Molluscicidal and ovicidal activities ofplant extracts of the Piperaceae onBiomphalaria glabrata (Say, 1818)

ABSTRACT

Schistosomiasis is a tropical disease caused by Schistosoma and occurs in 54countries, mainly in South America, the Caribbean region, Africa and the easternMediterranean. Currently, 5 to 6 million Brazilian people are infected and 30,000are under infection risk. Typical of poor regions, this disease is associated withthe lack of basic sanitation and very frequently to the use of contaminated water in agriculture, housework and leisure. One of the most efficient methods of controlling the disease is application of molluscicides to eliminate or to reduce the population of the intermediate host snail Biomphalaria glabrata. Studies on molluscicidal activity of plant extracts have been stimulated by issues such as environmental preservation, high cost and recurrent resistance of snails tosynthetic molluscicides. The aim of this study was to determine the molluscicideaction of extracts from Piperaceae species on adult and embryonic stages ofB. glabrata. Fifteen extracts from 13 Piperaceae species were obtained from stems, leaves and roots. Toxicity of extracts was evaluated against snails at two different concentrations (500 and 100ppm) and those causing 100% mortality at 100ppm concentration were selected to obtain the LC90 (lethal concentration of 90% mortality). Piper aduncum, P. crassinervium, P. cuyabanum, P. diospyrifolium and P. hostmannianum gave 100% mortality of adult snails at concentrations ranging from 10 to 60 ppm. These extracts were also assayed on embryonic stages of B. glabrata and those from P. cuyabanum and P. hostmannianum showed 100%ovicidal action at 20ppm.