Pesticide Residues in Agro-Horticultural Ecosystems

Agro-horticultural produce constitutes an essential part of human diet, and as per the recommendation of World Health Organization (WHO), there should be at least 30% fruits and vegetables in our daily diet, depending on the body weight of the person. Vegetables are the major source of vital nutrients.

But it is not heartening to know that instead of fulfilling the nutritional requirements, these fruits and vegetables carry pesticide residue harmful to the health of the consumers. Main reasons of finding the pesticide residues in these food stuffs may be because of providing shiny and fresh appearance and good color to the crop. This leads to usage of synthetic chemicals beyond the safe limits. Due to the persistent nature of some of the highly toxic pesticides, or maybe due to illegal use of prohibited/banned pesticides, these compounds have been detected in the environment worldwide.¹⁴⁵¹ So, usage of restricted pesticides is a matter of concern especially in case of vegetables. There is a general belief that these food items are much harmful if impregnated with pesticides in comparison to other food stuffs, because they are generally consumed raw or semi-cooked. Many studies support the presence of pesticide residues in vegetables, on an average, this percentage is 50%-70% in India as mentioned by I⁴⁶-⁴⁸!. In India, 51% of the food commodities have been detected with pesticide residues.¹⁴⁹¹ A study conducted by Charan et al. in 2010^|47l revealed that 67% of total contaminated samples exceeded the maximum residue limit (MRL) values recommended by the Food and Agriculture Organization (FAO)/WHO. Another study revealed the presence of monocrotophos, chlorpyrifos, cypermethrin, and endosulfan, etc. in the vegetables.¹⁴⁸¹ According to a report, over 98% of sprayed insecticides and 95% of herbicides reached nontarget destinations such as other species, air, water, and soil.

Most of the pesticides used on crops are persistent, especially organochlorines, which persist for a longer period in the environment (substrate). The organochlorine insecticides (such as DDT and BHC) that were banned still persist in soil and contaminate both organic and conventional crop produce. Baker and co-workers observed pesticide residues in organic fruit samples. The reasons for residues in organic fruit samples were in violation of organic methods of cultivation, pesticide-contaminated water used for irrigation, or pesticide residues left in the soil, if previously used to grow conventional crops.¹⁵⁰¹

Apple fruit crop is attacked by a number of insect pests and diseases such as apple scab, San Jose scale, wooly apple aphid, fruit scrapper, defoliating beetles, and tent caterpillar. Pesticides such as chlorpyrifos, endosulfan, carbendazim, propineb, and mancozeb are applied to control these pests. After spraying/ treatment, pesticide residues get deposited on the fruits and dissipate slowly depending upon the number of factors such as physiochemical characteristics of pesticide, weather conditions, and time after treatment. Preharvest or postharvest interval or waiting period between spray and harvest is required for safe consumption of fruits. Sometimes, the produce is sent to the market immediately after spraying, and consumers unknowingly consume the product and may be badly affected. Similarly, under Indian conditions, a number of synthetic pesticides, such as deltamethrin, cypermethrin, dimethoate, quinalphos, oxydemeton methyl and carbaryl, are used to control mango crop pests such as mango hopper, mango mealy bug, and fruit fly, as well as powdery mildew and malformations. Deltamethrin at 0.002% does not require any waiting period, but cypermethrin requires 11 days of waiting period. Mango is eaten after removing the peel, but the residues on its peel also find their way into the consumer by contact. Residues of mancozeb and lindane though within the permissible limit were detected in mango fruit samples.¹⁵¹¹ The repeated spray of bifenthrin on mango from flowering to 1 month before harvest resulted in residues that persisted on the peel for more than a month, and rate of degradation was very low.¹⁵²¹

The consumption of pesticide in India is low as compared to other countries, in spite of this, there is widespread contamination of food commodities with pesticide residues due to non-judicious use of pesticides. An earlier survey carried out by the Indian Council of Medical Research, New Delhi, revealed that 51% of food commodities contained pesticide residues, and out of these, 20% had pesticide residues above the MRL values, as compared to 21% contamination with only 2% of samples above the MRL on a worldwide basis.¹⁵²¹

Now, the scenario in India has started changing very rapidly as new pesticide molecules, whose application rate (as well as persistence in the environment) is very low, are being introduced every year. Heavy-duty pesticides have been either banned or put under restricted use. The pesticide load on the agro-horticultural ecosystem has declined as compared to the last decades. Maximum pesticides in India are used on cotton and rice. The Malwa area of Punjab, which is famous for cotton growing, has been named as the cancer belt of Punjab because pesticides have contaminated the whole environment, including groundwater, and caused cancer among its people. Out of the total pesticides used in India, only 13%—14% is used on fruits and vegetables; despite this, half of the fruits and vegetables were found contaminated with pesticide residues.¹⁵²¹ Pesticide residues in 10% of the samples were above the MRL value. Residues of methyl parathion, endosulfan, chlorpyrifos, Dimethyl 2,2-Dichlorovinyl Phosphate (DDVP), dimethoate, fenitrothion, monocrotophos, cypermethrin, deltamethrin, copper, etc., were above the MRL in fruits and vegetables.¹⁵²¹

