Thumbnail Image

Thesis

Browse

20115
Reset filters
Subject: Plant Pathology × End date: 2011 × Start date: 2011 × Type: Thesis × Thesis Type: M.Sc ×
Reset filters

Search Results

Now showing 1 - 5 of 5
  • Thumbnail Image
    ThesisItemOpen Access
    VARIABILITY IN Albugo candida (Pers.) Kuntze CAUSING WHITE RUST OF RAPESEED-MUSTARD
    (PAU Ludhiana, 2011) Yash Pal; P. S., Sandhu
    ABSTRACT White rust caused by Albugo candida (Pers.) Kuntze is a serious threat to the production of oilseed Brassica crops in India and around the world. Variation occurs w.r.t. infection of the pathogen on different species of oilseed Brassicas which encouraged us to carry out the studies on “Variability in A. candida (Pers.) Kuntze causing white rust of rapeseed-mustard”. Survey was conducted in different locations (Bathinda, Mansa, Barnala, Faridkot, Muktsar, Sangrur, Ferozepur, and Ludhiana) of Punjab to estimate disease incidence and severity of the disease. The disease incidence and severity of white rust ranged from 44.39-59.36 and 21.92-27.83 per cent, respectively, in different locations of Punjab. A total of 52 isolates were collected from different locations and varieties. These isolates were classified into three groups (AC-I, AC-II and AC-III) on the basis of pustule size, pustule shape and germination of sporangia. Three representative isolates of each group were tested on twelve differential host cultivars (B. juncea, B. nigra, B. napus, B. carinata, B. oleracea, B. tournifortii, B. rapa var. Toria, B. rapa (Brown sarson), B. rapa (Yellow sarson), Raphanus sativus, Sinapis alba and Eruca sativa) of rapeseed and mustard. AC-III group has most virulent and AC-II group showed least virulence based on disease reaction, incubation period, latent period, pustule size, shape, number of pustules per leaf and number of sporangia per pustule. Further, within AC-III group, Ac6 isolate was observed as more virulent than other isolates of same group. Hence, it is concluded that morphological and pathological variation exists in A. candida population from Punjab.
  • Thumbnail Image
    ThesisItemOpen Access
    MANAGEMENT OF BOTRYTIS BLIGHT (Botrytis gladiolorum Timm.) IN GLADIOLUS THROUGH CULTURAL AND CHEMICAL MEANS
    (PAU Ludhiana, 2011) SATYA PRAKASH PANDEY; Premjit Singh
    The incidence and severity of Botrytis blight of gladiolus (Botrytis gladiolorum Timm.) and yield of the crop were the minimum in the early- and late-planted crop, as compared to the recommended planting date, i.e. 15th October. Closer spacing resulted in higher incidence and severity of the disease but the corm yield was recorded to be higher in the closer spacing as compared to the wider spacing. Plant spacing of 20x 20 cm was found to be suitable. Incidence and severity of the disease were also found to be high in the un-weeded control. Pre-emergence application of weedicide Stomp at 650 ml/ac, alone, and in combination with one manual weeding at six-leaf stage of the crop, recorded low incidence and severity of the disease and also registered high corm and cormel yields. Two manual weedings, at three- and six-leaf stages of the crop, respectively, also gave good results. Among the non-systemic fungicides, Dithane M-45 showed the best result under in vitro conditions as it completely inhibited spore germination of the pathogen at 100μg/ml, while Kavach and Antracol completely inhibited spore germination at higher concentrations of 500μg/ml. Among the systemic-fungicides, Stroby was the most effective fungicide, followed by Flint and Bavistin. Germ tube length of the fungus was found to be the minimum in Kavach and Dithane M-45. The fungicides Stroby and Flint were found to be the most effective fungicides against Botrytis blight of gladiolus under field conditions. The fungicides Kavach and Dithane-M-45 also showed very promising efficacy.
  • Thumbnail Image
    ThesisItemOpen Access
    EVALUATION OF Pseudomonas fluorescens AS BIOCONTROL AGENT TO CONTROL BACTERIAL BLIGHT IN BASMATI RICE
    (Punjab Agricultural University, Ludhiana, 2011) Anjali Thakur
