01302nas a2200157 4500008004100000245016700041210006900208300001200277490000800289520066900297653001200966100002000978700001900998700001701017856011001034 1981 eng d00aEfficacy of Bacillus sphaericus Strain 1593 Against the Four Instars of Laboratory Reared and Field Collected Culex pipiens and Laboratory Reared Culex salinarius0 aEfficacy of Bacillus sphaericus Strain 1593 Against the Four Ins a379-3860 v1133 a

Culex pipiens pipiens and C. salinarius were found equally susceptible in laboratory tests to Bacillus sphaericus strain 1593 with LC50 values for the four instars ranging between 20 and 137 ppb (approximately 820 and 5600 spores/ml). Tests against field collected C. p. pipiens larvae revealed a regularly decreasing susceptibility with increasing larval age, the first instars being between 2 and 5 times more susceptible than fourth instars. In contrast, no significant differences in the susceptibility of second, third, and fourth instars were found in tests of laboratory reared larvae.

10abiology1 aWraight, S., P.1 aMolloy, D., P.1 aJamnback, H. uhttp://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=8542389&fileId=S0008347X0001912X