Browsing by Author "Srinivasan, N."

Now showing 1 - 20 of 54
  • Thumbnail Image
    Item
  • Thumbnail Image
    Item
  • Thumbnail Image
    Item
    An appraisal of symptom expression in coconut due to leaf rot disease
    (2007-02-08) Srinivasan, N.; Gunasekaran, M.
  • Thumbnail Image
    Item
    Appraisal of the distribution of coconut root wilt and heavy incidence of the disease in Cumbum Valley of Tamil Nadu
    (2007-02-08) Srinivasan, N.; Koshy, P.K.; Kamalakshi Amma, P.G.; Sasikala, M.; Gunasekaran, M.; Solomon, J.J.
  • Thumbnail Image
    Item
    Biocontrol agents against pathogens of coconut leaf rot disease
    (Indian Society for Plantation Crops, 2006) Srinivasan, N.; Bharathi, R.
  • Thumbnail Image
    Item
    Changes in foliar pigments in yellow leaf disease of arecanut
    (2007-02-08) Srinivasan, N.
    Yellow leaf disease remains as a serious disease of arecanut in Kerala and Karnataka. The precise etiology of the disease is unknown. Serious alterations in foliar pigments were noticed and the content of chlorophyll declined significantly depending upon severity of the disease. Pigments, carotene and xanthophyll seem to superimpose the yellowing of foliage in affected palms. The significance of changes in major plant pigments has been discussed.
  • Thumbnail Image
    Item
  • Thumbnail Image
    Item
    Coconut leaf rot disease complex - A review
    (2007-02-08) Srinivasan, N.; Gunasekaran, M.
    Occurrence of leaf rot disease (LRDC) of coconut is related to increased incidence of root wilt disease (RWD). The palms with RWD irrespective of age are susceptible, young ones are more susceptible to LRDC. Tender leaves especially the spindle play a critical role in LRDC incidence and the disease attributed to fungal complex. Among the 14 species of LRDC fungi, several were proved to be pathogenic; Colletotrichum gloeosporioides (Penzig) Penzig and Sacc and Exserohilum rostratum (Drechsler) Leonard and Suggs are discerned as the main pathogens. C. gloesporoides was aggressive during monsoons and positively correlated with rainfall and relative humidity (% RH, whereas E.rostratum less strongly correlated. Fusarium spp. predominated in dry seasons. Importance of microclimate, survival and quiescence of the pathogens are to be determined. Diagnosis of RWD by techniques such as PCR and understanding the molecular basis of vulnerability of palms to LRDC would help to initiate early control measures. Planting of RWD cum LRDC resistant/tolerant varieties after eradicating the RWD infected palms is desirable. Protection of young leaves by chemical or biocontrol agents or a combination of both with phytosanitation is important. A system approach with integrated measures needs to be utilized for sound management of LRDC.
  • Thumbnail Image
    Item
    Coconut leaf rot intensity and fungal incidence
    (2007-02-08) Srinivasan, N.; Gunasekaran, M.
  • Thumbnail Image
    Item
    Coconut root wilt - The malady and remedy
    (2007-02-08) Solomon, J.J.; Nair, C.P.R.; Srinivasan, N.; Gunasekaran, M.; Sasikala, M.
  • Thumbnail Image
    Item
    Comparison of enzyme activities with diagnostic potential in healthy and root (wilt) diseased coconut palms, differing in cultivars and growth stages
    (2012-08) Chaturvedi, V.K.; Srinivasan, N.; Sasikala, M.; Jacob, P.M.; Rajeev, G.
    Activities of superoxide dismutase (SOD), succinic dehydrogenase (SucDH), exochitinase (Cht) and 1, 4 β-glucanase (Glucn) were quantified to assess their diagnostic potential for detection of, or their role in imparting tolerance against, root (wilt) disease (RWD). The enzymes were determined in healthy and infected palms of contrasting coconut cultivars - Chowghat Green Dwarf (CGD) and/or Malayan Green Dwarf (MGD) tolerant and West Coast Tall (WCT) - susceptible, in the adult palms and in some at the seedling growth stage. Healthy and RWD plants differed little and that too inconsistently with respect to the activities, specific activities and soluble protein content of all the 4 enzymes, offering no diagnostic potential, in the three cultivars. However, cultivars and growth stage differences for enzyme activities were found to be significant for some enzymes. The RWD tolerant cultivar CGD (10-year old palms) had higher SOD and SucDH activity, higher soluble protein in the SOD and SucDH extract and lesser SOD specific activity than the RWD susceptible cultivar WCT (40-year old palms). The RWD tolerant cultivar MGD had lesser SOD activity than WCT in the seedling stage, lesser SOD specific activity in the adult stage (15-year old palms), higher SucDH activity and specific activity, higher soluble protein in the SOD extract, but lesser soluble protein in the Cht extract than 40-year old WCT adult palms. Seedlings of WCT and MGD had higher SOD activity than their adult plants. Seedlings of WCT and CGD had higher soluble protein in SOD extract than their adult plants. Seedlings of CGD had higher soluble protein in SucDH extract than its adult plants. Metabolic differences in enzyme activities indicated that the cultivars CGD followed by MGD and the seedling stage or younger plants seem to have a better capacity in resisting the effects of root (wilt) disease.
