First, let’s discuss last week’s precipitation a bit. The area received rainfall at the beginning of last week. Western Kansas and much of our area received significant rainfall and areas to the south of Barton County were under a flood watch for a bit. Amounts locally appeared to range for around an inch to over four inches. This certainly helps but doesn’t eliminate for many acres a lack of soil moisture. The top part of the soil profile is in pretty good shape for most but subsoil moisture in many places is short. This is enough to establish the 2018 wheat crop and help perennial plants prepare for winter. It slowed down harvest and shouldn’t result in major loss except for a soybean field or two. It does make following a summer row crop with wheat a bit more challenging. Now back to insects.
The question to answer this week is “Why are we seemingly having more problems with insects in our crop?” We have always dealt with insects “attacking” crops throughout history. With the advent of pesticides following World War II, the problem decreased significantly but returned with a bit of a vengeance from the late 1960s on. Why?
• Natural ecosystems are messy mixes of plants and animals adapted to the region, they typically have great species and genetic diversity. All the ecological niches, places in the environment, are filled. And it is a system that requires the least input of energy to maintain. Managed ecosystems, crop fields, are just the opposite with many niches unfilled (bare ground between rows for example), little species diversity (one crop in a field), and little genetic diversity within species. It takes a great deal of energy and management to maintain this immature, unstable ecosystem. And the crops, compared to the natural environment, are better food sources for insects which leads to the next point.
• There is a theory stating that nature abhors those well-maintained fields lacking diversity that require a lot of energy to maintain and seeks to overturn them and return them to a lower energy state. Insects are part of that problem. Or if you are less esoteric, the next point.
• If you are an insect flying around looking for food and/or a place to lay eggs what would you chose. Would you choose the natural low energy field or would you choose a field with lush, well-maintained, buffet? Probably the buffet where you could supply your needs with little effort.
• The climate is changing. Winters are warmer and more open. Killing frosts are occuring later on average. Plant growth is starting earlier in the spring for plants like winter wheat and canola. Milder winters have expanded the range of many insect pests and allowed those not overwintering in Kansas to move in earlier, often before beneficial insects. And those that overwinter in Kansas lose less of their population overwinter.
• While we are returning to crop rotations, monoculture favors increase in insects, especially as tillage decreases. And the inappropriate and over use of pesticides has resulted in “super” insects resistant to pesticides.
Next week, “What can we do about it?”
Dr. Victor L. Martin is the agriculture instructor/coordinator for Barton Community College. He can be reached at 620-792-9207, ext. 207.
