Cross-resistance between strains of Bacillus sphaericus but not B. thuringiensis israelensis in colonies of the mosquito Culex quinquefasciatus.
Two colonies of Culex quinquefasciatus Say (Diptera: Culicidae) were selected with Bacillus sphaericus strains C3-41 and IAB59 in the laboratory for 13 and 18 generations; they attained 145,000- and 48.3-fold resistance, respectively, in comparison with a susceptible laboratory colony (SLCq) and showed very high levels of cross-resistance (8500- to 145,000-fold) to B. sphaericus strains C3-41, 1593, 2297 and 2362. They were relatively susceptible to B. sphaericus strains LP1-G and 47-6B (only 0.8- to 2.8-fold tolerance), with 24.8- to 48.3-fold cross-resistance to strain IAB59. B. sphaericus-resistant mosquito colonies remained highly susceptible to B. thuringiensis israelensis, suggesting that B.t.i. would be of value in the management of B. sphaericus-resistant Cx. quinquefasciatus colonies. The demonstration of low or no cross-resistance of two selected resistant Cx. quinquefasciatus colonies to IAB59, LP1-G and 47-6B strains of B. sphaericus and the finding of a major 49 kDa protein in these strains suggest that there is likely to be another mosquitocidal factor in the three strains.
Yuan
Z M
ZM
Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China. yzm@pentium.whiov.ac.cn
Pei
G F
GF
Regis
L
L
Nielsen-Leroux
C
C
Cai
Q X
QX
D000818:Animals; D001407:Bacillus / Q000145:classification* / Q000302:isolation & purification; D001413:Bacillus thuringiensis / Q000145:classification* / Q000302:isolation & purification; D001426:Bacterial Proteins / Q000302:isolation & purification; D003465:Culex / Q000382:microbiology*; D007113:Immunity, Innate
D001426:Bacterial Proteins