Chemical Crop Protection in Modern Agriculture for Food Security and Environmental Crisis: Relevant Facts, Issues & Strategy (Part II)
By Prof. Ashim Chowdhury (Former Professor, University of Calcutta & Former Professor, BCKV, W.B.)
Pest Break havoc on 4,000-acre paddy field in Kerala
“Army Worms” or “Swarming Caterpillar” (Spodoptera sp.) has wreaked havoc in more than 4,000 acre under paddy in Trissur district in just five days. Insecticides like ekalux and carbaryl has helped control the spread in Kole farm lands of Trissur. With 13,632 hectare, the Kole wetlands is spread over Trissur and Malappuram districts and constitutes a major part of the state’s overall paddy growing area.1,000 acres were destroyed in a single night. After application of insecticides and proper manure, paddy cultivation in the affected area could be brought to normal level.
However, it is noted that the pesticides have inherent toxic properties, due to which caution has to be exercised at all the steps, beginning with their discovery till the final used up to the storage at Post harvest. The discussion would be mainly focused on the different issues &strategy thus adopted related with pesticides/agrochemicals.
Unforeseen consequences : But the safe use concept was not in the picture. This broad plant protection chemicals issue was mainly the Inputs in crop protection. As a result the consequences-Toxicity related problem, Resistant, Resurgence & emergence of minor pests as major pest & their mechanism. Residue & effect on non target organism including beneficial flora & fauna are the various issues coming up.
Effective hygiene control, therefore, is vital to avoid the adverse human health and economic consequences in ecosystem, food borne disease. Everyone, including farmers and growers, manufacturers and processors, food handlers and consumers, has a responsibility to assure that food is safe and suitable for consumption. Indiscriminate use of inputs like pesticides to enhance the food production has led to residual problems, resistance, and negative impact on environmental, human and animal health front. These indicating clearly need for an comprehensive approach for pest management. Biorational pest management is one such approach for proper pest management and also in the storage, pesticide use are restricted to those who are not posing any negative impact on crops and other components of the environments. For such reasons, the Government of India has banned 20 pesticides which besides being toxic were damaging the environment. The use of 18 others has not been allowed so far. The fate of 13 others is under review and another 9 pesticides have been permitted for restricted use only. They should be biodegradable, capable of reducing the damage level and safe to fishes, bees, pollinators and other non-target organisms. Leaving less residues or no residues or residues below tolerance level. However, pesticides will continue to remain as one of the main weapons in the hands of farmers to control insects pests, mites, weeds, nematodes and diseases.
Issues & Research Requirements for the Agrochemicals Sectors under New Perspective
- Natural pesticides from resources like Plant, Animal, Microorganism, Arthropod.
- Synthetics, Transformation Products, Intermediates.
02Safe use of agrochemicals
- Residue dissipation study.
- MRL development & pre-harvest Intervals.
03Registration requirement: Analysis of Agrochemicals at the Precision levels using sophisticated methodologies viz., GC, LC, GC-MS,LC-MS, HPTLC, etc.
04Mechanisms of Resistance & resurgence of pests against some chemical agents on different substrates and their management is very much relevant field for the scientist.
05Formulation of Chemical actives both synthetics & Natural products.
06Evaluation of Chemicals actives, formulation products, Mixture of chemical actives formulations, at the Laboratory & field levels on various target crops pests of economic importance.
07Quality control of Actives in various formulations batch wise.
08Contamination of fruits, Vegetables , Cereals raw & processed products.
09Content of Agrochemical, Toxic metals & POPS contents in Environmental substrates.
The research thrusts may be on development of new molecules, target specific with new mode of action but of course with healthy collaboration with Research Institutes – University, & also with Corporate .The problems to be identified as target specific molecules with new chemistry. At present we are lacking in proper laboratory & field performance evaluation of the developed molecules. The laboratory & Field evaluation is to be rightly performed at the Institute or University level. For doing so some course orientation both theory & Practical in relevant discipline (Ento /Patho/ Weed sc. etc.) would have been very much helpful. The strategy is to be develop Plant based/Microorganisms/other natural resource based biocides alone or in combination followed by good formulations.Formulation (with one or different active ingredients) research & academic courses must be strengthened of course with healthy collaboration with University & also with Corporate. Proper orientation of analytical methodologies for residue & dissipation study, Institution/University wise should be mandatory because for any crop in any region as chemical plant protection differs region wise.
Research for finding out the mechanisms of resistenec/ resurgence of pests against some chemical agents on different substrates, is very much relevant field for the chemists. Phenomena of disease resistance/immunity of plant ( May be due to the formation / interaction of some secondary metabolite/ Phytoalexins /else) may also be a field to tackle of course in collaboration with relevant discipline.Post Harvest Processing /Preservation /Value addition of Agri/Horti/Animal source commodities is one very unexplored key issue & can also be tackled. Chemicals of different Sources -Natural, Synthetic, Combination, some herbal, Secondary metabolites, Terpenoids, Essential oils, flavonoids, quinines, some enzymes etc for this post harvest processing issues. Development of Plant /Natural products for other useful purposes viz; Natural dyes, natural perfume/scent, Natural Drugs/disinfectants, Natural detergents, Growth promoter & Inhibitors, ripening agents etc may also be an issue.
