Inducing Stemphylium Blight in Onions (Allium cepa L.)

Stemphylium blight of onion incited by S. vesicarium is one of the economically important diseases, causing severe yield losses in onion crop. The present investigation was carried out to evaluate efficacy of different bioagents against S. vesicarium under in vitro conditions. The experiment was laid out in a Completely Randomized Design (CRD) with three replications per treatment. Five fungal biocontrol agents viz., Trichoderma harzianum, T. viride, T. hamatum, T. virens and a fungal consortium from MPKV, Rahuri along with two bacterial biocontrol agents namely Pseudomonas fluorescens and Bacillus subtilis were evaluated for their effectiveness against S. vesicarium. The results showed significant variation in the inhibitory effects of bioagents on the mycelial growth of the test pathogen with percent growth inhibition ranging between 53.70 to 85.19 per cent. T. harzianum was reported to be most effective, showing a minimum colony diameter of 13.33 mm with the highest growth inhibition (85.19%) thus reported as superior to all other treatments whereas, Pseudomonas fluorescens was reported with a least percent growth inhibition (53.70%).

Evaluation of bioagents and chemicals for the management of mulberry root rot incited by Lasiodiplodia theobromae and Macrophomina phaseolina

Evaluation of bioagents and chemicals for the management of mulberry root rot incited by Lasiodiplodia theobromae and Macrophomina phaseolina

In vitro evaluation of fungicides and bio-control agents against sunflower collar rot (Sclerotium rolfsii)

The efficacy of different fungicides against Sclerotium rolfsii was tested using poison food technique under in vitro conditions and through seed treatment in screen house. Efficacy of fungicides in vitro against S. rolfsii showed that carboxin, vitavax power and hexaconazole completely inhibited mycelial growth up to 100 per cent at 100 ppm concentration. Thiram inhibited 95.8 per cent and propiconazole inhibited 98.1 per cent at 1000 ppm. Captan inhibited 80.6 per cent at 1000 ppm while, carbendazim only inhibited 18.5 per cent at 1000 ppm. Pencycuron have failed to show antifungal activity against S. rolfsii even at 1000 ppm. Evaluation of bio-agents against S. rolfsii in vitro revealed that Trichoderma harzianum showed maximum antifungal activity with 70.1 per cent inhibition of mycelial growth followed by T. viride (63.1%) and Bacillus spp. (53.7%). Seed treatment with fungicides and soil treatment with bio-agents significantly reduced the disease incidence of collar rot. Maximum collar rot control wasfound by carboxin (73.9%) followed by vitavax power (69.9%) and thiram (69.4%) by seed treatment under screen house conditions. For the bio-agents, T. harzianum showed maximum control of the disease (40.8%) followed by Bacillus spp. (36.9%) and T. viride (34.6%) in comparison to control.

Evaluation of Bioagents as Seed Treatment on Dominant Seed Mycoflora of Chilli Var. Gvc 111 In Vitro

Study to check the efficacy of seed treatment by bioagents on the seed germination and vigour by inhibiting the most dominant seed mycoflora (A. niger, Colletotrichum sp. and Fusarium sp.) of chilli variety GVC 111 was carried out by paper towel method in vitro. Treatment of seeds with T. harzianum+P. fluorescens (5+6g/kg seeds) and P. fluorescens (6g/kg seeds) found effective in seeds pretreated with A. niger, while T. harzianum+P. fluorescens (5+6g/kg seeds) and P. fluorescens+B. subtilis (6+6g/kg seeds) found effective in seeds pretreated with Colletotrichum sp. and P. fluorescens+B. subtilis (6+6g/kg seeds) and T. viride+P. fluorescens (5+6g/kg seeds) found effective in seeds pretreated with Fusarium sp. However, overall results indicated that seed treatment with P. fluorescens+B. subtilis @ 6g + 6g/kg seeds and T. harzianum+P. fluorescens @ 5g + 6g/kg seeds proved very effective with higher seed germination, seedling length and vigour index in all pretreated seed mycoflora i.e, A. niger. Colletotrichum sp. and Fusarium sp.

Evaluation of bioagents against Macrophomina phaseolina and its effect on root weight of cowpea (Vigna unguiculata (L.) Walp)

The efficacy of bio-agents on dry root weight of cowpea (Vigna unguiculata (L.) Walp) studied consecutively for three year at bundelkhand region showed maximum increase in the dry weight of root due to Trichoderma harzianum followed by Trichoderma viride at various doses. Both the biological agents acted more effectively at 10 to15 g dose. The study also revealed that T. pseudokoningii and T. koningii did not visualize any significant difference in their efficacies when compared with each other. Aspergillus flavus and Aspergillus niger were least effective in comparison with other bioagents

Characterization and potential antifungal activities of three Streptomyces spp. as biocontrol agents against Sclerotinia sclerotiorum (Lib.) de Bary infecting green bean

