ECOLOGICAL AND BIOLOGICAL STUDIES ON THE EFFECT OF SOME FUNGI AGAINST BIOMPHALARIA ALEXANDRINA SNAILS

Abstract

Along a year from March 2012 to January 2013, the present study was carried out to determine the environmental conditions which affect the distribution and density of some freshwater snails in certain water canals representing four Egyptian governorates (El-Giza, El-Ismailia, El- Gharbeya and El-Menoufiya). Also, the correlation between such conditions and the abundance and percentages of terrestrial fungi living in the surveyed water canals and adjacent soil was recorded. In addition, the study aimed at finding out a new molluscicidal agent from a biological origin instead of chemical molluscicides which adversely affect the environment. In this respect screening tests were carried out on 236 fungal isolates, 20 species were effective against B. alexandrina snails causing 100% death of snails at 10% concentration of the fungal filtrate. The LC50 values were calculated, where the most effective species were Penicillium janthinellum and Aspergillus terreus. The sublethal concentrations of these two species were used for further