Right across the Region and almost without exception, the farmers and extension workers cited the banana weevil as being the dominant problem they encounter in banana shambas. In shambas displaying chlorosis on all the plants, not just bananas, suggestions as to a need for manuring or other improvements in crop husbandry, for example, often met with a less than enthusiastic response and a repetition of the perceived problems with banana weevils. Nematode damage was very rarely known about, let alone recognised, even in areas where the uprooting of many of the plants was common, with dead and dried-up roots clearly visible.

As the project had an extension component paralleling the research programme, the survey also enabled the delimitation of the Region into areas with different crop status and, therefore, different needs in the strategy for extension work. Using the Categories listed on the previous page, the areas, which can be located on FIGURE 1 and the appropriate District maps [Bukoba, Muleba, Karagwe and Ngara] were:

1. The littoral area of Lake Victoria

   Running south from Bugabo, at the northern limit of Bukoba District and of the Region, some 80 km to Kagoma, in Muleba District, and bounded on the inland side by the Ngono-Kagera River. This is the area shown as the "Crisis Zone". The western boundary corresponds to the 1250 mm isohyet and, from estimates by the writer, has some 25,000 ha of banana shambas, occupying, it is claimed, almost all suitable land. Most of this is on the ridge-tops but none of the land is above 1400 m. The great majority of the shambas fall into Category D, with the yield low to almost non-existent and all stools with severe to total root infestation by nematodes. The high to very high rainfall, 1250- > 2000 mm, has led to leaching and often depleted soil fertility was obvious, with all the vegetation showing chlorosis. Some of these shambas have been abandoned or given over to other crops, notably cassava. The remainder of the shambas are nearly all Category C, with serious pest levels and poor yields. A very few shambas, usually, if not always, belonging to cattle-owners, will give good to moderate yields, especially for some two to three years after replanting. This last group does not really conform to Category B, as the pests are distributed throughout the shamba, but the worst effects of the nematodes are temporarily alleviated by the replanting, which often has been with some addition of manure.

2. Other areas of Bukoba and Muleba Districts

   a) Inland Bukoba, mainly in the Katelero Division. Much of this area is low-lying around 1250 m, and of comparatively recent settlement. The shambas vary widely; from true Category B, generally healthy but with pests in small patches; through an intermediate Category B-C, with widely spread pests but probably still reasonable soil fertility, no manure having been added since planting, 10 or so years before; to Category C, where decline is in evidence. In the area the problems facing banana cultivators include the element of drought stress - the total annual rainfall may be sufficient, 890 to 1150 mm,but for some months every year the precipitation is less than 75 mm per month, which generally is held to be the minimum to avoid drought stress.

   b) Muleba littoral, south of Kagoma. The shambas are rather better than those to the north of the District but still are in general decline and in Category C. The more southerly parts and those in the inland rain-shadow are drier, 1000-1250 mm, and have some drought stress problems.

   c) The Kamachumu Plateau, Muleba District. This is the prime banana growing area of the whole Region. It all lies at an altitude of some 1500 m, the highest point being 1578 m, with rainfall over 1250 mm. In many instances, the shambas are of Category B, and some fall into Category A or an intermediate A-B. There are patches of Category C shambas, usually belonging to poorer farmers who have no cattle, where the principal problem is declining soil fertility. It maybe that some of the origin of the problems of these last farmers is sociological, in that they are farming the marginal land, having been unable to obtain or inherit the traditional shamba land.

3. Karagwe District
   a) The eastern ridge, from the northern limit south to Nyaishozi. Here the settlements are long-standing, with coffee plants over 60 years of age. The shambas are all over 1550 m up to 1650 m, with annual rainfall of 900-1000 mm. Pest problems appear to be on the increase, which perhaps can be ascribed to declining soil fertility coupled with a non-recognition of nematode damage. The shambas are mostly in Categories B or C.

   b) Scattered ridge-top sites, most running west from the eastern ridge, of similar altitude but in the rain-shadow and often with soil of a more sandy nature. The poorer soil and drought stress mean that the bananas have a general low level of vigour, Category C-D.

   c) Newer settlement areas, mostly in the valleys (e.g. Mabira) and the western low-lying part, near the Kagera River (e.g. Nkwenda), around 1280-1300 m high and with annual rainfall around 850 mm. Many of the shambas are in Category B.

4. Ngara District
   The southern extension of the high western dissected plateau, all the banana lands lying above 1550 m and with rainfall above 900 mm. Ingeneral, the very dense banana shambas were in Category B, with the more sandy areas being Category C-D. Marked pest problems were not seen in many shambas. Banana weevil damage was observed in the area of the land border with Burundi.

5. Biharamulo
   Most of the District is too dry for Banana cultivation but the valley stretching around the District town of Biharamulo has an area of quite good banana cultivation. Some incidence of nematodes was seen but the severest problems appeared to be low soil quality and drought stress.

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