AGRICULTURE NEWS - Fungicides are widely used by South African wheat producers against foliar diseases. Common diseases treated with them include leaf rust, stripe rust, stem rust, powdery mildew, Septoria tritici blotch (STB) and Stagonospora nodorum blotch (SNB).
Because genetically resistant cultivars may not be available, or because of new pathogen strains that break down resistance, fungicides will remain an important part of local wheat production.
For example, the emergence of new stripe rust races in 1998 and 2005 resulted in the outbreaks of this disease on previously resistant wheat cultivars such as Hugenoot and PAN 3191.
New stem rust races that are virulent on the resistance gene Sr31 were detected for the first time in South Africa in 2009 and 2017. Similarly, several leaf rust races that resulted in the breakdown of resistance genes such as Lr37 were identified locally in recent years.
Minimise fungicide usage
When previously resistant cultivars become susceptible due to the emergence of new races, fungicides are used to control these rust diseases.
Despite this, disease control options other than fungicides should be considered first. This includes the use of resistant cultivars. Fungicides should be used as a component of an integrated disease control strategy, not in lieu of it.
Read the full article here on the Caxton publication, Farmer's Weekly
