Abstract:
The molluscicidal effect of Croton tiglium seeds and leaves
on Oncomelania hupensis quadrasi,an intermediate host of
Schistosoma japonicum was studied. Acclimatized snails were
exposed to various concentrations of organic and aqueous
extracts of C. tiglium seeds and leaves for 24-, 72-, and 120-
hours. LC50 and LC90 were determined using probit analysis.
Seed extracts of Croton tiglium proved to be more effective than
the aqueous leaf extract. Organic extract of the seeds was the
most effective molluscicide based on the mortality rates of the
snail. Organic extract of Croton tiglium seeds had the lowest
LC50 and LC90. The response of the snail was time and dose
dependent. As duration of exposure and concentration
increased, mean percent mortality also increased. The
histopathological effect of the seed and leaf extracts on the foot
muscle and hepatopancreas of Oncomelania hupensis quadrasi
revealed that the toxin in the seed and leaf extracts of Croton
tiglium was systemic, as well as contact poison. Histological
changes of the foot revealed epithelial damage and increase in
the number of amoebocytes and mucous cells. Microscopic
examination of the hepatopancreas also showed membrane
damage. Digestive cells became highly vacuolated and calcium
cells increased.
