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Sclerotium rolfsii Sacc. is a soil-borne necrotrophic plant pathogen that causes diseases in over 500 plant species including vegetables, fruits and ornamental plants. An in vitro study was undertaken to assess the potential of thiophenate methyl 70% WP, metalaxyl+mencozeb 72% WP and fosetyl-Al 80% WP to control this pathogen. Five concentrations (50, 100, 150, 200 and 250 ppm) of each fungicide were prepared by mixing the appropriate quantities of each product in autoclaved malt extract agar. For comparison, a control treatment (0 ppm) without fungicides was also included. Metalaxyl+mencozeb was found the best fungicide with 29-84% control of fungal growth in different concentration. The other two fungicides viz. thiophenate methyl and fosetyl-Al were less effective and controlled the fungal pathogen by 10-35% and 30-48% over control, respectively. Regression analysis showed a linear or a polynomial relationship between the concentration and the fungal growth with R² = 0.9631, 0.9797 and 0.9106 for thiophenate methyl, metalaxyl+mencozeb and fosetyl-Al, respectively. This study concludes that metalaxyl+mencozeb is a highly effective fungicide for the control of S. rolfsii. [ABSTRACT FROM AUTHOR]

Sclerotium rolfsii is a soil-borne plant pathogen that causes root diseases in hundreds of plant species. It also causes collar rot disease in chickpea (Cicer arietinum L.). The present pot study was carried out to investigate the effect of soil amendment with dry biomass of a weed Chenopodium album L. and two antagonistic fungi, namely Trichoderma harzianum and T. viride, on growth and yield of chickpea variety Noor 2009 in soil infected with S. rolfsii. The pathogen-contaminated soil was amended either with 1, 2, or 3% C. album dry biomass, T. harzianum, and T. viride alone, or combinations of either of the two Trichoderma species and plant dry biomass. The lowest shoot and root dry biomass and grain yield of chickpea were recorded in S. rolfsii inoculation alone without any soil amendment (positive control). Plant growth and yield were significantly and gradually increased over positive control with an increase in C. album dry biomass application in the soil. Likewise, soil application of either of the two Trichoderma species significantly enhanced plant growth and yield over positive control under biotic stress of S. rolfsii. Combined application of either T. harzianum or T. viride with 3% dry biomass of C. album also proved highly effective in alleviating biotic stress of S. rolfsii on growth and yield of chickpea. [ABSTRACT FROM AUTHOR]

Chickpea (Cicer arietinum L.) is an important grain legume that is attacked by the fungal pathogen, Sclerotium rolfsii, responsible for collar rot disease. In the present study, the pathogen was isolated from diseased chickpea seedlings and identified on molecular basis using internal transcribed spacer (ITS) and β-tubulin markers. To control this pathogen, an in vivo study was carried out, using Neem (Azadirachta indica A. Juss.) leaf dry biomass (1, 2, and 3%) as soil amendment. A broad-spectrum fungicide mancozeb was selected as a reference and the data regarding plant growth and mortality rates were calculated. In positive control, the highest seedling mortality (56%) was recorded in comparison to negative control (0%) after 30 days of sowing. In 1, 2, and 3% concentrations of A. indica dry leaf biomass, the seedling mortalities were 49, 38, and 38%, respectively. On the other hand, the mancozeb-treated seedlings showed the lowest plant mortality rate (28%). Soil treatments with mancozeb as well as with 1 and 2% leaf biomass concentrations showed marked differences in root and shoot dry biomasses over positive control. In a laboratory bioassay, methanolic leaf extract of Neem of 0.5 to 3.5% concentrations reduced biomass of S. rolfsii by 86–90% over control. The present study concluded that 2% A. indica leaf amendment was the most useful concentration for management of collar rot disease of chickpea. [ABSTRACT FROM AUTHOR]

