Causal
Agent:
Corynespora cassiicola
Distribution:
USA, Europe, India, Nigeria, and the Caribbean
Symptoms:
All above ground parts of the plant may become infected. Symptoms
begin on leaves as tine lesions which rapidly enlarge and develop
into light brown lesions with distinct yellow halos. Often, the lesions
grow together causing the infected tissue to collapse. Symptoms on
stems also begin as small lesions which rapidly enlarge and elongate.
These lesions may eventually become large enough to girdle the stem,
resulting in the collapse of the tissues above that point. When disease
is severe numerous leaf and stem lesions form on plants causing extensive
collapse of tissues and eventually the death of the plant. Infection
of immature fruit begins as minute, dark brown sunken spots which
enlarge as the disease progresses. Large brown circular lesions with
cracked centers develop on mature fruit. Fungal sporulation commonly
occurs in these lesions.
Conditions
for Disease Development:
This fungus has a broad host range on which it can survive. Infection
occurs readily during periods of mild temperatures between 16-32°
(61-90°F) and high moisture. Fungal spores, which often form abundantly
on the surface of infected tissues, are spread by air movement and
rainfall.
Control:
A good fungicide spray program initiated prior to the onset of symptoms
can help reduce losses from this disease.
