Thumbnail Image

Dr. Y. S. Parmar University of Horticulture & Forestry, Solan

Dr. Yashwant Singh Parmar University of Horticulture and Forestry, Solan, was established on 1st December, 1985 with the objective to promote education, research and extension education in the fields of Horticulture, Forestry and allied disciplines. Late Dr. Yashwant Singh Parmar, the first Chief Minister and the architect of Himachal Pradesh perceived the importance of Horticulture and Forestry to develop and improve the State economy which led to the establishment of this University. Its history lies in erstwhile Himachal Agricultural College, Solan, established in 1962 and affiliated to the Panjab University. It became one of the campuses of Agriculture Complex of Himachal Pradesh University on its formation in 1970. Consequent upon the establishment of Himachal Pradesh Krishi Vishvavidyalaya in 1978, this campus became its Horticulture Complex and finally in 1985, assumed the status of a State University, being the only University in the country engaged exclusively in teaching, research and extension in Horticulture and Forestry. The University is located at Nauni in Solan District of Himachal Pradesh, 13 km from Solan on Solan-Rajgarh Road, at an elevation of 1300 metres above mean sea level. Solan town is situated on national highway (NH-22) and is well connected by train and bus services. The University has four constituent colleges, out of which, two are located at the main campus Nauni, one for horticulture and the other for forestry, having 9 and 7 departments, respectively. The third College i.e., College of Horticulture & Forestry is located at Neri in Hamirpur District on Nadaun-Hamirpur state highway, about 6 Km from Hamirpur town and is well connected with bus service. The college offers three Undergraduate Degree Programmes i.e. BSc (Hons.) Horticulture, BSc (Hons.) Forestry and B. Tech. Biotechnology and MSc degree programme in a few subjects. The fourth college i.e. College of Horticulture and Forestry, Thunag (Mandi) is located at Thunag District Mandi. This college offer BSc (Hons.) Horticulture and BSc (Hons.) Forestry degree programme. In addition, there are five Regional Research Stations, 12 Satellite Stations and five Krishi Vigyan Kendras (KVKs) situated in different zones of the State.

Browse

2014 - 201922
Reset filters
Subject: Plant Pathology × End date: 2019 × Start date: 2012 × Type: Thesis × Thesis Type: Ph.D ×
Reset filters

Search Results

Now showing 1 - 9 of 22
  • Thumbnail Image
    ThesisItemOpen Access
    EPIDEMIOLOGY AND MANAGEMENT OF LATE BLIGHT OF TOMATO
    (UHF,NAUNI, 2019-04) KAUSHAL, SONIA; KANSAL, SANDEEP
    ABSTRACT Late blight caused by Phytophthora infestans (Mont.) de Bary has been recorded as one of the most destructive disease of tomato among various other diseases. It appeared in moderate to severe form in different tomato growing areas of Solan, Sirmaur, Shimla and Kullu districts of Himachal Pradesh. The different isolates of fungus collected from infected leaves and fruits of diseased plants revealed of white to creamish white, submerged to densely arial mycelium on OMA. Mycelium was coenocytic with sympodial branching of sporangiophores bearing ovoid to limoniformsporangia. The molecular identification revealed a PCR product of 900bp using ITS1 and ITS4 primers. Thus, based upon morphological, cultural characters and molecular characters the causative fungus was identified as Phytophthora infestans (Mont.) de Bary. The pathogenicity tests revealed peculiar symptoms on leaves as water soaked lesions which later enlarged rapidly and turned to black necrotic spots bearing mildew like downy growth covering most of leaf surface. Dark olivaceous greasy spots covering fruit surface were also observed. The variability study of different isolates of Phytophthora infestans (Mont.) de Bary collected from different tomato growing localities of H.P had manifested varied cultural, morphological, pathogenic and molecular characters. Epidemiological studies revealed that the temperature of 20ºC, relative humidity of 100%, leaf wetness period of 24 h and inoculum concentration of 5x104 sporangia/ml were optimum for the rapid progression of disease reflecting significant higher infection rate under artificial epiphytotic conditions. Under field conditions, disease was affected by variation in weather variables, as cool (16-20°C) and wet weather coupled with high relative humidity (>90%) favoured the progression of late blight disease. The screening of twenty seven genotypes using detach leaf and whole plant assay revealed Arka meghali, Solan Lalima, Him Sona, EC-526146 and BT-1012 as moderately susceptible against the disease. In vitro and in vivo evaluation of fungicides indicated Sectin 60 WG (fenamidone 10%+ mancozeb 50%) and Curzate M8 (cymoxanil8%+mancozeb64%)) as potent inhibitors of P.infestans while garlic and neem extracts were most promising amongst different botanicals. Trichoderma harzianum had proved the most efficacious antagonist. Field evaluation studies inferred the soil application of Trichoderma harzianum @ 2.5 Kg/50 FYM/ha in combination with six periodic spray of fungicides including fenamidone 10%+ mancozeb 50% @ 0.2% followed by copper oxychloride @ 0.3% and mancozeb @ 0.25% at ten days interval started with the initiation of disease to be most efficacious in limiting late blight of tomato and enhancing the fruit yield (532,75q/ha) with ICBR ratio of 1:16.50.
