INDI A

SINGAPORE

M A L AY S I A

Notion Press Media Pvt Ltd No. 50, Chettiyar Agaram Main Road, Vanagaram, Chennai, Tamil Nadu – 600 095 First Published by Notion Press 2021 Copyright © Eugene Sebastian J. Nidiry 2021 All Rights Reserved. ISBN 978-1-63940-371-4 This book has been published with all efforts taken to make the material errorfree after the consent of the author. However, the author and the publisher do not assume and hereby disclaim any liability to any party for any loss, damage, or disruption caused by errors or omissions, whether such errors or omissions result from negligence, accident, or any other cause. While every effort has been made to avoid any mistake or omission, this publication is being sold on the condition and understanding that neither the author nor the publishers or printers would be liable in any manner to any person by reason of any mistake or omission in this publication or for any action taken or omitted to be taken or advice rendered or accepted on the basis of this work. For any defect in printing or binding the publishers will be liable only to replace the defective copy by another copy of this work then available.

This book is dedicated to the loving memory of my mother Late Mrs. Mariakutty John

PREFACE

SPRING NOT SILENT FIFTY-EIGHT YEARS AFTER ‘SILENT SPRING’ Pesticides are the only group of artificially developed chemicals which have contributed towards improvement of public health and food production. While synthetic pharmaceuticals have applications in human medicine, they do not have much application in agriculture. While fertilizers have applications in agriculture, they do not contribute to human health directly. Pesticides control vector borne diseases like malaria, dengue, chikungunya and plague and save million of lives. On the other hand they contribute to food production by preventing the crop plants from the attack of pests and diseases and save millions of people from starvation. In spite of their tremendous contribution to epidemic control and food production, they happened to be the most condemned chemicals, thanks to the environmentalist movement started in 1962 with the publication of the book ‘Silent Spring’. ‘Silent Spring’ authored by Rachel Carlson from USA was published in 1962. This best seller was hailed by environmentalists all over the world as an ‘eye opener’ against the use of pesticides in epidemic control and agriculture. In 1962 the total pesticide consumption in USA was around 90000 metric tonnes, but by the year 2018, it rose to more than 400000 metric tonnes. World consumption of pesticides in 1962 was 0.6 million metric tonnes, but by the year 2018 it rose to 4.1 million metric tonnes. As criticisms on pesticide use mount upon, we find that the consumption of pesticides also increases. In ‘Silent Spring’ the authoress had predicted that the use of some pesticides will affect the reproductive system of birds so much so that it will lead to a ‘Silent Spring’ in which human beings will not able to enjoy the melodious songs of birds in spring season. When this ominous prediction was v

vi

Preface

made in 1962, there were only three billion human beings with an average life expectancy of 53 on earth to enjoy the melodious songs of birds in the spring. Fifty-eight years after this prediction, we find that more than seven billion human beings with an average life expectancy of 68 enjoy the songs of birds in the spring. The apprehension that pesticide use will make the spring silent was the biggest myth of 20th century. We find improved agricultural production, forest conservation, improved life expectancy and general health conditions. If pesticides are inherently harmful there would not have been discussion on their intellectual property rights at international levels, adulteration pesticides would not have been a criminal offence, farmers would not have asked subsidy for pesticides and health departments would not have used them for epidemic control. Have we gone wrong in our understanding about the effects of pesticides? Yes. In the subsequent chapters of the book, attempts are made to dispel the common myths about pesticides. Historical, scientific and statistical data are being presented to highlight the tremendous contribution of pesticides not only to agricultural production and general health conditions but also to forest conservation. EUGENE SEBASTIAN J. NIDIRY E-mail: [email protected] Cell phone: 9886541035

ACKNOWLEDGEMENTS

I thank my son John for his skilful assistance in depicting the structures and graphs given in this book. The encouragement and co-operation given by my wife, Ancy and my younger son Joseph are also being acknowledged. EUGENE S. J. NIDIRY

