Agriculture Reference
In-Depth Information
The latest surveys have shown some recovery in production, but the overall
incidence of CMD still exceeds 50%. This is due largely to the continued use of
infected cuttings of local varieties and the limited availability of resistant material.
Tanzania:
South-west districts of Uganda bordering Tanzania were considered to be
in the 'pandemic expansion' zone in 1997 to 1998 (Legg
et al.,
1999). By 1999 the
epidemic was reported in Bukobo district of Kagera region of Tanzania on the
western shore of Lake Victoria and the epidemic-associated virus was identified in
the area (Legg, 1999). Subsequent spread southwards has been unusually rapid and
the epidemic has now reached the important cassava-growing areas in southern parts
of Lake Victoria near Mwanze, as established during OFDA-funded monitoring
surveys.
Rwanda:
Cassava is particularly important in Rwanda which has been at risk since
the onset of the epidemic in the late 1990s in adjacent parts of Uganda to the north
and Tanzania to the east. A survey in July 2000 provided the first evidence of the
epidemic in Rwanda. It was at the time restricted to Umutana province where CMD
incidence and severity were greater than elsewhere in the country and the epidemic-
associated virus was identified (Legg
et al.,
2001). There has since been further
spread and the epidemic is having particularly serious consequences for a country
that has already been severely affected by civil war and a prolonged period of
insecurity.
Burundi:
Burundi has been at risk from Rwanda to the north and Tanzania to the
east. This accounts for the first occurrence of the epidemic in the north-east regions
of Kirundu and Muyinga in 2003. The incidence and severity of CMD as recorded in
surveys were greater than elsewhere in the country, there was evidence of
considerable spread by whitefly and the epidemic-associated virus was identified
(Bigirimana
et al.,
2004).
Sudan:
Cassava is an important staple food crop in southern parts of Sudan
bordering Kitgum and other districts of northern Uganda that were severely affected
by the 1990s epidemic. However, it is unclear whether the epidemic has affected
Sudan and if so whether there has been spread from Uganda to Sudan or
vice versa
.
Access has been restricted because of the prolonged period of insecurity, although
the epidemic-associated Uganda recombinant virus (EACMV-UG) was detected in
samples collected from cassava in Sudan and tested in the UK (Harrison
et al.,
1997b).
Democratic Republic of Congo (DRC):
There is similar uncertainty in DRC
(formerly Zaire) to the west of Uganda where access has been difficult because of
civil war and general insecurity. Cassava crop failure was reported by aid workers in
c
. 1990 in Kivu region near the Ugandan border, but it is not known whether this
was due to CMD, cassava bacterial blight, cassava mealybug, cassava green mite or
drought. Subsequently, EACMV-UG was detected in samples from around
Kisangani
c
. 500 km from the western border with Uganda (S. Winter, unpublished,
