Storm damage resources: Have had a number of calls throughout the State this week
from those who have experienced hail, flooding, and/or wind damage. The warmer temperatures were helpful for regenerating plant growth after hail; however, they’re not helpful for those who had heavy rains and flooding that didn’t recede. I shared this last week too but here’s a Hail Damage Assessment resource with many videos: https://cropwatch.unl.edu/hail-know/assess-my-damage. For flooding, corn plants prior to V6 can survive under water for 2-4 days if temperatures do not exceed 77°F. From V7-V10, plants can survive 7-10 days if temperatures do not exceed 86°F. For soybeans, yield losses are minimal if flooding lasts less than 48 hours. If flooded for 4-5 days, fewer nodes develop and plants will be shorter. If flooded for 6+ days, possible stand and yield loss. The longer it takes a field to dry out, the more yield loss that may occur. For soybeans at flowering, there’s potential for yield loss, especially on poorly drained soils.
As we deal with corn leaf loss due to natural sloughing off, early frost, and recent hail
and wind damage, it can make corn development staging tricky for post- pesticide applications. The reason I keep emphasizing development stages is because I’ve been called out to many ear formation concerns the past several years. No one intends for these things to happen! These are opportunities for all of us to learn. In all cases, mis-diagnosis of development stage occurred prior to the pesticide application (whether herbicide, insecticide and/or fungicide). The use of non-ionic surfactant (NIS) in the tank from V10-VT resulted in the ear formation issues in addition to increased surfactant load from multiple products in the tank mix. My hope in emphasizing corn development staging this year is to hopefully reduce the incidence of ear abnormalities that occur from post- pesticide applications. I put together the following video to hopefully help: https://twitter.com/jenreesources/status/1272370173853470720?s=20.
Gardening 101 resources: A team within Extension pulled together all the vegetable gardening resources to create a one-stop place for vegetable gardening. This resource, housed on the backyard farmer website, is a place for beginning gardeners and experienced ones. Check it out at https://go.unl.edu/veggies101!
Sunscald/scorch on green beans: This past week I received a few pictures of green beans that had large brown ‘burnt looking’ areas. This is caused by sunscald. The sun and wind has been intense. Seek to evenly water and avoid watering the foliage.
Trees: Lots of tree questions past few weeks. If leaves are pre-maturely turning yellow and dropping, it’s most likely due to fungal disease. This is mostly happening since the 3” rain over Memorial Day. All the trees I’ve looked at are already starting to develop new leaves. Weed whackers cause more injury to trees that one realizes, so be very careful using them around trees, or put mulch around them to reduce weeds. Remove ‘mulch volcanoes’ around trees as the mulch against the trunk can cause rot. Mulch should not be piled against the trunk. Seek to make clean and proper pruning cuts for all the storm damage that has occurred to trees. For those who’ve experienced bark removal from lightning strikes or winter cracking, don’t paint anything over the wound and don’t fertilize or do anything to the tree. Allow the tree to seek to heal on its own. It’s amazing what trees can overcome! Winter and spring dessication injury may be causing evergreens (cedars, junipers, yews, and arborvitae) to suddenly turning brown. Kelly Feehan, Extension Educator shares, “During warmer than average temperatures in February and March, moisture was lost from green needles and could not be replaced from frozen or cold soils. This was followed by a dry spring; and then above average temperatures and extreme winds. These conditions increase the rate of transpiration and increased moisture loss from needles. If the moisture is not replaced quickly, tissues dessicate and eventually die. Evergreens growing in open exposed sites, near pavement or light colored houses, and those planted in the last three to five years are most susceptible. Other than using organic mulch and keeping soil moist, there is not much to do. Once an evergreen or a branch turns completely brown, it will not recover.” You can prune out dead branches/areas and see how the plants overall recover.
Corn: I really enjoy this stage when corn is just tall enough to give the fields a green cast when looking at them from an angle. There continues to be discussion and questions about uneven corn emergence. Like many, I wasn’t anticipating seeing uneven emergence after having great soil conditions (right moisture and a warming trend of temps) for planting. Variations in soil temp, depth, and moisture can delay germination from a few days or longer. Residue blowing back over the row explained much difference in emergence this year. I wish I would’ve noted the days on my calendar, but there’s a couple warm days in late April during planting where it just seemed like the moisture rapidly left the soil surface. And, in conversations it seems as if others noticed that too. So I think moisture around seed was another factor as was fertilizer burn in some situations. Purdue University has some research which showed yield reductions of 6-9% for plants emerging 1.5 weeks later than a uniformly emerging stand. They also found yields of uneven stands to be similar to planting the stand 1.5 weeks later.
If you’re side-dressing nitrogen and interested in testing different rates, we have some on-farm research protocols available at: https://go.unl.edu/tv63.
With warmer temperatures anticipated, corn will grow rapidly. This week we wrote an article in CropWatch regarding proper growth staging of plants; this will be extra critical once we hit V6+. Remember to use the leaf collar method and this is how I explain it. A collar develops at the leaf base near the stalk after each leaf fully expands. Think about collars like the collar on a button-down shirt. The collar flares slightly at one’s neck, just as a true exposed leaf collar flares at the base of the leaf at the stem. Start counting leaves at the base of the plant with the smallest rounded-tip leaf with a collar as #1. From there count every leaf with a true collar. Leaves that are still wrapped in the whorl around the main stem without exposed leaf collars are not counted. I recommend taking a picture inside the end rows to document the growth stage of your field prior to the post-application of herbicide. Next week I will share my experiences with proper growth staging to avoid ear abnormalities. Also be aware of potential off-target movement with dicamba products and higher temperatures.
Soybean: In most cases, soybeans are looking really good. There have been situations this week with herbicide damage to beans that may have been cracking when irrigation or rainfall event occurred allowing some pre-emergent herbicide to enter the row. Pre- herbicides can also rain splash onto cotyledons and first leaves making them look bad, but usually doesn’t kill them unless the weather stays cold and wet. If the plants end up severely pinched below the cotyledons, they won’t survive. Otherwise, keep watching them as they may continue to grow (warm weather will allow them to grow and metabolize the chemical better). I think we’re also possibly seeing some environmental effects from the cold conditions that occurred after planting/emergence when we can’t always explain the appearance of injury on the plant by herbicide. The ‘halo’ effect of ILeVo is another thing that is being mistaken as herbicide and/or environmental injury but it doesn’t last past the cotyledon stage.
Coronavirus Food Assistance Program for Crop Producers Webinar: There will be a webinar on June 4th at Noon (CST) to learn more. Registration is required at the following site: https://go.unl.edu/wj0e. In the meantime, Dr. Brad Lubben has put together an article with more information at: https://go.unl.edu/h3aq. All webinars are also archived at that same web link.
Irrigation Scheduling Equipment: It’s also a great time to get irrigation scheduling equipment installed! I decided to make a quick video instead of writing; it can be found at: https://youtu.be/4r5gn2pvvB4.
Gardeners: For all of you gardening for the first time, congrats! Some tips: keep soil moisture even by ensuring plants have around 1” of water/week (Best to water at base of plant; if use sprinkler, do so in early morning). Mulching gardens with leaves, grass clippings, straw, newspapers aids in conserving moisture, reducing weeds, and maintaining stable soil temperature. If herbicides were added to grass clippings, make sure to read the label for if/when they can be applied to a garden. In general, many labels will say grass clippings are safe after 4 mowings.