Molluscicidal activity of Arisaema erubescens mixed with fertilizers against Oncomelania hupensis and its effect on rice germination and growth.

To explore a new molluscicide with dual effects of fertilization and molluscicidal activity, an organic-inorganic compound fertilizer molluscicide was prepared by mixing the water extract (or powder) of Arisaema erubescens tubers with nitrogen fertilizer, phosphate fertilizer, potash fertilizer, and three mixed fertilizers (hereinafter referred to as ANF, APF, AKF and ACF, respectively). Leaching using the mixture was performed to test for molluscicidal activity, and indoor rice germination, seedling growth, and pot experiments were monitored. ANF exhibited superior molluscicidal activity, with respective 24-h and 48-h Oncomelania mortality rates significantly increased, reaching up to 67.7% and 92.3%. ANF, APF, and AKF significantly promoted rice germination and growth of rice, with ANF showing superior effects. The respective 3-day and 5-day germination rate of rice seeds treated with ANF significantly increased by 25% and 21% relative to that of the control group, and the respective 10-day and 20-day growth length of rice seedlings (aboveground part) increased by 106.2% and 33.2%. A positive correlation between ACF molluscicidal activity and concentration and treatment time were observed. The Oncomelania mortality rate at 48 h after treatment with a low ACF concentration (0.25 g/L) was 70.7%, whereas that at 24 h after treatment using a higher concentration (0.5 g/L) was 80.7%. ACF promoted rice seed germination and seedling growth, whereas inhibitory effects were observed using a high ACF concentration. Therefore, the combined application of A. erubescens and chemical fertilizers not only enhances molluscicidal activity, but also promotes rice growth, with the combined application of A. erubescens and nitrogen fertilizer and mixed fertilizer showing superior dual effects (molluscicide and fertilization).