Management of Sclerotium Rolfsii With Integration of Non-Conventional Chemicals, Vermicompost and Pseudomonas Syringae (original) (raw)
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Crop Protection, 2007
Four non-conventional chemicals, viz., zinc sulphate (ZS), oxalic acid (OA), sodium malonate (SM) and sodium selenite (SS), were applied as foliar sprays to chickpea (Cicer arietinum) and the plants were subsequently challenged against Sclerotinia sclerotiorum, the causal agent of stem rot in chickpea. All the chemicals reduced mortality of chickpea from S. sclerotiorum infection. Among them, ZS at 10 À3 mmol gave the best result as only 13.6% mortality was recorded after 28 d compared to 100% in the control. High performance liquid chromatographic analysis of treated chickpea leaves revealed activation of shikimic acid as well as phenyl propanoid pathways and synthesis of several phenolic compounds increased specially after application of OA, ZS and SM. Individual treatment of the chemicals showed better results than their combinations as plant mortality was reduced and accumulation of phenolics increased in their individual treatments. A positive correlation was observed between induction of phenolic compounds and survival of the plants. In vitro assay of the four chemicals showed only SS to be antifungal. The protection of plants by ZS, OA and SM is possibly because of induction of resistance in the host against S. sclerotiorum. r
Asian Journal of Microbiology Biotechnology and Environmental Sciences, 2022
Chickpea is the most important pulse crop widely grown in India, accounts for nearly 75 per cent of the total pulse production in the world. Chickpea crop is prone to many diseases. Among these, collar rot caused by Sclerotium rolfsii is one of the destructive soil-borne diseases of fungal origin and which is gaining importance elsewhere has been recently observed in and around different parts of country is a serious hazard. S. rolfsii survives in mycelium in the infected tissues and plant debris and as sclerotial structures in the soil or associated with plant debris and usually attacks the collar region of plants. Biological control of the disease through antagonists is an eco-friendly approach apart from superior alternative to the use of chemicals. In the present study, the four antagonistic microorganisms were evaluated by dual culture and paper disc technique for their antagonistic effect against S. rolfsii under in-vitro conditions. Maximum inhibition of mycelial growth (78.61%) was noticed in T. viride which was followed by T. harzianum (75.28%). Least inhibition was observed in P. fluorescence (68.89%).
Efficacy of Microbial Bioagents for the Control of Collar Rot Disease in Chickpea
Pak. J. Bot, 2007
Study was conducted In vivo to evaluate the antagonistic effects of two microorganisms against collar rot disease of chickpea caused by the fungus Sclerotium rolfsii. The effect of microbial amendments viz., Vesicular arbuscular mycorrhizae (VAM) and root nodulating bacteria Rhizobium sp., on the collar rot disease in Cicer was studied individually and in combination when applied to the soil. The results depicted that 100% seedling mortality was recorded in the control treatment where only test fungus i.e., S. rolfsii was added to the soil. Maximum reduction in seedling mortality was obtained when VAM and Rhizobium sp. were applied in combination. Likewise, the two microorganisms when used alone significantly reduced the effect of disease on plant growth. Treatment with Rhizobium sp., had greater synergistic effect on plant height, shoot and root weight, nodules plant-1 , pods plant-1 and 100-seed weight of chickpea as compared to VAM. It was inferred that both the amendments used have effectively improved various yield parameters by controlling the disease and reducing seedling mortality.
Biological control of Sclerotium rot of sunflower
Three hundred rhizosphere bacteria were tested for antagonism against Sclerotium rolfsii, the causal organism of rooUcollar rot in sunflower. A modified dual medium containing Potato Dextrose Agar for pathogen growth and Nutrient Agar or Pseudomonas Agar (for fluorescence) or Tryptic Soya Agar for bacterial growth in the same plate was used to test for antagonism in dual culture. This dual medium method was most suitable to screen for antagonists in vitro. Eleven rhlzobacteria antagonistic to S. rolfsii were identified which included Pseudomonas fluorescens (PDBCAB 1,2, 15 and 26), Pseudomonas spp. (PDBCAB 7, 8, 15), P. putida (PDBCAB, 19), Streptomyces sp. (PDBCAB 23), Bacillus pantothenticus (pDBCAB 28) and Alcaligenes odorans (PDBCAB 12). Pseudomonas putida completely inhibited S. rolfsii under dual culture. All the eleven isolates were tested for HC production and four of the isolates showed positive reaction. One Pseudomonas sp. (pPDBCAB 7), B. pantothenticus and A. odorans were antagonistic to S. rolfsii under dual cuture, but pot culture percent disease free plants were minimum (13 to 27%) for these three antagonists. Highest disease suppression was exhibited by Pseudomonas fluorescens (PDBCAB 2) and P. putida (PDBCAB 19) (60 to 63 % disease ftee plants). The results indicate that selection of antagonistic bacteria must be based on greenhouse performance instead of relying on lab results.
