Crop Knowledge Master Fungi

Cladosporium sp.

internal blight of papaya (Plant Disease Pathogen)
Hosts Distribution Symptoms Biology Epidemiology Management Reference

Author

Wayne Nishijima, Extension Plant Pathologist

Department of Plant Pathology

CTAHR

University of Hawaii at Hilo

HOSTS

Internal "blight" is a disease of papaya fruit that occurs when one of several fungi enter the seed cavity and cause an internal infection. Although this is the most common fungus involved, both Fusarium sp. and Penicillium sp. are occasionally recovered from diseased fruit.

DISTRIBUTION

Although Cladosporium sp. has only been reported to occur on papaya in Hawaii, other Cladosporium spp. occur widely in other states, causing a variety of diseases on many different hosts.

SYMPTOMS

Infected tissue is watersoaked and translucent in the early stages to black and firm in the later stages of infection. Infected fruits yellow prematurely and unevenly in the fruit column. People harvesting or packing papaya fruits, therefore, can easily recognize infected fruits and cull them.

BIOLOGY

Once inside the seed cavity the fungus grows through the mucilaginous coating surrounding the seeds, causing it to shrivel, dry and darken. The entire seed cavity is usually colonized and the adjacent flesh also can be infected.

MANAGEMENT

NON-CHEMICAL CONTROL

Apparently, the incomplete closure of the blossom end is genetically controlled thus proper seed selection, i.e. consistently selecting seeds only from trees on which this problem does not occur, is important in minimizing this disorder.

CHEMICAL CONTROL

Preventive field sprays can reduce inoculum level in the field.

REFERENCES

Hine, R.B., Holtzmann, O.V., and Raabe, R.D. 1965. Diseases of papaya (Carica papaya L.) in Hawaii. Hawaii Agric. Exp. Stn. Bull. 136, Univ. of Hawaii, 25 pp.

Zee, F.T., Nishina, M.S., Chan, H.T., and Nishijima, K.A. 1989. Blossom end defects and fruit fly infestation in papayas following hot water quarantine treatment. HortScience, 24:323-325.

 

 

JANUARY 1993

 

3A-CLASP

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