Many anthropologists consider the great expansion of agricultural yield to be the singular achievement of the modern era. But from a thermodynamic perspective, modern agriculture is the least productive form of agriculture in history. It uses far more energy inputs like pesticides per unit of every output than in any previous period (Farb, 1978). This accomplishment was attained by increasing reliance on petrochemical-based pesticides to protect yields (Clifford et al., 2008). Recently, an international panel of experts identified ten nanotechnology applications that are most likely to benefit developing countries. The top on the list was agricultural pesticide. Science has advanced to the point that cutting edge research involves working with individual atoms and molecules. Nanotechnology holds the promise to exceed the advances achieved in recent decades in crop biotechnology and is expected to have dramatic impacts, such as improving agricultural inputs like pesticides in developing countries (Anane-Fenin, 2006). Nanotechnology promises to reduce pesticide use, development of a range of inexpensive nanotech applications for slow release and efficient pesticides for plants (Zhu et al., 2006).
Applied research has rapidly advanced pesticide formulation technology over the past 5 years despite having few new chemicals approved for use. Progress has been due principally to increased efforts by agrochemical companies to renew older products that no longer have patent protection. Glyphosate is the best example of this trend where patents are filed monthly and manufacturers introduce new salts and formulations yearly. Many agrochemical markets are overwhelmed with “new and improved” formulations. Customers want manufacturers to “put all the good things into one product” to ensure performance and ease of use. Ingenuity by the pesticide formulation researchers has kept the patent literature active and the commercial pipeline full (Green and Beestman, 2007).
Pesticides are conventionally applied to crops via periodic broadcasting and spraying. Very high and possibly highly toxic concentrations are applied initially and these often decrease rapidly below the `minimum effective concentration’ level. As a result repeated application becomes necessary to obtain effective control. The formulation of a pesticide must thus be designed to meet the demands of efficacy and suitability to the mode of application and minimizing the damage to the environment. Nanoencapsulated pesticides meet these demands in that they enable smaller quantities of the pesticides to be used effectively over a given period of time interval and in that their design enables them to resist the severe environmental processes that act to eliminate conventionally applied pesticides, i.e., leaching, evaporation and photolytic, hydrolytic and microbial degradation. Although several approaches have been undertaken to develop nanopesticide formulations around the world, but research on the molecular mechanism of action of nanopesticides in insects, biosafety and molecular interaction with plant, soil and environment is scanty. When the nanoformulations are applied as foliar spray or in the soil, the carrier and pesticide interact with the soil, insect, plant and atmosphere. We have little knowledge how these nanoencapsulated pesticides are degraded in the soil. Researches on these areas are of paramount importance both at the basic and strategic level. It is expected that by 2015, a large number of nanoformulations will be introduced in the Indian market. Within this period, development of study models, molecular protocols for understanding these aforementioned issues will be very helpful for Indian agro-industry and agro-research in particular. The environmental problems caused by overuse of the aforesaid pesticides have attracted a lot of attention of scientists in recent years engaged in basic research. It was estimated that about 2.5 million tons of pesticides are used on crops each year and the worldwide damage caused by pesticides reaches $100 billion annually. The reasons for this are two folds: (1) the high toxicity and non-biodegradability of pesticides and (2) the lack of scientific formulations, i.e. only few percentage of pesticides is effectively used for killing insects, many of them either been washed away into soil, water bodies and atmosphere causing pollution of soil, water resources, atmosphere and fishes or remained on the crop surfaces affecting public health, living and non-living components of the existing ecological niches. While, the benefits and prospects of the nanocapsulated pesticides are huge, but addressing some of the following issues are also equally important while designing the nanocarriers. They are- (1) cost of the material and processing of the nanoencapsulated formulations should be low compared to the existing formulations, (2) Fate of the nanocarriers in the environment, plant and soil (3) Fate of nanocarrier additives like fillers, stabilizers, antioxidants etc., (4) Environmental impact of the degradation of the carriers and additives in response to heat, hydrolysis, oxidation, solar radiation and biological agents, and (5) possibility of getting approval for registration from the regulatory agencies. As these carriers are new in the field of Indian agriculture, therefore, all the pesticide efficacy studies must be done at the controlled atmosphere of the green house level and at least three different soil types should be used. Towards this end, we propose to work with lateritic soil, soils from hilly regions as well as alluvial soil. Three soil types will also allow us to perform comparative studies on the soil degradation pattern of the nanocarriers. In future modeling studies can be undertaken with these rigorous and exhaustive dataset. |