Sclerotium rolfsii, a soil-borne pathogen of over 500 plant species, causes collar rot disease in chickpea plant and reduces its survival rate, growth and yield. This study was undertaken to assess the benefits of soil amendment with a weed Chenopodium album L., on growth, yield and physiology of chickpea var. Bakhar-2011, against S. rolfsii. For this purpose, soil was sterilized by fumigation with formaline and then inoculum of S. rolfsii was mixed. After one week of pathogen inoculation, soil was amended with dry biomass of C. album aerial parts at 1, 2 and 3% (w/w), irrigated and left for one week for leaching. Thereafter, chickpea seeds were sown in the pots. Experiment was conducted in a completely randomized design with six replications. S. rolfsii significantly reduced dry biomass of shoot, root and grains of chickpea by 21, 36 and 50%, respectively, as compared to negative control (without fungus or C. album). Likewise, chlorophyll and carotenoid contents were also reduced by application of S. rolfsii. Application of different concentrations of dry biomass of C. album (DBC) significantly improved shoot and root dry biomass, grain yield, and chlorophyll and carotenoid contents of chickpea over S. rolfsii inoculated treatment (positive control). The positive effects of DBC on plant growth and yield were increased by increasing its concentration. In general, S. rolfsii increased phenolic content, and activities of phenylalanine ammonia lyase (PAL), catalase (CAT) and peroxidase (POX), which were gradually reduced with increasing concentration of DBC. This study concluded that application of 3% DBC improve resistance of chickpea var. Bakhar- 2011 to S. rolfsii and increase crop growth and yield. [ABSTRACT FROM AUTHOR]

Series of experiments were conducted to identify the possible antifungal components of Chenopodium album leaves for the management of a highly destructive soil-borne fungal pathogen Sclerotium rolfsii. A 4% methanolic extract caused up to 82% reduction in biomass of the target organism. This extract was partitioned using solvents of variable polarities, and the obtained subfractions were evaluated for their activity against S. rolfsii. The best antifungal activity was detected for the ethyl acetate subfraction (60–74%) followed by n- hexane (51–69%), n- butanol (50–60%), chloroform (20–40%) while the aqueous sub-fraction had the lowest activity (9–35%) as detected by the decrease in biomass of the pathogen. Ethyl acetate and n- hexane sub-fractions were analyzed for their chemical constituents by GC–MS technique. Literature survey showed that among the identified compounds kitazin P, imidazole-4-carboxylic acid, 2-fluoro-1-methoxymethyl-, ethyl ester and 9,12,15-octadecatrienoic acid, 2,3-dihydroxypropyl ester, (Z,Z,Z)- had antifungal activities against other fungal species and could be responsible for control of S. rolfsii by methanolic extract in the present study. [ABSTRACT FROM AUTHOR]

Sclerotium rolfsii Sacc. is a devastating soil-borne fungal pathogen that causes collar rot disease in chili (Capsicum annuum L.) and causes pronounced yield losses. In the present study, S. rolfsii inoculated soil was amended with 1, 2, 3 and 4% (w/w) dry leaves of Eucalyptus camaldulensis and their effect was studied on disease incidence, mortality, growth and physiology of the host plant. In positive control, there was 73% disease incidence that was further enhanced to 93% in 1% soil amendment treatment. However, further increase in dose of soil amendment (2% and 3%) decreased disease incidence to 66% and 53%, respectively. A similar effect of soil amendment was observed on plant mortality. A 3% dose of E. camaldulensis leaf biomass alleviated biotic stress of S. rolfsii and increased leaf dry biomass of chili by 67% as compared to positive control. Chlorophyll content and polyphenol oxidase activity were significantly lower in E. camaldulensis amended treatments over positive control. Protein content was gradually increased by increasing leaf amendment dose while reverse was recorded in case of peroxidase activity. The present study concludes that soil amendment with 3% leaf dry biomass of E. camaldulensis can alleviate biotic stress of S. rolfsii on growth of chili to some extent. [ABSTRACT FROM AUTHOR]

A pot experiment was conducted to evaluate the effect of Sclerotium rolfsii inoculation and soil amendment with leaves of Azadirachta indica A. Juss. on southern blight disease, growth and physiology of chili (Capsicum annuum L.). The highest disease incidence (60%) and plant mortality (46%) were recorded in positive control where S. rolfsii was inoculated without soil amendment. Application of lower doses (1% and 2%) generally enhanced disease incidence. However, in 3% soil amendment, minimum disease incidence (27%) and plant mortality (27%) were recorded. S. rolfsii significantly reduced root and shoot growth as well as leaf chlorophyll and protein content. None of the soil amendment treatments significantly improved crop growth over positive control treatment. However, 3% soil amendment significantly enhanced chlorophyll content over positive control. In contrast, all the soil amendment treatments significantly declined leaf protein contents as compared to negative and positive control treatments. Application of different doses of A. indica significantly enhanced polyphenol oxidase (PPO) and peroxidase (PO) activities as compared to both the control treatments. This study concludes that soil amendment with 3% dry leaves of A. indica significantly decreased disease incidence and plant mortality in chili caused by S. rolfsii, possibly by enhancing production of defence related enzymes viz. PPO and PO. [ABSTRACT FROM AUTHOR]

