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Crossandra [Crossandra infundibuliformis (L.) Nees.] is an economically important ornamental flow... more Crossandra [Crossandra infundibuliformis (L.) Nees.] is an economically important ornamental flower plant and is commercially grown in about 719 ha in Andhra Pradesh with an annual production of 503 t. Out of this, majority of the area is in Chittoor and the casual organism was identified as Sclerotium rolfsii Sacc. and the disease was named as collar rot (Harinath Naidu, 2000). The symptoms observed were shrunken and brown coloured bark which first appear on the collar region later spreading to roots. When the bark was peeled off, the internal tissue revealed brown to black discolouration with rotten roots. Yellow to pink discolouration followed by shedding of leaves was observed leading to drying of plants.
International Journal of Applied Biology and P, 2011
Crossandra is an important flower plant of our country earning a lot of revenue and trade. Of dif... more Crossandra is an important flower plant of our country earning a lot of revenue and trade. Of different diseases affecting crossandra cultivation, collar rot induced by Sclerotium rolfsii Sacc. is an important soil borne disease causing devastating losses. In the present study, the sensitivity of the collar rot pathogen was investigated. Also the compatibility of fungal biocontrol agent, Trichoderma spp. with these fungicides was worked out to for further devising Integrated Management strategies for collar rot disease. Four fungicides, viz., captan 50% WP, propiconazole 25% EC, thiophanate-methyl 70% WP and thiram 75% SD were evaluated at five different concentrations against collar rot pathogen, S. rolfsii. Further, the compatibility of these fungicides and the antagonist Trichoderma isolate-1 (T 1 ). Results indicated that the fungicides, propiconazole, thiram and captan have significantly reduced the mycelial growth of test pathogen over control. Maximum inhibition was with prop...
Sclerotium rolfsii Sacc. is a major soil borne pathogen that causes stem rot of groundnut. Per ce... more Sclerotium rolfsii Sacc. is a major soil borne pathogen that causes stem rot of groundnut. Per cent incidence of stem rot will be influenced by soil health that include soil pH, electrical conductivity, organic carbon and which in turn influence soil microflora (fungi, actinomycetes and bacteria). Integrated Disease Management practices like combination of Indigenous Technology Knowledge inputs like Modified Panchagavya, Combination fungicide Hexaconazole 4%+Zineb 68% (Avtar), biocontrol agent Trichoderma asperellum GT4 and organic amendment (Neem cake) were combined in the form of 14 treatments including inoculated control and un-inoculated control. In the present investigation impact of these soil health aspects on disease incidence of stem rot of groundnut was studied. With the soil pH 7.4 (at 45 DAS) and 7.2 (at the time of harvest) per cent disease incidence of stem rot was least (9.08% and 14.13%) in treatment T12 that includes seed treatment with Hexaconazole 4%+Zineb 68%(Avt...
Current Biotica, 2011
Collar rot disease (Sclerotium rolfsii) is an economically important disease in Crossandra causin... more Collar rot disease (Sclerotium rolfsii) is an economically important disease in Crossandra causing significant yield losses. In the present study, certain fungal and bacterial antagonists were screened against the disease under greenhouse conditions. Pseudomonas spp and Trichoderma viride were isolated from crop rhizosphere, and elite strains were selected through in vitro antagonistic studies. These strains with compatibility to the fungicide, Thiram were further screened under greenhouse conditions. Seedlings of Crossandra were raised in GH and 35-days-old seedlings were transplanted into pots containing sterilized soil. The bacterial antagonists were applied as seedling root dip and to soil at 10 9 CFU/ml at the time of transplanting. The pathogen was added to soil in pots at the time of transplanting. These biocontrol agents were also applied in conjunction with Thiram to evaluate the combined efficacy against collar rot and in enhancing seedling growth and dry weights. Of different treatments evaluated, collar rot incidence was lowest in combined application of Thiram (as seedling root dip) and antagonist mixture (Pseudomonas sp + Trichoderma viride) as seedling root dip and soil application (6.7%), followed by application of antagonistic mixture as root dip and to soil (13.3%) as against inoculated control (73.7% disease incidence) with no significant differences. Seedling height was maximum in combined application of thiram and bioagent mixture (16.2 cm), followed by application of bioagent mixtures as root dip and to soil (11.9 cm). The shoot and root dry weights were also significantly enhanced with combined application of thiram and bioagent mixture. Overall, our results offer a scope for combined application of thiram and bioagents in managing collar rot disease of Crossandra under the conditions evaluated.
International Journal of Applied Biology and Pharmaceutical technology, 2011
Crossandra [Crossandra infundibuliformis (L.) Nees.] is an economically important ornamental flow... more Crossandra [Crossandra infundibuliformis (L.) Nees.] is an economically important ornamental flower plant and is commercially grown in about 719 ha in Andhra Pradesh with an annual production of 503 t. Out of this, majority of the area is in Chittoor and the casual organism was identified as Sclerotium rolfsii Sacc. and the disease was named as collar rot (Harinath Naidu, 2000). The symptoms observed were shrunken and brown coloured bark which first appear on the collar region later spreading to roots. When the bark was peeled off, the internal tissue revealed brown to black discolouration with rotten roots. Yellow to pink discolouration followed by shedding of leaves was observed leading to drying of plants.
