Journal of Pure and Applied MicrobiologyVol. 7 No. 4

A Fungal Infection Caused by Lagenidium sp. and its Control Measures in Hatchery Reared Shrimp Larvae Penaeus monodon in Bangladesh

Sheikh Aftab Uddin1*, Chowdhury Kamrul Hasan2, Mohammad Nurul Azim Sikder1 and M. Ali Hossain2

1Institute of Marine Sciences and Fisheries, University of Chittagong, Chittagong - 4331, Bangladesh. 2Department of Environmental Science, School of Environmental Science and Management, Independent University, Bangladesh.

Received on 17 June 2013 and accepted on 08 August 2013

 

ABSTRACT

The shrimp farm industries in Bangladesh have long been facing problems with the supply of poor quality seeds being produced in shrimp hatcheries. In light of this, the present study was conducted between February to August 2012, concerning the fungal diseases of P. monodon larvae reared in a commercial shrimp hatchery in Cox's Bazar, Bangladesh. The causative fungus was identified as a member of the genus Lagenidium (Oomycetes, Lagenidiales). High mortalities up to 50% was observed soon after infection. The affected larvae were whitish and filled with numerous aseptate hyphae and larvae lost equilibrium and exhibited respiratory difficulties. The fungal growth was observed on PYGS agar medium at 25?C. Infected untreated populations of nauplii, zoea and mysis stages showed mortalities of 15.75?0.76%, 31.25?3.12%, and 49.5?3.9% respectively. A 0.75 ppm treatment with trifluralin significantly reduced the mortality of the infected larval population. The pathogenicity tests of the infected fungi against the larvae of P. monodon by immersion method showed that the isolates were pathogenic causing 50%, 80% and 82% mortality in nauplii, zoea and mysis stage respectively in 96 hours post exposure at 104 zoospores/mL. This is the first report of Lagenidium sp. infection in shrimp larvae in Bangladesh.

Keywords : Lagenidium sp., Fungal infection, Penaeus monodon larvae, Trifluralin, Bangladesh