Collar rot caused by a fungus Sclerotium rolfsii, is a serious soil-borne disease of chickpea (Cicer arietinum L.). Present study was carried out to manage this disease by commercial fungicides under in vitro and in vivo conditions. In vitro bioassays were carried out using four fungicides namely Tegula (tebuconazole), Thiophanate Methyl, Ridomil Gold (metalaxyl + mancozeb) and Mancozeb at 50, 100, ..., 250 ppm concentrations. All the concentrations of these fungicides significantly decreased radial growth of S. rolfsii over control. In vivo bioassays were carried out in plastic pots of 15-cm diameter and 20 cm deep with 1 kg soil in each pot. Treatments included a negative control, a positive control (with pathogen only), and two chemical fungicides viz. Thiophanate methyl and Mancozeb. There was 95% and 50% reduction in plant mortality due to Thiophanate methyl and Mancozeb over positive control, respectively, after 30 days of sowing. [ABSTRACT FROM AUTHOR]

Tolerance of plant pathogens to heavy metal stress is an important area of research that has been rarely explored in Pakistan. The current research work was carried out to investigate the impact of Cr(III) on growth of Sclerotium rolfsii Sacc., the cause of collar rot of chilli (Capsicum annuum L.). Laboratory bioassays were conducted in using solid as well as liquid malt extract growth medium amended with 14 different concentrations (0, 5, 10, 20, 30, ...,100, 150, 200, 300, 400, 500 ppm) of Cr(III). Growth medium flasks with different concentrations of Cr(III) were inoculated with the pathogen and incubated for 7 days at 25±2 °C. Results showed that radial growth of S. rolfsii on solid medium and its biomass on liquid medium were significantly decreased with the increase in concentrations of Cr(III) up to 100 ppm, while fungus was unable to grow at concentrations above 100 ppm. There was a linear relationship (R2 = 0.9242) between Cr(III) concentrations and fungal biomass on liquid medium, and a non-linear relationship (R2 = 0.9264) between Cr(III) concentrations and fungal radial growth on solid growth medium. [ABSTRACT FROM AUTHOR]

Bioassays were performed to assess the potential ofCoronopus didymusfor managing collar rot disease of bell pepper, caused bySclerotium rolfsii. In laboratory bioassays, methanolic shoot extract ofC. didymuswas partitioned withn-hexane, chloroform, ethyl acetate andn-butanol. Concentrations from 3.125 to 200 mg ml− 1of each fraction were evaluated against the target fungal species. All concentrations of the ethyl acetate fraction gave complete inhibition of fungal growth. Thin layer chromatography of the ethyl acetate fraction yielded two unidentified compounds1and2withRfvalues of 0.531 and 0.787, respectively. Antifungal activity of these compounds was assessed using the minimum inhibitory concentrations (MICs) technique. Mancozeb was used as a reference compound. Compound2was found to be highly effective againstS. rolfsiiwith MIC value 7.81 μg ml− 1which was at par with the MIC of mancozeb. In a pot trail, dried powdered shoots ofC. didymuswere mixed at 1%, 2% and 3% (w/w) in soil already inoculated with the target fungal pathogen. A negative control with no fungal inoculation or soil amendment and a positive control withS. rolfsiiinoculation but no soil amendment were also included. The treatment with 3% soil amendment significantly suppressed the collar rot disease. There was 50% and 13% disease incidence and mortality, respectively, with 3% treatment compared with 91% and 40%, respectively, in the positive control. This study suggests that collar rot of bell pepper can effectively be managed by exploiting the antifungal potential ofC. didymus. [ABSTRACT FROM AUTHOR]

