Journal of Tea Science Research. 2015, Vol. 5, No. 10, 1-4
1
Research Report Open Access
Cumulative effect of foliar application of copper oxychloride on Pb content in
black tea
Seenivasan S. , Muraleedharan N.
1. The Institute of Environmental and Human Health, Texas Tech University, Lubbock – 79415, Texas, USA
2. Tea Research Association, Tocklai Tea Research Institute, Jorhat-785008, Assam, India
Corresponding author email
Journal of Tea Science Research, 2015, Vol.5, No.10 doi: 10.5376/jtsr.2015.05.00010
Received: 13 Sep, 2015
Accepted: 23 Oct., 2015
Published: 18 Nov., 2015
© 2015
Seenivasan
, This is an open access article published under the terms of the Creative Commons Attribution License, which permits unrestricted use,
distribution, and reproduction in any medium, provided the original work is properly cited.
Preferred citation for this article:
Seenivasan S., Muraleedharan N.
, 2015, Cumulative effect of foliar application of copper oxychloride on Pb content in black tea,
Journal of Tea Science
Research, 5(10), 1-4
(doi
Abstract
Copper oxychloride was found as one of the sources of lead contamination in tea as this fungicide is being widely used in
tea fields to control the blister blight disease. In India, there is no specification for this heavy metal in copper oxychloride
formulations. Commercial brands of copper oxychloride were collected from market and analyzed for lead (Pb) an element of
environmental concern. Results were compared with limits prescribed by Food and Agricultural Organization (FAO) of United
Nations with a view that these results could be used for fixing limits of heavy metal impurities in national level for the copper
oxychloride formulations. Field trials were initiated using the lead contaminated copper oxychloride and in combination with
hexaconazole. The study indicates lead contaminated copper oxychloride is one of the sources for lead contamination in black tea.
The accumulation of lead content in tea was positively correlated with the application of contaminated copper oxychloride
formulations.
Keywords
Fungicide; Impurities; Food chain
Background
In southern India blister blight incited by
Exobasidium vexans
Massee is the most important
leaf disease in tea, causing heavy crop loss. The
pathogen is an obligate parasite without any
alternate host and it completes its life cycle within a
short period of 11 to 28 days. Since climatic
conditions prevailing during the monsoon are
conducive for this pathogen, the crop has to be
protected with periodical application of fungicides
throughout the season. Earlier, only protectant
fungicides were used to control blister blight. Later,
a combination of protectant and eradicant fungicides
and of late, systemic fungicides are used to control
the disease. Among the protectant fungicides copper
formulations have wide acceptance. Among the
copper fungicides, (COC) copper oxychloride 50
WP (Wettable powder) is being used in tea
plantations of south India against blister blight for
the past five decades. Copper content was 50 per
cent and suspensibility was 84 per cent in copper
oxychloride. Under natural weather conditi ons,
retention of copper oxychloride on the leaf surface
was superior to other inorganic fungicides. The
fungicides were regularly applied on the field grown
susceptible clonal tea at an interval of 7 – 10 days.
Hexaconazole, propiconazole and tridemorph are the
recommended fungicides. In southern India, the
disease is largely controlled by the use of triazole
fungicides along with the combination of copper
oxychloride (Hudson et al., 2002)
.
Based on the above observations and literature
survey this study was undertaken. The present study
was to determine the heavy metal, Pb in different
brands of commercial grade copper oxychloride
formulations. The Food and Agricultural Organization
of United Nations give the specification of
permissible amount of heavy metal impurities in
copper oxychloride as 250 mg kg
-1
to lead (FAO,
1991). The impurity profile study indicates that
copper fungicides contain heavy metals. Lead is a
major contaminant in copper oxychloride.
