Innocent Zinga^1,, Ephrem Frantial Ignaleamoko¹, Régis Dimitri Longué Soupké¹, Adonise F. Valam Zango¹, Semballa Silla¹, Emmanuel Kamba Mebourou¹, Simplice Prosper Yandia^{1, 2}, Brice Toko Marabana¹, Nicole Gado Yamba Kassa¹, Ngurepende Odilon Simplice¹, Alain Romaric Doli¹, Kosh Komba Ephrem¹, Yongo Olga Diane³

Cassava is the leading crop in the Central African Republic. Since 2000, severe mosaic symptoms have been observed on cassava in this country. Thus, surveys carried out between 2005 and 2011 showed an incidence of mosaic of 85% with the presence of ACMV and the severe Ugandan strain of EACMV-UG diagnosed. The surveys showed more than 50% of the plants were co-infected by the two species and the viral synergy increased the severity of the disease and made it possible to estimate 50% of harvest losses and to demonstrate that the main factor in the spread of the disease was the deplorable phytosanitary state of the cuttings used by farmers for replanting plots with 79% of cuttings contaminated. Subsequently, several studies were conducted to identify disease control measures. This is how; A varietal selection was carried out between 2008 and 2011 and resulted in the identification of 14 mosaic-resistant varieties with high yield potential and better meeting the population's culinary habits. Our work revealed through Farmer Field Schools that conventional technical itineraries double cassava production unlike traditional practices. In the strategy of sanitation of plant material by the therapy technique, contaminated cuttings of a local variety susceptible to mosaic were heat-treated in hot water baths between 41°C and 51°C for 30 minutes and then evaluated in the open field over a period of 12 months until harvest. Our results show that 49°C represents the optimal treatment temperature, without negative impact on the regeneration capacity of the cuttings, and for which we observed the highest tuber yield (4.7 kg / plant), equivalent to untreated cuttings from asymptomatic plants (4.6 kg / plant). Our studies have shown that regeneration of infected cuttings in a high-temperature room (37°C to 40°C) for 15 days followed by meristem culture effectively disinfects the contaminated plant material. The combination of thermotherapy and meristem culture techniques is an effective way to disinfect infected plant material. The popularization of resistant varieties and the sanitation techniques tested in this study constitute an effective means of disease control.

Mosaic, epidemic, begomovirus, control, sanitation, Central African Republic