Indigenous post-harvest knowledge in an Egyptian oasis

Anne M. Parrish

Over the past three decades, a new approach to pest management has been introduced in Mut (El Dakhla), in the Western desert of Egypt. This has included the free distribution of pesticides in order to encourage their adoption in place of indigenous practices. According to some farmers, these changes have made pest problems worse and created environmental problems as well.

The farmers of Mut have long had to contend with pests that infest stored food. Because the area has only recently been subject to development, many traditional methods of pest control are still practised or at least known. Included within this body of knowledge are indigenous strategies for local-level integrated pest management (IPM).

The development programme of the Ministry of Agriculture has brought many changes for the inhabitants of Mut. Although the traditional crops of wheat, paddy rice, dates, and fodder have remained the same, new technologies and inputs have been introduced. These include diesel irrigation pumps, certified seeds, chemical fertilizers, farm mechanization and commercial pest management practices. Newly dug wells have allowed for expansion into previously uncultivated desert areas, and for yield increases on existing croplands (Abd El Ela, 1992). Electricity, a piped water system and consumer goods such as gas stoves and televisions have also been brought to the oasis. These in turn have affected the socio-cultural fabric of the farming system.

Ironically, one cause of the post-harvest losses and problems experienced by some farmers has been the increased yields made possible by the new technologies. Many farmers reported problems with pests. Data were obtained between October 1991 and July 1992 through open-ended interviews with 60 farmers in various areas in and around Mut. Farmers living in different types of houses, having different kinship arrangements, and using different technologies were included in the research.

Post-harvest pests
Although farmers named many field-crop pests, they cited only two major categories of post- harvest pests:

1. Sus**1: red or black insects. Red sus include Tribolium confusum, Tribolium castaneum, Sitophilus granarius, and Lasioderma serricorne, all of which infest rice, wheat and dried vegetables. Black sus (Bruchidae) are a problem in stored faba beans (Vicia faba). Some farmers said that 'in the old days' there were no sus. One even said that there were no sus until the Ministry of Agriculture came to the oasis. But others explained that 'the old days' were also 'the poor days'. Food was consumed before insects could cause serious economic losses.
2. Feran: rodents. Feran include both rats and mice, but are most often just rats, which are recognized as formidable enemies. To illustrate how rodents adapt, one farmer said: 'Rats are so clever that they send their young in to eat first. If they don't die, then the old ones come in to eat'. Rodents feed both on crops in the fields and on food in storage, and also cause losses of poultry.

Indigenous storage technologies
Many of the traditional storage methods are excellent for helping to prevent or control pest infestation. One of the most efficacious storage methods involves burying grain in the sand. The grain's moisture content is reduced by the sand and solar heat. This eliminates some insect pests and inhibits the movement of others. Farmers reported that even rats do not dig up the grain. Although many farmers in other villages of the oasis still bury grain today, few Mut farmers do. One reason is that the sand has become saturated with water from increased irrigation, and is no longer suitable. Another reason is that winds have caused the sand dunes to shift so that sand is no longer available near the houses.

The most common place for storage is granary rooms inside the houses. While identical to other rooms, the granaries have low retaining walls to separate the different products. Cereal grains are stored in the compartments in burlap or cotton bags, or in palm baskets. Dates, faba beans and seeds are stored in pottery jars or metal containers that are sometimes sealed with mud. Because cereal grains continue to give off carbon dioxide that displaces oxygen, the sealed containers are in fact elementary forms of fumigation chambers.

Some farmers said that putting granaries on the second floor reduces infestation problems brought about by ground moisture. Others said that they do not have problems with pests if they clean the granary prior to putting grain in it, and if they keep the granary ventilated during storage. Construction materials were also mentioned as either helping or exacerbating storage problems. There was no consensus, however; some farmers believe that the traditional mud brick construction was better, while others prefer the newly introduced concrete blocks.

Another type of storage farmers described is mud silos (souma). These are constructed on ground-floor courtyards or threshing floors, or directly on the houses' roofs. They are of various sizes, but all are taller than they are wide.

Indigenous post-harvest management
Although almost all of the pest management practices described here are still being used by some farmers, most have been replaced by newly introduced methods of control. Some farmers, however, are picking and choosing from both traditional and introduced methods. For example, farmers who said they use one or more of the traditional methods are the same ones who reported little or no problems with insects.

The methods of control can be divided into three types: chemical, mechanical, and biological. Each of the practices has merit, and if used in combination with others, would provide an effective form of local-level IPM.

Chemical control:
One practice is a form of 'fumigation', whereby a combination of kerosine, wood, rice straw or stalks, and capsicums is burned in the closed granary room prior to its use for storage. This practice would probably work well against certain adult insects if the smoke and heat are sufficiently intense.

Another practice is to mix ashes, lime and crushed capsicums in with the stored grain. These are irritants to insects. The lime and ashes fill the spaces between the cereal grains and inhibit insects' movement. They also act as desiccants.

Handel (Citrullus colocynthis), an uncultivated desert plant, is used both fresh and dried for pest control. When used fresh, the fruit is cut in half and rubbed along the granary walls. When used dried, the fruit is crushed and mixed with the grain. Farmers reported that four or five dried handel are sufficient to protect a 10-by-12-foot granary.