    Bacterial blight caused by Xanthomonas oryzae pv. oryzae is one of the most devastating disease in south-east Asia including India. Fluorescent pseudomonads have been successfully employed in controlling major plant diseases due to their antimicrobial metabolites. The present study focuses on isolation, characterization, in-vitro, in-vivo evaluation and rhizosphere competence of Pseudomonas fluorescens. Isolations were done from the rice and wheat rhizosphere which were identified on the basis of cultural characters and molecular markers. It was found that the isolates showing fluorescent characteristics in the selective media showed the amplification of the targeted ITS region. In-vitro evaluation by dual culture method revealed that isolate Pf-4-R was inhibitory to the test pathogen showing maximum inhibition zone of 5.5 mm. The result was supported by the use of phl gene specific primers and HPTLC based method characterizing the production of antimicrobial compound DAPG. Isolate Pf-4-R was also found to have stimulatory effect on germination and radical elongation. Talc based powder formulation of the effective isolate Pf-4-R was prepared for further evaluation. Pot-house and field evaluation revealed that seed treatment and root dip and post-inoculation foliar spray significantly reduce the disease showing least disease index (25.6%) and maximum disease suppression efficiency (62.4%). Rhizosphere competence was studied by raising rifampicin (rif) resistant mutant, it was found that once introduced bioagent was able to establish in the root zone effectively and maintained its count for whole of the crop season. Shelf life of the formulation was studied at room temperature and low temperature, it was found that bacterium remained viable and at optimum number for 60 days in the formulated product and storage at low temperature was more effective as compare to room temperature.
  • Thumbnail Image
    ThesisItemOpen Access
    Variability and management of Alternaria brassicae (Berk.) Sacc. causing leaf blight of rapeseed and mustard.
    (Punjab Agricultural University, Ludhiana, 2011) Remander Singh
    Disease surveys revealed that disease incidence and disease severity of Alternaria leaf blight ranged from 10 to 80 per cent and 5 to 35 per cent respectively in different locations of Punjab. Based on type of symptoms, the disease samples were grouped into three categories for making isolations. In all, 25 isolates of A. brassicae were obtained. They were grouped into three groups (AB1, AB2 and AB3) based on their cultural and morphological characteristics. Representative isolates (Ab4, Ab7 and Ab14) of A. brassicae produced maximum growth and sporulation at temperature of 20±1°C on Mustard extract medium. Pathological behavior of representative isolates of A. brassicae (from each group) differed on twelve host cultivars of rapeseed and mustard. Ab5 isolate appeared to be most virulent and Ab4 isolate showed least virulence. Under in vitro conditions, Score proved most effective and completely checked the fungal growth at 10μg/ml followed by Folicur and Tilt. Indofil M-45, Antracol and Amistar were less effective. Differences in sensitivity of A. brassicae isolates were evident only at lower concentrations of Indofil M-45, Antracol and Amistar. However, they were masked at higher concentrations. Some isolates also exhibited differential sensitivity response to Score, Folicur and Tilt. In field conditions, Amistar @ 0.1 per cent proved most effective to control Alternaria leaf blight followed by Score, Folicur and Tilt each @0.1 per cent. Indofil M-45 and Antracol each @ 0.25 per cent proved less effective
  • Thumbnail Image
    ThesisItemOpen Access
    Variability and management of Alternaria brassicae (Berk.) Sacc. causing leaf blight of rapeseed and mustard.
    (Punjab Agricultural University, Ludhiana, 2011) Remander Singh
    Disease surveys revealed that disease incidence and disease severity of Alternaria leaf blight ranged from 10 to 80 per cent and 5 to 35 per cent respectively in different locations of Punjab. Based on type of symptoms, the disease samples were grouped into three categories for making isolations. In all, 25 isolates of A. brassicae were obtained. They were grouped into three groups (AB1, AB2 and AB3) based on their cultural and morphological characteristics. Representative isolates (Ab4, Ab7 and Ab14) of A. brassicae produced maximum growth and sporulation at temperature of 20±1°C on Mustard extract medium. Pathological behavior of representative isolates of A. brassicae (from each group) differed on twelve host cultivars of rapeseed and mustard. Ab5 isolate appeared to be most virulent and Ab4 isolate showed least virulence. Under in vitro conditions, Score proved most effective and completely checked the fungal growth at 10μg/ml followed by Folicur and Tilt. Indofil M-45, Antracol and Amistar were less effective. Differences in sensitivity of A. brassicae isolates were evident only at lower concentrations of Indofil M-45, Antracol and Amistar. However, they were masked at higher concentrations. Some isolates also exhibited differential sensitivity response to Score, Folicur and Tilt. In field conditions, Amistar @ 0.1 per cent proved most effective to control Alternaria leaf blight followed by Score, Folicur and Tilt each @0.1 per cent. Indofil M-45 and Antracol each @ 0.25 per cent proved less effective.