Stink bugs have made their way into many corn fields in Indiana. Stink bug damage appears as round or elongated holes in a straight line across the leaf, usually in corn around the V5 growth stage.
Scout's Report 6/17: Insect flight and hatching coming soon
These insects feed on leaf fluids by inserting their tubular mouth in the plant matter. Stink bugs can cause destruction of tissue, loss of entire leaf ends, or some deformities. These can lead to limited leaf area and reduced photosynthesis. Along with this concern is the concept that the plant is setting its number of rows of kernels on its ears at this stage. Any significant stress to the plant during V5-V6 stages can reduce yield.
In wet conditions with temperature variations, this damage can lead to infection in a corn plant. I found this situation in a central Indiana farm this week. It appeared as white smut or wart type growths on the leaves and stalks. The plants that were infected will more than likely not grow through this condition and cause a loss in yield.
Most corn around the state is still showing a yellow color due to excess water and difficulty with nutrient uptake. In poorly drained soils, these plants are now facing a stunted growth and may fall behind other areas of the field.
The corn will look inconsistent through the field from many angles. The pattern is likely to follow tile lines, soils types, or elevation changes. Most soybeans have appeared to handle the wet conditions with temperature swings better than corn and have only suffered a slight population decrease on average.
Scout's Report 6/11: Indiana corn struggles with micronutrient uptake, rapid growth syndrome
The moth traps throughout north central Indiana have turned up fairly light captures. I have found 2 black cutworm moths and 10 European corn borer moths, and 23 unidentifiable moths. These 23 moths appear to be of no threat to the crop, but keep watch for egg masses and insect feeding in fields.
Check Purdue University Entomology and Agronomy updates for more information.
Kettler writes form Tipton. The Purdue University junior is an intern for Beck's Hybrids. She works with Ben Grimme, Kris Johnson and Denny Cobb