With the number of Bt corn hybrids commercially available, it can be confusing to decide which product best fits one’s needs.

Corn root worm resistance to the Bt trait Cry3Bb1 has been confirmed by researchers in the four Midwestern US states of Illinois, Iowa, Minnesota, and Nebraska. Resistance has also been documented for the mCry3A Bt event, and now cross-resistance has been documented for both traits.

Both adult and larval forms of corn rootworm can cause significant crop damage. Larvae feed on corn root hairs and roots, and develop through three instars phases before pupating into adult beetles. Larvae rob the plant of valuable water and nutrient flow and put the corn under yield-reducing physiological stress.