Insects are the invertebrate species which are more than half of the all living organisms. Insect’s body is divided into three parts Head, Thorax, and Abdomen. These creatures have compound eyes, pair of antennae and joined legs.
Pests are the organisms which are detrimental and troublesome to human and his concerns. Pests cause damage to human and to the agricultural production.
Not all the insects are pests. There are wide criteria in naming an insect as pest. Even animals can become pest when they carry hazardous germs with and communicate or transfer it to human s e.g. Rats carrying plague etc.
These pest insects can be beneficial and both hazardous in their various stages of life. Like
- Pest insects can cause damage and kill agriculture crops,
- Pests can be harmful to humans but they might be strong pollinators e.g. Honey bees,
- Pest can be harmful in their one stage of life and can be highly beneficial in their other stage of life e.g. caterpillar feed on leaves whereas butterflies are excellent pollinators.
Types of Pest Control
There are various methods to control the insect pest and to manage the insect pests.
Biological control is a process where the natural predators of the pests are bred. These natural predators prey on the pests and hence, it controls the pests from harming the crops. These predators are natural enemies of pests.
But the establishment of this method is difficult and time consuming as the reproduction of predators are slow compare to pests but once it gets established it works brilliant.
- Augmentationà is a process of increasing the number of natural predators. There are two types in augmentation,
- Inoculative/inundative where species of natural predators are reproduced in mass.
- Tritropic paradigm is process of attracting natural predators by applying trichogramma chilonis on host plants.
- Conservation à is a process of attracting of multiplying the number of natural predators or enemies by providing favourable conditions to them.
- Banker plant concept – in this technique the not host plants are planted e.g. cereals plants in cotton farm. Where the pests attack cereal plants and not cotton plant.
- Strip cutting – based on the needs selective pesticides are used maintain untreated refuges which also help in the conservation.
These are physical ways of removing pest from farm like handpicking, trapping, screens, sticky bands etc are few of mechanical controls. But this method cannot be performed on large scale as it needs more labour and also time consuming.
Cultural control is the way of creating unfavourable environment to the pest or bringing certain changes in the normal farming method like
- Crop Rotation - by crop rotation technique the pest insects which have long life are isolated from food supply and hence reduce their growth.
- Location - crops should be planted adjacent to each other which will help in reduction of insects.
- Trap crop - in trap crop method small amount of preferred crops are planted near major crops so that the insects are attracted towards preferred crops which are treated with insecticides.
- Tillage - in tillage the soil inhabiting insects are treated. Some insects are buried some are exposed and the plants breeding pests are removed.
- Clean culture - in clean culture the field is cleared by removing the unwanted plants, residues of crops, burning of inedible residues of crops.
- Timing - planting of the crops should be done at the time where the growth of pest is less.
- Resistant Plant Varieties -
- Non-Preference - the pests gets attracted to host plants depending on the colour, light reflection, structure of the surface and chemical stimuli like taste and odour.
- Antibiosis - is process where certain chemical on plant are hazardous to pest.
- Tolerance - is process of increasing the ability of the crop to resist the attack of pest by repairing the damaged tissues.
This process is very economical and effective if established thoroughly.
Reproductive control is the means by which the insects’ reproduction is disturbed by physical treatment which cause infertility.
Chemical control method is the process where the insects are poisoned or killed by various devices which attract them. This technique is highly effective, quick and also economical. The chemical control has its own pros and cons such as,
- Fast and adequate crop protection,
- It also helps in preservation of human health by protecting from pest.
- Few pests are least effected from pesticides,
- It leads to growth of new pest,
- Pesticides is temporary and needs timely repetition,
- Residues of pesticides on harvested crops are very much hazardous to the consumers,
- It is harmful to natural parasites, cattle, birds and other wildlife which are natural and helpful pollinators,
- It hampers the quality of the harvested crops.
Usage of pesticide is legally accepted in spite of its harmful effects, as it is faster than the natural predators in protecting the crops from pests.
In microbial control technique micro organisms such as protozoan, fungi, bacteria and viruses are used to control the pest insects. The products of these microorganisms are also used such as toxins.
Protozoan - protozoan are unicellular organism which are used against grass hoppers.
Fungi - fungi are pathogenic to insects’ pests. As they develop as spore and enters into the insects pests. As they develop as spore and enters into the insects cuticle and spreads all over the insects and leads to the death of insect pest.
Integrated control is the process of using all the suitable technique in order to reduce the damage caused by the insect pest and increase the yield economically with less adverse effects.
This approach is combination of biological, physical, chemical and cultural tools in such a way that it minimizes the economic, health and environmental risk. The underlying principle of integrated control approach is
Agro ecosystem - Agro ecosystem is the basis of agriculture system. This shows the start of injury i.e., tolerable level of the pest attack, Where natural control techniques are used for regulating the pest population.
Economic Threshold - Economic Threshold is the condition at which the action must be taken to prevent the of pest insects from crossing economic injury level i.e., lowest pest population level causing less economic injury.
The major steps in carrying Integrated Pest Management are.
- Identification of correct pests and its life stage.
- Should gather proper biological information about the pest found and the crop planted in order to formulate the proper strategy to treat the pest.
- By conducting careful study on the field and crop to analyse the preventive strategies.
- Periodic assessment should be carried out with regard to pest, crop and environmental factors.
- Based on the periodic assessment the decision should be taken on the further action.
- Suitable pest control tactics should be taken in order to maintain the economic level.
- The implementation of the pest control strategy should be carried out on timely manner.
- Regular assessment of the strategy is compulsory to overcome the risk of untimely action.
The various methods to monitor the pest control strategies are as follows.
- Absolute methods – estimates of pest population density are expressed as level per unit of crop area.
- Relative methods – estimates of pest population activity per unit of effort or time but not expressed with units of the crop area.
Indices – estimate of crop damage or the frequency of pest population.
Among all the pesticide the use of chemical pesticide is more because of its economical advantage.
There are totally 260 technical grade pesticides and 585 pesticide formulations registered under registered under registration committee.
Pesticide Action Network India has submitted a report titled “Conditions of Paraquat used in India” which says about the consumption of pesticides in India.
GRAPH SHOWING THE CONSUMPTION OF PESTICIDES FROM YEAR 2012-2015
The pest insect control depends entirely on the environment, where the crop is grown. At the earliest crop rotation technique or any other cultural control technique would help in controlling the pest. Whereas chemical control approach is the final, very effective and also to an extent hazardous to human, natural predators and cattle which feed on the crops due to the residual of the chemical pesticide on it which can also affect the balance chain.
The chemical control method has been reduced to some extent. And the farmers are adopting cultural and biological control method to reduce the harmful effect of chemical pesticide.
Therefore pest insects can be helpful and also harmful to the human in its various stages of life span. The same way is the use of pest insects control techniques, balanced control is all what is required.
- BURKHARDT, C. C. INSECT PESTS OF FIELD CROPS.