 Hello, my name is Jan Knudel. I'm the Extension Entomologist for North Dakota State University. Today we're out in a local cornfield near Arthur, North Dakota. And we're going to be checking the roots for corn rootworm activity to determine if there's larval activity feeding on the roots of the corn plant by corn rootworm. We need to dig up the corn plants and examine the roots. And another symptom of corn rootworm, which is evident in this plant, is the goose-necking and the lodging of this corn plant. After we dig up the corn plant root mass, then we can soak the roots in buckets of water and loosen up the soil and then power wash the soil off the roots. And then we can rate them for corn rootworm damage. For rating corn rootworm injury, we use the rating scale of 0 to 3 that was developed at Iowa State University. 0, no injury. 1, 1 complete node pruned to within 1.5 inch of the stock. 2, 2 complete nodes pruned to within 1.5 inch of the stock. 3, 3 complete nodes pruned to within 1.5 inch of the stock. This root injury rating scale correlates to the level of plant lodging and yield loss caused by corn rootworm. Corn rootworm injury rating of more than 0.25 is equivalent to the economic threshold level. Producers should be concerned with BT resistant problems if BT corn hybrids have a root injury rating of more than 1. You can compare a healthy root mass on the left with the corn rootworm damaged root on the right. To help delay the development of corn rootworm resistance to BT, consider the following pest management strategies. Avoid continuous corn and rotate corn with other non-corn rootworm hosts such as soybean, wheat, sunflower, flax, use a different BT trait in BT corn hybrids, rotate the modes of action of soil insecticides, plant your non-BT corn refuge, control any volunteer corn in soybeans. Thank you for watching this video and learning more about corn rootworm.