BackgroundWhite mold disease, caused by Sclerotinia sclerotiorum the devastating pathogen, attacks green beans (Phaseolus vulgaris L.) and several crops worldwide. The present investigation was carried out to introduce some antagonistic microorganisms as novel antifungal substances to be an alternative and secure method to effectively control the disease.ResultsThree Streptomyces species, i.e., S. griseus (MT210913 “DG5”), S. rochei (MN700192 “DG4”), and S. sampsonii (MN700191 “DG1”) were isolated, biologically, molecularly characterized, and evaluated in vitro and in vivo. Molecularly, polymerase chain reaction (PCR) amplification and nucleotide sequencing were used to characterize the pathogen and bio-agents. PCR amplification of the pathogen and Streptomyces species (bioagents) exhibited amplicons of around 535 bp and 1300 bp, respectively. The nucleotide sequence analysis of the three Streptomyces spp. indicated that S. rochei was closely related to S. griseus, and both had a distance relationship with S. sampsonii. The evaluation of bioagents was carried out against S. sclerotiorum. Reduction percentages in the mycelial growth of the pathogen ranged between 60.17 and 52.30%, indicating that S. rochie gave the highest inhibition percent. Incorporations of Streptomyces spp. culture filtrate components into culture media proved that S. sampsonii was more efficient as a bioagent in reducing mycelial growth pathogen by 84.50%. The effectiveness of the bioagent volatile compounds inhibited the pathogen growth at a rate of 54.50-72.54%, respectively, revealing that S. rochei was the highest inhibitor followed by S. griseus. The parasitic activity of Streptomyces spp. upon S. sclerotiorum showed deformation, contraction, and collapse when observed by light and scanning electron microscopy. Molecular characterization of the 3 Streptomyces spp. revealed that S. griseus was closely related to S. sampsonii (96%), secondly ranked by S. rochei (93.1%). Viability and germination of pathogen sclerotia were reduced when they dipped into the Streptomyces spore suspensions for 10, 20, and 30 days. Application of the 3 Streptomyces spp. in the field proved a great potential to control the disease.ConclusionsThe results suggested that the 3 Streptomyces strains and their secondary metabolites can be potential biocontrol agents and biofertilizers for controlling S. sclerotiorum, the causative agent of bean white mold disease.

Evaluation of bio-agents and neem based products against late blight disease (Phytophthora infestans) of potato

Late blight disease incited by Phytophthora infestans (Mont) de Bary is a major limitation for potato cultivation. Organic based products are vital in organic cultivation; because these are non-hazardous and eco-friendly in nature. Few bio-products were evaluated against late blight on two popular potato cultivars in India like Kufri Bahar (highly susceptible) and Kufri Mohan (moderately resistant) in two consecutive years (2018–19 and 2019–20). All the seven treatments were found effective up to certain extent for managing the late blight disease. Among the bio-based products neem oil @ 6.0% showed lowest average terminal diseases severity (46.67%), followed by 64.67 and 66.67% with Pseudomonas fluorescens @ 1.0% and Trichoderma viride @ 2.0%, respectively on Kufri Bahar. The highest tuber yields was 28.23 t/ha with neem oil @ 6.0% followed by 28.10 t/ha with Trichoderma viride @ 2.0% against control (24.40 t/ha). Similarly, the lowest average terminal disease severity (27.25%) was recorded with copper hydroxide 53.8% DF @ 0.2%, followed by 28.50% with copper oxychloride 50% WP @ 0.2% on cv. Kufri Mohan. Among the bio-based products, minimum average terminal disease severity (30.92%) was recorded with neem oil @ 6.0% followed by 46.17% with Trichoderma viride @ 2.0% and 47.84% with fermented neem giri @ 1.0% on cv. Kufri Mohan. The highest tuber yields was 40.14 t/ha with copper hydroxide 53.8% DF @ 0.2%, followed by 39.68 t/ha with fermented neem giri @ 1.0% against control 34.64 t/ha. These evaluated treatments could be applied for managing late blight disease in organic cultivation of potato.

Evaluation of bioagents and chemicals for the management of root rot disease of bell pepper

Bell pepper (Capsicum annuum L. var. grossum Sendt.) a member of Solanaceae family, commonly known as “Sweet pepper ” or “Capsicum ” or “Shimla mirch ” has attained a status of high value crop among vegetables in India because of its delicacy and pleasant flavor besides being rich in fatty acids, flavanoids, volatile oil and carotene. Out of total six bioagent tested under in vitro condition, Trichoderma harzianum (SMA-5) and Trichoderma sp. (AF2) were observed as potential bioagents which inhibited the mycelial growth upto 84.7 per cent. Studies on different methods of application of bioagent revealed that drenching was effective in controlling disease (61.1%). In vitro evaluation of fungicides revealed that out of seven fungicides tested, Ridomil MZ and Moximate @ 100 μg/ml were highly fungitoxic as compare to other fungicides. Under pot experiments, Ridomil MZ and Moximate @ 0.25 per cent were found highly effective in managing root rot disease upto 64.7 and 59.0 per cent, respectively. Integrated application of Trichoderma sp. (PF2) with Ridomil MZ (1.75g/l) was found most effective in the management of Phytophthora root rot of bell pepper under polyhouse conditions.