  • Thumbnail Image
    ThesisItemOpen Access
  • Thumbnail Image
    ThesisItemOpen Access
    VARIABILITY STUDIES IN BEAN RUST (Uromyces appendiculatus (Pers.) Unger) AND ITS ECOFRIENDLY MANAGEMENT
    (UHF,NAUNI, 2019-02) DEVI, BANITA; GUPTA, S K
    ABSTRACT Rust is an important disease of French bean particularly of pencil types in mid hills of Himachal Pradesh. The disease was found to occur in moderate to severe form in major French bean growing areas of Himachal Pradesh with severity ranged from 23.45 to 72.42 per cent. Present investigations were undertaken during 2016 and 2017 crop seasons with an objective to study the yield loss assessment, variability studies among U. appendiculatus isolates, identification of races and to develop suitable disease management strategies. Pathogenicity of the associated pathogen was proved on leaves and stems with 114 h and 212 h incubation period. Average green pod yield loss of 53.61 per cent was recorded in control plots. Present studies explicitly indicated that the pathogen overwinter as urediniospores upto one year under polyhouse conditions. French bean rust was not found seed transmissible. In all twenty samples were collected fromthe major French bean growing areas of Solan, Shimla, Kullu, Sirmour, Mandi and Kangra districts of Himachal Pradesh. All isolates produced obovoid, ellipsoid and globose shaped urediniospores which were light brown to reddish brown in colour with some variations in size. Pathogenic and molecular variability among all 20 collected isolates of U. appendiculatus was studied. According to new international classification system and binary nomenclature, these 20 U. appendiculatus isolates were grouped into 7 different races viz. 5-2, 37-2, 5-0, 39-0, 39-2, 37-0 and 15-2. Among thirty five different germplasm lines/cvs. screened against pathogen, both under natural epiphytotic and artificial inoculation conditions, twelve germplasm lines were found highly resistant. Thirteen germplasm lines viz. EC 500929, EC 500935, EC 500979, IC 328389, IC 341797, IC 341807, EC-385259, EC397824, EC-398527, EC-398586, EC-398591, EC-13099, EC-21754 were found highly resistant against all the 20 isolates of U. appendiculatus under artificial inoculation conditions. Under in vitro conditions cent per cent urediniospore germination inhibition was recorded in azoxystrobin, difenoconazole+azoxystrobin, pyraclostrobin+ metiram, kresoxim-methyl, fluopyram+tebuconazole, trifloxystrobin+tebuconazole, propiconazole+difenoconazole at 200 ppm concentration. Foliar sprays of azoxystrobin (0.1%) were found most effective both in reducing the rust severity (3.81%) and increasing the green pod yield (7.10 kg/plot) followed by azoxystrobin+difenconazole. Among different botanicals evaluated, Neemazal, nimbicidine, achook and A. sativum caused maximum urediniospore germination inhibition under in vitro conditions and also increasing the green pod yield. Minimum disease severity was recorded in plants sprayed with KH2PO4 both under in vitro and in vivo conditions. The application of IR chemicals triggered the activity of defense related enzymes (phenol, PO, PPO and PAL) in bean plants upon challenge inoculation with U. appendiculatus. In integrated disease management, treatment comprising of ST with azoxystrobin (0.1%), FS with the potassium dihydrogen phosphate (200mM) after 15-20 days of sowing, FS with azoxystrobin with the initiation of disease, alternate FS with Neemajal (2%) and azoxystrobin at 7 days interval was found most effective in reducing the rust severity (1.05%) and increasing the green pod yield (7.67 kg/plo
  • Thumbnail Image
    ThesisItemOpen Access
