Diopsids (Diopsis thoracica and D. apicalis) Damaging Rice Production in Africa: A Review

Abstract

Diopsids are pests responsible for significant losses in rice and other cereal crop production. Damages resulting from this attack particularly during tillering and flowering stage are fatal. Research studies have been undertaken since 1950s in West Africa for effective control and eradication of these enemies. Chemical control however became predominant because insects were considered sporadic. Diopsids are dipterans that are prolific under high humidity and near water points such as lowlands. Climate change characterized by heavy rainfall, increased temperature and water volume associated to uncontrolled flooding are in favor of their increase. In recent years, diopsids has spread in virtually all rice growing ecologies. These insects are hosted by wild rice species such as Oryza longistaminata and other plants in humid regions in the absence of rice crop. Research has shown the influence of climatic factors and alternative hosts in the expansion of these pests. Some resistant varieties belonging mainly to the species O. glaberrima as CG14 have been identified. Breeding showed a transmissibility of this resistance to the progenies as NERICA4.