Evaluation of bio-agents and botanical against Tomato damping-off (Pythium aphanidermatum)

Owing to the great loss of the seedlings due to damping-off disease thus an investigation was conducted under in vitro and in situ to observe the effect of Trichoderma viride, Pseudomonas fluorescens and Azadirachta indica leaf extract against Pythium aphanidermatum Maximum inhibition of mycelial growth of the pathogen by dual culture method was used with T. viride (38.8%) and T. viride + A. indica (32.9%). In situ condition, the maximum germination was recorded in P. flurorescens + A. indica (75.6%). Minimum disease incidence was observed in T. viride (4.0%), whereas maximum root and shoot length were recorded in T. viride + A. indica (2.95 cm) and P. fluorescens (10.03cm), respectively.

Occurrence of Black Scurf Disease of Potato in Multan (Punjab) Alongwith Its in vitro Chemical and Biotic Elicitor Mediated Management

Black scurf disease of potato, caused by fungus Rhizoctonia solani, is the most common and one of the oldest diseases of potato affecting stem and stolons. In recent years, the disease is reportedly present in the fields of potato in Pakistan especially in Punjab. Survey of different locations viz. Narangaabad, Band Bosan, Kaian Pur, Kotla Abdul-Fateh and Dhillun was conducted to assess the prevalence of disease in Multan region. Maximum disease incidence and severity of 95.00% and 3.1 rating, was recorded in Kotla Abdul-Fateh respectively. Sclerotial pieces showing characteristic symptoms of black scurf were detached from tuber surface and the fungus was isolated on potato dextrose agar medium. For in-vitro chemical and biotic elicitor testing, three different fungicides viz., Monceren, Topsin-M, and Triton were evaluated using poisoned food technique and antagonistic effect of two accessions of Triochoderma spp . viz. Trichoderma harzianum and Trichoderma viridae was determined against the sensitivity of fungus. Triton was found to be superior at all concentrations in inhibiting the radial mycelial growth of the fungus followed by Topsin-M and Monceren. Satisfactory results were obtained by the antagonistic effect of Trichoderma harzinaum and Trichoderma viridae with 70.00% and 66.00% respectively under in-vitro conditions. Although the fungicide chemistries exclusively control the fungus yet the evaluation of bioagents also remained prolific towards antagonism against Rhizoctonia solani . These investigations provide fresh information on the current status of black scurf disease of potato in fields of Multan and regarding the biochemical management against Rhizoctonia solani under in-vitro conditions and serve as a guide for the future prospects against this holistic disease.

Evaluation of Bioagents and Biofertilizers for the Managament of Seed and Seedling Diseases of Sesamum indicum (Sesame)

The study was carried out to evaluate the response of biopeticides and biofertilizers on seed mycoflora and seed quality parameters of Sesame (Sesamum indicum L.). Untreated Sesame seeds were collected from farmers of Nizamabad and Karimanagar districts of Andhra Pradesh in India and discolored seeds were separated and treated with biofertilizers and biopesticides alone and in combination form. The seed mycoflora of Sesame seeds were screened by using Potato dextrose agar (PDA) medium and czaepek dox agar media. The results indicate that maximum numbers of fungi were recorded on PDA. The untreated seeds were found to be associated with maximum percent incidence of mycoflora and minimum population was recorded in the treatment of Trichoderma + Pseudomonas formulation followed by Azat obacter + Trichoderma, Pseudomonas and Azatobacter in the decreasing order of efficacy. This study also showed relation of biofertilizers and biopesticides and seed mycoflora on seed germination. Germination percentage was maximum in the treatment Trichoderma + Pseudomonas formulation, Azatobacter + Trichoderma, Pseudomonas and Azatobacter recording 96%, 94%, 90% and 88%, respectively. In the control, germination percentage was minimum compared with other treatments. Seeds treated with the mixed formulation were found beneficial in reducing the pathogenic fungi and decreasing seedling mortality.

Evaluation of Bioagents against the Infection of Green Mould (Trichoderma spp.) in Pleurotus sajor-caju Cultivation

Evaluation of Bioagents against the Infection of Green Mould (Trichoderma spp.) in Pleurotus sajor-caju Cultivation

Evaluation of Bioagents and Biopesticides against Colletotrichum lindemuthianum and its Integrated Management in Common Bean

Three bioagents (Trichoderma viride, T. harzianum and Gliocladium virens) and five biopesticides (Achook, Neemgold, Wannis, Spictaf and Neemazal) were evaluated under in vitro and in vivo conditions against Colletotrichum lindemuthianum. All the three antagonistic fungi caused significant inhibition of mycelial growth, maximum being with T. viride (69.21%) followed by T. harzianum (64.20%). Among the biopesticides tested at four concentrations, Wanis applied @ 1000 ?l/ml caused maximum inhibition of 82.12 per cent followed by Spictaf (52.85%). T. viride and Wanis @ 1000 ?l/ml were most effective in reducing the seed borne infection. Integration of bioagents with Bavistin showed that disease can be effectively managed with seed dressing either with Bavistin or biopesticide followed by foliar treatment with fungicide or biopesticide.

Evaluation of bio-agents and pesticide on root-knot nematode development and oil yield of patchouli

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.