Nandini Chowdary | Dr. YS Parmae university of Horticulture & Foorestry, nauni, Solan, HP, India (original) (raw)

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Papers by Nandini Chowdary

Journal of Pharmacognosy and Phytochemistry, 2018

An experiment was conducted to study the compatibility of fungicides with bacterial and fungal bi... more An experiment was conducted to study the compatibility of fungicides with bacterial and fungal biocontrol agents under in vitro conditions with seven fungicides commonly used in management of turmeric diseases by poisoned food technique for fungi, inhibition zone technique for bacteria. Each fungicide was tested at three concentrations viz., 0.05%, 0.1% and 0.2%. The results of the study proved that, bordeaux mixture and carbendazim (12%) + mancozeb (64%) were incompatible and showed cent percent inhibition on the growth of the fungal antagonist. Cymoxanil (8%) + mancozeb (64%) at 0.1 per cent concentration recorded lowest inhibition of 13.58 per cent on the growth of the fungal bioagent. Mancozeb (4%) + metalaxyl-M (64%), carbendazim (12%) + mancozeb (64%), Cymoxanil (8%) + mancozeb (64%), mancozeb, lower concentration of fenamidone (10%) + mancozeb (50%) were compatible with bacterial antagonist. The other fungicides recorded the inhibition in the growth of the bacterial antagonist in the range of 9.5 to 21.35 per cent. Among copper fungicides, bordeaux mixture was more inhibitory than copper oxychloride (50%) with bacterial antagonist.

International Journal of Pure & Applied Bioscience, 2018

Journal of Pharmacognosy and Phytochemistry, 2018

Turmeric (Curcuma longa L), "the golden spice of life" is one of most essential spice use as an i... more Turmeric (Curcuma longa L), "the golden spice of life" is one of most essential spice use as an important ingredient in culinary all over the world. Present investigation was done to understand the biocontrol potential of various endophytic microbes associated with turmeric against the pathogen causing rhizome rot disease of turmeric (Pythium sp.). A total of 15 endophytic fungi isolated from different locations of Andhra Pradesh state were evaluated. It was observed that Tc ed f 1(Acremonium kilense) was found to exert maximum antagonism against the pathogen. It was also observed that Acremonium kilense is incompatible with fungicides like Bordeaux mixture, Mancozeb 75%WP, Cyamoxanil 8% + Mancozeb 64%WP and Bordeaux mixture and higher concentrations of Fenamidone 10% + Mancozeb 50% WG and insecticides like Dimethoate, Malathion and Thiomethoxam showed 100 per cent inhibition indicating its poor level of compatibility.

Endophytes are microorganism colonizing healthy plants tissue without causing any apparent sympto... more Endophytes are microorganism colonizing healthy plants tissue without causing any apparent symptoms and noticeable injury to the host. Both fungi and bacteria are the most common microbes existing as endophytes and are to be found in virtually every plant on earth. It is also suspected that other type of microorganism's viz. archaebacteria and mycoplasmas can undoubtedly exist in plants as endophytes, but no such evidence for them has yet been explored.

The exploitation of symbiotic feature of AM fungi is one of the efficient approaches to improve c... more The exploitation of symbiotic feature of AM fungi is one of the efficient approaches to improve crop tolerance to unfavored environment. Generally, vascular plants have been considered as autonomous organisms especially when their performance has been interpreted at the genomic and cellular level. But in reality, vascular plants provide a unique ecological niche for diverse communities of cryptic symbiotic microbes which often contribute multiple benefits, such as enhanced photosynthetic efficiency, nutrient and water use and tolerance to stress. In fact, AM fungi are probably the most ubiquitous soil microbe that can colonize 80% of terrestrial plant species consisted of many fruit crops. Many beneficial effects from mycorrhizal colonization including increased seedling survival, enhanced growth, fruit yield and quality, uniformity of fruit crops, and earlier and increased flowering as well as induced resistance to abiotic and biotic stresses.

