By Robyn Joubert
Help is on the horizon for soybean smallholder farmers in sub-Saharan Africa, with the ramping up of an Early Warning System (EWS) on soybean rust.
The system, developed by the International Institute of Tropical Agriculture (IITA) and the Soybean Innovation Lab with support from Kvuno and Solidaridad, allows for early detection of potential rust outbreaks, giving smallholder farmers time to act before it spreads.
Soybean rust is a destructive, fast-spreading fungal disease that poses a major threat to soybean production. Causing yield losses of up to 80%, it threatens food security for many smallholder farmers, particularly those who rely on just one or two crops for their livelihood.
“Farmers in Zambia, Malawi and Mozambique are already using the EWS. We are scaling it up in these countries, and as part of our second scale up we would like to extend it to South Africa and Zimbabwe within the next two years,” said Shungu Kanyemba, Managing Director of Solidaridad Southern Africa.
The EWS works by planting soybeans in special “sentinel plots” two to three weeks prior to planting the main plot.
Measuring 2m x 2m or bigger, these sentinel plots are closely monitored. Scouting is performed biweekly prior to flowering and then weekly when environmental conditions become conducive for rust infection. The disease manifests as grey to tan lesions on the undersides of leaves, leading to yellowing and leaf drop.
“When rust is detected on the sentinel plots, farmers receive alerts on their mobile phones through a simple app,” said Dr Harun Murithi, Crop Health Specialist at IITA and Soybean Innovation Lab.Sentinel plots allow for early detection, before the disease gains a foothold in the main production fields, and can prevent unnecessary application of pesticides. Fungicides are currently the main option for controlling soybean rust. They are most effective if applied when disease levels are low, making proper and timely application of fungicides vital for effective control.
As a foliar disease, soybean rust causes a reduction in photosynthesis and an increase in premature defoliation. This leads to fewer pods, smaller seeds and lower yields.
In general, with every 10% increase in rust severity, there may be a 10% reduction in yield. Yield losses range from 10-80%, with losses in Sub-Saharan African reported to be between 27-80% and losses in Zimbabwe averaging 60-80%.
“The Early Warning System is changing how we fight soybean rust, and we look forward to seeing how it will help farmers across the region,” said Harun.
Shungu encouraged agricultural organisations and smallholder farmers across Southern Africa to participate in the EWS and take advantage of the real-time alerts to protect their crops.
“As we empower farmers with real-time data and digital tools to combat diseases like soybean rust, we’re strengthening the resilience of smallholder farmers across Southern Africa. This EWS is a crucial step towards sustainable farming practices that protect both livelihoods and food security in our region,” said Shungu.
For more information on planting a sentinel plot, contact infosaf@solidaridadnetwork.org
