Safety test of CSL-gel
The toxicity test of pesticides on aquatic organisms is an important measure strategy for the safety evaluation of pesticides (Tian et al., 2005). Our previous studies showed that the LC50 of LNT to crucian carp at 24, 48, 72, and 96 h was about 1.6, 0.8, 0.4, and 0.4 mg/mL, respectively. To evaluate the CSL-gel safety, the number of deaths of crucian carp was examined in the water immersed with a series of numbers of CSL-gel at 24 h, 48 h, 72 h and 96 h. Pure tap water was used as a negative control. As shown in Table 3 , no dead crucian carp was observed in the CSL-treated water with LNT concentration lower than 336 mg as well as in the water control. However, dead crucian carp was observed at 48 h in the water treated with 400 pieces of CSL-gel with an LNT concentration at 336 mg, indicating that CSL-gel maintained a relatively high safety to environmental organisms.