Rhizome rot caused by Pythium aphanidematum is one of the major constraints for the cultivation o... more Rhizome rot caused by Pythium aphanidematum is one of the major constraints for the cultivation of turmeric in Andhra Pradesh and cent per cent crop loss has been estimated in susceptible varieties. Biocontrol using endophytic microorganisms is one of alternative control methods to support agriculture sustainability. The objective of these experiments are to isolate endophytes from rhizomes of healthy turmeric plants from 16 locations of Andhra Pradesh and to estimate their biocontrol potential against the rhizome rot pathogen. Among 154 endophytic isolates obtained, 12 out of 79 bacteria, 16 out of 68 fungi, and four out of seven actinomycetes were antagonistic to Pythium aphanidematum in vitro. Several bacterial isolates belonging to four bacterial genera viz., Bacillus, Pseudomonas, Klebsiella and Citrobacter were obtained and identified using standard biochemical methods. Of the bacterial endophytes isolated in the study, only 50% of the isolates showed antagonistic activity against Pythium aphanidermatum, the pathogen causing rhizome rot disease in turmeric. Bacterial metabolites like siderophore, hydrogen cyanide, indole acetic acid and salicylic acid in the culture media were studied. The result showed that comparatively the maximum quantity of siderophore (53.6%), hydrogen cyanide (45%), and salicylic acid (48.7%) was produced by Pseudomonas and indole acetic acid (48.2%) by Bacillus. Among the isolated endophytes, Pseudomonas was found to exhibit superior antagonistic activity against the test pathogen. Introduction Turmeric (Curcuma longa L.) is a golden spice crop being cultivated in India since ancient times for its rhizomes, and has a potential to earn foreign exchange because of its wide utilization in Ayurvedic industry. Though it is well known for its medicinal value, its cultivation is hindered by several diseases. Turmeric is susceptible to diseases viz. leaf blight, anthracnose and rhizome rot. Among the various diseases, rhizome rot caused by Pythium sp. is a major constraint in all turmeric growing areas of India (Rathiah, 1987; Nageshwar Rao, 1994; Ramarethinam and Rajagopal, 1999) [17, 12, 15]. It causes severe yield reduction and reduces the quality of rhizome (Rathiah, 1982) [16]. Rhizome rot resulted in yield loss of 50% in the Erode district of Tamil Nadu. Biocontrol of plant pathogen is becoming an important component of integrated disease management. In view of the hazardous impact of pesticides and other agrochemicals on the ecosystem, biocontrol of plant diseases as an alternate strategy has received increasing attention in recent years. Therefore, the focus on the management of plant diseases has been shifted from chemical pesticides to more ecofriendly biopesticides to reduce environmental hazards and minimize the risk of development of pesticide resistant strains of plant pathogens. A novel method of biological control using endophytes has entered the arena of disease management with attempts to make the plant, defend itself from the pathogens. The beneficial effects that the endophytes can confer on plants have made their role highly significant in biological control of diseases in various crops (Bargabus et al. 2004; Kloepper et al. 2004) [2]. Therefore, an attempt was made to study the efficacy of the endophytic microorganisms isolated from turmeric against rhizome rot disease.

The compatibility of bio-control agents Trichoderma viridae and Pseudomonas fluorescens was asses... more The compatibility of bio-control agents Trichoderma viridae and Pseudomonas fluorescens was assessed with commonly used chemical insecticides in turmeric viz., thiamethoxam 25% WG (Cruiser), chloropyrifos 20% EC (Dursban), dimethoate 30% EC (Rogor), malathion 50% EC (Malathion) and phosphamidon 40% SL (Demecron) each at three (0.05%, 0.1% and 0.2%) different concentrations. The compatibility tests revealed that the response of the Trichoderma viridae isolate to different insecticides differed significantly. Cent per cent inhibition was noticed at all three concentrations of phosphamidon (40%) (Demecron). The lowest inhibition on growth of antagonist was noticed with dimethoate (30% EC) (Rogar) at 0.05 per cent concentration (19.75%) followed by thiamethoxam (25%) (Cruiser) at 0.1% recorded lowest inhibition of 21.36 per cent which were statistically on par with each other on the growth of the bio-agent where as in others the reduction in growth was in range of 24.70 to 84.44 per cent over control. The response of isolate Pseudomonas fluorescens to different insecticides at three concentrations varied significantly. The data revealed that the antagonist was found compatible with thiamethoxam (25%) (Cruiser) and phosphamidon (40%) (Demecron) at all the three concentrations with zero per cent inhibition. The other insecticides like chlorpyriphos (20%) (Dursban), dimethoate (30%) (Rogar) and malathion (50%) at all three concentrations showed the inhibition on the growth of antagonist in the range of 7.77 and 24.44 per cent. Moreover, the pesticide tolerance ability broadened the use as these bio-pesticides in conjugation with pesticides can be applied under integrated disease management for the management of soil borne plant pathogens.

Journal of Pharmacognosy and Phytochemistry, 2018

International Journal of Pure & Applied Bioscience, 2018

Journal of Pharmacognosy and Phytochemistry, 2018