Pranab Dutta ¹

Affiliations
1 Krishi Vigyan Kendra, West Tripura, P. O. Chebri, Khowai, Tripura 799 207, IN

Abstract

Bacterial wilt of tomato caused by Ralstonia solanacearum is the dreaded diseases causing severe yield loss (25-75%) in farmers field. A field experiment at demonstration farm of KVK West Tripura was conducted for the evaluation different chemicals, botanicals and bioformulation against the disease. The study revealed that all the treatments were significantly effective over the control. However, soil drench with antibiotic @ 100 ppm was found best with lowest (23.6%) disease incidence and highest yield (228.2 q/ha). This was followed by copper oxychloride in terms of disease incidence (28.4%) and Biofor Pf in terms of yield (220.6 q/ha). Highest disease incidence (78.67%) with lowest yield(86.5 q/ha) was recorded in control plot.

Keywords

Bacterial Wilt, Management, Tomato.

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Pranab Dutta ¹

Affiliations
1 Department of Plant Pathology, Assam Agricultural University, Jorhat 785 013, Assam, IN

Abstract

Bacterial wilt of tomato caused by Ralstonia solanacearum is dreaded disease causing severe yield loss (25-75%) in farmer's field. A field experiment at demonstration farm of KVK West Tripura was conducted for evaluation of different chemicals, botanicals and bioformulation against the disease. The study revealed that all the treatments were significantly effective over the control. However, soil drench with antibiotic @ 100 ppm was found best with lowest (23.6%) disease incidence and highest yield (228.2 q/ha). This was followed by Copper Oxychloride in terms of disease incidence (28.4%) and Biofor Pf in terms of yield (220.6 q/ha). Highest disease incidence (78.67%) with lowest yield (86.5 q/ha) was recorded in control plot.

Keywords

Bacterial Wilt, Management, Tomato.

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Purnima Das ¹, L. K. Hazarika ¹, D. Bora ², K. C. Puzari ³, Pranab Dutta ³

Affiliations
1 Department of Entomology, Assam Agricultural University (AAU), Jorhat 785 013, Assam, IN
2 Department of Life Sciences, Dibrugarh University, Dibrugarh 786 004, Assam, IN
3 Department of Plant Pathology, AAU, Jorhat 785 013, Assam, IN

Abstract

Potato broth, rice gruel, coconut water, rice husk, sawdust and rice bran were evaluated for mass culturing of Beauveria bassiana (Bals.) Vuill (Strain AAU-09). Amongst the solid media rice husk in addition of 2% dextrose was superior to others in terms of spore production (6.25 x 10⁷ conidia/ml) and pathogenicity (86.67%) to Dicladispa armigera (Olivier) adults. Likewise, amongst the liquid media potato broth supplemented with synthetic chitin (2%), dextrose (2%) and peptone (2%) supported maximum spore production.

Keywords

Entomopathogenic Fungi, Beauveria bassiana, Mass Production, Pathogenicity, Spore Production.

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Pranab Dutta ¹, B. C. Das ¹, M. Islam ²

Affiliations
1 Department of Plant Pathology, Assam Agricultural University, Jorhat, 785013, Assam, IN
2 Department of Life Sciences, Dibrugarh University, Dibrugarh, 786001, Assam, IN

Abstract

Sclerotinia rot caused by Sclerotinia sclerotiorum is a serious menace to the cultivation of french bean (Phaseolus vulgaris L.) in Assam. In vitro efficacy of antagonist by dual culture method was tested against S. sclerotiorum. Out of all the antagonists Pseudomonas fluorescens was found best causing growth reduction of 64.93 per cent followed by Bacillus snbtilis (62.86 %) and Trichoderma harzianum (59.08 %). Study on the mode of parasitism showed that the fungal antagonist initially caused coining and then lysed the pathogen hyphae and the bacterial antagonist ceased pathogen growth after coming in contact with the pathogen. Effect of fungal antagonist T. harzianum and bacterial antagonist's B. subtilis and P. fluorescens as seed treatment against Sclerotinia rot was evaluated under field conditions. Seed treatment with T. harzianum was found has most effective in improving seed germination (18.43%), reducing 90.46% infection and increasing yield (69.51%) over control plot. Efficacy of B. subtilis and P. fluorescence as seed treatment against the disease was next to T. harzianum treatment respectively.

Keywords

Antagonist, Biological Control, French Bean, Seed Treatment, Sclerotinia Rot.

