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Crop protection and sustainable agriculture
Agriculture
Ecosystems & Enwronment ELSEVIER
Agriculture, Ecosystems and Environment 51 (1994) 349-353
Book reviews Crop protection and sustainable agriculture Crop Protection and Sustainable Agriculture, CibaFoundation Symposium 177, Wiley, Chichester, UK, 1993,285pp., hardback, 45.00, ISBN 0471939447. This book is the proceedings of a symposium on world food production by means of sustainable agriculture and the role of crop protection. Scientists from various parts of the world (India, UK, Netherlands, The Philippines, China, Syria, Benin, Australia, Germany, France Malaysia, Kenya, Switzerland) met in Madras, India, to discuss the complex issue of feeding the growing human population without destroying the environment. The 15 articles include recorded discussions and two general discussions between natural and social scientists elucidating the topic from the technical, sociological and economic point of view. The content is structured from the general to the specific. The first articles, which deal with information about the ecological and economic background, are followed by specific case studies and field experiences concerning the implementation of integrated pest management (IPM) programmes, most of them referring to the host country India. At the beginning a hypothesis is put forward that the world is able to feed a population of 80 000 million people. The calculations are based on world biomass production due to photosynthesis not taking into account any socio-economic constraints of agriculture. By this theoretical approach it is shown that there is an enormous potential for food production. Whether we are able to use this potential or not Elsevier Science B.V.
depends on the knowledge of appropriate agricultural techniques and on the socio-economic conditions that make farmers use certain techniques. The main part of the book also deals with the explanation of the slogan-like words 'sustainable' and 'integrated'. Sustainable agriculture is understood generally as an agricultural concept where ecological stability and maintenance of the potential of future production are ensured as well as an increasing food production. Integrated production is defined as an assemblage of methods including modern technologies which are sensibly used in order to reach the goal of sustainability. However, most participants use the word 'integrated' as a synonym of'sustainable'. These progressive strategies are suggested considering failed agricultural concepts in the past. High input agricultural practices led to an excessive use of pesticides and fertilizers with a threatening impact on the environment. Genetic uniformity of crops developed, owing to the emphasis of plant breeding on high yield varieties. This in turn made crops susceptible to pest outbreaks. Examples of the damaging effect of pesticides in general and pesticide induced pests in particular are presented throughout various articles and the discussions. For example: ( l ) the outbreak of the brown plant hopper that is caused by the overuse of insecticides; (2) the loss of resistance to insecticides of the two main malaria vectors in India; (3) a higher population of whiteflies that is caused by an increased use of pyrethroids. The solution to the problem is likely to be a cessation of spraying and the use of different crop protection techniques. IPM is based on biologi-
350
Book reviews/Agriculture, Ecosystems and Environment 51 (1994) 349-353
cal control and integrates traditional knowledge as well as indigenous varieties, whereas the decisions regarding the use of pesticides are made according to locally developed thresholds. However, agricultural sustainability is not merely a matter of solving technical problems (Jones). Most of the right technologies are already known, but cannot be applied by the farmers because of complex socioeconomic reasons. Again the reader is introduced to a number of precise cases concerning this issue: ( l ) For example in many countries farmers use fertilizers at the wrong time because they cannot get financial credit in time to purchase the fertilizers. (2) In India pesticides have been subsidised by the government, hence they were more attractive to farmers than IPM methods. Following the subsidisation of IPM inputs such as pheromone and light traps they are able to compete with pesticide use. (3) In Thailand a correlation between the price of rice and the outbreak of brown plant hopper and ragged stunt virus was found. The high price of rice caused the farmers to grow higher yielding varieties and increase insecticide use. This in consequence led to the outbreak of the brown plant hopper. These cases (which the reviewer describes in a simplified way) demonstrate the complexity of economic and political factors that influence pest status and pest management. The necessity to influence agricultural development by economical programmes and subsidies is obvious. Government interventions in the pesticide market are discussed as well as other policy instruments which focus on reducing the dependence on pesticides. The analytical and theoretical side of this issue is described as a complex but logical system of socioeconomic and political interactions. However, the transfer of the concept into practise looks like an unsolvable problem, especially when there are powerful pressure groups such as the chemical industry that forces a different development. Norton compares the problem with the picture of a tiger. "We are sitting on a tiger of development," with the question, who is guiding?.
