Screening of molluscicidal strain against Oncomelania hupensis from the rhizosphere of medicinal plant Phytolacca acinosa Roxb

The research aimed to screen and exploit molluscicidal microorganisms against Oncomelania hupensis , from the rhizosphere of medicinal plant, Phytolacca acinosa Roxb . , and one strain named as SL-30 was obtained with excellent molluscicidal activity. The freeze-dried powder of exocellular broth (EXB) of SL-30 could kill 100% of snails at a concentration of 48 mg/l for a submerged period of 24 h, with stabile molluscicidal activity at a temperature lower than 60°C; furthermore, it could be gradually degraded after exposure to illumination for 15 days. The freeze-dried powder of SL-30's EXB was safe to fresh fish and shrimp, even at a concentration beyond LC 90 of 24-h exposure period. The glycogen and total protein content of soft tissues of snails decreased after treating with SL-30's EXB, and glycogen content's decreasing rate had a linear relationship with molluscicidal activity. Finally, phylogenetic analysis based on ITS sequence showed that strain SL-30 had a higher similarity to Aspergillus fumigatus with bootstrap value 98%; accordingly, it was identified as a species of Aspergillus .