International Journal of applied Biology and Pharmaceutical Technology, 2011
Crossandra is an important flower plant of our country earning a lot of revenue and trade. Of dif... more Crossandra is an important flower plant of our country earning a lot of revenue and trade. Of different diseases affecting crossandra cultivation, collar rot induced by Sclerotium rolfsii Sacc. is an important soil borne disease causing devastating losses. In the present study, the sensitivity of the collar rot pathogen was investigated. Also the compatibility of fungal biocontrol agent, Trichoderma spp. with these fungicides was worked out to for further devising Integrated Management strategies for collar rot disease. Four fungicides, viz., captan 50% WP, propiconazole 25% EC, thiophanate-methyl 70% WP and thiram 75% SD were evaluated at five different concentrations against collar rot pathogen, S. rolfsii. Further, the compatibility of these fungicides and the antagonist Trichoderma isolate-1 (T1). Results indicated that the fungicides, propiconazole, thiram and captan have significantly reduced the mycelial growth of test pathogen over control. Maximum inhibition was with propiconazole (100%), followed by thiram (81%) and captan (78%). Results on compatibility of Trichoderma spp. with these fungicides revealed that the bioagent was highly compatible with thiram (32% growth inhibition), followed by captan (47.5%). However, the Trichoderma isolate is not compatible with thiophanate methyl (88% growth inhibition) and propiconazole (100% growth inhibition). The Trichoderma isolate-1 (T1) and the fungicide, thiram were selected for further studies to devise integrated management strategies against collar rot disease.
The Andhra Agricultural Journal, 2013
In the present study, we have isolated nine fungi and three bacteria from the rhizosphere of Cros... more In the present study, we have isolated nine fungi and three bacteria from the rhizosphere of Crossandra by serial dilution method. Of various mycoflora, Trichoderma viride (T 1), Trichoderma spp (T 2 , T 3 and T 4), Penicillium spp, Rhizopus spp, Aspergillus flavus and A. niger and three rhizobacterial isolates including Pseudomonas spp were obtained. In dual culture studies, Trichoderma viride (T 1) was highly effective in inhibiting mycelial growth of Sclerotium rolfsii. upto 70% and sclerotial production by 91% followed by Trichoderma species (T 2). Pseudomonas spp was also effective among rhizobacterial isolates with mycelial and sclerotial inhibition upto 43.1% and 71% respectively.
Crossandra [Crossandra infundibuliformis (L.) Nees.] is an economically important ornamental flow... more Crossandra [Crossandra infundibuliformis (L.) Nees.] is an economically important ornamental flower plant and is commercially grown in about 719 ha in Andhra Pradesh with an annual production of 503 t. Out of this, majority of the area is in Chittoor and the casual organism was identified as Sclerotium rolfsii Sacc. and the disease was named as collar rot (Harinath Naidu, 2000). The symptoms observed were shrunken and brown coloured bark which first appear on the collar region later spreading to roots. When the bark was peeled off, the internal tissue revealed brown to black discolouration with rotten roots. Yellow to pink discolouration followed by shedding of leaves was observed leading to drying of plants.
International Journal of Applied Biology and P, 2011
Crossandra is an important flower plant of our country earning a lot of revenue and trade. Of dif... more Crossandra is an important flower plant of our country earning a lot of revenue and trade. Of different diseases affecting crossandra cultivation, collar rot induced by Sclerotium rolfsii Sacc. is an important soil borne disease causing devastating losses. In the present study, the sensitivity of the collar rot pathogen was investigated. Also the compatibility of fungal biocontrol agent, Trichoderma spp. with these fungicides was worked out to for further devising Integrated Management strategies for collar rot disease. Four fungicides, viz., captan 50% WP, propiconazole 25% EC, thiophanate-methyl 70% WP and thiram 75% SD were evaluated at five different concentrations against collar rot pathogen, S. rolfsii. Further, the compatibility of these fungicides and the antagonist Trichoderma isolate-1 (T 1 ). Results indicated that the fungicides, propiconazole, thiram and captan have significantly reduced the mycelial growth of test pathogen over control. Maximum inhibition was with prop...
Sclerotium rolfsii Sacc. is a major soil borne pathogen that causes stem rot of groundnut. Per ce... more Sclerotium rolfsii Sacc. is a major soil borne pathogen that causes stem rot of groundnut. Per cent incidence of stem rot will be influenced by soil health that include soil pH, electrical conductivity, organic carbon and which in turn influence soil microflora (fungi, actinomycetes and bacteria). Integrated Disease Management practices like combination of Indigenous Technology Knowledge inputs like Modified Panchagavya, Combination fungicide Hexaconazole 4%+Zineb 68% (Avtar), biocontrol agent Trichoderma asperellum GT4 and organic amendment (Neem cake) were combined in the form of 14 treatments including inoculated control and un-inoculated control. In the present investigation impact of these soil health aspects on disease incidence of stem rot of groundnut was studied. With the soil pH 7.4 (at 45 DAS) and 7.2 (at the time of harvest) per cent disease incidence of stem rot was least (9.08% and 14.13%) in treatment T12 that includes seed treatment with Hexaconazole 4%+Zineb 68%(Avt...
