Table 2 Mortality response (LC50) of different populations of Helicoverpa zea to Vip3Aa39 protein in diet-overlay bioassays.

From: First documentation of major Vip3Aa resistance alleles in field populations of Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae) in Texas, USA

Insect

N*

LC50 (95% CL) (μg/cm2)#

Slope ± SE£

X2

df

Resistance ratio§

SS

512

0.17 (0.14, 0.21)

2.84 ± 0.29

10.5

26

—

RR

512

>100

/

/

/

>588.0

  1. *Total number of neonates assayed.
  2. #Median lethal concentration (LC50) that caused 50% mortality and the corresponding 95% confidence limit (CL). The LC50 value of an insect population was considered to be greater than the highest Bt protein concentration used in the bioassay if its larval mortality was <50% at the highest concentration. Larval mortality was calculated based on the number of dead larvae plus survivors that were still in the first instar divided by the total number of insects assayed.
  3. £SE, standard error.
  4. §Resistance ratio was calculated using the LC50 value of RR divided by the LC50 of SS.
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