Any organism that is noxious destructive are pests. The chemicals used to kill eradicate and destroy pests are called pesticides.
- Insecticides: Which kill insects.
- Rodenticides: Kills mice and rats.
- Fungicides: – Fungi killer.
- Nematicides: – Kills nematode.
- Herbicides: Kills herb and weeds.
The uses of pesticides pose hazards to other organism including humans known as Biocides.
Classification of pesticides:
- Natural pesticides: There are no persistent natural organic compounds like pyrethrum nicotine from tobacco, rotenone from derris are sued to kill pests.
- First generation pesticides: It includes an inorganic pesticide accumulated in soil; These inhabit plant growth and poisoned other animals.
- Second generation pesticides: It includes new synthetic organic chemicals such as D.D.T. and organochlorines, dieldrin, endosulfur, endrin, heptach 1 or mirex etc.
D. D. T. increase, crop yield and reduced the pest damage drastically.
Environment and effects of pesticides;
- Reproductive failure and eggs were breaking before hatching in birds.
- Environment gets polluted and as result human beings are attacked by different disease like headache, breathing trouble, blood cancer, nausea, neurological problems, abortion of pregnant women, blindness etc.
- Insecticide pollution kills many animals including human being.
Insecticide pollution affects aquatic life in river and lakes such astish etc.
- High level of pesticides, stored in fatty tissues of prey organisms can kill many forms of predator wild life.
Different methods of pest control:
Different methods are used to control the pests as follows:
Farmer use cultivation methods like crop rotation, adjustment of planting times, timely harvest and multi crop-rotation, adjustment of planting times, timely harvest and multi crop agriculture in order to discourage or inhabit pests.
Rotating the types of crops from year to year can reduce pest population feed on a particular crop. Timely plantation and harvest will ensure that most of pests starve to death before the crop is available to them. Poly-culture on multi crop agriculture will ensure some returns to farmers.
Biological control pests:
It is effective, cheap and does not have any adverse environmental effects. By using lady-bags and spraying mantisew (predator) to control pest, control crop eating moths and flies. A bacterial agent. Bacillus thorigiensis, marketed as a dry power, is effective in controlling many stains of leaf eating caterpillars, mosquitoes and gypsy moths.
- It affects the target species and is non-toxic to other organisms.
- This is need of reintroduction of predator.
- It is economical.
- Development of generic resistance is minimized.
- Genetic control: the meals insects are sterilized males results is a decline of population.
- Natural chemical control: hormones and pheromones can be used to control the population of insects’ pest species.
- Integrated pest management: the present pesticides based approach to pest control can be replaced by a carefully designed ecological approach called integrated pest management.
Its accumulation in soil crops, animal’s tissues and even in humans, resulting many environmental hazards.
Chemical pesticides include malathion, parathion, phosdrin, azodrin and these are more toxic to birds, human beings and other animals.
Carbonates chemical pesticides and the examples of such are – carbary1, temik metacil, zectran, etc.
It includes texaphene, diazinon etc. It helps in pest resistance and it has adverse environmental and human health impact.
When pesticides are sprayed over an area, few organisms, like insects survive because they have genes that make them resistance to a specific-pesticide; those few resistant species reproduce a large number of resistant off springs in short time, resulting decrease in effectiveness of pesticides.
- Insecticides cause environmental pollution.
- It kills the beneficial organism like earth worms resulting soil infertile.
- Organic matter of soil is getting destroyed.
- Pesticides applied to crops cause death of insects which help in population of crop rushing decrease in crop yield.
- Excessive use leads to resistant pests which also hamper crop yields.
- Natural balance of agriculture and environment gets destroyed due to pesticide use.
- Most pesticides remain vegetable and fruits and cause ill health.
- Pesticides also kill soil bacteria’s; resulting decrease in crop yields and affects the agricultural eco-system.
- Toxic chemicals resist biological breakdown.
- Continuous spread of aldrin decreases the number of earth worn in soil.
- Aquatic life in rivers, and lakes like fish, are affected with insecticide pollution.