Browsing by Author "Ramachandran, N."

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    Effect of climatic factors on Phytophthora leaf infection in black pepper grown in arecanut-black pepper mixed cropping system
    (2007-02-08) Ramachandran, N.; Sarma, Y.R.; Anandaraj, M.; Jose Abraham
    Effect of climatic factors on the occurrence of foliar infection in black pepper caused by Phytophthora palmivora MF4 was studied during the years 1984-86 in arecanut-black pepper mixed cropping system. The correlation studies between the disease recorded at weekly intervals and the meteorological factors prevailing during the preceding seven days showed a positive correlation between the rainfall, number of rainy days and relative humidity whereas temperature and sunshine hours had a negative correlation. Average climatic factors worked out during increasing and decreasing phases of the disease showed that factors such as low temperature (22.7-29.6°C), shorter duration of sunshine (2.8-3.5 h/day) high rainfall (15.8-23.Omm/day) and high relative humidity (81-99%) contributed to the increase n disease.
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    Effect of two systemic fungicides, aliette and ridomil on Phytophthora palmivora isolate of Piper nigrum
    (2007-02-08) Ramachandran, N.; Sarma, Y.R.; Nambiar, K.K.N.
    The sensitivity of two systemic fungicides, Ridomil and Aliette to Phytophthora palmivora was tested by poison bait technique. Ridomil at 100 and 200 ppm showed 80% and 86% inhibition respectively, in the radial growth of the fungus and complete inhibition at 300 ppm. Aliette showed 22 % and 50 % inhibition of the fungus at 509 and 1000 ppm respectively and growth was absent at 1500 ppm. The systemic activity of the fungicides was evaluated by measuring the lesion diameter on the% inoculated leaves of black pepper pretreated with fungicides. Ridomil-treated leaves showed no lesion at 500 and 1000 ppm whereas Aliette-treated leaves showed inhibition of the lesion development to the extent of 57% and 71% at 500 and 1000 ppm respectively.
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    Phyllody Disease of Black Pepper (Piper nigrum L.)
    (2007-02) Sarma, Y.R.; Solomon, J.J.; Ramachandran, N.; Anandaraj, M.
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    Uptake And Persistence Of Metalaxyl In Black Pepper (Piper Nigrum L.)
    (1985-06) Ramachandran, N.; Sarma, Y.R.
    A study was conducted to know the exposure time required for the uptake of metalaxyl and duration of its persistence in black pepper (Piper nigrum L.) plants, using a leaf lesion bioassay. Metalaxyl at 1000 ppm applied as soil drench was translocated acropetally in significant quantity even one hour after application. The infection on the leaves of metalaxyl treated plants was negligible on the 50th day after which the activity of the fungicide gradually reduced. Thus metalaxyl has an advantage over contact fungicides in controlling infections of Phytophthora palmivora especially under heavy rainfall conditions.