C.O.R.N. Newsletter

  1. Author(s): Pierce Paul , Author(s): Andy Michel

    Foliar diseases continue to spread up the corn plant in some fields, so, this may be the year to apply a foliar fungicide to minimize losses due to diseases such as Northern Corn Leaf Blight (NCLB) and Gray Leaf Spot (GLS).

    Issue: 2015-21
  2. Author(s): Andy Michel

    The good news with all the rain is that it likely caused substantial mortality in corn rootworm larvae. However, growers should still be mindful of our most important corn insect. Over the next few weeks is the time that growers should dig corn roots and inspect them for rootworm feeding.  Dig at least 5 plants in 10 different locations in your field.  To determine the level of injury, use the Node Injury Scale—this scale ranges from 1 to 3, were 0.5 is half of a node of roots damaged, 1 is a full node of roots damaged, 2 is 2 full nodes damage, etc.

    Issue: 2015-20
  3. Gray Leaf Spot on Corn
    Author(s): Pierce Paul

    Foliar diseases, especially Gray Leaf Spot (GLS) and Northern Corn Leaf Blight (NCLB), are already showing up in some corn fields. Although this a little bit on the early side for Ohio, it is not at all surprising, since we have had several wet, humid days over the past few weeks, with moderate to warm temperatures. Both GLS and NCLB are favored by wet conditions, particularly if temperatures are within the favorable range like they have been (70 to 90 F for GLS and 66 to 80 F for NCLB).

    Issue: 2015-20
  4. Western Bean Cutworm Damage on Corn
    Author(s): Andy Michel

    Our trapping network has started to catch western bean cutworm (WBC) adults, meaning that flight is underway. WBC emergence occurs, for the most part, during July, although it can be extended into August, so we expect our counts to increase. Females lay eggs on corn, and, after hatch, the larvae feed on the tassel, pollen or silk before entering the ear.  Late season damage can be quite substantial, as shown in the figure.

    Issue: 2015-20
  5. Author(s): Steve Culman , Author(s): Peter Thomison

    Heavy rainfall over the past several weeks has left many producers across the state with few opportunities to side dress their corn with nitrogen. To make matters worse, excessive water means that significant soil nitrogen has likely been lost through denitrification and/or leaching. It’s not uncommon or surprising to see standing corn crops with severe yellowing, indicating some level of nitrogen deficiency. Most of the corn in the state has grown too tall for standard application equipment to pass over without crop damage, and some corn is entering late vegetative stages.

    Issue: 2015-20
  6. Author(s): Steve Culman , Author(s): Ed Lentz, CCA

    Additional Authors:  Anthony Fulford, Clay Dygert,

    Issue: 2015-20
  7. Wet Weather Plaques Ohio Corn Crop
    Author(s): Peter Thomison

    During the past two weeks, flooding and ponding have occurred across Ohio, especially in river bottoms and along streams. In some localized areas, this may have resulted in partial and complete immersion of corn in nearby fields, especially in low spots. When water drains off these fields, plants may be covered to varying degrees with a layer of mud. Will corn plants covered by a layer of mud survive and can it perform normally? The layers of silty mud covering plants will limit or prevent leaf photosynthesis.

    Issue: 2015-19
  8. Author(s): Pierce Paul

    We are already seeing Northern Corn Leaf Blight (NCLB) in some Ohio corn fields. Why are we seeing NCLB this early and how will this affect our yields? For this disease to develop this early, three basic conditions must be satisfied: 1) the fungus (Exserohilum turcicum) must be present; 2) the hybrid planted must be very susceptible to the prevalent races of the fungus; 3) and environmental conditions must be highly favorable.

    Issue: 2015-19
  9. Water Stressed Corn in Ohio
    Author(s): Mark Loux

    1.  Wet weather has delayed POST herbicide applications in both corn and soybeans.  This can result in weeds and crops that are larger and more advanced in growth stage than anticipated.  The larger crop is primarily a problem in corn, where a more advanced growth stage can start to limit herbicide options.  Be sure to check labels and the OH/IN/IL Weed Control Guide for information on maximum crop size and stage for herbicides (Table 8 on page 68 of 2015 edition).  Larger weeds may require higher rates or more complex POST herbicide mixtures.  Glyphosate and Liberty rates can be increased

    Issue: 2015-18
  10. Author(s): Ed Lentz, CCA , Author(s): Steve Culman

    Some parts of Ohio have recently experienced heavy rains, especially the northern part. Producers in these areas may have concerns about nitrogen loss in corn fields. Nitrogen losses occur by two main pathways: denitrification (gaseous loss of N) and leaching of nitrate from soil through water leaving the tile line or into groundwater. There is no tool or test that can tell how much has been lost. An estimate can made on the loss potential, which is based on N source, time of application, soil temperature, and number of days that soils have remained saturated.

    Issue: 2015-17