Developing Pest Management Strategies

 for Small Farmers

 Based on Traditional Knowledge

 Miguel A. Altieri
 Division of Biological Control
 University of California, Berkeley 94720


 For centuries traditional farmers have kept pest damage
within acceptable levels by employing a wide variety of
cultural practices based on local lore and resources. One such
practice is the use of polycultures. Factors involved in pest
regulation in polycultures include: increased parasitoid/pre-
dator populations, available alternative prey/hosts for natural
enemies, decreased colonization and reproduction of pests,
feeding inhibition or repellency from non-host plants and
prevention of movement and emigration. These elements of


natural pest control built into small farming systems should be
examined, so that the valuable ones are retained in the course
of agricultural modernization. Thus, traditional knowledge
must be considered to guide changes and attain optimum
yields in regions with low-input agriculture. All development
approaches should be village-based, with emphasis on self-
sufficiency, use of local resources and indigenous agricultural
regimes.


 Traditional farming systems represent centuries of accumu-
lated experience of interacting with the environment, by farmers
without access to scientific information, external inputs, markets,
capital, institutional services and high quality natural resources
(de Janvry, 1981). Such skills, using locally available energy and
materials, have often translated into farming systems with sus-
tained yields (Wilken, 1977; Egger, 1981). Western agricultur-
alists, however, often have curious perceptions of these systems
and their productivity potential, considering small farms to have
low productivity. Therefore, obtaining "bigger yields" becomes
the goal, and the justification for claiming the necessity of
technology transfer and institutional innovation (Alverson,
1984). Although productivity per unit of land may seem low,
peasants may obtain a high level of productivity from other
resources that are scarcer or more essential. Little attention is paid
by researchers to the ecological context and cultural organization
of agriculture. Not surprisingly, few significant technological
packages, capable of yielding increased net returns, have been
successfully offered to the majority of peasants (deJanvry, 1981).
 Improvement of peasant income by increasing agricultural pro-
duction through the use of expensive purchased inputs may no
longer be appropriate. Alternatively, what may be more ap-
propriate is to promote strategies centered on self-sufficiency in
production, so that the dependency of peasants on costly inputs
and industrial technology is minimized. To develop such systems,
traditional "know-how" must be assessed to guide the use of
modern agricultural science to progressively and carefully im-
prove the productivity of small farming systems. Such
assessments have gradually increased in the last decade (see
Altieri, 1983, and references cited therein) and many of them
have provided the basis for successful rural development projects.
An example is the development of alley cropping in Nigeria, in
which selected leguminous trees and shrubs are planted in
association with food crops to accelerate soil-nutrient regenera-
tion, thus shortening the fallow period required for shifting
cultivation (Wilson and Kang, 1981). Another example is the
replacement of the traditional lucerne undersown in barley fields
of the Bolivian highlands with vetch (Vicia villosa) to increase
forage production after the grain harvest (Augstburger, 1983).
 Evaluations of the dynamics of insect, weed, and pathogen
populations and of the methods of pest control commonly used
in traditional farming systems are few. The scattered information
of pests in subsistence agriculture is mostly of an anthropological
nature and does not provide quantitative details about the effects

VOL. XX-PROCEEDINGS of the CARIBBEAN FOOD CROPS SOCIETY


of various cultural control practices on pest dynamics or about the
ecological mechanisms involved in the regulation of specific pests
(Matteson et al., 1984). Most of our understanding about the ef-
fects of crop diversity on pest incidence derives from experimental
measurements often obtained in isolation from the total context
of farming systems and of social reproduction.

Pest Management in Traditional Agriculture
 The magnitude of pest problems in traditional agriculture is in
part a matter of perspective, because subsistence farmers may
have low yield expectations and tolerate relatively high pest losses
(Brown and Marten, 1984). Pests are tolerated because they are
either regarded as fellow creatures entitled to a share of the crop,
or merely because certain animal or plant "pests" are used for
food or other purposes. Many weeds are used by farmers as food,
medicine, animal fodder, fuelwood, etc. (Datta and Banertee,
1978). In fact, peasants in tropical Mexico manage a "nonweed"
concept; non-crop plants are classified according to use potential
and complementary positive effects on the one hand, and
negative effects on soil, pests and crops on the other (Chacon and
Gliessman, 1982).
 Some traditional cropping systems exhibit built-in pest sup-
presssion mechanisms resulting from the integrated interaction of
factors such as:
 1. arrangement of crops in time and space;
 2. composition and abundance of non-crop vegetation within
 and around fields;
 3. species and genetic diversity of crops;
 4. soil characteristics;
 5. the surrounding environment; and
 6. the type and intensity of cultural management.
Pest populations may fluctuate depending on their degree of
association with one or more of the vegetational components of
the system or their sensitivity to change in crop patterns, soil
management, etc. Although pest losses in traditional agriculture
can reach 40% (Brown and Marten, 1984), these losses fall in the
same range in modern agriculture, despite its use of chemical
pesticides. When pesticides are removed from modern systems,
losses can often approach 100% (Schwartz and Klassen, 1981).
Conversely, in traditional systems, pest damage is kept within
certain bounds by a variety of management practices based on
locally available resources.
 Temporal and spatial crop diversity which characterizes tradi-
tional polycultures often results in lower pest incidence. The fac-


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