    INTEGRATION OF SOIL SOLARIZATION AND BENEFICIAL SOIL MICROFLORA FOR MANAGEMENT OF RHIZOCTONIA STEM ROT OF CHRYSANTHEMUM
    (UHF, NAUNI, 2018-11) TYAGI, ANKUR; GAUTAM, H R
    ABSTRACT The present investigation entitled “Integration of soil solarization and beneficial soil microflora for management of Rhizoctonia stem rot of chrysanthemum” was conducted in the laboratories and experimental farm of the Department of Plant Pathology. Among different bio-control agents evaluated under in vitro conditions against the Rhizoctonia stem rot pathogen, T. viride resulted in maximum mycelial growth inhibition (68.8 %) followed by T. harzianum (66.1 %) and T. hamatum with 58.4 per cent inhibition in mycelial growth of the stem rot pathogen, respectively. Among bacterial antagonists, P. fluorescens was found most effective resulting in 56.9 per cent mycelial inhibition followed by B. subtilis (53.5 %). Combination of Trichoderma viride with soil solarization was found most effective with no incidence of the disease and this treatment also reduced the viability of the sclerotia by 99.2 per cent. Combination of neem cake with soil solarization was found most effective with no incidence of the disease and this treatment also reduced the viability of the sclerotia by 93.7 per cent.Soil amendment ofresidues ofmustardcropbefore solarization was found most effective with no incidence of the disease and it also reduced the viability of the sclerotia 100 per cent. Soil solarization resulted increased average maximum soil temperature to 45.9and 44.9 °C, during the years 2016-2017 with an increase of 7.8 and 7.07°C at 5 cm soil depth over unsolarized pots. Treatment combination of soil solarization with green gram was found most effective with 85.6 per cent reduction in the stem rot incidence and also improved plant growth and quality parametersof the flowers. Soil solarization increased the average maximum soil temperature to 41.4, 40.7 and 40.3°C, during the years 2013, 2015 and 2016 with an increase of 7.2, 7.5 and 6.0°C at 5 cm soil depth over unsolarized plots. Soil solarization of the sclerotia of Rhizoctonia stem rot pathogen with transparent polyethylene sheet at 5 cm soil depth for 40 days reduced the viability of sclerotia by 88. 7 per cent. Treatment combination of green gram in the year 2016-2017 with soil solarization was found most effective with 62.5 per cent increasein the spore countof AM fungi with root colonization of 60 per cent. Soil solarization of thesclerotia of the stem rot pathogen with transparent polyethylene sheet at 5 cm soil depth for 40 days increased the incubation period of the disease by 21.2 per cent.Eight native species of AM fungi related to four genera viz., Glomus, Acaulospora, Gigaspora, Scutellospora sp. were isolated from the rhizosphere soil of the chrysanthemum field. Treatment combination of soil solarization with Trichoderma viride formulation and growing of green gram crop was found most effective in all the trials in the years 2013, 2015 and 2016 with 81.7, 85.1 and 85.8 per cent reduction in the stem rot incidence. Treatment combination of soil solarization followed by growing of green gram crop and application of Trichoderma viride formulation improved plant height by 36.3 to 41.7 per cent, increased flower size by 31.8 to 37.8 per cent, increased number of flowers by 27.9 to 38.3 per cent and reduced the time taken to first flowering from 4.0 to 6.0 days in comparison to unsolarized control in different years. Treatment combination of Trichoderma viride formulation and green gram in solarized soil was found most effective in 2013, 2015 and 2016 with an increase of 75, 66.6 and 63.1 per cent inspore population ofAM fungi and 72.1, 72.8 and 72.6 per cent higher root colonization.
