RNAi for Western Corn Rootworm Management: Lessons Learned, Challenges, and Future Directions.

Area of Science:

• Agricultural Entomology
• Molecular Biology
• Pest Management

Background:

• Western corn rootworm (WCR), *Diabrotica virgifera virgifera*, is a major maize pest in the U.S. Corn Belt, causing significant economic losses.
• WCR has evolved resistance to conventional management strategies, necessitating the development of novel control methods.
• RNA interference (RNAi) is a gene-silencing mechanism that has been explored for pest control.

Purpose of the Study:

• To introduce a novel RNA interference (RNAi) strategy for managing the western corn rootworm (WCR) in maize.
• To highlight the development and approval of the first *in planta* RNAi product for insect control.

Main Methods:

• Maize engineered to express double-stranded hairpin RNA targeting the WCR *snf7* gene.
• Utilizing RNA interference (RNAi) to trigger gene silencing and insect mortality.
• Combining RNAi trait with *Bt* proteins (Cry3Bb1 and Cry34Ab1/Cry35Ab1) for enhanced durability.

Main Results:

• The U.S. Environmental Protection Agency approved the first *in planta* RNAi product in June 2017.
• This product targets the WCR *snf7* gene, inducing mortality through RNA interference.
• Commercial introduction of this WCR management tool is planned for 2022.

Conclusions:

• RNA interference (RNAi) in maize offers a promising new tool for managing the resistant western corn rootworm (WCR).
• The combination of RNAi and *Bt* proteins aims to provide durable and effective pest control.
• This represents a significant advancement in the development of insect-protected crops.