Another issue that is discussed frequently throughout the book is the problem of how to convince farmers to accept IPM programmes. It is generally agreed that top-down centrally organized groups do not work and that projects that are based on participation should be promoted. But some kind of re-education of the farmers has to be carried out first, because former extension concepts were based on increasing pesticide use and turned farmers into 'consumers of technology'. A lot of participants made the observation that farmers use pesticides for prevention thinking that in that way they reduce the risk of crop loss. The discussions concerning the social structures and the psychology of farmers reveal that most participants are just beginning to work on that issue. Farmers' attitudes and objectives as well as the way they make their decisions are described as something arbitrary and not logical. There seems to be a lack of understanding of social and psychological processes which makes further investigation and an emphasis on this subject necessary. In this context it is not surprising that the fact, that the majority of farmers in Asia and Africa are women, is described like the latest discovery of agricultural sociology. Although in the summary of the symposium the chairman Jan Zadoks emphasizes the gender issue as an urgent one, scarcely four pages of the whole book are dedicated to that subject. Nevertheless, women are starting to be included on IPM training courses. Dr Escalada recommends that the courses be scheduled to make it possible for women to participate. Further measures need to be taken and new methodologies developed to increase the participation of women in IPM research, development and training. In a specific part of the book the reader gets detailed information about IPM methods and their constraints. The valuable contributions of many field experienced participants make it possible to grasp the complexity of agroecological systems and to start thinking in complex structures. Amongst the IPM methods that are discussed the reviewer would like to comment on one method, biotechnology, that is recommended throughout the book and that the last ar-
Book reviews/Agriculture, Ecosystems and Environment 51 (1994) 349-353
ticle (which is entitled Perspectives for crop protection in sustainable agriculture) is dedicated to. The transfer of genes conferring resistance against pests and diseases to crop plants is described as a promising technology that should be incorporated in IPM programmes. Longterm ecological impacts and other risks of growing transgentic plants are not discussed. Biotechnology in agriculture can be seen as a technically modified continuation of plant breeding. Its' promotion means at the same time to 'put it all into the seed', which is the simple philosophy that Zadoks reveals at the beginning of the book as a failed agricultural strategy of the past. Furthermore, the emphasis of a technological solution as the perspective for sustainable agriculture is contradictory to the message buried in the proceedings that IPM can only be successful if more emphasis is put on social, political and economical issues. As a whole the book can be seen as a documentation of a major change that is going on in agricultural research. It is a change towards interdisciplinary and ecological thinking on a long-term basis. This is definitely a step in the right direction but it shows at the same time that it is just the very beginning. HILDEGARD SCHILLER
Landesanstalt fur Pflanzenschutz Reinsburgstrasse 107 70197 Stuttgart Germany
Pesticide drift
The Environmental Effect of Pesticide Drift. English Nature, Peterborough, UK, 1993, 96 pp., ll.00, ISBN l 85716 124 6. Most people are apprehensive about the use of chemical pesticides and possible effects of sublethal doses. The impact of DDT on birds owing to the accumulation of residues in the food chain still affects people's attitude. This contrasts with the apparent acceptance that road accidents will
351
occur and cause injuries. Accidents are seen, whereas spray drift is often not noticed unless you happen to pass the field while it is being sprayed and smell some of the chemical. The quantities that may be blown outside the treated area are very small, but these can have undesired effects. In view of this, those concerned about protecting Sites of Special Scientific Interest (SSSI) and the wider implications of pesticides in the environment, initiated studies in 1986 to estimate the safe distance a spray source has to be from a sensitive organism, community or SSSI to avoid unacceptable effects from spray drift. Apart from identifying which pesticides are most toxic and the applications most likely to result in drift, one aspect of the studies was to carry out plant and invertebrate bioassays to quantify the effects of potentially damaging pesticides. The results of the initial studies were reported at a conference in February 1992, but English Nature has now published this volume to bring the information to a wider audience. The first chapter summarises the principles of droplet drift which is likely to occur more with insecticides than herbicides owing to the choice of droplet spectrum. It suggests that a safe distance or 'buffer' zone is determined by bioassays with a sensitive species at measured distances downwind to determine the distance at which no significant effect is recorded, although recognising that hazards from some pesticides may be due for example to sub-lethal effects altering the competitive balance of species. The complexities of vapour drift are then discussed as well as consideration of the effects of herbicides on established perennials and seedlings. This data has suggested that severe damage to plant species is confined to within l0 m downwind of tractor mounted sprayers but a buffer zone of 150 m to over 200 m is needed with aerial applications. One special case that was considered was the effect of pesticides on lichens on which the effect of drift appears to be minimal where there is a single exposure to normal concentrations. To assess effects of insecticide drift, a standardised field bioassay was developed using batches of 2 day old Pieris brassicae larvae. Estimates of buffer zones with ground equipment varied be-
Ecosystems & Enwronment ELSEVIER
Agriculture, Ecosystems and Environment 51 (1994) 349-353
Book reviews Crop protection and sustainable agriculture Crop Protection and Sustainable Agriculture, CibaFoundation Symposium 177, Wiley, Chichester, UK, 1993,285pp., hardback, 45.00, ISBN 0471939447. This book is the proceedings of a symposium on world food production by means of sustainable agriculture and the role of crop protection. Scientists from various parts of the world (India, UK, Netherlands, The Philippines, China, Syria, Benin, Australia, Germany, France Malaysia, Kenya, Switzerland) met in Madras, India, to discuss the complex issue of feeding the growing human population without destroying the environment. The 15 articles include recorded discussions and two general discussions between natural and social scientists elucidating the topic from the technical, sociological and economic point of view. The content is structured from the general to the specific. The first articles, which deal with information about the ecological and economic background, are followed by specific case studies and field experiences concerning the implementation of integrated pest management (IPM) programmes, most of them referring to the host country India. At the beginning a hypothesis is put forward that the world is able to feed a population of 80 000 million people. The calculations are based on world biomass production due to photosynthesis not taking into account any socio-economic constraints of agriculture. By this theoretical approach it is shown that there is an enormous potential for food production. Whether we are able to use this potential or not Elsevier Science B.V.