  • Thumbnail Image
    ThesisItemOpen Access
    STUDIES ON ALTERNARIA BLOTCH OF APPLE AND ITS MANAGEMENT
    (UHF, NAUNI, 2018-10) CHAUHAN, PRANEET; GUPTA, A K
    ABSTRACT Alternaria blotch caused by Alternaria alternata f. sp. mali is one of the economically important disease of apple particularly in Himachal Pradesh. Therefore, the present investigations were undertaken with the objectives to record the prevalence of this disease; study the variability of causal agent Alternaria isolates and evolve effective disease management strategy through the use of fungicides, plant extracts, bioproducts, biocontrol agents and their combinations as well as host resistance during the year 2015-2017. Alternaria blotch of apple was found to occur in moderate to severe form in different apple growing areas of district Shimla of Himachal Pradesh. The mean disease incidence ranged from 11.00 to 50.00 per cent with maximum at Summerkot and minimum at Khadrala of district Shimla, while highest disease severity was recorded at Chaithla and lowest at Khadrala in the same district with an average of 6.20-27.57 per cent. Pathogenicity test revealed that symptoms appeared after 4 to 7 days of inoculation. Eleven isolates of Alternaria spp. were isolated from apple cv. Royal Delicious and fiveisolates were isolated from tomato, cabbage, marigold, carnation and pear. These isolates differed in their ability to produce typical symptoms. Morphological, cultural and molecular studies were made to ascertain the prevalence of variability among the isolates. Colonies varied in their cultural behaviour ranging from velvetty to cottony, mostly appressed, with regular to irregular margins. Colour of the colonies varied from light to dark olivaceous. The mean ,of the isolates was between 32.90 to 66.92 mm after 8 days of inoculation with highest growth in Isolate 1 on potato dextrose agar medium and lowest in Isolate 8 on Dimmick’s agar medium. Morphological studies revealed variations in their size, shape and septations of conidiophore and conidia. Maximum conidial size was 19.38-38.8× 9.90-20.7 μm and minimum was 9.9-23.8× 5.3-13.6 μm in Isolate 10 and Isolate 9, respectively. Isolates when tested for their pathogenic behaviour showed variation in incubation period, latent period and disease reaction. A positive reaction was observed on the susceptible apple cv. Royal Delicious during the leaf necrosis bioassay, demonstrating the host specific nature of the toxin. Molecular characterization of the seven isolates of Alternaria spp. showed 99-100% homology with Alternaria alternata, Alternaria mali and Alternaria spp. Phylogenetic tree depicted that all the isolates were closely clustered to Chinese isolates deposited earlier in the NCBI. The sixteen isolates of the Alternaria spp. were differentiated on the basis of location, host, cultural and morphological characteristics using RAPD markers. Leaves collected during autumn produced the maximum inoculum in the month of August i.e. 3.7 ×103conidia/ml whereas, the production of primary inoculum was least (1.8×103 conidia/ml) on the leaves during April. Alternaria alternata f.sp. mali infection on host physiology revealed that reducing and non reducing content were more in uninoculated plants in all the test cultivars with time lapse. Total phenolics content, polyphenol oxidase, peroxidase, PAL activity and ROS were more in inoculated plant during all the sampling hours in all the three test cultivars. Screening of cultivars revealed that only one cultivar Top Red Delicious showed highly susceptible reaction and Starking Delicious showed susceptible reaction. Six cultivars viz., Manchurian Crab, Tydeman’s Early Worcestor, Hardeman, Stark Spur Golden, Gold Spur and Scarlet Gala were found to be moderately susceptible at RHR&TS Mashobra while, two cultivars viz., Royal Delicious and Vance Delicious showed susceptible reaction at Nauni. Out of ten systemic and non-systemic fungicides evaluated under in vitro conditions, two fungicides viz., difenoconazole and propineb exhibited complete mycelial growth inhibition against the test pathogen. Amongst eight plant extracts tested under in vitro conditions, leaf extract of neem was found to be most effective with 72.89 per cent mycelial growth inhibition, while in case of bioproducts tested, Neemazal, cow urine and field formulation gave cent per cent mycelial growth inhibition. Under pot conditions, difenoconazole + propineb gave good disease control as compared to all other combinations. Among SAR chemicals tested, BABA @2000 ppm found to be the most effective in all the cultivars, with minimum disease severity rangingfrom 5.24-7.15per cent and maximum disease control rangingfrom 69.71-75.85per cent. In case ofSAR chemicaltreatments, there was an increasein reducing sugar and non reducing sugar over the untreated controlin all three cvs. of apple with maximum in salicylic acid and minmum in calcium carbonate treated leaves, respectively. Total phenol content in apple leaves after treatment with SAR inducers was found to be maximum in salicyclic acid treated leaves and minimum in calcium carbonate. Polyphenol oxidase, Peroxidase and PAL activity was found to be highest in salicyclic acid treated leaves in all the three cultivars. Production of Reactive oxygen species was found to highest in salicyclic acid treated leaves in all the three cvs. Among biocontrol agents, Pseudomonas flourescens @105cfu/ml found to be best in all the cvs. tested with minimum disease severity ranging from 1.90-13.33 per cent and maximum disease control ranging from 63.79-89.01 per cent. Maximum suppression of the primary inoculum was observed when the leaf litter was dipped in urea (50000 ppm) followed by difenoconazole (1000 ppm) and hexaconazole (1000 ppm). Under field conditions, the combination of difenoconazole and propineb was most effective(95.30%)in disease control, whileBacillus subtilis was found least effective (58.66%).
  • Thumbnail Image
    ThesisItemOpen Access
    POTENTIAL OF PLANT EXTRACT BASED SILVER NANOPARTICLES FOR THE MANAGEMENT OF GREEN MOULD (Penicillium digitatum) OF CITRUS
    (UHF,NAUNI, 2018-06-26) SHARMA, KISHOR; GAUTAM, H.R.
    ABSTRACT The present investigation titled “Potential of plant extract based silver nanoparticles for the management of green mould (Penicillium digitatum) of citrus” was conducted in the laboratories of the Department of Plant Pathology, experimental orchards of Dr. YSP, University of Horticulture and Forestry (RHR&TS) at Jachh. During the survey of the disease, incidence of green mould rot ranged between 16.5 to 27.0 per cent recorded. Average severity of disease was recorded maximum in Paonta Sahib (21.33%). Silver nanoparticles were synthesized from tulsi and neem leaf extract. Reduction of silver nanoparticles during exposure to plant extract was observed as result of colour change from light brown then to dark reddish brown. In case of O. americanum origin SNPs, absolute absorption peak was obtained at 448 nm which confirmed the reduction of AgNO3 in to silver nanoparticles. In case of SNPs synthesized from neem, the band concentrated around 442 nm. SNPs synthesized from tulsi were spherical to irregular in shape and size distribution in case of tulsi ranged between 100-250 nm and neem were also spherical to irregular in shape and size distribution ranged between 150-500 nm. Atomic force microscope image of tulsi SNPs indicated the height of sub-microscopic spherical to irregular shape silver nanoparticles ranging from 300 nm to 500 nm and 150-250 nm in case of neem SNPs. In Transmission electron microscopy (TEM) studies, the size of the SNPs of tulsi ranged between 22.8 to 70.0 nm. While, in case of neem, the size of the SNPs ranged between 26.5 nm to 85.0 nm. Aqueous leaf extract of Ocimum americanum was found most effective and significantly superior amongst all the treatments with 58.6 per cent average mycelial growth inhibition. SNPs of O. americanum origin silver nanoparticles proved most effective followed by A. indica origin SNP’s with 80.7 and 77.4 per cent mycelial growth inhibition at 1000 ppm concentration. Among sixteen treatments, treatment comprising of water extract of tulsi SNPs (1000 ppm) + water extract (10%) of tulsi was found most effective with no incidence of green mould rot, restriction in lesion size (98.85%), effective in retaining minimum fruit TSS (12.68oBrix), maximum titratable acidity (1.01%) and Minimum physiological loss in weight (2.94%) after 30 days of storage. Foliar sprays of treatment comprising of tulsi SNPs (1000 ppm) and water extract (10%) of tulsi and treatment comprising of neem SNPs (1000 ppm) and water extract (10%) of neem were found at par with the treatment where fruits were treated with fungicide (Score) with no incidence of green and blue mould on the fruits after 30 days of storage.
