TABLE 1.

Toxicity to C. elegans of Cry21Fa1 and Cry21Ha1 single protoxins and their mixtures

Cry21Fa1/Cry21Ha1 ratio	LC50 (μg/ml)		Synergism factorc
	Observeda	Expectedb
1:0	13.6 (10.07–19.6)
0:1	23.9 (18.07–33.25)
1:1	8.7 (6.21–11.98)	17.33	1.99
1:2	7.98 (4.75–12.76)	19.08	2.39
2:1	6.1 (3.88–8.56)	15.88	2.6

^aLC₅₀s were determined experimentally; 95% fiducial limits determined by Probit analysis are given in parentheses.

^bTheoretical LC₅₀s were calculated by using Tabashnik's equation and assuming a simple additive effect.

^cSynergism factors were calculated by dividing the expected LC₅₀ by the observed LC₅₀.