Approaches for Pesticide Use Reduction

Since the excessive and indiscriminate use of pesticides has polluted every component of the environment, people all over the world have realized the need for pesticide reduction so as to prevent the environment from further deterioration. The use of pesticides in fruits and vegetable production has been developed in many countries and the range of pesticides is very large, most of them are chemicals used since the 1950s, quite often pesticides not licensed for use on food crops (typically cotton pesticides and consumers health).

However, it is not an easy task, as agrochemical market and crop protection knowledge are increasingly controlled by few multinationals. Today, more than 80% of worldwide pesticide sales fall to the share of only six companies. Presently, efforts are being made to reduce pesticide applications worldwide by organic and integrated pest management (IPM) approaches. IPM system relies on biological, cultural, and other less chemically intensive approaches to pest management and are best options to minimize residues in several horticultural commodities requiring cooperation between farming community and pesticide dealers while providing high quality and pest-free produce in developing countries. IPM strategies need to be concentrated on improving the cultural practices and reducing pesticide use, substituting less costly ecofriendly pesticide, continuous monitoring of the pest menace, and finally, training the extension officers/farming community to make IPM a successful event.

However, in countries like India, this alternative pest management approach to reduce pesticide use could not find much success due to poor farmer participation. An all-India survey confirmed that 34% of the respondents have no idea about IPM and only less than 5% of them follow complete IPM technology.¹⁵³¹ Nowadays in many states of India, government authorities are promoting natural farming and urging the farming community to adopt it in order to discourage the use of chemical pesticides.

However, IPM techniques are still characterized by a large amount of pesticide use and by the application of many different pesticides, e.g. organic apple production does not use any herbicides and applies only biological control, but fungal diseases like apple scab demand for the intensive use of sulfur and copper in organic apple orchards and copper has a negative impact on the environment. IPM techniques have not been widely implemented on many crops, e.g., wheat. There is a great need to modify “good agricultural practice” and change it to “pesticide avoidance practice” and to improve the education of farmers so as to promote organic farming or natural farming and IPM as the best alternatives for pesticides.

References

• 1. Dhaliwal, G.S., and Arora, R. Integrated Pest Management Concepts and Approaches. Kalyani Publishers, New Delhi, 2001, 427pp.
• 2. Imhoff, D. King Cotton—Pesticide Residue is Commonin Cotton Byproducts Used in Agriculture- Brief Article. Sierra, 1999.
• 3. Pesticides Industry Sales and Usage: 2000 and 2001 Market Estimates; U.S. Environmental Protection Agency, May 2004, Table 3.4, available at www.epa.gov/oppbeadl/pestsales/01pestsales/ market_estimates2001.pdf (accessed March 2,2019).
• 4. Anonymous. Scientific Agriculture Prevents Mass Starvation. Herxter. J. Agvet Div., Hoechst, Australia Inc., 1992.