  • Thumbnail Image
    Item
    Cultivation of spiroplasma from seasamum affected by phyllody in chick embryos
    (2007-02-08) Srinivasan, N.; Solomon, J.J.
    A spiroplasma (helical mycoplasma) from the tissues of sesamum plants affected by phyllody disease was successfully cultured in embryonated hen's eggs. The organism adapted to the egg system and grew in the yolk and the allantoic fluid. It readily readapted from eges to as serum enriched cell-free culture medium. Helical, filamentous, pleomorphic bodies were constantly observed in allantoic fluids of inoculated eggs under electron microscope. The egg inoculations triggered faster adaptation of the mollicutes in vitro.
  • Thumbnail Image
    Item
  • Thumbnail Image
    Item
    Curative and prophylactic control of fungal leaf rot complex in root (wilt) affected coconut palms in India
    (2003) Srinivasan, N.; Gunasekaran, M.
    Root wilt disease (RWD) is a debilitating malady of coconut in India that is caused by phytoplasma. In RIVD affedrd palms, leaf rot disease (LRD) is commonly superimposed. The LRD is due to fungi and this leaf rot phase forms an integral part of RIVD complex. Control of LRD is important as it severely disfigures the palm and brings about rapid deterioration in its health and productivity. Control trial involving Phytosanitation of young leaves, pouring of broad spectrum - systemic fungicide, Contaf 5 E (Uexaconazole 5% EC) into the axil of spindle leaf besides a number of other measures was conducted to study their ameliorating qffecf^nn LRD. Prophylactic control (rial, especially with the broad-spectrum fungicides was also conducted. Pouring of Contaf into the axil of spindles along with phytosanitory measures on the spindle and other young leaves significantly reduced the incidence, of LRD in newly emerging spindles effecting cure. Application of the fungicide on RIVD palms prior to the onset of LRD. offered prophylactic protection to emerging leaves against LRD. Relevance of practising integrated control measures, cure of LRD at an early stag< i''elf the need for strict adoption of crop management technology etc. for effective disease control are highlighted here.
  • Thumbnail Image
    Item
    Cylindrocladium scoparium in relation to leaf rot disease of coconut
    (2007-02-08) Srinivasan, N.; Gunasekaran, M.
  • Thumbnail Image
    Item
    Development of Technology and Popularization of Biological Control Agents for Integrated Management of Coconut Leaf Rot Disease
    (2011) Srinivasan, N.; Chandra Mohanan, R.; Bharathi, R.; Radhika, N.S.; Shanty Issak
    Coconut is an important social crop of livelihood concern for millions of small- medium farmers.Leaf rot disease (due to a fungal complex-Colletotrichum gloeosoprioides, Exserohilum rostratum and Fusarium solani as major pathogens), in association with root(wilt),is a major problem of coconut in southern districts of Kerala besides certain districts in Tamil Nadu etc. Central Plantation Crops Research Institute(CPCRI) has evolved biological control teclmology for integrated management of leaf rot to improve the health of disease affected palms.Application of biocontrol agents in the disease affected areas was aimed for creation of widespread awareness on eco-friendly disease management,crop sustenance and in realizing human resource potential. Effective strains of biocontrol agents­ Bacillus subtilis,Pseudomonas jluorescens and Trichoderma viride-were evolved, their multiplications in media including coconut water standardized and the antagonists processed into bioformulations (totally 2000 Kg. talc formulations evolved distributed/utilized).Coconut gardens and rural groups in various districts of southern Kerala(Thiruvananthapuram, Kollam, Alappuzha,Pathanamthitta,Kottayam,Idukki, Ernakulam and Thrissur), various blocks in Theni district besides specified blocks in Dindigul district of Tamil Nadu could be selected.Through effective contacts with extension­ developmental agencies, coconut Research & Development (R&D) meetings etc. reached out to rural people and implemented the technology of mass production-use of biological control agents,and knowledge imparted to rural people. Conducted trainings and allied programmes by on-campus trainings (396 beneficiaries), off-campus trainings (1854 beneficiaries), household/field contacts of rural people (689 beneficiaries) and other awareness programmes encompassing lectures, interfaces etc.(661 beneficiaries) and enlightened women, rural people, youths etc. representing various locations (totally 3600 beneficiaries in three years).Field demonstrations of disease management with biological control agents in coconut gardens (55 units) besides clusters-compact gardens(1850 coconut palms) were also done. Also,promotional materials were made available to various stakeholders. An innovative participatory programme implementation approach for technology transfer was the outcome of the work.Creation of widespread awareness, percolation of knowledge on biocontrol agents to women and other rural people could be visualized that would go a long way.
  • Thumbnail Image
    Item
  • Thumbnail Image
    Item
    Diseases and disorders of coconut and their management
    (Pointer Publishers, Jaipur, 2001) Srinivasan, N.
  • Thumbnail Image
    Item
  • Thumbnail Image
    Item
    Etiology - Phytoplasma
    (2007-02) Solomon, J.J.; Nair, C.P.R.; Rajan, P.; Srinivasan, N.; Govindankutty, M.P.; Mathen, K.; Pillai, N.G.