Through natural selection, insects and other pests continue to thwart efforts to control them, developing resistance to sprays, seed treatments and even plant-incorporated protectants (PIPs). Corn rootworm (CRW), for example, has recently begun shrugging off some of the Bt traits introduced starting in 2003 to control it

Taking a simplified historical view, this adaptation is very rapid, especially considering that the main previous method of CRW control — crop rotation — delayed resistance for decades.

RNAi Technology

The introduction of Bt corn reduced the impacts of CRW considerably, but with that technology now facing challenges, scientists have turned to a new biotech tool — RNA interference (RNAi). 

In fact, in 2017 Bayer’s SmartStax PRO, a GM corn seed featuring an RNAi-based mode of action, became the first RNAi insect control product to be approved by the EPA and just recently achieved approval for import and food/feed use from China, opening the door to a 2022 commercial release.

Using RNAi technology is promising because it can be deployed in a very targeted way. According to Graham Head, head of global resistance management for Bayer, “RNA interference allows one to target particular aspects of an insect’s biology and use that to control them. 

“By using this technology, we’re able to look at the genes that…