Identify and Manage Corn Ear Molds

October 21, 2019

Cooler and wet conditions in the Western Corn Belt have delayed harvest and slowed grain drying, leading to increased ear rot diseases and grain molds. Some producers and consultants also are observing rotted cobs, which can be related to several ear rot diseases.

What you should know:

  • Scout for ear molds beginning at late-dent stage by pulling husks back and examining each ear for rot or mold.
  • To identify a disease, consider conditions in which the crop was planted, field history, husk type and environmental conditions at tasseling, silking and pollination.
  • If you can’t identify the ear mold, send the entire ear to your Hoegemeyer agronomist or university agriculture extension for evaluation.

Learn more here with this Hoegemeyer agronomy profile on ear molds.

-Eric Solberg, Eastern Product Agronomist


Categories: corn, ear mold     Comments: 0    

Why We Need to Prioritize Our 2019 Corn Harvest

September 30, 2019

2019 brought us many adverse environmental conditions:

  1. We started with a challenging planting season. Continuous rain events caused most farmers to begin corn planting much later than normal.  We also saw cooler temperatures well into May causing soils to stay below our planting temperatures targets.
    1. Cloudy weather accompanied all the rain. Solar radiation was limited with all the clouds which had adverse effects on our plants.
  2. Tillage and no-till programs were far from perfect. Ground was worked wet or no-till planted into wet ground which created compaction and sidewall smearing.
  3. Most of our fertility programs were compromised. Many growers did not get the desired amount of fertility on the fields and what was put on may have been unavailable as nitrogen and sulfur ended up deep in the soil profile, out of reach from corn roots.
  4. The first-choice chemical program either wasn’t applied or had to be changed because of the weather creating weedy fields.

When summer came most of the Western Corn Belt continued to receive plenty of rain which was a good short-term fix to the problems stated above. The corn that did get planted grew and looked good, covering up most of the problems we had created. Even though the plants were put under an extreme amount of stress, they did everything they could to produce an ear. The ability to put on that ear may come with a price though, the plant may have had to cannibalize itself to finish out that ear.

As we look to start combining corn, harvest plans need to be made based on field evaluations. Stalk and root rots are hard to predict as one field may develop a problem while the next does not. Similarly, certain parts of the field can be affected worse than others as well. Some hybrids are more resistant then others, but if the environment is right, rots can show up in every hybrid. 

As the plant undergoes stress, photosynthesis slows down causing irregular growth patterns, irregular ear development of kernel abortion and ear tip back. Stress will also cause the sugar production to slow down during grain fill resulting in sugars being taken away from the roots, stalks and ear shanks.

Stalk and root lodging is caused by four major events:

  1. Severe weather – high winds and heavy rain can cause stalks and roots to bend and break.
  2. Insect feeding – insects can pierce the stalk and leaves to cause a weak point introducing disease.
  3. Saturated soils – the excess amount of rain caused soils to remain saturated all year long and created shallow roots giving the plant less stability as it grew.
  4. Stalk and root rots – the environment was a perfect storm to create many different types of stalk and root rots.  Figure 1 is an example of a Fusarium crown rot while Figure 2 is an example of Fusarium stalk rot.
        

It is important growers create a plan of which corn fields to harvest first. Scouting should occur any time after pollination by walking into the field well past the end rows and choosing at least ten locations with different environments in that same field.  Different environments can consist of soil types, hybrid changes, fertility zones, and slope of the ground.  Evaluate plants by using the push test (stand next to the plant and extend your arm straight out) or the pinch test (pinch the plant in several locations from ground level to the ear) to identify stalk integrity. 

If you find trouble spots, first identify how widespread the trouble spots are showing in the field and second prioritize the severity. As always, if you have any questions give your Hoegemeyer team a call.

We hope you have a safe 2019 harvest!

-Stuart Carlson, Northern Product Agronomist


Categories: harvest, stalk rot     Comments: 0    

Late Season Stalk Rots in 2019

September 24, 2019

In Hoegemeyer’s footprint, we started out 2019 with a cold finish to winter and a late start to planting season due to all the flooding and excess moisture. Most areas of Nebraska received more rainfall than needed during the growing season leaving just a few dry areas. Most of the state caught rain in the last week and they are calling for more later this week, resulting in an increased chance for below average stalk quality for harvest.   

There are two main culprits I have seen this growing season including Fusarium verticilliodes and Anthracnose stalk rot and top dieback. Fusarium is most commonly seen when we have dry conditions early and normal precipitation later in the growing season. Symptoms are a white color on the stem around the node, decayed pith tissue inside the stem while the vascular bundles stay intact, and a pink to salmon color inside the stem. The second pathogen I have seen above average incidence of is Anthracnose. 

The pathogen that causes Anthracnose infects in two ways. The first is anthracnose top dieback, and this form typically doesn’t have a major impact on yield. Anthracnose stalk rot on the other hand can cause significant yield loss. Symptoms of this phase include black discoloration under the leaf sheath on the stems and a brown discoloration at the nodes. This will lead to lodging later in harvest. 

