Sédentarisation des populations des mouches Diopsides dans les agro-systèmes rizicoles au Bénin

Sedentarisation of the Population of Diopsid Flies in Rice Agro-systems in Benin. The stalk-eyed fly or Diopsid (Diopsis spp.) has a significant economic impact in rice in Tropical Africa due to the yield loss it induces. The objective of this study is to evaluate the influence of cultural practices on the stabilization of Diopsid population in irrigated rice agro-systems in Benin. During three consecutive years (2006, 2007 and 2008), Diopsid occurrence was surveyed in three irrigated rice-growing locations (Lélé, Koussin and Kinwédji) according to 4 agro-systems (Ags) related to rice at tillering and panicle initiation stages, ratoon and fallow fields. Results showed that Lele and Kinwédji locations were permanently highly infested during the three growing seasons whereas the site of Koussin kept very low level of Diopsids populations. Moreover rice fields in tillering stage (Ags1) and ratoons fields (Ags2) were the most infested. The study identified rice ratoon as a predominant factor of Diopsids population stabilization in rice cultivation area. It is recommended an integrated management of irrigated zones including cleaning of rice fields after harvest