Table 1.

Larvicidal activity of B. sphaericus recombinant strains against C. pipiens subsp. pipiens larvae

B. sphaericus strainSuspension (all sonicated)aLarvicidal activityb
LC50cLC90
2297 (parental)Spore pelletd 2.1 ± 0.412.6 ± 8.8
Purified inclusion bodies8 ± 0.0515.5 ± 1.3
2297(pMK3)Washed FWC31 ± 2.559.7 ± 7.3
2297(pcyt1Ab1)Washed FWC73.3 ± 17.3181.3 ± 75.3
Spore pellet7.1 ± 0.918.6 ± 2.8
Purified inclusion bodies72.4 ± 4.8306 ± 222
2362Washed FWC15.9 ± 1.928.6 ± 4.4
2362(pcyt1Ab1)Washed FWC28.5 ± 4.564.5 ± 0.4
Iab872(pcyt1Ab1)Washed FWC27.9e 194  
Iab872(pcyt1Ab1)Spore pellet5.8 ± 3.527.4 ± 19
Iab872(pMK3)Spore pellet 2.6e  7.1
2297 asporulated(pMK3)Washed FWC95.8 ± 45 μg/ml526.9 ± 299 μg/ml
2297 asporulated(pcyt1Ab1)Washed FWC109 ± 29.4 μg/ml360.0 ± 180 μg/ml
B. thuringiensis SPL 407(pcyt1Ab1)Purified crystals5.7 ± 3.1 μg/ml29.7 ± 17.3 μg/ml
  • a All B. sphaericus suspensions were subjected to sonication two times for 10 min each before the experiments.

  • b Unless otherwise noted, values are in nanograms per milliliter.

  • c Lethal concentrations after 48 h of larval exposure.

  • d Spores pelleted after ultracentrifugation.

  • e The result of one experiment.