The depression years of the 1930s

The 1930s was climatically and economically a difficult period for the East African colonies, as mentioned earlier. During this time, tsetse research and control continued to be particularly worrisome. The challenge was how to sustainably put down the repeated tsetse outbreaks. Emergency programs for reducing the immediate adverse impacts of sleeping sickness did not allow for long-term investigations. Instead, tsetse research at this time focused on two issues: first, on the populations of the different species of tsetse flies and, second, on their biology. However, since the focus of the research was still on elimination of the flies, little attention was given to understanding the relationship between the fly and its various hosts.66 There were no comparative studies on the selection of habitats and hosts. Contrary to what had been expected, the destruction of large mammalian hosts did not deny the flies blood meals or starve them out of existence—other sources of blood were small mammals, reptiles and birds. Further, nearly all the mammalian hosts were mobile— as opposed to having fixed habitats, which made them an unreliable source of food for the flies.6' We now examine attempts at ecological control of the tsetse.

Until the 1930s, tsetse research and control had focused on two areas of action: research on the population dynamic of the fly; and bush clearing.68 Denying the tsetse a suitable habitat was claimed to reduce expansion of the fly populations. However, as we mentioned earlier, this was never accomp- lished. Additionally, two new methods of manipulating bush growth were tested in research experiments by the Shinyanga regional research center.

The first new method was to divide an area into blocks separated by cleared barriers. Each block was subdivided into squares of 1,829 m on all sides, and all the vegetation was removed in the border areas using hand hoes. The second method involved fire treatment, which varied according to seasons—fires were more effective in the hotter, dry season than the cool season.69 Repeated fires at four- to five-year intervals transformed the vegetation into grasslands. This was then followed by short-term fire intervals. The direct impact was that the fire either drove out or killed the tsetse, reducing fly populations in the experimental areas by 70 percent. However, the fly population in general increased by 300 percent—the flies from the treated blocks might have taken refuge in the adjacent grasslands that were protected from burning.'0 The finding was that, in the long term, the tsetse fly population recovered after fire.71

In 1931 in Sukumaland in Tanganyika, community labor and mechanical methods were used to clear some 1,347 km2 of bushland. In the same area, some ten years before the sleeping sickness outbreak, Goodenough and coworkers'2 reported that the advancing tsetse front had driven out about 30,000 people. The peasants were ‘greatly worried over this progressive loss of their country.’ In the Ugandan section of the Lake Victoria Basin that had earlier experienced the sleeping sickness pandemic, the methods of tsetse control again involved the use of fire which proved to be successful in eliminating the flies, albeit temporarily. Bush thinning and the periodic use of fires provided temporary respite from fly infestations.'5 Between 1936 and 1938, the fly populations increased in the area of Mbarara in Uganda, to which fire had been applied. On the advice of the researchers, the rehabilitated areas were allocated to settlement schemes.74

The methods of settling African peasants described by Ford'1 involved four steps over four years: ‘no anti-tsetse measures were needed before people could occupy the bush.’ In the first year, settlers would mark out their plots and fell enough bush to cultivate crops and build a house. In the second year, they extended their cultivation and brought in their sheep and goats. In the third year, the family brought in their calves and in the fourth year, the whole family joined the settlement, with their adult cattle. It is uncertain if the effectiveness of these proposed methods were tested. What was however clear was that efforts aimed at tsetse control had not produced sustainable success, despite repeated attacks using a variety of methods.76 Methods such as the mechanical trapping of the flies, the destruction of wildlife, bush clearing and the application of fire provided temporary reductions in fly population densities." In particular, experimental control of tsetse flies through deforestation caused the same outcome of environmental destruction for which the African peasants had been blamed by officials. The paradox of environmental destruction on the one hand, and tsetse fly control on the other, caused some experts to question the effectiveness of bush clearing.78 Perhaps, the most controversial subject was whether to control soil erosion or tsetse as a priority.

Tsetse or soil erosion control

A complicating challenge arose because the various institutions involved in tsetse control did not agree on the methods used.'9 This sparked discussions over institutional responsibilities—in terms of those that supported research and development schemes, and those that advocated soil erosion control above investment in tsetse control. Other researchers preferred to focus on the medical aspects of sleeping sickness (trypanosomiasis). Medical researchers from the London School of Hygiene and Tropical Medicine, headed by Professor P.A. Buxton, investigated preventative and curative control of trypanosomiasis80 in both cattle and humans.81 By putting their work into geographical and regional contexts, the medical researchers soon realized that the tsetse problems would not be solved piecemeal, and that integrated action was required—with ecological science running side by side with social science research and development. This implied that research activities should com- prehensively address questions related to land reclamations, resettlements, soil erosion control and the consequences of tsetse resurgence.82

Goodenough and colleagues85 described the contesting viewpoints between those who supported soil erosion control on the one hand, and tsetse control on the other—in the 1930s, both problems demanded equal research urgency. The paradox of the debate was whether the tsetse was a curse, or a possible boon for soil conservation. In other words, the tsetse flies had indirectly contributed to environmental conservation by returning the countryside to bushlands, while the relocation of human and livestock populations into the cleared areas had aggravated soil erosion. In avoiding the tsetse flies, people had been concentrated into smaller areas that inevitably became over-utilized resulting in soil erosion (as claimed by some). Consequently, from the soil erosion perspective, the debate considered the presence of tsetse fly as a boon, while on the other hand it was a bane for cattle keeping. The argument contended that ‘tsetse [is] a blessing in disguise, as it can be regarded as acting as the trustee of the land for future generations.’84 Conversely, the clearing of bushes increased grass production on rehabilitated land, and in absence of the tsetse, attracted grazing and crop cultivation.8’ Those concerned with public health advocated the safety of future human settlements, arguing that bush clearing and the application of fire would reduce tree regeneration and free the land from the flies.86 We move on now to consider the Second World War period which experienced various impacts on the progress of tsetse research and control.

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