Taxonomy: Fungi, scientific name Cercospora sojina

Description (Zimbabwe): Commonly on soya beans, however this disease can also effect tobacco and peas.  Lesions can form on the leaves and can be identified as small dark rings that are lighter in colour in the middle. These lesions are mostly found on upper leaf surfaces, are irregularly round and consist of red-brown to purple colored borders. 

Distribution on the plant: predominantly well distributed on the leaves of the plant however the Frogeye leaf spot can also form on the pods and stems of highly susceptible varieties.

Lifecycle: overwinter in crop residues and spores form when exposed to moisture and warm weather. 

Detriment to crops: Can lead to yield loss and detriment to pod quality. 

Monitoring remarks: Check for early signs on the low leaves of the crop. Monitor more frequently once the crop canopy has closed, and during periods of persistent rainfall.

Action threshold & control: Preventative fungicides are recommended. Take curative action at early signs of the disease.

Contact a Cropserve agronomist for further information.