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JenREES 10/2/22

Crop Update: What beautiful weather! Grateful for the crops that are being harvested! Also, grateful to hear some are blowing out combines after harvest in these heavily infested palmer fields before moving to the next field. That’s the first step in managing palmer for the future. Regarding combine cleanout, Market Journal had a video at: https://youtu.be/UtSAaWtMTS4 and CropWatch had an article at: https://go.unl.edu/skfh if you’d like more information.

Managing heavy palmer fields after harvest: Palmer and waterhemp seed survive for 5-7 years. With each plant producing an average of 500,000 seeds, it only takes a few plants to create a mess.

Heavy palmer pressure in hail damaged corn field.

It’s been encouraging to see the rye and other small grains being drilled in fields; I realize it’s also been hard to irrigate them up after such a long irrigation season. Small grains such as rye, wheat, and oats have been proven to significantly reduce palmer, even in the absence of residual herbicide use compared to a no cover crop control. With the addition of a residual herbicide, there was no difference between using a cover crop and the check treatment. However, the way I look at it, the cover crop was another tool to take some of the pressure off the herbicide from having to do all the work. The main reason for that is because these small grains keep the soil surface covered. Palmer germinates when it senses red light on a bare soil surface, so keeping the soil covered can help reduce early season palmer germination. The small grains are also beneficial at reducing diseases such as white mold and sudden death syndrome.

If one isn’t interested in cover crops but is already using reduced tillage, another plan going forward will be to use a PRE- herbicide with residual followed by POST- with residual and get to canopy closure. Essentially, the strategy there is to keep the seeds from germinating.

For those who plan on disking, the research showed that disking once and not disking again for 3 years resulted in palmer reduction of 80-100% by year 3. However, disking each year allowed the seed to keep coming to the surface where it could germinate (depending on the herbicides and timing used). So, planting a cover crop after disking to cover the soil is one option to help reduce palmer germination in the spring. For those not interested in cover crops, having a strong herbicide program of a PRE- with residual followed by a POST- with residual sooner than you think you may need it, may be a strategy. One can also include cultivation followed by a residual herbicide, depending on canopy closure. The use of tillage, flaming, and electrocution are also being used in organic and some conventional systems.

Finishing Replant Crops: Grateful to be at this point in the season where much of the replant corn is 1/4 milk or further! Hybrids will vary regarding growing degree units (GDUs) to finish. A GDD tracking tool to help is https://mygeohub.org/groups/u2u/purdue_gdd. Regarding irrigation, below is the amount of water needed to finish corn. Most of the beans should be close to done for irrigating.

  • Beginning dent needs 5.0” water, around 24 days to maturity, 25-55% yield loss potential.
  • ¼ milk needs 3.75” water, about 19 days to maturity, 15-35% yield loss potential.
  • ½ milk needs 2.25” water, about 13 days to maturity, 5-10% yield loss potential.
  • ¾ milk needs 1.0” water, about 7 days to maturity, around 3% yield loss potential.

We knew replant crops would be a target for insect and disease pressure. It’s hard to see the corn earworm impact crops for such a large area as what they have this replant corn. Even fields that were sprayed once still have ear damage on a good 50% of the plants. The earworm feeding has allowed entry of fungi such as those causing white/pink Fusarium ear mold to varying degrees on the ears. Also seeing some blue-gray Penicillium ear mold and some sprouted kernels. Unfortunately, there wasn’t much we could practically do about it and there’s nothing we can do now till harvest. The presence of mold does not automatically mean the presence of mycotoxins. For harvest, it’ll be important to set combines to blow out any lighter, damaged kernels. Will share more on grain management in storage later.

Stem Borer: Have heard some disappointment about soybean yields which I feel is mostly due to beans being pushed too fast with the weather. Soybean stem borer is also being blamed, but it hasn’t been proven via research to reduce yield unless beans become lodged/break off. To understand why, it’s important to understand corn and soybean physiology. Soybeans are dicots like trees and the xylem and phloem are found in rings towards the outside of the stem instead of the center. So the stem borer hollowing out the soybean center doesn’t affect the soybean vascular bundles, but insects like gall midge working on the outside of the stem can. This differs from monocots like corn where the xylem and phloem are arranged throughout the stem. Thus, I don’t think stem borer is the reason for lower soybean yields that weren’t due to lodging/breaking off this year.