A mixture of gypsum and sugar is used for rodent control. Because rodents are unable to vomit, they cannot expel the gypsum once it has expanded in their stomachs, and they die.

Mechanical control:
Some farmers reported applying fresh mud to the granaries before each new crop is stored. Sometimes crushed capsicums are added to the mud, and one farmer reported using a mixture of ashes, lime, salt, and mud. This procedure seals the crevices that serve to harbour pests. Farmers who still use this procedure said that they have no serious sus infestations.

Metal or clay traps were used for rodent control until commercial poisons were introduced. These were constructed of wire or consisted of small clay houses. A hinged door on one end was attached to a baited string. When the rodent pulled on the bait, the door snapped shut. Packed clay is also used to seal burrows found in fields and farmyards.

Biological control:
Although putting grain out in the sun to dry is a cultural practice, the results are biological. The sun's heat activates insects that have infested the grain, causing them to complete their life cycle before storage begins. Moreover, the sun's heat reduces the moisture content of the grain, thereby making it less susceptible to infestation. Because of larger yields, not many farmers nowadays put their grain out in to sun. Faba beans and dried dates, however, are still heated in an oven for five minutes before storage.

Another form of biological control involves, among other things, cats, egrets, owls and desert foxes. Many farm compounds have cats, and some farmers said they have few or no rodent problems because of the cats. Egrets are especially welcome and are frequently seen poised for action directly outside rodents' burrows. Desert foxes are considered a mixed blessing because they themselves are a threat to poultry, peanut fields and ripening watermelons.

The direction of pest-management practices
Talks with 60 interviewees indicated that newly introduced technologies have been adopted at quite a substantial rate. Most farmers have abandoned traditional methods in favour of introduced chemicals. Most respondents said they are using commercial rat poisons (83.3%) and insecticides (81.7%). By contrast, only 11.7% of the farmers questioned are using indigenous practices for rodent control, and fewer than one-fourth (23.3%) are still using traditional insect control methods. Some, however, are blending traditional and introduced forms (26.6%), but the majority are not.

The most common reasons given for discontinuing indigenous pest control practices included the following:

1. They are no longer needed because pesticides are available.
2. The use of commercial chemicals is less time-consuming. This is important for some farmers because less farm labour is available now that opportunities for off-farm employment have increased.
3. Traditional methods are 'old-fashioned'.

One perception that many farmers share is the observation that pests are worse now than they used to be**2. They cited several reasons for this, including the increase in crop yields already mentioned. Some blamed the commercial pesticides now widely used in both fields and storage areas. Farmers said that the use of pesticides has disrupted the balance of nature, allowing pest populations to multiply because natural predators have been eradicated. Moreover, some feel that because farmers are now dependent on commercial pesticides for control, they have become lax in other respects, including granary sanitation. Some said that the increase in arable land and the availability of more water have caused rodent populations to expand into areas where rodents never lived before. Other farmers believe that 'modernization' is partly to blame. Farmers used to prune away dead palm fronds and other brush that they were able to sell as fuel to other villagers. Because many people now have gas cooking stoves and buy bread from government-subsidized bakeries, they no longer need fuel. The farmers, therefore, are said to not clear brush as well, and these areas have come to harbour pests.

Prior to the government development programme, there was a low-input, sustainable system for pest management that employed a diversity of strategies. The interviews revealed that there is a general local awareness of the need for a balance of nature, and of the potentially harmful effects of continued application of chemical pesticides. For example, some farmers reported that they are sunning their grain after storage rather than before because they now wash the grain to remove insecticide residues prior to milling and baking. Others said they no longer use rat poison in the farm compound. Moreover, some farmers suggested that an environmental awareness group should be formed.

The Ministry of Agriculture should help to provide leadership for forming such a group. An appropriate IPM programme does not have to be an either/or situation, as has been shown by farmers who combine strategies. A safe and cost-effective pest management programme should include efforts by the Ministry of Agriculture to encourage farmers to build upon indigenous practices that they know to be both safe and effective. When these practices are prudently combined with the technologies of development workers, the result can be an environmentally sound and efficacious form of integrated pest management.

Anne M. Parrish
University of Kentucky
Department of Anthropology
211 Lafferty Hall
Lexington, Kentucky 40506-0024
USA
Tel: +1-606-257 6922
Fax: +1-606-258 1959
E-mail:antamp@ukcc.uky.edu

References
Abd El Ela, A. (1992) Director of the Ministry of Agriculture. Khaga City, El Kharga Oasis, Egypt. Personal Communication.

Bahemuka, J.M. (1989) 'Farming systems approach to small-scale farmers' perceptions of grain loss in Kenya', Culture and Agriculture 39:11-16.

Endnotes
**1 Sus is the colloquial Egyptian Arabic term for the insects that infest all stored products, and is used in the same generic way that 'weevils' is used in the USA.

**2 Bahemuka has reported similar responses among Kenyan farmers involved in a development project, where some 70% of those questioned reported an increase in insect pests (1989:13).