  • Thumbnail Image
    ThesisItemOpen Access
    ROLE OF ABIOTIC ENVIRONMENTAL FACTORS IN THE DEVELOPMENT OF FRENCH BEAN RUST AND ITS MANAGEMENT
    (UHF,NAUNI, 2018-05-19) SINGH, GURVINDER; GUPTA, S.K.
    ABSTRACT Rust is an important disease of French bean particularly of pencil types in mid hills of Himachal Pradesh. Present investigations were undertaken during 2015 and 2016 crop seasons with an objective to study the occurrence of the disease, role of abiotic environmental factors in disease development and to devise suitable disease management strategies. The disease was found to occur in moderate to severe form in major French bean growing areas of Himachal Pradesh. The samples collected from different locations were found infected with urediniospores. On the basis of morphological characters like shape, size, colour and echinulation of the urediniospores and molecular characterization the associated fungus was identified as Uromyces appendiculatus (Pers.) Unger). Pathogenicity of the associated pathogen was proved with 7 days incubation period. Among different substrates evaluated, sucrose was observed to be the best substrate with maximum (62.63%) urediniospore germination and germtube elongations (168.80 μm). Temperatures of 20°C and pH 7.0 were observed to be best for the germination and germ tube elongation of urediniospores. Moderate temperature (20ºC) and high humidity (>85%) were found to be most congenial factors for disease development, whereas high rainfall was deleterious to the disease development. Diurnal periodicity of spore release indicated that release of urediniospores was continuous throughout the day and night but 72.46 per cent of the total daily spore load was recorded in between 08:00 and 16:00 h. Among sixty six different germplasm lines/cvs./local selections screened against pathogen, thirty one genotypes were found to be highly resistant under natural epiphytotic and artificial inoculation conditions. Based on different components of slow rusting, five lines viz., EC-755318, EC-400442, EC-400406, EC-400390 and EC-405210 were recorded as slow rusters. Minimum rust severity and maximum green pod yield was recorded in 45×15 cm spacing as compared to other plant spacings. Under in vitro conditions mancozeb was found to be the best fungicide followed by chlorothalonil and tebuconazole + trifloxystrobin. Foliar sprays of azoxystrobin (0.1%) were found most effective both in reducing the rust severity and increasing the green pod yield followed by tebuconazole + trifloxystrobin and azoxystrobin + difenconazole. Azoxystrobin, EBIs and mancozeb exhibited good protective activity of 120 h, and 72 h, respectively, while only EBIs demonstrated excellent post infection (72 h) and pre symptoms activity. These fungicides also triggered the activity of defense related enzymes (PO, PPO and PAL) in bean plants upon challenge inoculation. Among different botanicals evaluated, Neemazal and A. stavium caused maximum urediniospore germination inhibition under in vitro conditions. In integrated disease management, 45×15 cm spacing + azoxystrobin was most effective in reducing the rust severity (4.39%) and increasing the green pod yield (9.46 kg/plot).
  • Thumbnail Image
    ThesisItemOpen Access
    STUDIES ON POST HARVEST DISEASES OF APPLE AND THEIR MANAGEMENT
    (UHF,NAUNI, 2018-03) NEELAM, KUMARI; SHARMA, J.N.
