Pesticides are mostly chemical in nature. DDT and related pesticides have reduced insect enemies of crops, at temporarily and have drastically checked insect borne diseases. Thus the death rates are reduced. With the increase in population, starvation is the end result. The ecological effects of these pesticides have in many cases proved disastrous. They harm a lot when used in excess. It can result in soil and water pollution. In the process of bio-magnification, it enters into our body. Pesticides consumed by us can cause several effects on our body.
DDT tends to be deposited in fatty tissues. Since it is not easily metabolizes and has a half-life of about thirty years, i.e. only half of it will be broken down after thirty years. It remains in most animals for lifetime. The long term effects of DDT on man are extremely difficult to determine. They can even cause cancer and might also have genetic changes. However, the initial benefits brought to agriculture by pesticides are backfired in many instances.
Chemical manure when used in excess comes automatically in the nearby water bodies through rain or so. Agricultural runoff carries high concentration of nitrates and phosphates. They usually lead to algal bloom, population explosion in algae. This increased level of inorganic ions is called eutrophication. It reduces the dissolved oxygen in the water bodies and causes death to the aquatic organisms present there. This is just one incident. There are thousands or more. Only the use of organic manure can replace this. Organic manure is manure developed from natural substances that do not cause any harm to the nature and environment.
The misuse or unexpected effects of herbicides, which are chemicals used to destroy vegetation, have led to considerable ecological damage. Its use could kill wildlife, expose forest soils to erosion and leaching of important nutrients, and could destroy valuable hardwood trees over large areas. Even though these chemicals could bring good productivity of crops, they could damage the whole environment. Use of natural substances can only bring changes to the problem. Integrated Pest Management is one such program. It is a system of pest management. It uses a combination of methods to help reduce pest problems. Natural insecticides are used in this method. GO GREEN.