Molluscicidal activity of Nicotiana tabacum extracts on the invasive snail Pomacea canaliculata

Abstract

Botanical molluscicides for controlling the invasive snail Pomacea canaliculata have attracted worldwide attention because of their cost and environmental friendliness. Aqueous extracts from discarded tobacco leaf (Nicotiana tobacum) were evaluated for molluscicidal activity against different-sized P. canaliculata under laboratory conditions. The results showed that over 90% of the snails died in 1 g/L tobacco extract within 4 days, and the survival of P. canaliculata was inversely proportional to the snail size, tobacco extract concentration and length of exposure time. Adult males were more susceptible to tobacco extract than females. The snails had few chances to feed or mate in 0.5 g/L tobacco extract, and reproduction was greatly limited in 0.2 g/L. The growth of juvenile snails was inhibited in 0.2 g/L tobacco extract, but adults were unaffected. The antioxidant capacity of P. canaliculata in response to tobacco extract can be size- and sex-dependent, and the activities of superoxide dismutase, catalase, and acetylcholinesterase and the contents of glutathione and malondialdehyde were increased in adult males. These results suggest that discarded tobacco leaves can be useful as a molluscicide for controlling the invasive snail P. canaliculata based on its effects on survival, behaviour, food intake, growth performance and antioxidant capacity.

Figure 1

Temporal changes in the survival rate of P. canaliculata exposed to various concentrations (0, 1 and 2 g/L) of tobacco extracts within 96 h. 0 g/L tobacco extract (dechlorinated tap water) served as the control group (CK). (a–d) Small, medium, male adult and female adult of P. canaliculata, respectively. Error bars indicate standard error (n = 3).

Figure 2

Temporal changes in the survival rate of P. canaliculata at low concentrations (0, 0.2 and 0.5 g/L) of tobacco extract within 15 days. 0 g/L tobacco extract (dechlorinated tap water) served as the control group (CK). (a–d) Small, medium, male adult and female adult of P. canaliculata, respectively. Error bars indicate standard error (n = 3).

Figure 3

Effect of tobacco extract on snail behaviour. (a,d,g) The activity status of small P. canaliculata in 0, 0.2 and 0.5 g/L tobacco extracts, respectively. (b,e,h) The activity status of medium P. canaliculata in 0, 0.2 and 0.5 g/L tobacco extracts, respectively. (c,f,i) The activity status of adult P. canaliculata in 0, 0.2 and 0.5 g/L tobacco extracts, respectively. There were three replicates for each treatment.