Browsing by Author "Peethambaran, C K"

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Distribution of species of phytophthora affecting coconut and pepper in Kerala
(Department of Plant Pathology, College of Agriculture, Vellayani, 1996) Veena, S S; Peethambaran, C K
The present investigation was undertaken to correctly identify the species of Phytophthora causing bud rot of coconut and foot rot of pepper in Kerala and to find out their comparative role in causing diseases on coconut and pepper. The study also aimed at isolation of viable antagonistic agents against the pathogen, so as to utilize them in future for biological control. The study was conducted during 1992-96 at College of Agriculture, Vellayani and Indian Institute of Spices Research, Kozhikode. Detailed symptomatology of both the diseases at different locations were studied. Periodic collections were made from diseased coconut and pepper from seven districts of Kerala. The morphological characters of the isolates were studied in detail. The length, breadth, L/B ratio, pedicel length and caducity of sporangia of coconut isolates were smaller than pepper isolates. The sporangial shapes differed considerably between and among the isolates. All the isolates except those collected from Kannur and Kasaragod districts (C7 - C16), produced abundant number of sporangia on carrot agar. Phytophthora are either heterothallic or homothallic. Generally P. palmivora and P. capsici are heterothallic. But ten coconut isolates obtained from Kannur and Kasaragodu districts produced abundant number of sexual structures on carrot agar, indicating their homothallic nature and this is the first report of homothallic Phytophthora causing bud rot of coconut in Kerala. All other 52 isolates were mated with known A1 and A2 mating type and all the coconut isolates produced oospores with A1 and all the pepper isolates produced oospores when mated with A2. Zoospore production was induced from sporangia using cold treatment. The number of zoospores in sporangia ranged from 6-15 in number. Chlamydlospore production was a rare phenomenon in pepper isolates while all the coconut isolates and five pepper isolates produced chlamydospores. All the isolates were inoculated into pepper seedlings, coconut leaves, tender coconut and coconut seedlings and the time required for infection, variation in symptom expression by different isolates etc. were studied. All the sixteen coconut isolates produced foot rot in pepper. Fourty six isolates of pepper produced lesions on coconut leaves and nut rot in tender coconut, while, only six isolates of pepper produced bud rot in coconut plants. The cross infectivity of pepper isolates needed further confirmation to prove the point beyond doubt. Eight cultivated plants, 9 ornamental plants and 12 weed plants were tested for the host range of coconut and pepper isolates. Many plants belonged to the above three groups took infection successfully. The microorganisms found associated with healthy and diseased pepper and coconut plantations and microorganisms from soils of pepper and coconut gardens of different parts of Kerala were isolated. Out of more than 200 microorganisms, only 28 fungi inhibited the growth of Phytophthora in vitro. On pepper plant, 12 isolates had inhibitory action. Three organisms, viz., Verticillium chlamydosporium, Aspergillus terreus and Chaetomium sp checked the pathogen completely even after seven days of spraying with the organisms.
