INTEGRATED PEST MANAGEMENT (IPM)
 

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