Recent increases in the number of resource and industrial developments in rural areas [10] have led to the creation of a large number of comprehensive planning models usually identified as “economic-demographic” projection models [see for example 1, 3, 4, 5]. These models are used to delineate systematically the interrelationships among various economic, demographic, and social factors. They differ in their basic model structure, their degrees of flexibility, and range of user input options, and in terms of the geographic and governmental units for which projections are made. Each, however, includes a basic economic module, a demographic module, and a module for interrelating or interfacing the economic and demographic modules. Additional modules, such as fiscal impact, settlement allocation, public service, and housing demand modules, also may be included but they tend to operate directly on the outputs of one of the other three basic components and are thus largely addendums to the economic, demographic, or interface modules of such models.

We surveyed three locations in West Africa, two in northern Nigeria and one in southern Niger, for the presence of wild alternative hosts of the legume pod borer (LPB) Maruca vitrata Fabricius, which could serve as natural unstructured refugia for transgenic Bacillusthuringiensis (Bt)-cowpea. We surveyed a total of 67 sites in proximity to cowpea fields in the Sudan Savannah (Kano, Nigeria), the Northern Guinea Savannah (Zaria, Nigeria) and the Sahel Savannah (Maradi, Niger) ecological zones. The results indicate that alternative host plants for LPB are scarce or absent during the cowpea-growing season in these areas.

Cowpea (Vigna unguiculata (L.) Walp) is an important food staple in sub-Saharan Africa. The legume pod borer Maruca vitrata Fabricius is one of the key pests of cowpea as the larvae feed on the tender parts of the stem, peduncles, flower buds, flowers and on pods of the plant, causing significant yield losses. Understanding the seasonal and geographical patterns of M. vitrata is essential for the establishment of effective pest management strategies. Sites in three ecological zones in Burkina Faso were sampled for the presence of M. vitrata adults and larvae both during and outside of the cowpea-growing season. Our data suggest that M. vitrata do not maintain a permanent population in the Sahelian or Sudano-Sahelian zones, but emigrate from the Sudanian zone where M. vitrata populations evidently may occur throughout the year.