Halo Blight is a bacterial blight

Blight

Blight refers to a specific symptom affecting plants in response to infection by a pathogenic organism. It is simply a rapid and complete chlorosis, browning, then death of plant tissues such as leaves, branches, twigs, or floral organs. Accordingly, many diseases that primarily exhibit this...

 disease caused by, Pseudomonas amygdali

Pseudomonas amygdali

Pseudomonas amygdali is a Gram-negative plant pathogenic bacterium. It is named after its ability to cause disease on almond trees. Based on 16S rRNA analysis, P. amygdali has been placed in the P. syringae group. Following ribotypical analysis several pathovars of Pseudomonas syringae were...

 pv. phaseolicola, in legumes. It causes small brown spots on the leaves with a light coloured edge.

Cause

The bacteria Pseudomonas amygdali

Pseudomonas amygdali

Pseudomonas amygdali is a Gram-negative plant pathogenic bacterium. It is named after its ability to cause disease on almond trees. Based on 16S rRNA analysis, P. amygdali has been placed in the P. syringae group. Following ribotypical analysis several pathovars of Pseudomonas syringae were...

 pv. phaseolicola, which would be present on the bean before planting.

Symptoms

Small brown circles sunken into the leaf. Light yellow/green area around the spot the "halo

Halo (religious iconography)

A halo is a ring of light that surrounds a person in art. They have been used in the iconography of many religions to indicate holy or sacred figures, and have at various periods also been used in images of rulers or heroes...

".
Yellowing of leaf and eventual death.