Dicot vascular bundles of xylem and phloem are arranged in a ring, whereas monocot bundles are sporadic. Diagram via Plants Grow Here. https://plantsgrowhere.com/blogs/education/monocots-vs-dicots-with-diagrams

Wheat and oats significantly reduced palmer biomass compared to no cover crop alone in the absence of a residual herbicide (black bars). Utilizing a residual herbicide (gray bars), the wheat and oat cover essentially eliminated palmer biomass and there was no difference between those treatments and the no cover crop with residual herbicide treatment.

JenREES 8-25-19

Crop Updates: An increase in disease pressure has been the theme the past few weeks. IMG_20190823_092914Sudden death syndrome is increasing in soybeans, but there’s also brown stem rot (BSR) and frogeye leaf spot in some fields. The foliar discoloration is the same for SDS and BSR with the yellow/brown discoloration between leaf veins. You can tell the difference by pulling a plant out of the ground. SDS is usually easy to pull as the taproot is rotted. Splitting the stem open, the root will show rot at the soil line but the stem pith will be white and healthy. With brown stem rot, the pith will have brown discoloration. The addition of stem borer can make it more difficult to tell the difference sometimes. Unfortunately there’s nothing one can do for SDS or brown stem rot now as both are caused by soil borne fungi. I would recommend taking soil samples for soybean cyst nematode (SCN) in areas currently impacted by SDS as the combination of diseases is synergistic in impacting yield loss. You only need 0-8” samples and they can be taken during soil fertility samples if you don’t want to take them now. The samples are free via your checkoff dollars and they can be sent to the Plant and Pest Diagnostic Lab at UNL in Lincoln.

In corn, foliar disease is increasing in mid-canopies. Most concerning are the number of stalk rot samples/situations I was called to the past week. They all appear to be bacterial stalk rot thus far. Symptoms include watersoaked nodes and below the nodes with plants breaking off/falling over. Damaged nodes are from the soil line to upper canopy. The bacteria disintegrates these stalks creating a stringy appearance within them where the nodes break and when slitting open stalks. It also has a distinct foul smell. This is more of a problem in wet years such as this and hybrid susceptibility varies. The bacteria doesn’t typically transfer from plant to plant. I have photos of what I’m seeing on my blog at https://jenreesources.com.

There have been multiple late-season hail events in the area. For those fields hit by the 00100lPORTRAIT_00100_BURST20190823133135740_COVERAugust 6th storm, the rainy, cool conditions have allowed for increase in mold on the hail damaged side since many of those damaged ears were at milk stage. However, I’m also seeing mold damage on some back-side of ears in hybrids with tighter husks. The white/pink fluffy growth on the hail damaged side is caused by Fusarium/Gibberella fungi. The presence of these fungi does not automatically mean mycotoxins are present; they do have the potential to produce mycotoxins. The green fungal growth in ears are caused by secondary and minor fungal pathogens that don’t produce mycotoxins. The white fungus overtaking ears on some tight-husked hybrids is diplodia which can cause for light test weight but does not produce a mycotoxin. It will be important to continue to watch grain quality over time prior to harvest.

Wild and Burcucumber on Trees has also been a huge question. Do Not apply 2,4-D to trees for

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Thanks to Randy Pryor for demonstrating how easy these are to pull while we were on a field call together!

control as that has been the most common question! The simplest way to kill wild and burcucumber is pull or hoe the plant at its base below the tree. There’s not much to the plant root and the vines will then die on the tree!

It’s been a hard year for our growers and livestock producers with continued challenges. Seeking to end this column on a positive note, this year is the 10th year of the Nebraska State Fair in Grand Island and the 150th Fairabration. I’m grateful for the focus on agriculture, families and youth! And, it’s encouraging to me to see youth learning life skills whether competing in public speaking, IMG_20190824_181614working with and showing livestock, or studying and competing in contests such as weed and grass ID at the State Fair. 4-H is where I got my start and it’s exciting for me to wonder at the futures these 4-H and FFA youth have ahead of them as they continue to work hard and put into practice the life skills they are learning! Hope you can make it out to the State Fair at some point!

*End of News Column. Bacterial stalk rot photos below.


 

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Plants still standing showing various symptoms of dying and death

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Some plants exhibiting bacterial stalk rot are already lodged or broke off at or around plant nodes.

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Plant nodes show discoloration with watersoaking around the nodes (notice the soaked appearance on internode where I removed the outside sheath).

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Majorly impacted nodes and internodes by bacterial stalk rot. There’s a distinct foul odor. Notice how wet and watersoaked nodes and internodes are and there’s even bacterial ooze in this case on the stalk.

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Plants break at nodes. Also notice the stringy appearance of stalk pith.

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Commonly seeing this with impacted nodes from the soil line through upper canopy…stringy appearance of pith tissue.

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