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| Pests are known
to exist on this planet from prehistoric periods
and are described as "Organisms that demerits
the value of resources in which man is interested."
These organisms affect health of human beings, infest
and damage crops cultivated and destroy stored grains.
Controlling these pests by available means has been
the priority of mankind. |
| Agricultural production
has to keep pace with growing population worldwide.
Introduction of high yielding and nutrient responsive
varieties, application of high doses of plant nutrients,
increasing irrigation potential and other methods
of modern cultivation ushered in "Green revolution".
These methods also brought into forefront a variety
of pest complex, control of which became an integral
part of crop management. Over the years, some pests
developed resistance to some chemicals and flare
up of minor pests was observed. Flare up of Brown
Plant Hopper in rice fields of Kerala some years
ago is often quoted as an example of adverse effect
of use of pesticides. In fact it was a man made
disaster. Thousands of frogs which keep BPH under
check were caught from paddy fields and exported
to foreign countries for culinary purpose. This
greedy act disturbed the balance of nature. A minor
pest hither to became a major pest. By using pesticides
"as optimum as possible but as much as necessary",
these products can be beneficially amalgamated with
integrated pest management. |
| Integrated pest
managementt (IPM) has been defined as "a pest
management that in the context of the associated
environment and the population dynamics of pest
species, utilises all suitable techniques and methods
in a compatible manner as possible and maintains
pest population at levels below those causing economically
unacceptable damage or loss." |
| Integrated pest
management is not new to our farmer community. Summer
and post harvest ploughing has been in practice
with the farmers to expose soil insects and pupae.
Growing marigold plants in commercial crops like
chillies and vegetables has been practiced by many
farmers. Use of neem twigs while storing grains
was also practiced by our fore fathers. Picking
up and destroying grown up caterpillars was not
unknown to them. Even house wives used to dust lab-lab
plants in kitchen gardens with ash from the hearths
to check aphid population. More scientific, practical
and adoptable measures have been developed and recommended
to farmer community. These measures can be used
hand in hand with need based and judicious application
of pesticides. |
| IPM involves a
combination of various measures to ensure effective
pest management without disturbing the ecosystem,
reducing environmental pollution and eliminate direct
and indirect health hazards to human beings. |
| These methods can
be broadly divided into three categories |
| » |
Observation
methods |
| » |
Preventive methods
|
| » |
Intervention
methods |
|
| Observation
methods: |
| (a) |
Identification
: |
| |
Identification of pests
and beneficial insects is of prime importance
before any pest control operation is executed.
Proper education at farmers level is very
essential so that farmers can identify beneficial
insects/pests and take proper and appropriate
measures in time to check pest menace. |
| (b) |
Surveillance
and forecasting : |
| |
Periodical studies have
to be made in climate changes, rainfall, temperature
etc. which can be congenial for a pest or
a disease of the agroclimatic zone. Observation
made from light trap collection, sticky trap
studies, pheromone traps etc. can be analysed
and appropriate forecasts made on possible
pest or disease appearance. Scientific surveillance
and forecasting will enable extension workers
to pass on proper recommendations to farmers
for timely and appropriate crop protection
measures. |
| (c) |
Diagnostics: |
| |
Many a time, symptoms
manifested on crops due to insect attack are
not properly diagnosed. This might probably
result in improper use of plant protection
measures not only include pest but also its
intensity, stage etc. to enable planning all
possible preventive and curative operations. |
| (d) |
Scouting: |
| |
Each and every farmer
should scout for pests and beneficial insects
in his individual holding. Periodical visits
during cropping season and detailed observation
will enable him to plan for strategic measures
in pest/disease control. In cases where beneficial
insects are in abundance and pest incidence
is low, farmer need not go in for chemical
control at the stage. Experience gained on
individual crops over years will go a long
way in effective pest management. |
| (e) |
Economic threshold
levels : |
| |
Economic threshold level
(ETL) can be defined as "the population
density of pest which will cause sufficient
loss to justify cost of control". ETL
for all major pests should be standardised
and this scientific information should be
disseminated among farmers. Farmers then can
observe their fields very closely to ascertain
whether any pest has reached its ETL so that
appropriate control operations can be initiated. |
| (f) |
Pheromones: |
| |
Pheromones play an important
role in IPM. Pheromones to attract adults
of some major pests like fruit borers (Heliothis)
are available. Erecting pheromone traps in
fields helps in pest monitoring. It can also
be used for "attract and destroy"
method of pest control where in adult males
collected in these traps are destroyed which
indirectly helps in reducing mating, egg laying
and pest multiplication on crop. |
|
| Preventive
methods |
| (a) |
Cultural
Operations: |
| |
Cultural practices like
summer and pre monsoon ploughing will expose
soil insects, pupae, white grubs, cut worms
etc. to adverse seasonal conditions in which
they perish. Birds pick up these pests reducing
primary inoculam on main crop. Similarly soil
borne pathogen are exposed and destroyed.
Periodical intercultivation operation should
be done to remove weed population in fields
which compete with main crop for nutrients
and also act as alternate hosts for many pests.
Similarly keeping field bunds free from weeds
eliminates alternate hosts. |
| (b) |
Crop rotation
: |
| |
Monocropping provides
a continuous and suitable micro environment,
and host plant availability for some insects
which thrive, multiply and destroy the crop.
