Aedes larvae developed resistance to Cry11Aa and Cry4Aa but not to Cry4Ba and Cry11Ba. Resistance ratios for individual toxins from mosquitocidal Bacillus thuringiensis israelensis (Bti) and Bacillus thuringiensis jegathesan (Btj) were tested at four generations during resistance development to Cry11Aa (A). G30 showed 124-, 66-, 13-, and 2-fold resistance ratio to Cry11Aa, Cry4Aa, Cry4Ba, and Cry11Ba (B). Cry11Aa (■), Cry4Aa (●) and Cry4Ba (▲) from Bti, and Cry11Ba (▼) from Btj. Resistance ratios for individual toxins were obtained by comparing the LC50 of the resistant strain to that of susceptible WT.