Coffee is
the popular beverage name for a species of plants of Coffea genus cultivated for their beans that are used for preparing
stimulating drinks. They are small evergreen shrubs with multiple stems and
smooth leaves; bear green fruits that become crimson when ripe and normally
contain two coffee seeds or beans. The trees can live for 20-30 years. Coffee
primarily comes in two varieties, Arabian coffee (C.arabica) and Robusta coffee (C.cenephora)
and originates from Africa. They grow in a wide range of soil but generally
prefer deep, well draining loam with pH
between 5 & 6.
Among
the coffee producing countries India is the 6th largest producer and
exporter of coffee in the world after Brazil, Vietnam, Columbia, Indonesia and
Ethiopia with the state of Karnataka accounting for 71% production
followed by Kerala at 21% and Tamil Nadu at 5% with an annual
production of 8,200 tons. Both Arabica coffee and Robusta are produced in the
proportion of 32:68. Indian coffee is
unique because it is grown under the canopy of shady trees (a popular
Agroforestry practice) making it one of the most eco-friendly crops in India
that helps preserve the bio-diversity in the eco-sensitive Eastern and Western
Ghats.
Coffee
production in India steadily rose from 1951 to 2002 after
which there was a huge slump for almost a decade owing to drop in global market and prices
of coffee, occurrence of drought and outbreak of pests and diseases. Peak production
was achieved
in 2011-2012 because of responsive
measures
to mitigate the problems listed above. While
the problem with prices and global market was
left
for economists, the remaining two domains required in-house
mitigation.
Measures
proposed included:
·
Development of drought tolerant and
pest/disease resisting species
·
Development of irrigation and water retention
technologies
·
Development of pest and disease management
methods.
The Central Coffee Research Institute
has been actively trying to develop new breeds of resistant crops but it has a
long way to go and long term programmes for high yield crops and disease
resistant strains is a matter of uncertain future right now. Emphasis is laid
on the present practices to sustain the production while creating minimal impact on soil health, plant and
environment and the need for integrated management of pests and diseases and Eco-friendly
biocide disinfectants.
Bacterial Blight: Caused by
Bacterium Pseudomonas syringae, the
disease can spread over long distances through infected seedlings or via water
splash in the field. Symptoms include spots on leaves leading to necrosis on
lamina and shoot tips that spread down the branches leading to dead leaves on
branches. Only mitigation is use of protective pesticide spray.
Cercospora Leaf spot: Caused by
Fungus Cercospora coffeicola, it
spreads by wind, water splash and human movement through wet fields. Symptoms
include brown spots on foliage and red leaf margins, premature shedding of
leaves and infected discolored disfigured berries. Use of pesticides in case of
occurrence of disease.
Coffee Berry disease: Caused by
Fungus Colletotrichum kahawae, very
serious disease that spreads within the plantation by air/water/physical
contact media and can destroy 80% of the harvest. Symptoms include lesions on
green berries, premature fall offs and mummified berries. Protective sprays of
pesticides and removal of infected berries are the only remedies.
Coffee
leaf rust: Caused by Fungus Hemileia
vastatrix, it spreads by air and water. Symptoms include lesions on ventral
sides of leaves, infection starts from near the bottom of plant and infected
leaves drop off premature leaving twigs and defoliated branches. Spraying
fungicides and total removal of infected plants seem to be the only remedies.
Rootknot Nematodes: Nematodes
are wormlike organisms that attack the root system of plants, feeding on the
sap. They can form knots in the roots that inhibit the plant from properly
feeding. Meloidogyne
exigua, M. incognita, M. coffeicola, Pratylenchus brachyurus, and P. coffeae are
the most common species of rootknot coffee nematodes. Symptoms of a nematode
infestation are galls, splits, scales and decreased mass in the root system,
and chlorosis and defoliation in the upper plant. They are among the most
harmful coffee diseases and pests. Application of pesticides seems to be the
only preventive option.
Pesticides
and Fungicides:
Copper and its compounds have had a
wide-ranging employment in agriculture. It has been used as an active
ingredient in various pesticidal and fungicidal formulations to protect crops
from major fungal leaf and fruit diseases. Around
6% of world copper production is used in agriculture which directly affects the
environment and represents the most important source of copper dissipation
directly into soil and environment. It was not before 1880s that accidently
copper’s fungicidal properties were discovered by French Scientist, Millardet
and from 1885 the Cu-based Bordeaux
mixture officially became the first fungicide to be used on a large scale world-wide. Copper based fungicides are inorganic
compounds that have a multi-site activity with low risk of pathogen developing
resistance at any stage; hence popularly used as agricultural pesticides to control
fungi, bacteria, and in some cases invertebrates and algae. Following
absorption into the pathogen, the metal ions link to various chemical groups
present in many proteins and disrupt protein functions. Thus the mode of operation is non-specific denaturation
of cellular protein. Copper hydroxide fungicide and Copper sulfate
fungicide are the most common salts of copper used as plant fungicides.
It is applied in two possible ways:
Contact
Fungicide: These are applied but not absorbed by the plant. They act on
surface and prevent infection and germination of the infective propagules of
the pathogen. They are sprayed in advance and produce a toxic barrier against
pathogen infestation. The biggest limitation is the need to be applied at
regular intervals to prevent new growth flushes.
Systemic Fungicide: These
are absorbed through the foliage and roots and transported around the plant in
vascular tissues. Thus lower doses and less frequent application is required.
They are applied after the infection has occurred to treat symptoms and
eradicate the disease mostly during seed treatments or by root dips, in-furrow
treatment or soil drenching. They are site specific and hinder particular
metabolism functions. They are expensive; sometimes induce defoliation of the
plant and often the pathogens become resistant through simple cellular
mutations.
