Black Gill Disease (Fusarium Disease) - Fungal Diseases of Crustaceans

Black Gill Disease (FusariumDisease)

CAUSATIVE AGENT:

Fusarium solani

SPECIES AFFECTED:

All Penaeus species

GROSS SIGNS:

Appearance of “black spots” that preceded mortalities in juvenile shrimps grown in ponds.

EFFECTS ON HOSTS:

Infection usually starts on damaged tissues such as wounds, gills damaged from chemical treatments or pollutants, and lesions resulting from other dis-ease processes. Once infection is established, it is usually progressive with 30% remission rate. Lesions may also serve as a route of entry for other opportunis-tic pathogens.

DIAGNOSIS:

Microscopic examination of wet mounts of infected tissues will reveal the pres-ence of canoe-shaped macroconidia (Fig. 4-8).Fusarium spp. are ubiquitous soil fungi. Infection may begin at different loci and spread slowly. Fusariumsolani is an opportunistic pathogen of penaeids and are capable of establishinginfection in shrimps compromised by other stresses or overcrowding.

PREVENTION AND CONTROL:

Preventive measures include the elimination of sources of Fusarium conidio-phores and destruction of infected individuals. Several fungicides show promise in vitro but none proved to be effective in actual field trials.