So how do I know which fields are affected? First check both the stalk strength and anthracnose ratings in your Hoegemeyer seed guide. Checking all fields would be best, but if time is of concern start with fields that have lower ratings in the seed guide.

To test stalk strength this time of year we can do a simple push test. 

  1. Stand next to a corn plant and put your arm from your hand to your elbow parallel to the plant.
  2. Simple extend your arm out and see if the plant breaks off below the ear or is the plant able to continue standing.
  3. This should be done in five different areas of the field, 20 plants at a time. If you have 10 to 15 plants that break you may want to harvest that field first.

If you have any questions, feel free to contact your local Hoegemeyer agronomist or dealer.

-Craig Langemeier, Western Product Agronomist


Categories: corn, stalk rot     Comments: 0    

Soybean Diseases: SDS & Brown Stem Rot

September 9, 2019

Lately we’ve seen a few soybean diseases show up within our growing region. It’s important to be able to differentiate between diseases that may show similar symptoms out in the field, such as brown stem rot (BSR), sudden death syndrome (SDS) and charcoal rot. While a disease like frogeye leaf spot may be easily distinguishable, it may be harder to verify what these other diseases are without taking a closer look into the plant.

     

SDS and BSR are similar looking when they start to show symptoms on the leaves, but when you break the stem of the plant, BSR will have a brown inner pith, compared to a more normal, healthy looking stem on SDS. You may also find blue growths on the roots of an SDS affected plant. Charcoal rot has more of a yellowing leaf symptom than interveinal chlorosis and typically shows up when the plant is stressed from heat and drought. Charcoal rot also creates small dark spores in and around the stem of the plant.

Crop rotation, choosing varieties with tolerance, average-to-later planting dates can all help to minimize issues with these diseases later in the season. Seed treatments will not help with BSR or charcoal rot, but ILEVO can help with SDS susceptible areas. 

It is necessary to have a game plan if you have had a history of seeing any of these diseases present on your acres. Thinking ahead with variety selection, crop rotation, as well as other management techniques can help you maximize yield through susceptible fields.

- Jonathan Williams, Southern Region Product Agronomist


Categories: brown stem rot, sds, soybeans     Comments: 0    

The Effect Aphids Can Have on Corn Yield

August 26, 2019

     

While walking in corn fields this past week I noticed the corn aphid population has dramatically increased. A few  weeks ago it was hard to find any corn aphids, but now they are making walking corn very uncomfortable. This particular corn field was in West Central Iowa and was treated with fungicide and insecticide two weeks prior.

Corn aphids are becoming a common pest for corn growers and have the potential to develop into massive populations. Aphids can be found throughout the corn-growing season, but post-pollination corn aphids are a relatively new issue. It’s important to understand the damage aphids can cause to determine if management is necessary.

Here are a few facts you should know about corn aphids:

  • Aphids feed on the sap from the plant phloem and excrete sugar-rich honeydew that covers the plant, which can interrupt both plant growth and pollination. Aphids colonize deep within the whorl. Excessive feeding within the whorl before tassel emergence leads to incomplete kernel development or barren ears.
  • Aphids are problematic during tasseling and can colonize corn later in the summer, threatening yield potential. Drought-stressed corn plants also can be sensitive to aphid feeding.
  • Beneficial insects, such as ladybugs, can help control aphids.
  • In extreme cases, aphids are associated with dying leaves or, rarely, the death of entire plants. Sooty molds can colonize these sugary leaf surfaces, further reducing leaf photosynthesis.
  • Aphids can, and often do, leave corn as it begins to mature to dough stage.  If subsequent rainfall washes off the sooty mold, honeydew and cast skins, the only evidence of the infestation may be small discolored areas on the leaf sheath and shanks.

Management Tips:

  • Spot damage: Heavily infested plants are discolored and stunted with wilted, curled or yellowed leaves and sometimes shriveled ears.
  • Scout: Start scouting three weeks before tasseling. Check five locations within the field and 20 plants at each location.  Examine the ear, leaves and stalk.
  • Control before tassel emergence: Protect yield by controlling aphids two to three weeks before tassels emerge. Treat plants if 50 percent are infested with colonies of over 75 aphids per plant.
  • Manage late-season: Treat if more that 50 percent of the tassels are covered with aphids and their honeydew, before pollination is halfway complete.
  • Historically, little attention has been paid to the late-milk stage bird-cherry oat populations. 

Summary:

  • Aphid infestation can lead to significant yield loss in corn.
  • Aphids can populate quickly and cause extensive damage.
  • Post-pollination aphids rarely cause significant yield loss.
  • Scout and treat fields before tasseling to prevent costly damage.

-Eric Solberg, Eastern Region Product Agronomist


Categories: aphids, Corn     Comments: 0     Tags: aphids    

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