to Bt pollen, risk of Bt pollen to monarch butterflies was determined to be negligible
(Sears et al. 2001) (ERA step 4). Again, the amount of Bt maize pollen force-fed to
monarch butterfly larvae was much higher than in field exposures, therefore indicating over-
estimation of risks. It is interesting to note here that the degree of hazard would not change
Figure 13.3.Weed strip of white mustard (Sinapis alba) in a cornfield for collection of butterfly
larvae on top of weed leaves.
Figure 13.4.Collection of butterfly larvae was done by dislodging them into a cotton tray.
Taxonomic knowledge and experience is needed for identifying the right caterpillar species
because of the small size of the larvae.
318 FIELD TESTING OF TRANSGENIC PLANTS