According to available evidences, insects came into existence on this planet Earth several millions of years before man appeared on this Earth. To satisfy his basic needs of food, clothing and shelter, man started raising different crops. In the mean while, some of the insects had deterred from their original feeding habits and started feeding and destroying the crops grown by man. As such, man considered such insects as his prime enemy and tried to destroy them by various means. From time immemorial, man had used products obtained from plant origin as well as from animal origin for the control of harmful insects. Side by side some of the inorganic chemical compounds were also used to destroy such insects. After the invention of the first synthetic pesticide Dichloro diphenyl trichloro ethane (DDT) in 1939, several other Organo chlorine, Organo phosphorus, Carbamate, Pyrethroid and many other pesticides were introduced. Most of these pesticides were found to be non-specific, highly toxic and the toxic residues persisted in the applied plant parts for a considerably long time. Further, most of these pesticides were not compatible with other plant protection chemicals. Because of their high mammalian toxicity many of these supposed to be old generation pesticides were banned for plant protection use. Subsequently several new pesticides were introduced for pest control. These new generation pesticides, although recommended for the control of specific insect pests, are capable of controlling many other pests besides the target pest. Most of these pesticides although highly toxic to insect pests have less mammalian toxicity and less residual toxicity. They possess quick knock down effect on flying insect pests. Most of these pesticides are compatible with other plant protection chemicals. Of late many mixed insecticide formulations and insecticide - fungicidal formulations have been introduced. These mixed formulations can control many insect pests or insect pests and fungal parasites simultaneously

Pests The English name ‘Pest’ is derived from the Latin word ‘Pestis’, which means causing destruction. Pests are defined as ‘those organisms, which compete with man in his food supply, damage his possessions and attack himself’. They are of vital concern to mankind in their everyday life, as they cause considerable damage directly as well as indirectly to crops, domestic animals, birds and to man himself. They are also responsible for causing or transmitting many serious diseases. Pests include thousands of invertebrates such as, insects, nematodes, mites, ticks, snails and slugs, crabs etc. and vertebrates such as, rats, squirrels, jackals, pigs and boars, porcupines, rabbits, deers, bats, some species of birds etc., which are destructive to plants and livestock. Several microorganisms such as, fungi, bacteria, viruses, mycoplasma, phytoplasma etc. are also pests in nature. Weeds and phanerogamic parasites are also pests in the true sense.

‘Insect pest control’ includes all measures adopted to make the life of insects hard and ultimately to destroy them or to prevent their multiplication and spread. Such measures can be taken up before the appearance of the pests or after occurrence of the pests. To achieve this purpose , it is quite necessary to know the factors, which favor the occurrence of the pests and acquire enough knowledge about the nature and life cycle of the pests, the vulnerable growth stage at which they can be effectively destroyed and appropriate measures of control to destroy them Control measures may be either preventive or direct. Need for pest control Control measures for the control of pests have to be taken up as soon as the infestation reaches the economic threshold level. Failure to control the pests at this stage will result in further increase in the pest population and consequent loss in yield and economic loss. The need for pest control is of two kinds : i) For yield maximization. The only objective of pest control in this method is to maximize the yield. The cost incurred for pest control is most often more than the income accrued as a result of pest control. The method is adopted only with the object of increasing the yield as much as possible so that the country and the people may be benefited. In this method, pest control operations are taken up before the actual occurrence of the pest or before the pest infestation reaches the economic threshold level. Such treatments taken up to control the pests before their occurrence are known as ‘prophylactic treatments’

The chemicals, which can destroy pests or prevent their occurrence by their chemical action are known as ‘Pesticides’. Pesticides include ‘insecticides’, acaricides’, ‘nematicides’, rodenticides’, molluscicides’ etc., which are used to destroy insect pests, mites, nematodes, rodents, slugs and snails respectively. Pesticides have been used even before the time when man never knew how to read and write. Even before 200 BC, several substances were known to control pests. Sulfur, arsenic poisons, fluorine poisons, as well as some plant extracts and oils were used to control pests. However, these substances could destroy only a few specific pests only to some extent. Advances in the invention of pesticides The invention of many of the present day pesticides started only after 1867. ‘Paris green’, a synthetic chemical was the first pesticide used to control the ‘Colorodo beetles’ of potato. Up to 1939, only a few inorganic chemical compounds and plant poisons were used as pesticides. Only after the Second World War much advances were made in chemical research. After the invention of DDT in 1939, a revolution had started in the field of pest control. Following the introduction of DDT, several other pesticides were identified and introduced for pest control. In 1941, BHC was invented by the British and French scientists. During the same period, organophosphorus pesticides were invented by the German scientists and parathion, malathion, demeton etc. were introduced.

For effective and economic control of pests, besides selection of appropriate plant protection chemicals, application of the chemicals at the most vulnerable growth stage of the pests and use of chemicals at the correct dosage, selection of proper plant protection appliances to carry out the operation is also of vital importance, so as to ensure uniform application of the chemicals. Plant protection chemicals are mostly used as sprays and dusts using sprayers and dusters respectively. However, in most of the cases spraying is preferred to dusting. Different types of sprayers and dusters are being used for these operations and in both, there are manually operated as well as power operated equipments and in sprayers there are both hydraulic and pneumatic types of sprayers. The nature of the pesticide formulations to be used and the purpose for which they are used also determine the type of equipment to be used. Dusters are used for dusting insecticidal dust formulations. Sprayers are used for spraying insecticidal liquid formulations. Granular applicators are used to apply granular formulations. Fumigators are used to apply fumigants to fumigate godowns, warehouses, rat holes etc. Soil injectors are used to inject pesticides at a particular depth of soil under pressure. Flame throwers are used to throw f lames at specified targets.