Residue issue for Agrochemicals
Less use of pesticides than other countries does not justify to increase their use indiscriminately, because whatever is currently applied is appropriated by a few crops only, e.g., cotton 54% (non food), rice 17%, vegetables and fruits 13%, plantation crops 8% and all remaining crops 8%. Irony of the situation is that increased pesticide dependence aggravates their use because, native pests develop more virulence against them and the natural enemies which would have maintained an auto-control on pest spread also fall prey causing pest resurgence and infestation by previously harmless secondary pest species to them. Although pesticides have become an integral part of modern agriculture, their excessive and non-judicious use has not only resulted in environmental pollution but also developed resistance to several pests, caused pest resurgence and adversely affected beneficial organism like honeybee, pollinators and natural enemies viz., parasites & predators. Above all, indiscriminate pesticidal use leaves not only more harmful residue in the produce, but persistence in soil and water manifests their ill effects long after their application.
The food chain compromise practiced by farmers and consumers assumes that pesticides are used according to Good agricultural practices (GAP) in a manner which minimizes residues in harvested food and does not adversely affect human health. The maximum residue limit (MRL) is regulatory standard that reflects GAP and allows control of pesticides use and residues in food. The MRL has been defined as “the maximum concentration of pesticides residue that is legally permitted or recognized as acceptable on and food, agricultural commodity or animal feed”. Although not a safety standard per molecule proposed MRLs based on field residue trials are assessed for potential human dietary risk for both chronic and if relevant, acute intake exposures. Above all, indiscriminate pesticidal use leaves not only more harmful residue in the produce, but persistence in soil and water manifests their ill effects long after their application.
In terms of intensity of pesticides consumption (g a.i./ha), India consume minimum (350-500) as compared to USA, Germany, Taiwan, Japan, Mexico & even China. Basically indiscriminate & unorganized pesticidal use leaves some undesirable residues in some of export oriented crops in our country for which there is of criticism all over. Increased international trade of fruits & vegetables has increased the complexity of the food chain compromise. The world food code as promulgated by Codex has supported development of a system of Internationally harmonized MRLs and represents the best hope for ensuing fair trade and consumer protection on a world wide basis. Codex MRLs are promulgated based on technical evaluation and recommendation by the FAO/WHO Joint meeting on pesticides residue (JMPR) and have been established for more than 130 pesticides active ingredients on a Variety of crop commodities of Trade. The world Trade organization (WTO) through a 1995 agreement on the application of Sanitary & Phytosanitary (SPS) measures, identified Codex MRLs as the official reference for Food safety issues which affect international food trade and the basis for resolution. It is very much fortunate that Indian MRL for many pesticides for different crops has already been established in recent years.
How to proceed for chemical crop protection under recent environmental protection issue
Safe & judicious use of chemical pesticides that is right doses, right time of application. Right way of functioning of regulatory bodies for Registration, Licensing, Registration. Monitoring of residues of pesticides in all possible environmental substrates by contract laboratories crossed checked by Govt/federal laboratories. Use of Eco friendly chemical pesticides especially biorational pesticides. Botanicals of high potency to be introduced.
Pesticides under strict regulation in India
01Pesticides registered under the section 9(3) of Insecticides act, 1968, GOI as on 30.11.2012: 241 nos.
02Pesticides Banned for manufacture, import and use : 28 nos.
03Pesticide / Pesticide formulations banned for use but their manufacture is allowed for export :2 nos.
04Pesticide formulations banned for import, manufacture and use – 4 nos
05Pesticide Withdrawn:7 nos.
06list of pesticides refused registration:18
07Pesticides restricted for use in india:14
Make good manufacturing / handling practices and quality a watchword in every aspect of product development and domestic and international trade. The quality parameters and their limits should be prescribed carefully keeping the prevalent national conditions in view and not merely be a copy of the international standards. An independent and unbiased set up should evaluate and authenticate the quality parameters and the test methods before adoption as standards. Create a network of test and certification system with established credentials of men and machines (accreditation, international recognition etc.). Enforce quality through accountability of the erring party (industry as well as the enforcement authority) in a time bound manner, regulation, quality etc. Consumer awareness is vital for the health of a progressive society. Both the positive as well as the negative effects of chemicals must be known. In particular, awareness about the shelf and field lives of chemicals, their quality, use spectrum, disposal, decontamination, handling of accidental poisoning cases, various antidotes etc. is paramount.
Integrated Pest Management Model
This model involves the need based use of pesticides only when the pest reach at the economic thresh hold level(ETL) This will promote the build up of many biocontrol agent in the agro ecosystem. In fact it is greener alternative to the conventional use of chemicals , an alternative to promote natural, conomic& sociological farming methods. The most effective combination of farming techniques & judicious & limited use of chemicals. With this perspective in view there is also a great role of chemicals which are safe, target specific, different mode of action & leaving no hazards in cropping system as well as environment.
Right ways of doing it
In spite of introduction of Biorational & Biepesticides for management of pests, in country like ours, Academy Industry interaction/collaboration/PPP model where there is a huge fluctuation of weather along with very small holding of growers, there is no other option but, to recommend the execution of concept of IPM in which the use of chemical pesticides is included. Conceptual Motivation of IPM at the Lower beneficiary level & side by side proper execution of IPM in reality to down the level through the Govt & non Govt organization is indispensable. Training & awareness of real users /farmers /growers by the competent scientist & officers at the all levels who are supposed to provide services is very important.
Despite the obvious attractions of using natural products in agriculture, particularly at a time of great public concern about man-made pesticides they still make up a vanishingly small proportion (<1%) of the global market for Insecticides/ Weedicides & fungicides and bactericides. Some of them like, -methoxyacrylates, cartap, acetamiprid etc. appear to have a much more promising future. The widespread use of antibiotics in agriculture might lead to the creation of resistant strains, which could limit the efficacy of medical treatments for human. In contrast, commercial products derived from natural products (such as pyrrolnitrin) and in the absence of new outlets for existing products. It seems likely that the natural products currently in the marketplace will be progressively replaced by more effective natural and synthetic compounds that can offer advantages in terms of cost-efficacy, resistance-breaking potential.