Growing non preferred crops alternatively
in each agrosystem will not only break the
chain of host pest relationship but also reduce
pest pressure on both crops. Crop rotation
with shallow and deep rooted crops regulates
uptake of nutrients from different layers
of soil. It also checks effectively soil borne
pests. Suitable crop rotation can be developed
for individual agroclimatic zones. |
| (c) |
Intercropping
/ Trap Crops : |
| |
Intercropping of two
or more crops has been followed by our farmers
from a very long time. Sorghum / red gram
is one of the popular systems which is followed
even today. While intercropping was practiced
mainly from economic angle, it has also an
effective bearing on pest preference and incidence.
Many intercropping systems have been evolved
over years which has become an important arm
of pest management. Certain intercropping
like peanut / coriander, maize / soyabean
etc. are helpful in enhancing activity of
beneficial predators like lady bird beetles,
spiders etc. and reducing weed population. |
| |
Some plants are more
preferred by some pests. These plants can
be grown as "trap plants" to reduce
pest incidence on the main crop. Marigold
attracts fruit borer (Heliothis) pest. Growing
of these plants in main crops of chillies
will reduce fruit borer damage in these crops.
It is also reported that soil nematodes are
attracted to the root zone of marigold plants.
Growing castor plants on borders in chillies,
cotton etc. will reduce fruit borer (Spodoptera)
in these crops. Similar trap crop can be identified
and cultivated to reduce pest infestation. |
| (d) |
Resistant varieties |
| |
Breeders have developed
many resistant / tolerant varieties of many
crops. Cultivation of resistant varieties
helps in suppressing pest population specially
in endemic areas. This is one of the cost
effective method of pest management without
disturbing ecosystem. |
| (e) |
Water management: |
| |
Irrigation water is becoming
a scarce resource due to erratic climate conditions.
Even underground water table is gradually
going down. All crops require certain optimum
moisture levels to give higher yields. Proper
water management by judicious irrigation,
adopting drip and sprinkler system wherever
possible will reduce weeds population which
act as alternate hosts for numerous pests.
Soil pests can also be effectively managed
by proper irrigation water management. |
| (f) |
Staggered planting: |
| |
Each pest develops into
menacing proportion only under favourable
macro and micro climatic situations. While
avoiding monocropping, staggered sowing/planting
does not provide a conductive microclimate
for pest to develop into damaging proportion
and help build up of biocontrol agents. |
|
| Intervention
methods |
| (a) |
Mechanical
Control: |
| |
Mechanical control can
be effectively practiced either by individual
farmers or on community basis. Light traps
and burning of trash in camp fires attract
adult stages of many destructive pests. These
adults are killed reducing development of
pest on crops. Collection and destruction
of egg masses of fruit borer pests, digging
of trenches on farm borders to stop migration
and trapping of red hairy caterpillars and
other cut worms can be practiced on community
basis to reduce crop damage. Uprooting virus
infected plants, removal of pest infested
plant parts and destruction will check further
spread of major pests. Picking and destroying
of grown up caterpillar is one method to reduce
crop damage and further spread of pest. |
| (b) |
Biological control: |
| |
In nature many organisms
are surviving by feeding on-other insects.
Predators, parasites and diseases of pests
are available in abundance which have been
identified to maintain natural balance and
reduce pest incidence. Use of these naturally
occuring living organisms to check pest population
is one of the safest methods of pest management.
In agrosystems when pest population is low
or moderate and population of beneficial insects
is high, chemical control can be postponed.
For example, lady bird beetles are potential
natural enemies of aphids. Many beneficial
insects like mirid bugs, beetles, praying
mandtids, spiders, etc. have been identified
which control innumerable soft bodied insects
on crops. Scientific rearing and inundative
release of such beneficial insects will play
a major role in pest management without slightest
disturbance in ecosystem or environmental
pollution. Many strains of bacteria, fungi
and viruses have been identified which have
insecticidal property without being detrimental
to beneficial organisms. For example, Bacillus
thruingenisis (bacteria), nuclear polyhedrosis
virus are used for control of pod borers of
chilli and other vegetables. |
| (c) |
Chemical control: |
| |
There is absolute need
for judicious application of chemicals as
a part of Integrated Pest Management as improper
or overuse of chemicals are resulting in health
hazards, environmental pollution and residue
problems. Even while selecting a chemical
environmentally safe products should be preferred
which may have minimum adverse effect on beneficial
insects or destroy the balance in nature,
target specific pesticides should be preferred
over broad spectrum pesticides. Need based
chemical control at Economic Threshold Level
stage will help in proper control of pest
and will be cost effective. Intervals between
the pesticide application and harvest of the
crop should be strictly followed to avoid
pesticide residue and health hazards. All
precautions must be taken while applying chemicals
for the safety of operators. |
| |
Botanical pesticides
- Using derivatives of plant parts as pesticides
are becoming popular. These are effective
in checking pest build up and are safe for
humans and environment. Neem based products,
extracts of tobacco waste, Pongamia seeds,
garlic extracts are some of the formulations
which have been found to be effective on many
important pests. These botanical products,
have antifeedant, insecticidal and repellant
properties which can be used in initial stages
of pest incidence. |
|
| Equipment
and Spraying Techniques |
| Proper application
equipment plays an important role in obtaining desirable
benefits from chemical control. Use of faulty or
defective equipment will not only be hazardous to
the spray men, but also phytotoxic to crops. Similarly
improper application of chemicals can be disastrous.
Use of overdose or underdose of chemicals, incomparable
combinations and unscientific cocktails can result
in developing of resistance and is certain to be
hazardous to human beings and environment. Use of
proper equipments and following the scientific recommendation
of chemicals will make chemical control safe and
effective |
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