Environment and Development Economics Volume 11, Issue 4 August 2006 , pp. 453-475The paper treats the economy of controlling an African pest rodent, the multimammate rat, causingmajor damage in maize production. An ecological population model is presented and used as a basis for the economic analyses carried out at the village level using data from Tanzania. This model incorporates both density-dependent and density-independent (stochastic) factors. Rodents are controlled by applying poison, and the costs are made up of the cost of poison plus the damage to maize production. We analyse how the present-value costs of maize production are affected by various