Several laboratory strains of Australorbis glabratus were compared for their relative susceptibilities to the lethal action of sodium pentachlorophenate. A Venezuelan, a Puerto Rican, a Brazilian (Bwt), and a Brazilian albino mutant (Bm) strain derived from the latter, were used. Each strain had been maintained in the Laboratory for at least 3 years.
The estimated LD50's, at 24 hours and at a mean temperature of 80° F. (78°–84° F), for the Bm, Bwt, and Venezuelan strains were 0.68 ± .016, 0.80 ± .013, and 1.06 ± .020 p.p.m., respectively. Significantly different slopes were also obtained when probit lines were fitted to the dosage-mortality data for each strain. These findings indicated that these three strains of A. glabratus differed in average susceptibility and in homogeneity. On the basis of results with fewer tests, the dosage-response characteristics of the Puerto Rican strain appeared to be similar to those of the Venezuelan strain.
The relationship of these findings to the general problem of the control of A. glabratus with sodium pentachlorophenate is discussed.
The authors wish to acknowledge with gratitude the technical assistance of Mr. Paul C. Shade and the statistical assistance of Mr. Marvin Schneiderman, Biometrics Section, National Cancer Institute.