Univeristy of Nebraska-Lincoln (UNL) scientist Ana Maria Vélez is pioneering a genetic treatment to contain western corn rootworm. The research seeks to contain agricultural pests by targeting rootworm genes with RNAi technology.
According to UNL, western corn rootworm annually causes up to $2 billion in yield loss and control costs in the Corn Belt.
Vélez’ technique increases rootworm larvae mortality to protect the corn plant.
Vélez, an associate professor in the University of Nebraska–Lincoln’s Department of Entomology, explained the research area in a recent presentation at North Carolina State University.
Vélez and graduate students in her lab are advancing the research in multiple ways. The researchers focus on small interfering RNA molecules derived from applied double-stranded RNA molecules. The interfering RNA molecules bind to targeted rootworm genes and prevent them from producing proteins that enable particular physiological functions.
Researchers are developing RNAi science to engineer crops for insect resistance traits or as a sprayable bioinsecticide for use in integrated pest management programs. Another research area is development of oral RNAi to control mosquitoes transmitting pathogens.
Vélez and her lab students, along with Lance Meinke, professor emeritus of entomology at Nebraska, pursue multiple projects in this area. They identify relevant rootworm genes, then study how the desired RNAi molecules enter a cell, are processed by it and move throughout the rootworm body. One project looks to identify the specific rootworm gene that guides larvae toward corn plant roots, which the larvae then attack.
Adding genetic techniques to the inventory of preventive actions against this crop threat has particular importance in light of corn rootworms’ extraordinary adaptive ability, Vélez said.
“They have evolved resistance in different locations to different kinds of pesticides, to Bt’s (proteins toxic to rootworms) and even to crop rotation,” she said, noting the insects have even learned to nest in nearby soybean plants to evade detection.
Considering that demonstrated resistance ability, it’s best to use multiple preventive methods against rootworms by incorporating RNAi, Bt proteins, insecticides and crop rotation, Vélez said.
SmartStax PRO, a genetically engineered corn seed using RNAi and Bt proteins to address the rootworm threat, became available in 2022 to U.S. producers and is seeing increased usage.
The rootworm’s resistance ability threatens over time to erode the efficacy of SmartStax PRO, according to the University. The increased resistance to Bt underscores the need to develop a comprehensive understanding of RNAi science regarding the pest.
