Ecologically-based rodent management

In Madagascar the rodent problem is linked to one species, the black rat (#Rattus rattus$). This chapter will describe its population dynamics in agro-ecosystems and its impact in agricultural crops, in stored grain, on human health and on the endemic rodent community. The black rat has spread absolutely everywhere : from sea level to more than 2,000 m - in houses, fields and also in the forests. It represents more than 95% of rodent catches in the fields and inside houses. Reproduction of rats living in fields stops during the cold season when their maximul annual abundance is observed. Irrigated rice crops suffer the greatest damage with losses estimated at 2.5% of the harvest. Rodent damage is also important for pluvial rice and to a lesser degree for cassava, sweet potatoes and tomatoes. Damage to cacao and sugar cane are important only in the small, poorly-maintained personal plantations. Plague is undeniably the most important disease linked with rodents in Madagascar. It is endemic to the centre of the island in rural areas located above 800 m and its revalence is increasing. Rodent control in Madagascar is extremely complex because of the economic difficulties facing the country and because the black rat has displayed such successful colonisation in absolutely all habitats. (Résumé d'auteur