Even though it’s an efficient biocide,
copper is still a heavy metal & long years of accumulation in soil and
water does have its environmental consequences. Heavy metals tend to accumulate
and persist in agricultural soils for a long time. A study conducted by
Savithri et al. (2003) in India confirmed significant copper accumulation
in surface and subsurface soils due to extensive use of Bordeaux.
Horticulture operations with long history of copper fungicide were the main
culprits. It is well presumed, heavy metals present in soil may have negative
impacts on human health and environment.
i) Copper accumulation in soil above threshold
values may be responsible for phytotoxicity
to higher plant species and associated soil properties. The phenomenon is
mainly observed in acidic soils with pH
<6; just the type of soil coffee plants prefer. This can disturb the
overall productivity of Agroforestry farms present in India
ii) Copper biocides have negative effect on soil pH, available phosphorous and organic matter.
When in soil, it binds to organic matter, clay minerals and hydrated metal
oxides thus making them unavailable to
plants. It has been found to suppress
nitrogen fixation by Rhizobium.
iii) Earthworms are known as farmer’s friend. Their
feeding and burrowing activities help regulate organic matter in soil and
maintain soil porosity. Copper residues
negatively affect soil microbial activity and earthworm population and processes
like bioturbidation. Thus depleting soil health.
iv) They affect the working and life cycles of
naturally occurring bio-pesticides and bio-controls, reduce efficiency of mycorrhizal inoculations.
v) Regardless of accuracy of application, copper
fungicide spray has the possibility of drift
risks & metal contamination in adjacent field damaging non-target sensitive
crops and plants, especially in Agroforestry practices.
vi) Runoffs from farms containing dissolved copper
and copper sulfate toxicity is fatal to
aquatic fauna.
vii) Long term exposure to copper can cause
irritation to nose, mouth and eyes, headaches and vomiting; accidental ingestion of contaminated foods
may cause copper poisoning and liver and kidney damage in humans.
Silver
Hydrogen Peroxide: An eco friendly agricultural biocide
Silver Hydrogen Peroxide, as the name
suggests is a synergized composition of
hydrogen peroxide stabilized with silver ions in the form of silver nitrate or
infused Silver Nano particles. Hydrogen Peroxide is a strong oxidizer
formed by combination of water with ozone. The bonds between the molecule and
oxygen atom are unstable and easily break releasing free oxygen that oxidizes
organic matter. Thus H2O2 disinfects by oxidizing cell
membranes and inner cell structures of pathogens. It is a great biocide; being
a strong oxidizing agent.
H2O2 is
stabilized using silver so as to increase its efficacy. Silver acts both as a
stabilizer and an activator. In addition to this, silver is shown to have
certain disinfectant properties of its own. Addition of silver greatly reduces
the quick decomposition of H2O2. In presence of silver, the peroxide
decomposes only in presence of biological contaminants. The decomposed H2O2 oxidizes the cell wall, cell
membrane and cytoplasm of the pathogens, the DNA is destroyed thus killing the
organism. Silver is known to react with certain proteins in the DNA and act as
a biostat, inhibiting further growth of the pathogens.
Hydrogen Peroxide and Silver are
neither toxic nor produce DPBs upon decomposition. It dissociates producing
water and oxygen and the residual silver has been proven to have no ill effects
on man and environment. Breaking into water and oxygen, it is world’s safest biocide and eco disinfectant. At
recommended concentrations of application, it is harmless to the plant and soil
biota except pathogens.
The most impressive feature of Silver
Hydrogen Peroxide is its varied modes of application:
A properly
diluted solution of the biocide can be spouted or fumigated on wet soil 12
hours prior to plantation of fresh saplings. This kills most disease causing
organisms.
A diluted
biocide solution can be directly fed to plant roots by drip lines at stipulated
growth periods to prevent re-growth of infectious pathogens.
Soil can
be directly drenched with a diluted solution in the early growing season to
eradicate most of the pathogens that infect at early stages of growth.
Foliar
spraying in the early morning at periodic intervals can keep leaves free from rust and commonly
occurring fungal infections
Pruning
tools can be sterilized in a diluted solution before operations to minimize
infection by contact.
Fresh
seeds can be soaked in a diluted solution prior to planting to prevent pathogen
infestation during germination stage.
Mature
beans can be washed in a dilute biocide solution to remove organic and
inorganic residues increasing shelf life and processing operations.
Silver Hydrogen Peroxide is by far the
best all purpose multi-utility biocide because:
·
It is effective
against all kinds of bacteria, viruses, yeast, mould, nematodes and spore
formers
·
It is
Environmentally friendly - practically 100% degradable breaking down to water
and oxygen
·
Does not create
odor or alter the taste of beans
·
Highly effective over
long periods even at very high water temperatures and low pH
·
Has no toxic
effect in its diluted state
·
No carcinogenic
or mutagenic effect
·
Long shelf life: maximum loss of concentration
3% per year
·
Does not harm
other plant parts
· Equipment and
operation costs are low, can be easily applied without fear of environmental residue
Chemtex’s Alstasan Silvox is a unique
composition of Hydrogen peroxide and silver nano particles in presence of a
catalyst that provides high efficacy in killing of pathogens in all possible
modes of application in soil or on the plants. It is FDA (Food and Drugs Administration) approved and NTC (National Toxicology Center) has tested
it as a safe product even in case of direct human consumption in water upto
25ppm concentration. It has been tested by SGS
Laboratory for zero heavy metal content and tested highly efficient on bacteriological pathogens by NDRI, Karnal.