    ABSTRACT The present study was conducted to assess yearly losses due to biotic spoilage of apples and to develop methods of post harvest management of apple fungal decays including cultural, physical, biological and chemical ones; and their integration to evolve a workable, eco friendly control strategy to increase shelf life of apple fruits. In different fruit markets surveyed in Himachal Pradesh, total losses due to apple decay varied from 7.80 to 21.93 per cent. Fourteen different types of post harvest fungal pathogens were found associated with rotting of apple fruits in Himachal Pradesh. Blue mould rot due to P. expansum was found to be the foremost cause of post harvest rot of apple with a mean per cent incidence of 4.73 and 9.19 in Shimla and Solan districts, respectively. The susceptibility of Scarlet Spur was found to be highest followed by Golden Delicious with mean per cent rotting of 63.40 and 63.07 per cent, respectively. Tydeman’s Early Worcester was found to be most tolerant to all the rot causing fungi. Minimum fruit rotting of Starking Delicious apples was observed in fruits picked at 106 DAFB (12.81%) and also those picked during early morning hours (16.34%). Precooling treatment with HIWC (ice water and calcium chloride) for 30 min was found most effective with 82.26 per cent control of fungal decay. Treating apples in water at 48˚C for 3 min was highly effective in controlling various fungal rots under study with control of 70.79 per cent. UV exposure of 15 min was highly effective (65.04%) in controlling various fungal rots under study. Neem oil (1%) as skin coating provided complete control of all the fungal decays under study. The next effective skin coatings were eucalyptus, cinnamon and clove oil at 1 per cent concentration with 99.21, 98.70 and 97.93 per cent disease control, respectively. Impregnation of fruit trays with Botanical Formulation 2 (BF2) at 10 per cent concentration provided 97.67 per cent control of all the test fungi. Cow urine was most effective in providing 79.21 per cent growth inhibition of test fungi under study. Overall maximum growth inhibition of all the test fungi (71.97%) was recorded with T. hamatum followed by the yeast isolate (66.63%), B. subtilis (64.98%) and T. harzianum (62.43%). Sodium ortho-phenylphenate (SOPP) at 1 per cent concentration was most effective in checking the fungal decay under study. Under in vitro conditions, mancozeb (0.1%) was the most effective fungicide providing 84.83 per cent growth inhibition. The efficacy of mancozeb as dip treatment at 0.1 per cent concentration was again judged to be significantly superior followed by 0.05 per cent carbendazim with per cent control of 95.97 and 92.35 per cent. Preharvest spray of mancozeb (0.3%) was highly effective in checking all the test fungi under different type of storage for 6 months. 1-methyl cyclopropene (MCP) fumigation of apple fruits immediately after harvesting was most effective in checking the test fungi under study providing 89.60 per cent control. In integration experiment, minimum rot incidence and per cent fruit rotting were observed in fruits treated with combination T7 i.e. Mancozeb preharvest spray (0.3%) + HIWC + Bacillus subtilis + Neem oil (1%) + BF-2 impregnated trays followed by T6 and T8. CA storage was highly effective in checking fungal rotting of Starking Delicious apples followed by refrigerated storage and air-cooled storage. Among different treatments, maximum mean firmness (14.17 lbs/sq.inch), minimum TSS (9.24 ˚Brix), minimum total sugar content (7.66%), maximum total phenol content (694.59 mg/Kg) and maximum titratable acidity (0.26%) was recorded in fruits treated with combination T7. Minimum mancozeb residues (4.86 mg/Kg) were reported in fruits stored in ambient conditions of Shimla, followed by air-cooled storage (5.40 mg/Kg), CA storage (7.13 mg/Kg) and refrigerated storage (7.14 mg/Kg) after 45 days. Irrespective of different types of storage conditions, maximum residues (10.10 mg/Kg) were recovered on the initial day (0th day) of storage whereas, minimum (2.69 mg/Kg) at 45th day of storage with half life of 24 days.
