Gabriele Stoll
Natural Crop Protection in the Tropics
Letting Information Come to Life
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Methods of Field Protection
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Insects
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Principles of preventive crop protection
Important advances have been made during
the past decade in the development of Integrated Pest
Management (IPM) concepts, both at the technical level and in
training methodology. However, there are quite diverse
interpretations of what IPM is. These are due to differences in
backgrounds, attitudes and intentions.
This book is not about IPM. It is a
resource book on non-chemical crop protection practices,
addressed particularly to smallholders and organic farmers. It
attempts to make maximum use of local knowledge and resources,
and to enrich these with external knowledge and scientific
know-how. The experience of recent decades has made it clear
that singular crop protection measures have their limitations
and their costs and that crop protection must be viewed from a
holistic perspective.
Smallholders work under conditions
of great agro-ecological diversity, often exposed to adverse
conditions such as erratic rainfall, soil erosion and nutrient
depletion which can affect the crop’s ability to tolerate
or resist pests. Moreover, the farmers live in diverse and
often adverse socio-economic situations and may have production
goals which differ from purely market-oriented goals. Thus it
is clear that appropriate crop protection strategies for small
farmers can only result from a thorough understanding of the
natural, technological and socio-economic conditions and their
interrelationships. In these situations it is decisive that
farmers understand the principles of crop protection and adapt,
rather than adopt, promising pest management techniques to
their situations.
Preventive crop protection must be
the first step. Managing the farming system towards a high
degree of self-regulatory mechanisms which reduce the need for
curative crop protection is the most intelligent and rewarding
way to cut down expenses. Expenses for crop protection include
at the individual household level time, money and health, while
at the community and national levels they may include water
pollution, reduction in pollination, loss of biodiversity,
foreign exchange, and public health.
Preventive crop protection practices are
employed to counteract the nature and behaviour of the pest, to
encourage the activity of natural enemies or antagonistic
organisms or to strengthen plants to resist or tolerate pests
and diseases. To practice preventive crop protection
successfully, knowledge of biological factors such as the soil,
the plants, the pests and their natural enemies as well as the
agro-ecosystem and the farming system are all essential in
order to develop site-appropriate crop protection strategies.
Discussion of much of this is outside the scope of this book.
Nonetheless, the following presentation outlines some of the
basic principles.
More information in this chapter about:
1. Knowledge of agro-ecosystems
2. Healthy plants and healthy soils
3. Natural rhythms and optimal planting
season
4. Crop rotation
5. Mixed farming and diversification
6. Host plant resistance and tolerance
7. Managing natural enemies
8. Field sanitation
9. Social aspects
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