Effect of solarization on damping off diseases of vegetables
(Department of Plant Pathology, College of Horticulture, Vellanikkara, 1992) Sainamol Kurian, P; Peethambaran, C K
Entry of Cercospora Fuligena into tomato leaves
(Kerala Agricultural University, 1976) Peethambaran, C K
Fruit rot of bitter gourd
(Kerala Agricultural University, 1980) Sukumara Varma, A; Abi Cheeran; Peethambaran, C K
Fungal flora of Kerala II
(Kerala Agricultural University, 1970) Peethambaran, C K; Wilson, K I
In vitro effects of certain herbicide formulations on Corticium Sasakii (Shirai) matsumoto
(Kerala Agricultural University, 1978) Varma, A S; Peethambaran, C K; Balakrishnan, S; Menon, M R
Influence of soil solarisation on soil ,icroflora plant growth and incidence of diseases
(Department of Plant Pathology, College of Agriculture, Vellayani, 1989) Chandran, C R; Peethambaran, C K
The influence of solarization on soil microflora, plant growth and incidence of disease was studied during 1985-87 at Madavoor on collar rot of cowpea caused by Rhizoctonia solani Kuhn. The effectiveness of solarization was tested in open and partially shaded conditions in coconut garden using 0.05mm transparent polythene sheets as the mulch. The atmospheric temperature during the period of solarization ranged from 28.50C to 34.20C. The increase in soil temperature, as a result of solarization was more in open field than in partial shade. The soil temperature variation in open nonsolarized treatments was 100C while it was 12.50C in solarized plots. Corresponding figures for partially shaded conditions were 5.50C and 70C respectively. Maximum soil temperature recorded at 15cm depth in open solarized soil was 42.50C. Based on the experimental data two statistical models (1) for predicting soil temperature under polythene mulch and (2) for predicting collar rot of cowpea were developed during the study. Soil solarization significantly reduced collar rot of cowpea. Least incidence of the disease (3.6%) was noticed in open nonirrigated solarized treatments while maximum incidence (24%) was recorded in shade irrigated control. The interaction effect of shade, solarization and irrigation was not significant. Solarization reduced the total fungal population in open conditions while the population of bacteria was not significantly changed. In the case of actinomycetes population, a slight increase was noticed in solarized plots. The nematode population was significantly reduced by solarization in open field. Eventhough solarization substantially reduced weed population in open, it was less effective under partially shaded conditions. Growth parameters like height and number of leaves per plant were not significantly influenced by solarization. But it improved the stand of the crop and yield. An yield increase ranging from 7.62 to 21.69 per cent was obtained in solarized plots over the control. Availability of nitrogen, phosphorus and organic carbon was improved by solarization while there was no change in the level of potassium, calcium, PH and electrical conductivity.
Jeevavalangal
(Kerala Agricultural University, 1993-11) Nair, S K; Peethambaran, C K
Laboratory evaluation of fungicides against Pestalotia palmarum cooke
(Kerala Agricultural University, 1970) Wison, K I; Peethambaran, C K
Microflora associated with earthworms and vermicompost
(Kerala Agricultural University, 1997) Nair, S K; Naseema, A; Meenakumari, K S; Prabhakumari, P; Peethambaran, C K
Studies on the phyllosticta leaf spot of ginger
(Department of Plant Pathology, College of Horticulture, Vellanikkara, 1981) Premanathan, T; Peethambaran, C K
Laboratory and field experiments of “The studies on the Phyllosticta leaf spot of ginger” were conducted at the College of Horticulture Campus, Vellanikkara during 1979-1981. The first visible symptom of the disease was observed as chlorotic specks. Fructification was more during the later stages of crop growth. The detailed study on the plant and environmental factors influencing the disease development in the field revealed that the average number of leaves per plant has a significant positive correlation with the disease intensity. Koch’s postulate and morphological studies proved that the pathogen causing the disease is Phyllosticta zingiberi Ramakr. Uninjured leaves and first three leaves, even after injury, failed to exhibit the symptoms on inoculation. Conidia germinated by putting forth single or double germtubes. Sucrose solution (1,000 ppm) supported faster and maximum spore germination and the bipolar germination noted was maximum in this solution. The fungus entered the leaf by direct penetration of epidermal cells without appressoria formation. The pycnidiospores and mycelia of the pathogen were found to survive even after seven months in soil under different depths and moisture conditions. The type Maran was found to be the least susceptible followed by Karakkal and Bajpai, whereas type Vengara was the most susceptible one. Out of the 12 fungicides tried, one per cent Bordeaux mixture and 2,000 ppm Bayer 5072 gave cent per cent inhibition of the fungal growth in both solid and liquid media. Antracol 2,000 ppm and panolil above 500 ppm in solid medium; bavistin 2,000 ppm and cuman above 500 ppm in liquid medium gave cent per cent inhibition of fungal growth. In the field trial cuman, was found to be the most effective fungicide in controlling the disease, followed by Bordeaux mixture and panolil. Maximum rhizome yield was noticed in cuman treated plots followed by Bordeaux mixture.