  • Thumbnail Image
    ThesisItemOpen Access
    STUDIES ON MANAGEMENT OF ROSE POWDERY MILDEW (Podosphaera pannosa (Wallr.) de Bary)
    (UHF,NAUNI, 2017-11) VIJAY, KUMAR; CHANDEL, SUNITA
    ABSTRACT Rose powdery mildew caused by the Podosphaera pannosa (Wallr.) de Bary is one of the most serious and devastating diseases of roses grown worldwide including Himachal Pradesh in natural as well as protected cultivation. Rose powdery mildew was recorded to occur in moderate to severe form in different rose growing areas of districts Bilaspur, Kangra, Mandi, Sirmour, Shimla and Solan. The mean disease incidence and per cent disease index (PDI) varied between 48.50 to 66.75 and 22.22 to 36.02, respectively with highest incidence in district Solan and highest PDI at Shimla while lowest incidence and PDI in district Kangra. Pathogenicity test revealed that symptoms appeared after 161 hours of incubation. Different isolates of six districts were morphologically distinguished from one another with respect of the size of the mycelium, conidia and conidiophores which ranged between 4.0 to 4.8, 22.8 x 12.4 and 72.0 to 78.0 μm, respectively. Molecular characterization with RAPD markers revealed the similarity index among the ten fungal isolates ranged between 19 to 73 per cent with an average of 46 per cent. Maximum similarity about 73 per cent was found between isolate-5 and isolates-8. Least similar was isolate-7 which had 19 per cent similarity with other isolate as it belongs to wild roses. Association of Ampelomyces quisqualis with Podosphaera pannosa was observed in months of the September to November and in other hosts like Chotta dhatura (September to November), Zinnia and Dahlia (May to July) at Nauni. Maximum growth of mycelium was reported in malt extract agar medium. Fusarium sp., Botrytis sp., Cladosporium sp., Penicillium sp., Aspergillus sp., Alternaria sp., Trichothecium sp., Trichoderma sp. and two bacterial isolates (1 and 2) were isolated from the phylloplane of the rose leaves in summer and winter seasons in year 2015. The highest conidial inhibition of 21.88% was recorded from the culture filtrate of Trichoderma sp. among all the culture filtrates. The disease initially appeared in the second week of April with severity of 5.85 per cent and increased upto 48.35 per cent at mid of June month. Simple correlation was between per cent disease index, mean temperature (0.910), cumulative rainfall (-0.545), average relative humidity (0.616) and total sunshine hours (- 0.760). Partial correlation was between per cent disease index, mean temperature (0.475), cumulative rainfall (-0.872), average relative humidity (0.172) and total sunshine hours (-0.273) and reported to be positive and negative according to different environmental factors. Multiple correlation of determination indicated powdery mildew severity was dependent upon meteorological factors about 97.2 per cent for the disease development during 2015 and 2016. Germplasm screening of 50 rose cultivars were undertaken, none of cultivar was immune, 6 were resistant, 8 were moderately resistant, 24 were moderately susceptible, 12 were susceptible to powdery mildew in their reaction. Under in vitro evaluation among fungicides, bio-control agents, bio-products, botanicals, the best efficacy was obtained with difenoconazole, Bacillus subtilis, neem oil, and garlic (Allium sativus). Under greenhouse evaluation of fungicides, difenoconazole gave the highest efficacy against Podosphaera pannosa for two years 2015 and 2016 with 85.96 per cent disease control. Best efficacy of Ampelomyces quisqualis was observed among the bio-control agents application under greenhouse conditions with 78.51 per cent of disease control. Neem oil gave maximum per cent disease control of 76.18 per cent under greenhouse condition among all the bio-products. Among the botanicals, garlic (Allium sativus) gave the highest efficacy against powdery mildew of rose with 71.87 per cent disease control. Maximum anti-sporulant activity was obtained with difenoconazole, Ampelomyces quisqualis, neem oil and garlic among the fungicides, bio-control agents, bio-products and botanicals, respectively. Dipotassium orthophosphate have the highest efficacy against rose powdery mildew at both 0.05 and 0.075 per cent concentration. Dipotassium orthophosphate increased the content of the reducing (146.33 μg/g) and non-reducing sugar (39.28 μg/g), total phenol (137.67 μg/g), polyphenol oxidase activity (0.261), peroxidase activity (0.416) and PAL activity (0.586). In compatibility test, Ampelomyces quisqualis was not compatible while Bacillus subtilis was moderately to highly compatible with fungicides, bio-products, botanicals and SAR chemicals. From the integrated disease management trial highest disease control was obtained with two applications from treatments with dipotassium orthophosphate + Bacillus subtilis + neem oil (86.88%) and difenoconazole + Bacillus subtilis + neem oil (85.43%) in comparison to individual treatments where six sprays were applied.