A pest is any animal or plant harmful to humans or human concerns. The term is particularly used for creatures that damage crops, livestock, and forestry or cause a nuisance to people, especially in their homes. Humans have modified the environment for their own purposes and are intolerant of other creatures occupying the same space when their activities impact adversely on human objectives. Thus, an elephant is unobjectionable in its natural habitat but a pest when it tramples crops.
Some animals are disliked because they bite or sting; snakes, wasps, ants, bed bugs, fleas and ticks belong in this category. Others enter the home; these include houseflies, which land on and contaminate food, beetles, which tunnel into the woodwork, and other animals that scuttle about on the floor at night, like cockroaches, rats and mice, which are often associated with unsanitary conditions.
A pest is any animal or plant which has a harmful effect on humans, their food or their living conditions.
Pests include animals which:
carry disease-causing micro-organisms and parasites, for example, mosquitoes which carry Ross River virus and Murray Valley encephalitis.
attack and eat vegetable and cereal crops, for example, caterpillars and grasshoppers.
damage stored food. For example, rats and mice may eat grain in silos, rice or biscuits in shops and homes and contaminate this food with their faeces (droppings) and urine.
attack and eat farm and station animals. For example, feral dogs (dingoes) kill or maim many sheep and goats each year; foxes will kill poultry, lambs and many species of native wildlife; and feral cats also prey on native wildlife.
damage clothing. Silverfish, for example, eat holes in clothes.
damage buildings. For example, termites can cause considerable damage to timber in buildings.
bite people. For example, bed bugs (so called because they often bite people in their beds) are very difficult and expensive to control. Their bites can cause great irritation to those bitten and, like mosquito bites, can become infected if scratched.
There are thousands of different kinds of pests which are harmful to humans. The great majority of these are types of insect.
These are important and major pests. Insects have three pairs of legs, two pairs of wings, segmented body and characteristic compound eyes and antennae. Insects are tricky and cause damage in different ways viz. sucking sap from plants, biting plant parts, boring in to fruits, twigs and leaves, attacking roots, barks and blossoms etc. The damaging stages of different insect pests are larvae, adults and nymphs.
2) Mites:
These are creatures like insect but have soft body and four pairs of legs. These tiny creatures have red or pale yellow colour. They suck the sap from the plant and attack the crops in huge number.
3) Rodents
This group of pest eat away large amount of human food and also damage the crops on large scale. They are also responsible for heavy loss to stored grains on farms, in warehouses and houses.
4) Animals:
Animals like Wild Boar, Deer, Elephants, Wild Buffalo, Jackals, Monkeys, Squirrels cause direct damage to crop plants. They eat away the plants and by and large they waste huge amount of crops.
5) Birds:
Birds attack the crop plants and eat grains. Crow, Parrots and Sparrows are major among birds that attack the crops.
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Methods of pest control
Pest causes lot of reduction in the yield and quality of crops. Broadly the measures of pest control are of two types, preventive and protective. Preventive measures are used before the attack of the pest and protective measures are used to control the pest after their attack. The methods of controlling pest are as follows.
A) Mechanical methods:
1) Picking of pests, larvae by hand and destroying them. 2) Remove the part or whole plant that is infested. 3) Use of traps. 4) Catch them with the help of net.
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B) Physical methods:
1) By heat: High temperature kills the pest.
2) Low temperature.
3) X-rays and gamma ray.
C) Cultural methods:
1) Crop rotation.
2) Deep ploughing.
3) Clean cultivation.
4) Proper use of fertilizers and water.
5) Growing pest resistant Varieties.
6) Timely or late sowing.
7) Proper harvesting
D) Chemical methods
This method is used on large scale for direct control of pests. In these methods, chemicals that kill the pest are used. These chemicals are called as pesticides/ Insecticides. The chemical method is effective and faster as compared to other methods but it is hazardous to environment. Improper use of these chemical leads to development of resistance among the pests causing heavy out break which leads to increase in cost of cultivation and heavy loss. Dusts, Wettable powders, Seed dressers, Emulsions and granules are the insecticides formulations.
E) Biological methods
Use of biological agents to control pests is called Bio-control. Ninety eight percent pests are controlled by nature. There are certain predators, parasites, birds, animals, micro-organisms that can be used for control of pests. Certain biological factors used to control the pests are : Tricogama, Crysopa, HNPV, LLNPV, Chilonus, Copidosoma, Bacillus thuringenesis.
F) Plant Quarantine measures
Control of distribution and spread of pest by laws, (Indian Quarantine Act 1925)
Integrated Pest Management
Owing to uncontrolled use a pesticides, the control of pest has not remained as effective as earlier. This raises resistance of pests against chemicals; increases cost of cultivation, increase residues in the produce, etc. The environmental imbalance is another effect of such methods so it is the necessity of the time to use IPM. IPM- Use of cultural, physical, mechanical, biological, environmental and legal methods collectively to control pest is called as IPM. It also uses biological extracts, traps, repellents etc. for pest control.