depends on the knowledge of appropriate agricultural techniques and on the socio-economic conditions that make farmers use certain techniques. The main part of the book also deals with the explanation of the slogan-like words 'sustainable' and 'integrated'. Sustainable agriculture is understood generally as an agricultural concept where ecological stability and maintenance of the potential of future production are ensured as well as an increasing food production. Integrated production is defined as an assemblage of methods including modern technologies which are sensibly used in order to reach the goal of sustainability. However, most participants use the word 'integrated' as a synonym of'sustainable'. These progressive strategies are suggested considering failed agricultural concepts in the past. High input agricultural practices led to an excessive use of pesticides and fertilizers with a threatening impact on the environment. Genetic uniformity of crops developed, owing to the emphasis of plant breeding on high yield varieties. This in turn made crops susceptible to pest outbreaks. Examples of the damaging effect of pesticides in general and pesticide induced pests in particular are presented throughout various articles and the discussions. For example: ( l ) the outbreak of the brown plant hopper that is caused by the overuse of insecticides; (2) the loss of resistance to insecticides of the two main malaria vectors in India; (3) a higher population of whiteflies that is caused by an increased use of pyrethroids. The solution to the problem is likely to be a cessation of spraying and the use of different crop protection techniques. IPM is based on biologi-
350
Book reviews/Agriculture, Ecosystems and Environment 51 (1994) 349-353
cal control and integrates traditional knowledge as well as indigenous varieties, whereas the decisions regarding the use of pesticides are made according to locally developed thresholds. However, agricultural sustainability is not merely a matter of solving technical problems (Jones). Most of the right technologies are already known, but cannot be applied by the farmers because of complex socioeconomic reasons. Again the reader is introduced to a number of precise cases concerning this issue: ( l ) For example in many countries farmers use fertilizers at the wrong time because they cannot get financial credit in time to purchase the fertilizers. (2) In India pesticides have been subsidised by the government, hence they were more attractive to farmers than IPM methods. Following the subsidisation of IPM inputs such as pheromone and light traps they are able to compete with pesticide use. (3) In Thailand a correlation between the price of rice and the outbreak of brown plant hopper and ragged stunt virus was found. The high price of rice caused the farmers to grow higher yielding varieties and increase insecticide use. This in consequence led to the outbreak of the brown plant hopper. These cases (which the reviewer describes in a simplified way) demonstrate the complexity of economic and political factors that influence pest status and pest management. The necessity to influence agricultural development by economical programmes and subsidies is obvious. Government interventions in the pesticide market are discussed as well as other policy instruments which focus on reducing the dependence on pesticides. The analytical and theoretical side of this issue is described as a complex but logical system of socioeconomic and political interactions. However, the transfer of the concept into practise looks like an unsolvable problem, especially when there are powerful pressure groups such as the chemical industry that forces a different development. Norton compares the problem with the picture of a tiger. "We are sitting on a tiger of development," with the question, who is guiding?.
