Liz Stahl, Extension educator – crops and Fei Yang, Extension corn entomologist Overwintering European corn borer larva and its feeding damage within the lower stalk. Photo: Bruce Potter Although European corn borer (ECB) populations dropped dramatically after widespread adoption of Bt-corn hybrids, the discovery of Bt-resistant populations reminds us to not let our guard down on this pest. Corn rootworm (CRW) is another major corn pest in Minnesota where resistance to Bt traits has led to management challenges. ECB and CRW were the topic of discussion on the March 13th, Strategic Farming: Let’s Talk Crops program with Dr. Fei Yang, Extension Entomologist with University of Minnesota Extension. European corn borer (ECB) European corn borer, specifically the larva, caused significant yield losses and economic damage throughout the U.S. Corn Belt prior to the introduction of Bt hybrids. Injury from ECB can lead to stalk breakage, ear droppage, stalk rots, ear rots, mycotoxins,
By: Dan Kaiser, Extension nutrient management specialist When it comes to soil tests, I commonly receive questions about pH and liming. Below are some common questions I get and my answers. What exactly is the buffer pH? Soils are routinely analyzed for water pH where equal weights of water and soil are mixed, and a pH electrode is used to determine the pH of the solution. The water pH represents what we call the “active” pH of the soil. When the water pH drops below a certain point, most labs will then run a buffer pH on the soil, which is used to determine the amount of limestone needed to raise the water pH to a desired value. Buffer pH methods use various extraction solutions and are meant to measure both the active and reserve acidity of the soil, which provides a better indication of how the active acidity will change when limestone is applied. The two tests will not return the same value and it is common for the buffer pH value to be higher than the water pH in nearly all soils