Farmers in Kenya are fighting a new strain of Ug99 wheat stem rust disease, which chokes nutrients in the stalk and stops wheat kernels from forming, putting incomes and food security at risk.
Wheat breeder Sridhar Bhavani, who heads the CIMMYT stem rust screening nurseries in East Africa, examines wheat at a quarantined site near Njoro, Kenya. Photo: Julie Mollins.
So far, Ug99 and its variants have been detected in Ethiopia, Eritrea, Iran, Kenya, Mozambique, Rwanda, South Africa, Sudan, Tanzania, Uganda, Yemen and Zimbabwe.
Scientists and governments are working together under the umbrella of the Borlaug Global Rust Initiative to aid farmers to try and stop the disease spreading by developing disease-resistant varieties.
In the following interview, Sridhar Bhavani, a wheat breeder who heads the stem-rust screening nurseries in East Africa for CIMMYT describes some of the challenges farmers face.
“We’ve now identified eight variants within the Ug99 lineage throughout Africa, showing that Ug99 has a complex virulence to several genes previously believed to be resistant,” said Bhavani, who is at the forefront of the battle.
Q: How can farmers produce healthy wheat crops?
Many people believe that productivity – or wheat gains – can be obtained by just using improved and resilient wheat varieties. However, farmers who engage in a variety of farm management practices, using all available knowledge about crops and diseases, have a better chance at harvesting healthy wheat. For example, some successful farmers with large landholdings may be able to adapt modern technologies such as precision farming, zero tillage, fertilizers and chemicals to control diseases and pests commonly found in wheat. Farmers can see a drastic difference in terms of yield in the same variety, but which has been subject to different management practices. At the end of the day, it’s not just the wheat variety, but the entire package of practices that a farmer undertakes in the field that actually makes a big difference.
Q: How are farmers coping with stem rust disease?
We know that the widely grown wheat variety Robin is now susceptible to the variant of the stem rust disease prevalent in Kenya, and we advocate the use of fungicides for farmers who wish to continue growing it, if the disease is not too severe in their fields. On the other hand, we have varieties such as Eagle 10, Kenya Sunbird, Kenya Thai and Kingbird that have been released and are quite resistant. These varieties could be alternatives, if farmers want to adopt new varieties and replace Robin. New breeding materials are in the pipeline and will be released in the coming years.
Q: What specific challenges do smallholder farmers face?
B: When it comes to small- and medium-scale farmers in developing countries, often their education level about diseases and modern farming systems is insufficient. Limited knowledge about practices that can be undertaken to realize better gains in yield is something that’s lacking and creates a big gap between large-scale farmers who have higher yield gains and small-scale farmers who can end up suffering large losses. Many small-scale farmers are also resource-poor and lack access to funding, which means they are usually prone to taking certain drastic measures like cutting down on the cost of inputs such as fertilizers, fungicide, using less effective substitutes because they cost less, or reducing the dosage to save costs. They may not realize the future effects on yield potential as they try and reduce production costs. In the long run, they may end up losing much more, suffering major yield losses or at times even losing their entire crop. They don’t realize they will recoup their costs through bigger gains at harvest.
How can scientists decrease the gap between resource-poor and resource-rich farmers?
A: The most effective government-run national agricultural extension programs are actively involved in educating farmers not only about adopting new varieties, but also recommending a package of practices that will ensure they get better productivity from their wheat farms. Finding this balance has been a challenge in almost all developing countries with all crops, not just wheat. Governments need to guide them by hosting farmer demonstrations at field days that show both the superior performance of varieties and better agronomic practices. This will be a solution for many of the farmers and allow them to realize gains in the near future.