Browsing by Author "Mathen, K."

Now showing 1 - 20 of 44
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    Addition to the Record of Host Plants of Stephonitis typicus Distant
    (1972) Mathen, K.; Shanta, P.; Chandy Kurian
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    Association of Stephanitis typicus distant with coconut root (wilt) disease
    (2007-02-08) Shanta, P.; Mathen, K.; Chandy Kurian
    The root (wilt) disease of coconut, widely prevalent in Kerala is a major threat to this important cash crop. A sap-transmissible pathogen has been demonstrated to be systemically present in the affected palms. Stephanitis typicus Dist. was first reported as a possible vector of the pathogen in 1956. Positive transmission of the disease through this insect both in the field and under controlled conditions were reported. Further studies on this insect have shown that it is also a minor pest of coconut foliage. The range of its food plants, details of life history and information on the predacious habits and life-history of a natural enemy in the field have been gathered. Other studies have thrown light on the pattern of distribution of the insect on the palm, seasonal abundance of the bug in the field and its correlation with meteorological factors as well as its comparative abundance in healthy and diseased trees.
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    Biology and bionomics of Stephanitis typica (Distant)
    (2007-02-08) Mathen, K.; Chandy Kurian
    Direct and indirect evidence is available on Stephanitis typica (Distant) (Tingidae) transmitting Coconut Root (wilt) disease in Kerala, responsible for an annual loss in yield of 34 crores nuts. The lace bug, originally recorded from banana, is polyphagous. On coconut foliage, the bug completes its life cycle in about 25 days with an average incubation period of 12 days and a total nymphal period of 13 days covered under five instars. Both the imago and nymphs drain the contents of the mesophyll tissue. There are two peak periods of abundance in March-May and September-October. Fluctuations in populations are directly correlated to temperature and sunshine, inversely to relative humidity and rainfall. On individual palms, abundance increases from outer to the tender leaves. On each leaf, they occur in greater numbers in middle leaflefts. Diseased palms harbour more insects than the healthy. The insect is preyed upon by a mirid bug. The pest is easily controlled by praying carbaryl.
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    Coconut root (wilt) disease -A practical approach-"Contain the disease and live with it"
    (2007-02-08) Bavappa, K.V.A.; Pillai, G.B.; Mathen, K.
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    Comparative abundance of the Tingid vector Stephanitis typica (Distant) in root (wilt) disease affected and healthy coconut palms in Kerala
    (2007-02-08) Mathen, K.
    Direct and indirect evidences are available on the role o Stephanitis typica (Distant) (Heteroptera: Tingidae} as vector of Coconut Root (wilt) disease in Kerala. The indirect evidence is* supported in this paper by a study on comparative abundance of the lace bug on diseased and disease-free coconut palms at different localities. Analysis of pooled data on the population of the tingid on palms in the three borders demarcating the disease prevalent and disease-free zones In the northern, southern and eastern coconut gardens in the State has brought out significant increase in the numbers of the insect on palms under different intensities of the disease (apparently healthy, early disease and advanced disease) as compared to those on healthy palms. Count of the vector on seedlings also gave two to four times increase in population in diseased condition over the healthy.
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    Description of the salivary gland of the lace bug: Stephanitis typica (Distant)
    (2007) Mathen, K.; Rajan, P.; Radhakrishnan Nair, C.P.
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    Description of the salivary gland of the lace bug: Stephanitis typica (Distant)
    (2007-02-08) Mathen, K.; Rajan, P.; Radhakrishnan Nair, C.P.
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    Description, life-history and habits of Stethoconus praefectus (Distant) (Heteroptera : Miridae), predacious on Stephanitis typicus Distant (Heteroptera : Tingidae), a pest of coconut palm
    (2007-02-08) Mathen, K.; Chandy Kurian
    Nymphs and imago of Stethoconus praefectus (Distant) recorded from Kerala for the first time feed on nymphs and adults of Stephanitis typicus Distant, a pest of coconut foliage. The redescription of imago given here relates to the external morphology of the head, thorax and abdomen. Description of the immature stages and details of its life-cycle and habits arc reported for the first time. There are 5 nymphal instars. The life-cycle occupies a period of 16.6 ± 0.61 days, with an incubation period of 7.1 ± 0.53 and total nymphal period of 9.6 ± 0.95 days. There is a slight preponderance of females in the field. Males live for 2-20 days and females for 12-45 days. The pre-oviposition period is 4.25 ± 0.67 and the post-ovipo-sition period is 3.2 ± l.72 days. A single female lays on an average 2.1 ± 0.5 eggs a day. A single metamorphosing nymph devours 62.3 ± 6.0 host nymphs. An adult on an average sucks 5.2 ± 0.94 hosts a day.
