 Hello, my name is Jan Knodl. I'm the Extension Entomologist for North Dakota State University. This video is about scouting for spider mites and field corn. Spider mites are a very tiny arthropod found on the underside of the leaf. They feed on the corn plant with piercing sucking mouth parts. They feed on the plant sap. When you're ready to go out and scout, you start in the field edge to determine if spider mites are present. Look for the stippling on the leaves and or discoloration. Here you can see the mite infestation is fairly severe. You can see the yellowing and the necrosis of the plant tissue. In a severe situation, the leaves will go brown and you'll have leaf loss. If you turn the leaf over, you can see some gray area along the midrib. This is actually webbing of the spider mites. As with soybeans, spider mites infest corn plants from the bottom upwards. The management goal is to keep damage from reaching the leaf ear. The easy technique for looking for spider mites is to use a white sheet of paper. Take the leaves that you suspect having spider mites and tap them to dislodge the spider mites. Then look at the sheet of paper for mites that may be moving around. After you check the field edge and you found spider mites, you want to continue to check the rest of the field by sampling 20 sites and a couple plants per site and walking a U pattern through the field. Try to determine how far the mites have moved into the field. The goal of preventing spider mites economic loss is to prevent the spider mites from reaching the leaves near the ear. Prevent the stippling from getting up to that leaf. The threshold is when it's in the lower quarter to third of the plant is when you see stipplings would be an action threshold. Corn is susceptible to spider mite damage from tasseling through the hard-dose stage. When corn has reached the hard-dose stage, it is no longer susceptible. Thanks for joining me today and learning how to scout for spider mites in field corn. Please see the Extension Entomology website for more information. All rights reserved.