Present study was undertaken to investigate the antifungal potential of methanolic fruit extract of Datura metel L. (Syn. Datura alba Nees.) and its various solvent fractions against Sclerotium rolfsii Sacc., the cause of devastating collar rot disease of bell pepper (Capsicum annuum L.). In an in vitro study, conducted in 250-mL conical flasks, different concentrations of methanolic fruit extract (0.5, 1.0, 1.5,..., 4.0%) significantly reduced the fungal biomass by 69-94%. Methanolic fruit extract was successively partitioned among n-hexane, chloroform, ethyl acetate and n-butanol in order of increasing polarity. Different concentrations (3.125, 6.25, 12.50, 25, 50, 100, 200 mg mL-1) of these fractions were used against the test pathogen. Pronounced variability in antifungal activity was recorded with respect to extracting solvent and the extract concentration. Chloroform fraction exhibited the highest antifungal activity resulting in 36-50% reduction due to different concentrations. Ethyl acetate was found comparatively less inhibitory where only 8-35% reduction in fungal biomass was observed due to different concentrations of the extract. n-hexane, n-butanol and aqueous fractions generally stimulated the fungal growth to variable extents. The present study concludes that S. rolfsii can be controlled by natural antifungal compounds in chloroform fraction of methanolic fruit extract of D. metel. [ABSTRACT FROM AUTHOR]

Sclerotium rolfii Sacc. causes collar rot disease in bell pepper (Capsicum annuum L.) that results in significant yield losses. Since use of fungicides causes environmental pollution and health hazards, therefore, an alternative environment friendly strategy was used to control this pathogen. Methanolic leaf extract of weed Datura metel L. (family Solanaceae), was evaluated for its efficacy in controlling in-vitro growth of S. rolfii. Extract concentrations ranging from 0.5 % to 4.0 %, significantly controlled the fungal growth by 29-88 % over control. Based on the polarity, various constituents of methanolic leaf extract were partitioned with n-hexane, chloroform, ethyl acetate and n-butanol. Bioassays with 3.125 to 200 mg mL-1 concentrations of these fractions revealed that chloroform fraction was the most antifungal followed by ethyl acetate fraction that reduced the biomass of S. rolfsii by 36-47 % and 5-43 %, respectively. The best antifungal chloroform fraction was subjected to GC-MS analysis to identify its antifungal constituents. A total of 19 compounds were identified in this fraction. The most abundant compound were 1-hexacosanol (12.87 %), 1-octadecene (10.69 %), 2-methyl-3-phenyl-2-propenal (8.72 %), 1-eicosanol (6.80 %). 1-heptadecene (6.66 %), 1-octadecanol (6.62 %), 1,3(15),10-bisabolatriene (6.41 %) and 1,6,10-farnesatrien-3-ol (6.38 %). This study concluded that chloroform soluble fraction of methanolic leaf extract contained potent antifungal compounds to control S. rolfsii. [ABSTRACT FROM AUTHOR]

Pot experiment was designed to assess the effect of southern blight pathogen Sclerotium rolfsii Sacc. on growth, yield, qualitative gene expression and metal uptake in pea (Pisum sativum L.). Soil was spiked with 25, 50, 75 and 100 ppm of Cu(II) and inoculated with S. rolfsii. Growth, biomass and yield of pea plants were significantly declined by 10-70% in treatments inoculated with S. rolfsii, and 10-50% due to different concentrations of Cu(II) alone or combined with the pathogen after 30 and 60 days of growth. Cu(II) uptake capacity of pea plants were increased under combine stress of metal and pathogen as compared to metal alone. Higher metal concentration was recorded in roots than in shoots and pods. Expression of defensin like gene was intense due to combined influence of S. rolfsii and Cu(II) than in plants under pathogenic stress alone. Metallothionein gene was expressed only in Cu(II)-incorporated treatments. The present study concludes that solitary influence of S. rolfsii or Cu was more detrimental to growth and yield of P. sativum as compared to combined stress of both the factors. [ABSTRACT FROM AUTHOR]

A study was performed to investigate the influence of Sclerotium rolfsii (pathogen of southern blight diseases) on germination and growth of pea (Pisum sativum L.) under Cu(II) toxicity stress. Experiments were conducted in petri plates (9-cm diameter) lined with sterilize filter papers inoculated with S. rolfsii (spore suspension 2.0 × 106) and different concentrations of Cu(II) solution viz. 25, 50, 75 and 100 mg L-1. Germination and different growth parameters were declined by 10-70% in treatments inoculated with pathogen alone. There was 10-50% reduction in these parameters either due to effect of metal alone or combined with the pathogen. Root growth showed more susceptibility to both stresses than shoot growth. In another petri plate bioassay, effect of Cu(II) on growth of S. rolfsii was checked, Cu(II) suppressed the growth of fungus by 10-50% at concentrations of 25-100 mg L-1. Further pots and field trials are required to confirm the results of petri plate and recommendation to the farmers. [ABSTRACT FROM AUTHOR]