No doubt pesticides did serve a useful purpose in cutting down food grain and other agricultural crop losses very significantly and there were hundreds of chemicals found useful in destroying many predators of food in the field as well as storage godowns during the last few decades. But increasing knowledge, better monitoring and analytical techniques and highly efficient toxicity assessment methods have brought out the stark reality that most of the pesticides are environmental hazards, besides leaving toxic residues in the crops at significant levels affecting human health. The biggest challenge facing man to day is how to increase the food supply by increasing the land productivity as well as cutting down waste due to predatory vectors. Experience of Sweden which has cut down the use of pesticides by almost half while managing increased yield levels and of Indonesia being able to reduce pesticide use in rice dramatically without affecting the yield are encouraging examples as to how mankind can achieve a zero level use one day without adversely affecting food production.
Ever since Sulfur powder was used as a pesticide in ancient Mesopotamia almost 5000 years ago, the pesticide manufacturing industry has traveled through different eras, succeeding each other through Pyrethrum and Rotanone from plants, nicotine sulfate from tobacco leaves, chemicals based on arsenic, mercury and lead and finally arriving at the post-1950 modern era where chemical pesticides derived from Organochlorine, Organophosphate and Carbamate became standards for crop protection in the farms. DDT which was used world-wide for many years was banned though in many countries it is still in use. It is estimated that around 2.5 million tons of synthetic chemicals are produced annually as crop protectants out of which more than 70% is accounted for by the industrialized countries. Due to extreme hostility to the practice of using chemical pesticides by the consumer community because of their poisonous nature, even production statistics are not easily available. FAO's International Code of Conduct on the Distribution and Use of Pesticides serves a useful purpose in laying down country-level control guidelines for developing countries. Similarly FAO-WHO Codex Alimentarius Commission periodically comes up with standards for pesticide residues in foods considered safe for human consumption.
Recent action by the US authorities in "progressively" banning a relatively well known pesticide called Aldicarb in the country can evoke bitter memories of the environmental tragedy in the Indian city of Bhopal in 1984, when more than 3000 people lost their life besides another 15000 maimed for life due to a massive management failure by the erstwhile Union Carbide, now a part of the MNC Dow Chemicals of USA. Release of 40 tons of the deadly Methyl Iso Cyanate gas from a severely rusted storage tank caused the tragedy and this is an intermediate compound in manufacturing carbamate pesticide including Aldicarb. Is it not an irony that it has taken more than 25 years after the tragedy for this most powerful country on earth, which pioneered Carbamate pesticide technology, to arrive at the inevitable conclusion that it is a dangerous pesticide? Or is that this country woke up to the dangers of Aldicarb only after 2000 people were affected by consuming Watermelon contaminated with this deadly chemical in 1985? In stead of immediately banning the chemical, bowing to industry pressure, American government has shown its apathy towards consumer safety by giving a phase out period to the manufacturer who can continue to market it till 2015!
Organic food industry which has been able to capture more than 2% of food market since its humble beginning two decades ago is based on zero use of chemical pesticides during production, storage and processing. There is no dispute about the relative safety of organic foods though their claim of superiority in terms of nutrition is some what far fetched. There are a number of alternatives to synthetic chemical pesticides which include plant based substances with pesticidal activity, pheromone trapping of insects, microbial pesticides, composted yard waste with high carbon to nitrogen ratio and genetic engineered crops with built-in resistance to some pests. Bt crops are gaining increasing acceptance by the farming community, especially for sugar beets, cotton, corn etc and a substantial portion of world production is accounted for by them. However some serious long term safety and environment problems associated with GM crops cannot be wished away easily.
With progressive elimination of synthetic chemical pesticides due to their suspect safety credentials, a new area has opened up for development of new approaches in crop protection and there is an urgent need to consolidate the research activities going on globally in order to evolve acceptable protocols with no problem related to residue related toxicity and environmental pollution. Digging into traditional crop protection practices in Asia, Africa and South America with thousands of years of history behind them may provide many clues regarding safe practices of food conservation deployed by our ancestors which can be studied against the scientific knowledge available to day..