vii

CONTENTS

Preface

v

Acknowledgements

vii

1. Introduction

1

2. Pesticides and the Environment

58

3. Organic Farming and Organic Chemistry

80

4. Pesticides and their Toxicity

92

5. Pesticide Scare as a Part of Chemophobia

200

6. Pesticides as Unnatural Compounds

215

7. Alleged Presence of Pesticides in Soft Drinks

225

8. DDT, its Persistence and Role in Malaria Control

229

9. Alleged Relationship Between Pesticide Use and Cancer

237

10. Pesticide Use in the Background of Bhopal Gas Tragedy

259

11. Are Pesticides Contributions of Multinational Corporations?

262

12. Pesticides as Petrochemicals

265

13. Pesticides and Human Rights

268

Index

271

ix

1

INTRODUCTION

WHAT IS A PESTICIDE? A pesticide is a substance or mixture of substances used to kill a pest. A pest is an organism which has characteristics that are regarded by humans as injurious or unwanted. Pests include insects, plant pathogens, weeds, molluscs, birds, mammals, fish, nematodes and microbes that compete with humans for food, destroy property, spread or act as vector for a disease or cause nuisance. Photosynthesis is the basic process which sustains almost all life (except that of some microorganisms) on earth. In the process of photosynthesis, plants convert carbon dioxide, water and sunlight to oxygen and carbohydrates which provide energy for life in the form of food. Agricultural crops are those cultivated plants which man has discovered through centuries to provide food, shelter and clothing for survival. In the process of providing these basic requirements to human beings, agricultural crops are being threatened by 80000 plant diseases, 30000 weed species and 10000 insects. It has been estimated that if crop protection methods were not adopted, the potential loss of food production would be 44% (30% attributed to pests before harvest and 14% to post harvest loss). It is also estimated that in the world, more than one billion cases and one million deaths are reported every year due to vector borne diseases (www.who.int). Hence control of pests and diseases are needed for human survival. Table 1.1 gives the loss of food production due to diseases, insects and weeds.

1

2

Pesticides: Myths and Facts

Table 1.1. Loss of food production due to insects, diseases and weeds

Attainable crop production Actual crop production(-36.5%) Production without crop protection Losses prevented by crop protection Actual annual losses to world crop production

$1.5 trillion $950 billion $455 billion $415 billion $550 billion

Data from Agrios G.N. (2005), Plant Pathology, 5th Edition, Academic Press. The use of pesticides is often referred to as chemical method of plant protection. This is because most of the pesticides are artificially synthesized chemicals initially developed in chemistry laboratories. However, history of agriculture shows that man was using physical and biological methods also for pest control since time immemorial. These physical and biological methods can be collectively called as nonchemical methods.

NONCHEMICAL METHODS PHYSICAL METHODS 1. Temperature control Placing produce inside of cold storage containers hinder the growth of insects and microorganisms inside of them. Thus refrigeration is one of the most successful physical method of post harvest preservation used all over the world. Another method to use is to heat, as it will kill the insect larvae in certain types of produce. An example would be with mangoes, where they are placed into a hot water bath in order to kill any eggs and larvae. Stubble left after harvest is burned to reduce chance of infestation. Soil steaming is effective against soil pests particularly in green houses. 2. Electronic bug killer The light of the bug killer attracts flies or mosquitoes towards the system. High voltage wires are fitted near the light which instantly kill the insects with electric shock.

Introduction

3

3. Tillage measures Hoeing, harrowing and rolling of the soil have been traditionally used for the control weeds. Nowadays gasoline driven weed removers are available in the market. 4. Fences, ditches and traps Fences are often used to prevent terrestrial animals from damaging crops. Ditches protect conifers against pine weevils, cereals against cereal carabides or the broad-nosed weevils and beets against root weevils. For trapping insects, fly paper or sticky boards are used in order to capture insects as they land upon the surface of the trap. They are covered in a substance that attracts insects but are actually very sticky or poisonous. These traps are commonly used for flies or leaf hoppers. In India rat traps are widely used against field mice. 5. Temporary flooding Flooding can be used for controlling field mice, grubs and other soil pests. 6. Trimming of infected branches of trees Diseased branches can sometimes be removed before they infect the rest of the tree. Pruning blade can be dipped in a 10 per cent bleach solution between each cut to avoid spreading disease. Dead or broken branches can be removed before insects burrow inside to make a home. 7. Solarization For solarization, the ground is loosened to a depth of 15–25 cm (the entire top soil), well watered and covered with plastic sheets. Heat from the sun warms the top layer of soil up to a temperature at which most organisms will die. This method works against disease-causing bacteria and fungi, and also against weeds in nurseries. 8. Quarantines Plant quarantines are man made measures taken to prevent the introduction and spread of pests, diseases and weeds. These are vital to prevent the introduction of non-indigenous, potentially

4

Pesticides: Myths and Facts

damaging pests and diseases of plants into a country or to eradicate them before they can become widespread and well established.