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    Epidemiology of coconut root (wilt) disease
    (1980-12) Gopinathan Pillai, N.; Sasikala, M.; Mathen, K.
    Coconut root (wilt) disease of Kerala (S. India) is a debilitating disease of uncertain etiology. Out of 7,40,000 ha of coconut planatation, 2,50,000 ha are affected by this malady causing an annual loss of about 340 million nuts. Associations of fungi, bacteria, nematodes, and a transmissible virus-like pathogen with the disease have been reported. Observations recorded for seven years in 10 coconut gardens, each of approximately one ha in extent with very low percentage of disease incidence revealed indiscriminate spread in sandy, sandy-loam, and alluvial soils. The percentage of infection increased from 2.3 to 18.2 with 2-5 palms contracting infection every year. The spread of the disease was slower in laterite soils, with only one palm developing the disease in two years. The spread was erratic and irregular irrespective of soil conditions and occurred in jumps/leaps. The rate of spread was 1-4 km from the nearest source of infection. The pattern of spatial distribution or galaxial outbreak of the disease is suggestive of the involvement of aerial vector(s).
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    Epidemiology of coconut root (wilt) disease
    (2007-02-08) Gopinathan Pillai, N.; Sasikala, M.; Mathen, K.
    Coconut root (wilt) disease of Kerala (S. India) is a debilitating disease of uncertain etiology. Out of 7,40,000 ha of coconut planatation, 2,50,000 ha are affected by this malady causing an annual loss of about 340 million nuts. Associations of fungi, bacteria, nematodes, and a transmissible virus-like pathogen with the disease have been reported. Observations recorded for seven years in 10 coconut gardens, each of approximately one ha in extent with very low percentage of disease incidence revealed indiscriminate spread in sandy, sandy-loam, and alluvial soils. The percentage of infection increased from 2.3 to 18.2 with 2-5 palms contracting infection every year. The spread of the disease was slower in laterite soils, with only one palm developing the disease in two years. The spread was erratic and irregular irrespective of soil conditions and occurred in jumps/leaps. The rate of spread was 1-4 km from the nearest source of infection. The pattern of spatial distribution or galaxial outbreak of the disease is suggestive of the involvement of aerial vector(s).
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    Etiology - Phytoplasma
    (2007-02) Solomon, J.J.; Nair, C.P.R.; Rajan, P.; Srinivasan, N.; Govindankutty, M.P.; Mathen, K.; Pillai, N.G.
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    Evidences towards a mycoplasmal etiology for the root (wilt) disease of coconut in India
    (2007-02) Solomon, J.J.; Govindankutty, M.P.; Mathen, K.; Nair, C.P.R.; Sasikala, M.; Pillai, N.G.
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    Fish culture as means of additional income to coconut growers
    (2007-02) Mathen, K.; Thomas, P.K.; George, T.G.
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    Five new nematode species associated with coconut in Kerala, India
    (2007-02) Khan, E.; Seshadri, A.R.; Weischer, B.; Mathen, K.
    Five new species, Dolichodorus pulvinus, Macroposthonia oachirai, Discocriconemella recensi, Longidorus saginus and Paralotigidorus flcxus collected from sandy loam soil around the rlilzos-phere of coconut at Kayangulam (Kerala) are described and differentiated from the related species. The present investigation is a follow-up of an earlier project undertaken by B. Weischer, in collaboration with the Coconut Research Station, Kayangulam on the possible role of plant parasitic nematodes in the wilt disease of coconut in Kerala under an EPTA/UN programme in 1965 (Weischer, 1967). Five new species of nematodes collected around the rlmosphere of coconut at Kayangulam are described below. The soil in this area is a sandy loam, with a pH of 5-6.
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