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K. C. Puzari ¹, L. K. Hazarika ², Pranab Dutta ¹, P. Das ¹

Affiliations
1 Mycology Research Section, Department of Plant Pathology, Assam Agricultural University, Jorhat, 785 013, Assam, IN
2 Department of Entomology, Assam Agricultural University, Jorhat, 785 013, Assam, IN

Abstract

In vitro inhibition of 13 different insecticides and one botanical on Beauveria bassiana growth was tested. Two doses of chemical insecticides, one at recommended dose (RD) and another at half of recommended dose (½. RD) and for botanicals three doses, first one at recommended and one at ½ and another at ½ of the recommended dose were tested. 100 per cent of mycelial growth was observed when the entomopathogen was grown in presence of monocrotophos (0.31%) and dichlorvos (0.12%). Cypermethrin, deltamethrin, alphamethrin and phosphamidon at recommended dose showed growth inhibition of < 50 per cent. Half of the recommended dose of deltamethrin was found having lowest inhibition (14.06 %).

Keywords

Beauveria bassiana, Dicladispa armigera, Inhibitory Effect, Insecticides, Rice Hispa.

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B. C. Das ¹, B. K. Das ¹, Pranab Dutta ¹, D. K. Sarmah ¹

Affiliations
1 Department of Plant Pathology, Assam Agricultural University, Jorhat, 785 013, Assam, IN

Abstract

In vitro osmoticant (manitol) amended and osmoticant free media of potato dextrose broth (PDB), modified Richard's broth (MRB) and Czapek dox broth (CDB) were tested for biomass production of Trichoderma harzianum Rifai. Osmoticant amended MRB was found best for production of maximum sporulation, cfu and dry weight of biomass of the antagonist, Osmoticant amended media produced higher biomass of T. harzianum than osmoticant free media. Growth and sporulation of T. harzianum was assessed in different carrier viz. starch, talc and molasses enriched charcoal powder (MECP) based formulation. Starch and MECP based formulation of T. harzianum showed increased trend in sporulation of the antagonist upto 60 days, but after this, viability of T. harzianum was abruptly decreased. Talc based formulation-exhibited gradual declining trend in multiplication and sporulation of T. harzianum after 30 days onwards. Among the nine formulation evaluated for growth and sporulation, starch based formulation alone performed best upto 60 days, followed by MECP based formulation. But after 60 days onwards, talc based formulation @ 3: 1 dose showed highest sporulation and maximum cfu, followed by starch formulation @ 1: 1 dose. The overall performance of talc-based formulation was better for growth and sporulation of the antagonist. Potentiality of T. harzianum as seed treatment with talc based T. harzianum and chemical were assessed field condition against Rhizoctonia solani causing stem rot disease of soybean. Lowest disease index and highest % seed germination was observed when seeds were treated with formulation of T. harzianum + talc + osmoticant formulation with enhanced plant vigour and yield of the crop.

Keywords

Biomass, Osmoticant, Rhizoctonia solani, Soybean, Stem Rot, Trichoderma harzianum.

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Sarodee Boruah ¹, Pranab Dutta ¹, Joyarani Pegu ¹, Himadri Kaushik ¹, N. Gogoi ², K. C. Puzari ¹, G. N. Hazarika ³

Affiliations
1 Department of Plant Pathology, Assam Agricultural University, Jorhat-785013, IN
2 Department of Environmental Science, Tezpur University, Assam, IN
3 Department of Plant Pathology, Assam Agricultural University, Jorhat-785013

Abstract

Morphological changes in Metarhizuim anisopliae (Metschnikoff) Sorokin infected cow pea aphid, Aphis craccivora Koch were studied by scanning electron microscope (SEM). Aphids were caged on paired lantern chimney over cowpea twigs dipped in conical flasks with water infected and inoculated with fungal propagules of M. anisopliae at the concentration of 1X10⁶ spores /ml of water. Infected aphids were observed under SEM and it showed severe cuticular damage, abnormalities in sensory systems as well as deformation of all the body parts. The hydrophobic conidia of M. anisopliae were found to attach to all body regions. It was evident that mycelial growth and conidiophores with conidia of M. anisopliae covered the body surface and penetrates inside the body of infested aphid causing damage to the pest by disturbing its major physiological activities leading to its death.

Keywords

Aphis craccivora, Metarhizuim anisopliae, Scanning Electron Microscope.

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