• 5. Kennedy, I.R. Pesticides in Perspective: Balancing their benefits with the need for environmental protection and remediation of their residues in seeking agricultural produce free of pesticide residues. In Kennedy, I.R., Skerritt, J.H., Johnson, G.I., and Highley, E. (eds.) Proceedings of an International Workshop held in Yogyakarta, Indonesia, 17-19 February, 1998; The Australian Centre for International Research (ACIAR), 1998.
• 6. Tata Strategic Management Group: Next generation Indian agriculture-Role of crop protection solutions. A report on Indian Agrochemical Industry, 2016.
• 7. FAOSTAT. 2018, available at http//www.fao.org/faostat/en/#data/EP
• 8. Pesticides and the Agrochemical Industry. Pesticide use reduction in Germany Pesticide Action Network Germany Pesticide Action Network Europe, available at www.pan-germany.org (accessed February 27,2019).
• 9. Dhaliwal, G.S., and Koul, O. Quest for Pest Management from Green Revolution to Gene Revolution. Kalyani Publishers, New Delhi, 2010.
• 10. Anonymous. Ministry of Statistics and Programme Implementation. Government of India, 2018. http://www.mospi.gov.in/ Website (assessed on May 15,2020).
• 11. Indira, D.P. Pesticides in agriculture—A boon or a curse? A case study of Kerala. Economic and Political Weekly, 2010, xlv (26 and 27) EPW, 50-52.
• 12. Jayakrishnan, T. Health impacts of pesticides used in agriculture. In Devi, P.L. (ed.) Pesticide Use and Environmental Health, compendium of papers presented in the workshop, KAU/SANDEE; Kerala Agricultural University Publishers, 2006.
• 13. Johansen, C.A. Pesticides and pollinators. Annual Review of Entomology, 1977,22:177-192.
• 14. Hardin, M.R., Benrey, B., Coll, M., Lamp, W.O., Roderick, G.K., and Barbosa, P. Arthropod pest resurgence: An overview of potential mechanisms. Crop Protection, 1995,14: 3-18.
• 15. Ruberson, J.R., Nemotom, H., and Hirose, Y. Pesticides and conservation of natural enemies in pest management. In Barbosa, P. (ed.) Conservation Biological Control. Academic Press, San Diego, CA, 1998, pp. 207-220.
• 16. Croft, B.A. Arthropod Biological Control Agents and Pesticides. John Wiley & Sons, New York, 1990.
• 17. De Clercq, P., De Cock, A., Tirry, L., Vinuela, E., and Degheele, D. Toxicity of Diflubezuron and Pyriproxyfen to the predatory bug Podisus maculiventris. Entomologia Experimentalis et Applicata, 1995, 74:17-22.
• 18. Charleston, D.S., Kfir, R., Dicke, M., and Vet, L.E.M. Impact of botanical pesticides derived from Melia azedarach and Azadirachta indica on the biology of two parasitoid species of the Diamond back moth. Biological Control, 2005, 33:131-142.
• 19. Ware, G.W., and Whitacre, D.M. The Pesticide Book. Meister Pro Information Resources, Willoughby, OH, 2005.
• 20. Cioyd, R.A. Managing insect and mite pests. In Nau, J. (ed.) Ball Red Book (Vol. 2,18th Edition). Ball Publishing, West Chicago, IL, 2011, pp. 107-119.
• 21. Cioyd, R.A., and Bethke, J.A. Impact of neonicotinoid insecticides on natural enemies in greenhouse and interior environments. Pest Management Science, 2011, 67: 3-9.
• 22. Cioyd, R.A. Compatibility of insecticides with natural enemies to control pests of greenhouses and conservatories. Journal of Entomological Science, 2006,41:189-197.
• 23. Stapel, J.O., Cortesero, A.M., and Lewis, W.J. Disruptive sublethal effects of insecticides on biological control: Altered foraging ability and life span of a parasitoid after feeding on extra floral nectar of cotton treated with systemic insecticides. Biological Control, 2000,17: 243-249.
• 24. Jacobs, R.J. Kouskolekas, C.A., and Gross, H.R. Jr. Responses of Trichogramma pretiosum (Hymenoptera: Trichogrammatidae) to residues of permethrin and endosulfan. Environmental Entomology, 1984,13: 355-358.
• 25. Elzen, G.W., O’Brien, P.J., and Powell, J.E. Toxic and behavioral effects of selected insecticides on the Heliothis parasitoid Micropliti scroceipes. Entomophaga, 1989,34: 87-94.