Indian Phytopathology, 2020
Collar rot caused by Sclerotium rolfsii is one of the most economically important diseases of chickpea, which causes considerable loss every year. Since, control methods alone may not completely and effectively manage this ubiquitous pathogen, an attempt was made to control collar rot of chickpea more effectively by integration of Pseudomonas sp. (PUR46) along with vermicompost. Three enzymes, viz., catalase (CAT), peroxidase (POD) and phenylalanine ammonia lyase (PAL) were analyzed for their possible role in induction of resistance by the vermicompost and Pseudomonas activities in plants exhibiting induced resistance. The activities of POD and PAL enzymes were high, whereas CAT activity was found to be low in untreated plants than the vermicompost and PUR46 treated chickpea plants after they were challenged with S. rolfsii. Their maximum activities were appeared at 48 h after pathogen challenge. Interestingly, POD and PAL activities were higher in the stems, the site of collar rot infection than in leaves, whereas the reverse held true for CAT. This study showed that S. rolfsii infected untreated chickpea plant exhibited a non-coordination in antioxidant defense enzymes POD and CAT, which were proposed to facilitate penetration by the pathogen lead to mortality in chickpea. Combined application of 25% vermicompost along with seed bacterization showed minimal induction of POD and PAL activities in leaves and stems of chickpea plants in 48 h but maintained their activities throughout the sampling periods compared to inoculated control, indicating the lesser requirement of defense enzymes in the treated plants for encountering the pathogen.
Efficacy of Bioagents against Sclerotinia Rot of Chickpea Incited by Sclerotinia sclerotiorum
Legume Research, 2022
Background: Sclerotinia sclerotiorum (Lib.) de Barry is a soil-borne plant pathogen, capable of infecting more than 500 host plants worldwide. It is a major pathogen that plays a crucial role in reducing the yield of economically important crops. Sclerotinia rot also known as Stem rot or white mold, caused by Sclerotinia sclerotiorum is a serious disease of chickpea. Methods: The antagonistic potential of four bioagents i.e. Trichoderma harzianum (Th-BKN), Trichoderma viride (Tv-BKN), Pseudomonas fluorescens (Pf-BKN) and Bacillus subtilis (Bs-BKN) were isolated from chickpea rhizospheric soil. The fungal bioagents were tested for their antagonistic potential against the pathogen in vitro by modified dual culture technique on potato dextrose agar (PDA) medium. While bacterial antagonists tested for their antagonistic potential against the pathogen in vitro by paper disc inoculation technique on Nutrient Agar (NA) and Pseudomonas Agar Fluorescens (PAF) media. Each treatment was replicated four times, incubated at 23±10C, data on the antagonistic activity of different bioagents were recorded and percent inhibition was calculated for each antagonist. Result: The fungal antagonists T. harzianum (Th-BKN) resulted in maximum growth inhibition of the pathogen (70.48%) and bacterial antagonists, Pseudomonas fluorescens (Pf-BKN) (37.56%) was more effective than the Bacillus subtilis (Bs-BKN).
Crop Protection, 2008
Collar rot of chickpea (Cicer arietinum) is caused by the soil-borne pathogen Sclerotium rolfsii and management of this ubiquitous pathogen is not possible through a single approach. An integrated approach was adopted by using vermicompost and an antagonistic strain of Pseudomonas syringae (PUR46) possessing plant growth-promoting characteristics. Treatments with vermicompost (10%, 25%, and 50% v/v) and PUR46 alone and in combination reduced seedling mortality in chickpea under glasshouse conditions. The combined effect of 25% vermicompost substitution along with seed bacterization with PUR46 was the most effective treatment, which not only increased the availability and uptake of minerals like P, Mn, and Fe in chickpea seedlings, resulting in an increase in plant growth, but also reduced plant mortality. These effects are correlated with improvement in soil physical conditions and enhanced nutritional factors due to vermicompost substitution as well as plant growth promotion and the antagonistic activity of PUR46 against the pathogen. Dual cultures of PUR46 with the S. rolfsii isolate revealed a high degree of antagonism by PUR46 against the pathogen. Performance of PUR46 was enhanced in the presence of 25% vermicompost compared with its application alone and therefore this combination may be a useful tool to manage S. rolfsii under field conditions. r
International Journal of Chemical Studies
Lentil is an important pulse crop, contributes about 8-9% of the total pulse production in India and is also a major source of protein, minerals and vitamins. Collar rot of lentil is an important seedling disease caused by Sclerotium rolfsii Sacc. In this study, twenty isolates (Th1-Th20) of Trichoderma harzianum, one isolate of Pseudomonas fluorescence and nine commercially available fungicides were tested in vitro for their efficacy in inhibiting the growth of the pathogen. Trichoderma harzianum isolate Th16 and Th14 were found to inhibit maximum mycelial growth of the pathogen. The complete inhibition of mycelial growth of Sclerotium rolfsii was found with Propiconazole, Tabuconazole, Hexaconazole, Ridomil and Carbendazim+ Mancozeb at all (0.03%, 0.05% and 0.1%) concentrations. Other fungicides (Captan, Mancozeb and Carbendazim) also showed significant inhibition of the mycelial growth of the pathogen. No inhibition was recorded in the treatment with copper oxychloride even at 0.2% concentration.