First report of Rice yellow mottle virus on rice in the Democratic Republic of Congo.

Rice yellow mottle virus (RYMV), genus Sobemovirus, is a widespread rice pathogen reported in nearly all rice-growing countries of Africa. Although the virus was detected in Cameroon, Chad, Tanzania, Rwanda, Burundi, and Uganda (2,3), RYMV has never been described in the Democratic Republic of Congo (DRC). In July 2012, plants with leaf yellowing and mottling symptoms were observed in large irrigated rice production schemes 30 km south of Bukavu, in eastern DRC, and in lowland subsistence fields in the surroundings of Bukavu. Several dozen hectares affected by the disease were abandoned by the farmers. Symptomatic leaf samples were collected in different farmer fields. Back-inoculations to susceptible rice variety IR64 resulted in the same yellowing and mottling symptoms 7 to 9 days post-inoculation. Infected leaves gave positive results using double antibody sandwich (DAS)-ELISA tests with polyclonal antisera (as described in [1]), indicating for the first time the presence of RYMV in DRC. Triple antibod...