Current Biotica, 2011
Collar rot disease (Sclerotium rolfsii) is an economically important disease in Crossandra causin... more Collar rot disease (Sclerotium rolfsii) is an economically important disease in Crossandra causing significant yield losses. In the present study, certain fungal and bacterial antagonists were screened against the disease under greenhouse conditions. Pseudomonas spp and Trichoderma viride were isolated from crop rhizosphere, and elite strains were selected through in vitro antagonistic studies. These strains with compatibility to the fungicide, Thiram were further screened under greenhouse conditions. Seedlings of Crossandra were raised in GH and 35-days-old seedlings were transplanted into pots containing sterilized soil. The bacterial antagonists were applied as seedling root dip and to soil at 10 9 CFU/ml at the time of transplanting. The pathogen was added to soil in pots at the time of transplanting. These biocontrol agents were also applied in conjunction with Thiram to evaluate the combined efficacy against collar rot and in enhancing seedling growth and dry weights. Of different treatments evaluated, collar rot incidence was lowest in combined application of Thiram (as seedling root dip) and antagonist mixture (Pseudomonas sp + Trichoderma viride) as seedling root dip and soil application (6.7%), followed by application of antagonistic mixture as root dip and to soil (13.3%) as against inoculated control (73.7% disease incidence) with no significant differences. Seedling height was maximum in combined application of thiram and bioagent mixture (16.2 cm), followed by application of bioagent mixtures as root dip and to soil (11.9 cm). The shoot and root dry weights were also significantly enhanced with combined application of thiram and bioagent mixture. Overall, our results offer a scope for combined application of thiram and bioagents in managing collar rot disease of Crossandra under the conditions evaluated.
International Journal of Applied Biology and Pharmaceutical technology, 2011
Crossandra [Crossandra infundibuliformis (L.) Nees.] is an economically important ornamental flow... more Crossandra [Crossandra infundibuliformis (L.) Nees.] is an economically important ornamental flower plant and is commercially grown in about 719 ha in Andhra Pradesh with an annual production of 503 t. Out of this, majority of the area is in Chittoor and the casual organism was identified as Sclerotium rolfsii Sacc. and the disease was named as collar rot (Harinath Naidu, 2000). The symptoms observed were shrunken and brown coloured bark which first appear on the collar region later spreading to roots. When the bark was peeled off, the internal tissue revealed brown to black discolouration with rotten roots. Yellow to pink discolouration followed by shedding of leaves was observed leading to drying of plants.
International Journal of applied Biology and Pharmaceutical Technology, 2011
Crossandra is an important flower plant of our country earning a lot of revenue and trade. Of dif... more Crossandra is an important flower plant of our country earning a lot of revenue and trade. Of different diseases affecting crossandra cultivation, collar rot induced by Sclerotium rolfsii Sacc. is an important soil borne disease causing devastating losses. In the present study, the sensitivity of the collar rot pathogen was investigated. Also the compatibility of fungal biocontrol agent, Trichoderma spp. with these fungicides was worked out to for further devising Integrated Management strategies for collar rot disease. Four fungicides, viz., captan 50% WP, propiconazole 25% EC, thiophanate-methyl 70% WP and thiram 75% SD were evaluated at five different concentrations against collar rot pathogen, S. rolfsii. Further, the compatibility of these fungicides and the antagonist Trichoderma isolate-1 (T1). Results indicated that the fungicides, propiconazole, thiram and captan have significantly reduced the mycelial growth of test pathogen over control. Maximum inhibition was with propiconazole (100%), followed by thiram (81%) and captan (78%). Results on compatibility of Trichoderma spp. with these fungicides revealed that the bioagent was highly compatible with thiram (32% growth inhibition), followed by captan (47.5%). However, the Trichoderma isolate is not compatible with thiophanate methyl (88% growth inhibition) and propiconazole (100% growth inhibition). The Trichoderma isolate-1 (T1) and the fungicide, thiram were selected for further studies to devise integrated management strategies against collar rot disease.
The Andhra Agricultural Journal, 2013
In the present study, we have isolated nine fungi and three bacteria from the rhizosphere of Cros... more In the present study, we have isolated nine fungi and three bacteria from the rhizosphere of Crossandra by serial dilution method. Of various mycoflora, Trichoderma viride (T 1), Trichoderma spp (T 2 , T 3 and T 4), Penicillium spp, Rhizopus spp, Aspergillus flavus and A. niger and three rhizobacterial isolates including Pseudomonas spp were obtained. In dual culture studies, Trichoderma viride (T 1) was highly effective in inhibiting mycelial growth of Sclerotium rolfsii. upto 70% and sclerotial production by 91% followed by Trichoderma species (T 2). Pseudomonas spp was also effective among rhizobacterial isolates with mycelial and sclerotial inhibition upto 43.1% and 71% respectively.