Common, generally accepted names of the organism or disease agent Burn spot disease, Fungus disease.
Scientific name or taxonomic affiliation Ramularia astaci, Didymaria cambari and Fusarium spp.
Geographic distribution Widespread in Europe.
Host species Astacus astacus, Orconectes limnosus.
Impact on the host Fungal infection of exoskeleton and gills. Ramularia infection rates reported up to 85% possibly with significant mortality. Didymaria usually causes smaller lesions (up to 5 mm in diameter) and infects the uropods.
Diagnostic techniques Gross Observations: Melanized lesions on calcified areas of exoskeleton and gills may be up to 1 cm across, brown-black in colour with red margins and eroded in the centre. Hyphae may invade the gills and muscular system.
Wet Mounts: Examine lesions for mycelia.
Methods of control No known methods of treatment or control. References Alderman, D.J. and J.L. Polglase. 1988. Pathogens, parasites and commensals. In: D.M. Holdich and R.S. Lowery (eds.). Freshwater Crayfish ­ Biology, Management and Exploitation. Timber Press, OR., p. 186-187.
Sparks, A.K. 1985. Synopsis of Invertebrate Pathology Exclusive of Insects. Elsevier Science Publishing Co. Inc., Amsterdam. p. 226-227.
Unestam, T. 1973. Significance of diseases on freshwater crayfish. In: S. Abrahamsson (ed.). Freshwater Crayfish ­ Papers from the First International Symposium on Freshwater Crayfish. Austria 1972. Studentlitteratur, Lund, p. 135-150.
Citation Information Bower, S.M., McGladdery, S.E., Price, I.M. (1994): Synopsis of Infectious Diseases and Parasites of Commercially Exploited Shellfish: Burn Spot Disease (Fungus Disease) of Crayfish.