Another issue that is discussed frequently throughout the book is the problem of how to convince farmers to accept IPM programmes. It is generally agreed that top-down centrally organized groups do not work and that projects that are based on participation should be promoted. But some kind of re-education of the farmers has to be carried out first, because former extension concepts were based on increasing pesticide use and turned farmers into 'consumers of technology'. A lot of participants made the observation that farmers use pesticides for prevention thinking that in that way they reduce the risk of crop loss. The discussions concerning the social structures and the psychology of farmers reveal that most participants are just beginning to work on that issue. Farmers' attitudes and objectives as well as the way they make their decisions are described as something arbitrary and not logical. There seems to be a lack of understanding of social and psychological processes which makes further investigation and an emphasis on this subject necessary. In this context it is not surprising that the fact, that the majority of farmers in Asia and Africa are women, is described like the latest discovery of agricultural sociology. Although in the summary of the symposium the chairman Jan Zadoks emphasizes the gender issue as an urgent one, scarcely four pages of the whole book are dedicated to that subject. Nevertheless, women are starting to be included on IPM training courses. Dr Escalada recommends that the courses be scheduled to make it possible for women to participate. Further measures need to be taken and new methodologies developed to increase the participation of women in IPM research, development and training. In a specific part of the book the reader gets detailed information about IPM methods and their constraints. The valuable contributions of many field experienced participants make it possible to grasp the complexity of agroecological systems and to start thinking in complex structures. Amongst the IPM methods that are discussed the reviewer would like to comment on one method, biotechnology, that is recommended throughout the book and that the last ar-
Book reviews/Agriculture, Ecosystems and Environment 51 (1994) 349-353
ticle (which is entitled Perspectives for crop protection in sustainable agriculture) is dedicated to. The transfer of genes conferring resistance against pests and diseases to crop plants is described as a promising technology that should be incorporated in IPM programmes. Longterm ecological impacts and other risks of growing transgentic plants are not discussed. Biotechnology in agriculture can be seen as a technically modified continuation of plant breeding. Its' promotion means at the same time to 'put it all into the seed', which is the simple philosophy that Zadoks reveals at the beginning of the book as a failed agricultural strategy of the past. Furthermore, the emphasis of a technological solution as the perspective for sustainable agriculture is contradictory to the message buried in the proceedings that IPM can only be successful if more emphasis is put on social, political and economical issues. As a whole the book can be seen as a documentation of a major change that is going on in agricultural research. It is a change towards interdisciplinary and ecological thinking on a long-term basis. This is definitely a step in the right direction but it shows at the same time that it is just the very beginning. HILDEGARD SCHILLER
Landesanstalt fur Pflanzenschutz Reinsburgstrasse 107 70197 Stuttgart Germany
Pesticide drift
The Environmental Effect of Pesticide Drift. English Nature, Peterborough, UK, 1993, 96 pp., ll.00, ISBN l 85716 124 6. Most people are apprehensive about the use of chemical pesticides and possible effects of sublethal doses. The impact of DDT on birds owing to the accumulation of residues in the food chain still affects people's attitude. This contrasts with the apparent acceptance that road accidents will
351
occur and cause injuries. Accidents are seen, whereas spray drift is often not noticed unless you happen to pass the field while it is being sprayed and smell some of the chemical. The quantities that may be blown outside the treated area are very small, but these can have undesired effects. In view of this, those concerned about protecting Sites of Special Scientific Interest (SSSI) and the wider implications of pesticides in the environment, initiated studies in 1986 to estimate the safe distance a spray source has to be from a sensitive organism, community or SSSI to avoid unacceptable effects from spray drift. Apart from identifying which pesticides are most toxic and the applications most likely to result in drift, one aspect of the studies was to carry out plant and invertebrate bioassays to quantify the effects of potentially damaging pesticides. The results of the initial studies were reported at a conference in February 1992, but English Nature has now published this volume to bring the information to a wider audience. The first chapter summarises the principles of droplet drift which is likely to occur more with insecticides than herbicides owing to the choice of droplet spectrum. It suggests that a safe distance or 'buffer' zone is determined by bioassays with a sensitive species at measured distances downwind to determine the distance at which no significant effect is recorded, although recognising that hazards from some pesticides may be due for example to sub-lethal effects altering the competitive balance of species. The complexities of vapour drift are then discussed as well as consideration of the effects of herbicides on established perennials and seedlings. This data has suggested that severe damage to plant species is confined to within l0 m downwind of tractor mounted sprayers but a buffer zone of 150 m to over 200 m is needed with aerial applications. One special case that was considered was the effect of pesticides on lichens on which the effect of drift appears to be minimal where there is a single exposure to normal concentrations. To assess effects of insecticide drift, a standardised field bioassay was developed using batches of 2 day old Pieris brassicae larvae. Estimates of buffer zones with ground equipment varied be-