Bacterial and Viral Pathogens Associated with The White Garden Snail Theba Pisana (Müller)

Abstract

The present study was performed during a periodical interval of nine months in (2014) at Alexandria Governorate, Egypt. Whereas, a laboratory trial was carried out to inspect the field collected dead adult land snails ofThebapisana (693 individuals). The inspection revealed that 19.0 % of these collected snails were infected with three pathogenic; bacteria; Bacillus theuringiensis (B.t.) (2.7%), B. cereus (0.1 %), and Brevibacterium sp. (10.1%) in addition to a polyhedrosis virus (2.7 %). Moreover, the made laboratory evaluation showed that the assessed daily cumulative mortality of snails as well as LC 50 (Concentration of active ingredient responsible for killing 50% of the examined number animals) value of B.t post 13 days of snail treatment was (7.3x10 8 Visible spore (VS)/ml), while these determined values for Brevibacteriumsp. and polyhedrosis virus(P.V) were (7.6 x 10 8 VSs/ml) and (3.3 x 10 6 Polyhedral Inclusion Bodies (P.I.Bs) /ml) after four and 16 days, respectively. The LT 50 (Time in days, needed to kill 50% of the exposed pest) for Brevibacterium sp. ranged from 9.8 to 16.3 days for the different tested concentrations. The LT 50 of lower concentration of polyhedrosis virus was much prolonged up to (10.6 days) compared to that of the highest concentration (1.5-day). Also, the LT 50 values of B.t ranged from 10.2 to 17.5 day for the lowest and highest tested concentrations .The ease and simplicity of the followed bioassay procedures, and the reliability of the method described, as shown by the statistical evaluation of the obtained data, justify the use of the adopted method in the present study.