STRIGA: Control in maize

Striga (witchweed) is a parasitic weed that constrains the productivity of staples such as maize, sorghum, millet and upland rice in Sub-Saharan Africa. The weed survives by siphoning off water and nutrients from the crops for its own growth. Striga infests over 40 mill. hectares of smallholder farmland in the region and causes yield losses. Striga seeds remain dormant and viable in the soil for up to 20 years.

AATF is collaborating in a public/private sector partnership project to promote technological interventions for the control of Striga in maize in Africa.


To enable smallholder farmers in Sub-Saharan Africa have access to appropriate Striga management technologies such as seed of Imazapyr-resistant (IR) maize, Striga tolerant varieties, suppression and trap cropping management systems and soil fertility management.

The damage caused annually by Striga in Sub-Saharan Africa is estimated at US$ 1 billion, aff ecting the livelihoods of more than 100 million people. Fifteen countries of eastern, southern and western Africa account for 95% of the continent’s Striga infested fields.

The product combines a low-dose Imazapyr seed coating applied to Imazapyrresistant (IR) maize seed. Small quantities of Imazapyr (as little as 30 g/ha) act before or at the time of Striga attachment to the maize root and so prevent the phytotoxic effect of Striga. The low-dose herbicide seed dressing used in the STRIGAWAY® technology controls Striga without impacting sensitive intercrops when planted 10cm away from the maize hills. This allows smallholder farmers who practice intercropping to incorporate this technology in their farming systems. AATF encourages farmers to incorporate soil fertility practices such as use of legume rotation and intercrops and fertiliser additions to replenish soil nutrients and optimise crop yields.

The use of IR-Maize technology to control Striga leads to yields 38–82% higher than those currently obtained from traditional maize varieties. In Kenya, a conservative estimate indicates that when adopted, the proposed technology will lead to an extra 62,000 tonnes of maize in Western Province alone. This translates to US$ 5.3 million per year using the 2002 estimates of farm-gate price for maize in Kenya.