By Nathan Drewitz
Soybean Cyst Nematodes (SCN) cropped up in different places throughout Stearns, Benton, and Morrison counties this last year. It was one of the three issues that I heard from both Agronomists and growers in terms of diseases and insect pests in soybeans and corn. While we can look for similarities to the damage we associate with SCN and speculate that the nematode may be present; it is important that we collect samples and run the proper tests. These tests will identify if SCN is present in the soil and at what population density. Remember that SCN can cause more than 30% yield reduction in soybeans and will be influenced by soybean variety, weather conditions, and other soil factors. Also keep in mind that early detection is important. Keeping populations low will limit damage and help keep management options available for use. It is also helpful to know that once you have this issue it doesn’t go away. This means you will need to monitor the populations over the long-term to minimize yield losses, reduce population densities, and maintain the effectiveness of resistant varieties. Since monitoring over time is important it means that proper sampling over time is also important. Given its importance let’s review the basics components of a proper sampling procedure.
Start by dividing your field into 5 to 10-acre sections. Then following in a zig-zag pattern throughout the field collect 20 soil cores with a 1-inch diameter soil probe to a depth of 6 to 8 inches. Place your cores in a plastic bag and label your bag with the field identification. Make sure to store your samples at a cool temperature if you can’t send them to the lab right away.
Remember that both increasing the number of samples or decreasing the area covered will influence variability in the sample. Spatial distribution of SCN will also influence the results as you go from hot spots in the field to non-infested areas. Manage hot spots separately if possible, otherwise the best option is to manage the field based on the higher population density. You will also want to record the time of year when samples were collected. With SCN counts varying depending on the time of year it will be difficult to compare samples collected at different times between years. Long-term management is best when sample collection is consistent in location, crop, and time of year. Finally remember that samples taken after corn harvest but before soybean planting are the most useful in estimating potential yield loss. Sampling in the fall also allows the most time for a management plan to be drawn up. The above information was taken out of the UMN Extension Soybean Cyst Nematode Management Guide.
If you still need to renew your Private Pesticide certification for 2021 there are four options this year. Two of the options are familiar with the written and online exam. There are also two new options for this year, the self-paced Canvas course, and live online workshops. The online workshops are broken down by region. Dates for the Central Region workshops are January 27th, February 3rd, 10th, 17th, and 24th, from 12pm to 4pm, and February 4th from 5pm to 9pm.
Source : umn.edu