Prof. (Dr) R. D. Gupta
The use of chemicals to kill pests is not a new phenomenon but it is as old as 70 A.D. when Pliny Elder gobbled an idea for destroying insects with arsenic compounds. The use of arsenic compounds continued till during twentieth century as reported by Gupta (2006). However, the use of synthetic or chemicals gained momentum around 1940 with the coming up of large number of their manufacturing and formulating units all over the world after the development of Dichloro Diphenyl Trichloroethane (DDT). Although DDT was first discovered by O.Zeidler in 1874 yet P. Miller working for Geigy in Switzerland discovered that it has remarkable insecticidal properties.
In agriculture, use of various pesticides was started with the introduction of high yielding varieties of different crops during the year sixty of twentieth century. In fact, the new introduced varieties of rice, wheat, sugarcane, oilseeds, millets and many others possessed more response to applied nitrogenous, phosphatic and potassic fertilizers and as such they are liable to become more susceptible to an assault of different insects, diseases and weeds. Crop loss due to pest attack was found to range from 10-30 percent depending upon the crop and environment. The insect pests, diseases and weeds are the important biotic constraints which were always inflicting 20-25 percent loss in agriculture production, According to Saxena (1996) as reported by Gupta (2006) annual crops losses due to pests in India are estimated atRs.2, 00000 million per year. This crop loss ranged from 10-30 percent depending upon the crop and environment. The recent study conducted by (Rishipal) et al (2013) indicated that pest problem is one of the major constraints for achieving higher production in an agricultural crop. India loses about 30-40 percent of the crops due to pests and diseases every year. The damage due to these problems is estimated to be Rs. 1,40,000crores(14,00000million).
In Indian agriculture, use of various pesticides was started with the introduction of high yielding varieties of rice and wheat during “Green Revolution” which came to fore during 1967-1968. As already stated, the new introduced varieties of wheat and rice had lot of response of added chemicals fertilizers especially nitrogenous, phosphatic and potassic ones, and as a result these varieties of rice and wheat crops became more susceptible to an attack of different insects, pests and diseases. Thus, use of pesticides became an increasing necessary operation for checking pests and in the consistent and economic production of the crops throughout the world. No doubt that uses of pesticides provided an effective control of many pests not only in rice and wheat crops but also in the new introduced varieties of sugarcane, oil seed crops, millets and many others. But at the same time continuous use of pesticides year after year, adversely affected not only abiotic environment-land, soil, air and water but also that of biotic one i.e. through “Pesticidal Pollution” and creating ill effects on plants and animals.
PESTICIDAL POLLUTION
Pesticidal Pollution may be defined as the pollution caused by excessive and indiscriminate use of pesticides owing to their hazardous effects on human, animal and plant life through contaminating air, water and soil.
Presence of high and very high toxic amounts of Pesticidal residues in food grains, food stuff ,fruit vegetables, milk and milk products have been detected and reported (Gupta 2006: Gupta 2013: Girietal., 2015). Another study conducted by Sharma (2013) revealed that the number of insects is decreasing continuously due to more use of pesticides. This in turn reduces the availability of food for sparrows, especially for their young ones. It is because many rather most of the pesticides are non-biodegradable. As such they affect all global ecosystems, disrupting the relationship of one kind or the other. For example, use of pesticides by the farmers in the “Floating Gardens of Kashmir”, has caused a colossal damage to the flora and fauna of the Dal Lake (Gupta. 2016). Thus, there is a dire need for restoration of wetlands (Sriraj, 2018). Itis because wetlands across the world are getting diminished mainly due to policy paralysis, subversion of land use and this does not bode well for the fight against climate change. Currently, more than 14 percent of the world’s wetlands have been lost since 1990, and as wetlands are destroyed. more carbon is released into the atmosphere, thereby contributing to a global temperature rise.
Apart from the above, climatic variability directly impacts crop yields by way of effecting soil quality water resources as well as insects’ pests ,diseases and weeds etc(Laland Tondon,2019).
Since now we have approached to 21″ century so there is an increasing demand on conservation of biodiversity, unpolluted environment and to sustain high yields in various crops of agriculture as well as of horticultural fruit trees and olericultural/ vegetables production and sericulture/ mulberries production vis-a-vis various aspects of animal husbandry and bee farming.
To face the various kinds of pests instead of chemical pesticides, we have to tackle these challenges through the use of various kinds of Biopesticides (Mahajan and Gupta, 2009; Mahapatra 2012). It is remarkable to note that applied pesticides do not kill only the insects but always reside in the soils, fruits and vegetables (Kyu, 2007). When absorbed in the animal’s body including those of human beings they can do serious harm to their bodies and even their effects can be seen in the coming or next generations.
Several large national and multinational companies have now entered in to the fresh and processed food industries with a great thrust on exports as was referred to by (Dhall and Garg, 2008).
However, one of the most important constraints faced by the farmers of our country i.e. the Indian farmers today in the production of high quality vegetables is their frequent and heavy infestation by several kinds of insects pests which survived extremely well under irrigated and highly nutrients rich environment in the fields. To combat insects pests in vegetables farmers use several kinds of insecticides which are generally applied somewhat close to the harvest or picking time of vegetables. As a result, the residues of these chemicals remain in the vegetables and soil, water, air and environment. The farmers are therefore, required to use green pesticides and biocontrol agents in the Integrated Pest Management (IPM) modules so that safe and quality produce can be obtained for domestic and international markets.
Although pesticides are found quite effective in pest control yet are proved to be toxic(Gupta,2013). It is because after their application they leave residues in food stuffs i.e. food grains, vegetables and fruits. Studies have revealed that with the daily food and water intake, high number of pesticides, pathogens and bacteria vis-à-vis heavy metals are ingested. And they then pose increased risks to diseases like cancer, high blood pressure in women and men, and mental impairment of children. It is point to mention that most of the plant insecticides act as contact poisons being absorbed through the cuticle of the insect (Selvietal., 2008).
Researchers found that pesticides like pentachlorophenol, DDT and Methylparathionate recommend levels were present in farm soils interfered the leguminous plants like alfalfa peas and soybean significantly and symbiotic bacteria also(Girietal.2015).
Pesticidal pollution in the air and in water are, in fact, making our world increasing hostile to our good health and wellbeing (Husain, 2016). But lately there has been higher awareness of pollutants and how they lead to a build-up of toxins in the system. Our lifestyle can compound the problems further.
According to Shiva (2006) farmers suicides in various districts of Punjab state, were a direct result of debt and debt is a direct result of dependence on costly seed which require costly fertilizers and even more easily pesticides. costly Meantime, the prices of agricultural / horticultural commodities keep falling due to dumping and imports of artificially cheap, subsidized cotton, soybean, sugarcane, milk etc.
(The writer is Former Associate Dean Cum Chief Scientist KVK, SKUAST, Jammu)