Skip to main content
ARS Home » Office of Communications » Br » monarch » What Does this All Mean?

What Does this All Mean?
headline bar
Navigate to Home
Butterflies and Bt corn. Allowing Science to Guide Decisions.
Navigate to The Scene
Navigate to The Science

What Does this Mean When You Put it All Together?

In the formal risk assessment of Bt corn on monarch populations, scientists carefully considered all of the questions of toxicity and exposure. Their conclusion: Bt corn pollen does not pose a risk to monarch populations.

To reach this conclusion, scientists integrated the following results:

    • The density of Bt11, MON810 and TC1507 types of Bt corn pollen that overlay milkweed leaves in the environment rarely comes close to the levels needed to harm monarch butterflies. Both laboratory and field studies confirmed this.

    • There is limited overlap between the period that Bt corn sheds pollen and when caterpillars are present.

    • Only a portion of the monarch caterpillar population feeds on milkweeds in and near cornfields.
Navigate to The Support
A large monarch caterpillar feeds on a common milkweed plant.

Toxicity is negligible and exposure under field conditions is low.


< previous   |   next >