BIOLOGICAL METHODS Biological pest control is understood as the use of living organisms to limit the population of certain harmful animals and pests. 1. Breeding for resistance Selection, hybridization and mutation are being used all over the world to develop varieties resistant to fungi, bacteria and viruses. 2. Genetic engineering Genetic modification of plants is achieved by adding a specific gene or genes to a plant, or by knocking down a gene to produce a desirable phenotype. The plants resulting from adding a gene are often referred to as transgenic plants. The majority of commercially released transgenic plants are currently limited to plants that have induced resistance to insect pests and herbicides. Insect resistance is achieved through incorporation of a gene from Bacillus thuringiensis (Bt) that encodes a protein that is toxic to some insects. For example, if the cotton bollworm, a common cotton pest, feeds on Bt cotton it will ingest the toxin and die. 3. Insect control by insects Insects can act as predators or parasitoids of harmful insects. Predators consume large number of preys during their whole life time. For eg., lady bugs are vociferous predators of aphids. Parasitoids lay their eggs on the body of insect hosts which is then used as a food for developing larvae. The host is ultimately killed. Most insect parasitoids are wasps or flies. An important group is Ichneumoid wasps which prey mainly on caterpillars of butterflies and moths. 4. Weed control by insects. Some insects are found to be effective in controlling weeds. Mexican beetle (Zygogramma bicolarata) has been found to be effective in controlling Parthenium hysterophorus.

Introduction

5

5. Weed control by plants Some plants are able to suppress harmful weeds. For examples, growing of marigold and Cassia tora have been found to be effective in controlling the noxious weed Parthenium hysterophorus 6. Weed control by fungi Puccinia melampodii and P. abrupta var. parthenicola have been found to be effective against Parthenium hysterophorus. Puccinia lagenophorae Cook has been found to be effective against Senecio vulgaris L. 7. Microbial pesticides Microorganisms can be applied directly to control phytopathogenic fungi, animal pests or weeds. Bacillus thuringiensis is the most widely researched bacterium which has been found to be effective in controlling Lepidoptera insects. Entomopathogenic fungi like Beauveria bassiana have been found to be effective in the control of wide range of insects.The insect-killing fungus Metarhizium anisopliae has been found to be effective in controlling rhinoceros beetle, Oryctes rhinoceros which is one of the most damaging insects of coconut and oil palm crops. Trichoderma protects crop plants from soil-borne diseases and animals that attack plant roots. It also produces chemicals (antibiotics) that are toxic to other micro-organisms. Microorganisms used against pests are known as biopesticides also. 8. Intercropping Intercropping has been found to be effective in controlling some pests and diseases. Tomato Yellow Leaf Curl Virus (TYLCV) disease is transmitted from one plant to another by the whitefly, Bemisia tabaci. Planting coriander as a companion crop with tomato helps in the control of disease since coriander acts as a repellent; it keeps the whitefly away from the tomato plant. 9. Crop rotation Crop rotation is found to be effective in controlling several pests and diseases. Bacterial wilt of tomato can be controlled by rotation with crops like onion, garlic, leek, cauliflower and broccoli.

P E S T I C ID ES : MY T H S AN D FAC TS ‘PESTICIDES’. This word itself evokes aversion, scare and contempt thanks to the chemophobia widespread in the media. But they constitute the only group of artificially developed chemicals which have contributed simultaneously towards improvement of public health and food production. On the one hand pesticides control vector borne diseases and save millions and millions of human lives. On the other hand they contribute to food production by preventing the crop plants from the attack of pests and diseases and save millions of people from starvation. In this book historical, scientific and statistical data are provided to dispel the common myths about pesticides and to highlight the significant contributions pesticides have made towards public health, food security and forest conservation.

Dr. Eugene Sebastian J. Nidiry was born in Kerala in 1953. After graduation from University of Kerala and post-graduation from University of Calicut, he joined Indian Council of Agricultural Research in 1978 and was with this organization until retirement in 2015. He took his doctorate from the Division of Agricultural Chemicals in Indian Agricultural Research Institute, New Delhi in 1987. He is the author of several research papers in reputed national and international journals dealing with the chemistry of biologically active natural and synthetic compounds.

Price 445