• 26. Elzen, G.W. Sublethal effects of pesticides on beneficial parasitoids. In Jepson, P.C. (ed.) Pesticides and Non-Target Invertebrates. Intercept, Wimborne, 1990, pp. 129-150.
• 27. Roger, C., Vincent, C„ and Coderre, D. Mortality and predation efficiency of Coleomegilla macu- lata lengi Timb. (Col., Coccineilidae) following application of neem extracts (Azadirachta indica A. Juss., Meliaceae). Journal of Applied Entomology, 1995,119: 439-443.
• 28. Desneux, N., Decourtye, A., and Delpuech, J.M. The sublethal effects of pesticides on beneficial arthropods. Annual Review of Entomology, 2007,52: 81-106.
• 29. Moriarty, F. The Sublethal effects of synthetic insecticides on insects. Biological Reviews, 1969,44: 321-357.
• 30. Wright, D.J., and Verkerk, R.H.J. Integration of chemical and biological control systems for arthropods: Evaluation in a multitrophic context. Pesticide Science, 1995,44: 207-218.
• 31. Gerson, U., and Cohen, E. Resurgence of spider mites (Acari: Tetranychidae) induced by synthetic pyrethroids. Experimental and Applied Acarology, 1989, 6(1): 29-46.
• 32. Beers, E.H. Integrated Mite Control: Nontarget effects on predator and prey. 84th orchard Pest and Disease Management Conference, 13-15 January, 2010, Portland Hilton, Portland, OR, 2010.
• 33. Huang, J.K., Ruifa, H., Fan, C., Pray, C.E., and Rozelle, S. Bt cotton benefits, costs and impacts in China. AgBioForum, 2002, 5(4): 153-166.
• 34. Pray, C.E., Huang, J., Hu, R., and Rozelle, S. Five years of Bt cotton in China—The benefits continue. Plant Journal, 2002, 31(4): 423-430.
• 35. Qaim, M., and Zilberman, D. Yield effects of genetically modified crops in developing countries. Science, 2003, 299: 900-902.
• 36. Qaim, M., and Dejanvry, A. Genetically modified crops, corporate pricing strategies, and farmers’ adoption: The case of Bt cotton in Argentina. American Journal of Agricultural Economics, 2003, 85(4), 814-828.
• 37. Traxler, G., Godoy-Avila, S., Falck-Zepeda, J., and Espinoza-Arellano, J. Transgenic cotton in Mexico: A case study of the Comarca Lagunera. In Kalaitzandonakes, N. (ed.) The Economic and Environmental Impacts of Agrbiotech. Kluwer, New York, 2003, pp. 183-202.
• 38. James, C. Global Status of Commercialized Transgenic Crops: 2002. ISAAA Briefs 27. Ithaca, NY,
• 2002.
• 39. Pimental, D. Area-wide pest management: Environmental, Economic and food issues. In Vreysen, M.J.B., Robinson, A.S., and Hendrichs, J. (eds.) Area-wide Control of Insect Pests: From Research to Field Implementation. Springer, Dordrecht, 2007, pp. 35-47.
• 40. Sheety, P. K., Murugan, M., and Sreeja, K. G. Crop protection stewardship in India: Wanted or Unwanted. Current Sciences, 2008, 95: 457-464.
• 41. Dixit, A. Herbicide recommendation in different crops. Crop Care, 2009,35(2): 33-38.
• 42. Pispini, M., Schimpf, M., Lopez, J., and Chandrasekaran, K. Who Benefits from GM Crops? The Rise in Pesticide Use. Friends of the Earth International and Center for Food Safety, 2008, see especially pp. 8-12, available at www.centerforfoodsafety.org/WhoBenefitsPR2_13_08.cfm (accessed December 14, 2010).
• 43. Anonymous. 2011, available at www.beyondpesticides.org/pesticides/factsheets/Atrazine.pdf (accessed February 18,2011).
• 44. Nikolova, S. Pesticide use, issues and howto promote sustainable agriculture in Bulgaria. Published by Pesticide Action Network Germany (PAN Germany) in co-operation with Association, Agrolink, 2004.
• 45. Rajendran, R.B., and Subramanian, A.N. Chlorinated pesticide residues in surface sediments from the river Kaveri, South India. Journal of Environmental Science and Health, 1999, 34: 269-288.
• 46. Karanth, N.G.K. Challenges of limiting pesticide residues in fresh/vegetables: The Indian experience. In Hanak, E.E., Boutrif, P., and Fabre, M.P. (eds.) Food Safety Management in Developing Countries. CIRAD-FAO, Montpellier, 2002, pp. 11-13.

• 47. Charan, P.D., Ali, S.F., Kachhawa, Y., and Sharma, K.C. Monitoring of pesticide residues in farm gate vegetables of central Aravalli region of Western India. American-Eurasian Journal of Agricultural & Environmental Sciences, 2010, 7: 255-258.
• 48. Ranga Rao, G.V., Sahrawat, K.L., Srinivasa, R.C., Binitha, D., Reddy, K.K., and Bharath, B.S. Insecticide residues in vegetable crops grown in Kothapalli Watershed, Andhra Pradesh, India: a case Study. Indian Journal of Dryland Agricultural Research and Development, 2009,24: 21-27.
• 49. Gupta, P.K. Pesticide exposure. Indian Science. Toxicology, 2004,198: 83-90.
• 50. Baker, B.P., Benbrook, C., Groth, E„ III, and Benbrook, K.L. Pesticide residues in conventional, integrated pest management (IPM)—Grown and organic foods: Insights from three US data sets. Food Additives & Contaminants, 2002,19: 427-446.
• 51. Bhandari, R. Pesticide residues in vegetables and fruits. International Journal of Scientific Research in Chemical Sciences, 2015, 2(1): 11-17.
• 52. Soudamini, M., and Rekha, A. Persistence of dicofol residues in/on acid lime. Pesticide Research Journal, 2005,17(1): 64-65.
• 53. Shetty, P.K., Murugan, M„ and Sreeja, K.G. Crop protection stewardship in India: Wanted or unwanted. Current Science, 2008,95(4): 457.