Identifying cultural, climatic and temporal factors influencing Striga
asiatica abundance within rice--maize systems in mid-west Madagascar
Abstract
The parasitic weed genus Striga causes huge losses to crop production in
sub-Saharan Africa, estimated to be in excess of $7 billion per year,
affecting subsistence farmers who frequently lack access to novel
technologies proposed for control. Effective Striga management therefore
requires the development of strategies utilising existing cultural and
management practices. We report a multi-year, landscape-scale monitoring
project for Striga asiatica in the mid-west of Madagascar, undertaken
over 2019-2020 with the aims of examining cultural, climatic and edaphic
factors currently driving abundance and distribution. Long-distance
transects were established across the middle-west region of Madagascar,
over which Striga asiatica abundance in fields was estimated. Analysis
of the data highlights the importance of crop variety and legumes in
driving Striga density. Moreover, the dataset revealed significant
effect of precipitation seasonality, mean temperature and altitude in
determining abundance. A composite management index indicated the effect
of a range of cultural practices on changes in Striga abundance. The
findings support the assertion that single measures are not sufficient
for the effective, long-term management of Striga. Furthermore, the
composite score has potential as a significant guide of ISM control
beyond the geographic range of this study.