imperialism and poverty

Thanks to all who wrote with bibliographical suggestions.  The most 
useful thing I have found so far is Andre Gunder Frank's chapter in 
Crisis in the Third World about agribusiness--he points out how growing 
productivity in agriculture is often associatiated with increased 
poverty. The only problem is that this was published in 1980 and his 
sources were from the 70s.  Does anyone know a more up to date 
discussiion of how the growing influence of capitalist agriculture in the 
world is excerbating rural poverty? My sense of it is that in countries 
such as Mexico more land is coming under the control of major food 
conglomerates, undermining the position of traditional farmers, forceing 
them into the rural or urban or immigrating proletariat and extending 
their poverty. But recent case studies and analysis that make this 
argument in detail would be helpful, and I do not have them yet. So I am 
still looking for help.

Paul