How can mitten crab fungal disease be treated effectively?
How to treat mitten crab fungal disease
How to treat mitten crab fungal disease
Pathogen: The pathogen of mitten crab fungal disease is Lagenidium. The hyphae of this fungus are very long, irregularly cross-branched, generally without septa, curved, and 8-40 micrometers in diameter. The hyphae absorb nutrients from mitten crab larvae, grow and develop very quickly, and soon fill the host body. They can parasitize both the cephalothorax and the abdomen, resembling pine needles and poplar rootlets. The color of the hyphae inside the mitten crab larvae constantly changes, appearing black, green, cyan, gray, orange-yellow, and other colors. The hyphae near the larval surface form cryptic sporangia.
Symptoms: Fungi are generally more resistant to physicochemical factors than bacteria, tolerating a wide range of temperature, salinity, and pH, and can grow within a range containing 0.7% sodium chloride and pH 5-11. Infected larvae have a large head and small tail, a black body, reduced food intake, and weakened activity. The fungus spreads very quickly. On the 1st day, 1% of larvae may be parasitized; after 2-3 days, 100% of all larvae are infected, and in severe cases all die.
Epidemic situation: According to surveys, this disease is currently a major disease in artificial breeding of mitten crabs in China. From Liaoning in the north to Hainan Island in the south, from coastal to inland areas, it occurs in most artificial mitten crab nursery farms. From mitten crab embryos' eggs to larvae to crabs to adult crabs to parent crabs, the fungus Lagenidium can parasitize all stages, especially posing a great threat to larvae and juvenile crabs. The general survival rate is only 5%-6%. If crab seedlings are soaked in medication before rearing juvenile crabs, the survival rate can increase by 1-3 times.
Prevention and control methods: There is currently no effective way to kill the fungal pathogen, but its transmission routes and parasitic sites have been identified. Therefore, the first step should be to cut off its transmission routes, starting with parent crabs. All artificial mitten crab breeding farms should select adult crabs not parasitized by Lagenidium as parent crabs, and disinfect the parent crabs before inducing spawning.
Pathogen: The pathogen of mitten crab fungal disease is Lagenidium. The hyphae of this fungus are very long, irregularly cross-branched, generally without septa, curved, and 8-40 micrometers in diameter. The hyphae absorb nutrients from mitten crab larvae, grow and develop very quickly, and soon fill the host body. They can parasitize both the cephalothorax and the abdomen, resembling pine needles and poplar rootlets. The color of the hyphae inside the mitten crab larvae constantly changes, appearing black, green, cyan, gray, orange-yellow, and other colors. The hyphae near the larval surface form cryptic sporangia.
Symptoms: Fungi are generally more resistant to physicochemical factors than bacteria, tolerating a wide range of temperature, salinity, and pH, and can grow within a range containing 0.7% sodium chloride and pH 5-11. Infected larvae have a large head and small tail, a black body, reduced food intake, and weakened activity. The fungus spreads very quickly. On the 1st day, 1% of larvae may be parasitized; after 2-3 days, 100% of all larvae are infected, and in severe cases all die.
Epidemic situation: According to surveys, this disease is currently a major disease in artificial breeding of mitten crabs in China. From Liaoning in the north to Hainan Island in the south, from coastal to inland areas, it occurs in most artificial mitten crab nursery farms. From mitten crab embryos' eggs to larvae to crabs to adult crabs to parent crabs, the fungus Lagenidium can parasitize all stages, especially posing a great threat to larvae and juvenile crabs. The general survival rate is only 5%-6%. If crab seedlings are soaked in medication before rearing juvenile crabs, the survival rate can increase by 1-3 times.
Prevention and control methods: There is currently no effective way to kill the fungal pathogen, but its transmission routes and parasitic sites have been identified. Therefore, the first step should be to cut off its transmission routes, starting with parent crabs. All artificial mitten crab breeding farms should select adult crabs not parasitized by Lagenidium as parent crabs, and disinfect the parent crabs before inducing spawning.