WARDA IPM project 01: Integrated management of rice yellow mottle virus (RYMV) in lowland ecosystems

Duration: Started 1991; a rolling programme

Purpose: To develop environmentally-sound methods to manage RYMV in rice production systems and to generate information on disease epidemiology.

Background/description: The rice yellow mottle virus (RYMV) is one of the most economically damaging diseases of rice in sub-Saharan Africa and Madagascar. First identified in irrigated rice fields at Otonglo, Kisumu, Kenya in 1966. The virus belongs to the sobemovirus group characterized by being mechanically transmissible. The virus is environmentally stable and highly infectious. The host range of RYMV is narrow being restricted to gramineous species, mainly in the rice tribes Oryzeae and Eragrostidae. The occurrence of a disease epidemic depends very much on the population of the insects that serve as vectors. The regular occurrence of insects on diseased rice under field conditions in Africa has prompted close examination of these species as possible transmitting agents. Bakker (1970, 1971) identified some chrysomelid beetles and a long-horned grasshopper as vectors of RYMV in Kenya. The losses caused by this virus in paddy fields have reached alarming proportions and some farmers have suffered complete crop failure. Owing to the seriousness of the disease in limiting rice yields in Africa, the need to understand the dynamics of virus spread and the vector’s role in it became vital so that control options which would be both sustainable and accessible to the low-income farming community are well targeted.

Agroecozone(s) and location(s): Sahel, Sudan savanna, Guinea savanna, Humid Tropical forest, Mangrove swamps, rainfed and irrigated lowlands in Burkina Faso, Mali, Nigeria an dSierra Leone in West Africa

Expected outputs: a) Cost-effective diagnostic tool for the detection of the virus established; b) Improved understanding of the role of insect vectors and alternate hosts; c) Biological, serological and molecular variability of virus isolates characterized; d) Rice cultivars with resistant or tolerant to RYMV identified and transferred to NARS partners in West Africa; e) Natural gene from Oryza glaberrima for RYMV resistance identified and tagged for marker-assisted selection; f) IPM strategies against RYMV and vectors formulated for national and regional adaptation.

Potential impact and beneficiaries: The immediate beneficiaries of the research generated by this project will be rice breeders and IPM specialists. The ultimate beneficiaries will be rice farmers in irrigated and rainfed lowlands who will be able to replace their current susceptible varieties with new RYMV resistant varieties and use integrated RYMV control practices.

Partners: a) National Cereals Research Institute, Bida, Nigeria; b) Rice Research Station, Rokupr, Sierra Leone; c) Insititut d'Economie Rural, Sikasso, Mali; d) Institut d’Etudes et de Recherches Agricoles, Bobo Dioualasso, Burkina Faso; e) International Rice Research Institute; f) Institut de recherche pour le développement (IRD) ; g) Sainsbury Laboratory, John Innes Center, UK.

Development investor(s): DFID, Government of Japan, and WARDA

WARDA contact person(s)/principal investigator(s): Yacouba Séré y.sere@cgiar.org Website: www.warda.cgiar.org