Your are here:

Papaya Anthracnose

Scientific Name
Colletotrichum gloeosporioides
Scientific Author
(Penz.) Penz. & Sacc.
Taxonomy
Anamorphic fungi
Status
Native Australian Pest Species
Reliability
High
Download
PDF

Page menu options:

Diagnostic Images

Close
Caption
Source
Image Options
Close
Diagnostic Images (7)
Diagnostic Notes
The fungus:

Mordue (1971) published a detailed description of this species. A brief summary of his description is given here: Perithecia aggregated, globose to obpyriform, dark brown to black, 85-300 µm in diameter; The ostioles are periphysate and paraphyses are present. The asci are 8-spored and have short stalks, clavate to cylindrical, thickened at apex, 35-80 x 8-14 µm. The ascospores are hyaline, unicellular, narrowly oval to cylindrical to fusiform. Acervuli are produced on lesions, and usually setose. Conidiophores are cylindrical phialidic. The conidia are cylindrical with obtuse ends, 9-24 x 3-6 µm, unicellular, hyaline or faintly brown. Appressoria are 6-20 x 4-12 µm, ovate to obovate, sometimes lobed. See Arx (1957), Mordue (1971) and Sutton (1980) for additional information.

Symptoms

The fungus can infect immature green fruits attached to the plant and remain quiescent until the fruit begins to ripen, when symptoms of anthracnose or chocolate spot appear. A single isolate can causes both symptoms.

Anthracnose: The first symptoms are small well defined dried pink spots on the surface of ripening fruit. Later, these lesions grow to 5 cm diameter, become rounded, sunken (from 3 to 5 mm deep) and brown to black in colour. The lesions can be water-soaked or dried and hard. In the centre of the lesions, the fungus produces dark acervuli, frequently in a concentric pattern and orange to pink gelatinous mass of conidia can be observed. The whole lesion can be easily separated from the flesh of the fruit as a corkscrew, using a knife, leaving a well defined hole in the fruit.

Symptoms on immature fruits and leaves are uncommon. Post-harvest infection usually produces stem-end rot. On the petioles, it occurs as elliptical lesions, up to 1.5 x 0.5 cm, with dark acervuli in a concentric pattern.

Chocolate spot: Post-harvest, superficial lesions, seldom slightly sunken, irregular to rounded, up to 1 cm in diameter, well defined, with characteristic reddish-brown colour. As the fruit ripens the lesions can either remain superficial or grow and become sunken, resembling anthracnose. Sometimes these symptoms together with latex exudation on the centre of the lesion can be observed several days before harvest.

Usually, this fungus occurs on papaya as the anamorphic state. The teleomorph has been found on papaya in Brazil, Venezuela, Hawaii and Australia. Isolates of C. gloeosporioides in culture can produce the teleomorph.

Notes:

Synonyms: There are around 600 synonyms of C. gloeosporioides (Arx, 1957), among them are Gloeosporium papayae P. Henn. (1895), Colletotrichum papayae P. Henn. and C. papayae Petrak.

More Information
Specimen Contact
Dr Jose Liberato
Author
Liberato JR
Created
30/01/2006 03:06 AEST
Last Updated
09/10/2012 14:24 AEST
Citation
Liberato JR (2006) Papaya Anthracnose (Colletotrichum gloeosporioides ) Updated on 10/9/2012 2:24:18 PM Available online: PaDIL - http://www.padil.gov.au.
Image Use
Free for use under the Creative Commons Attribution 3.0 Australia License

Loading