Extension Update from Jenny Rees

UPCOMING EVENTS:
May 10:  Field Scout Training, 8am Registration with 8:25am training, (800) 529-8030, http://ardc.unl.edu/crop.shtml
May 30-21:  Youth Tractor Safety Class, 8am, Kearney Fairgrounds (308) 236-1235
June 28:  South Central Ag Lab Weed Science Field Day, SCAL near Clay Center (morning)
June 28:  South Central Ag Lab Cover Crop Field Day, SCAL near Clay Center (afternoon)
July 10-11:  Youth Tractor Safety Class, 8am, Grand Island College Park (308) 385-5088.
July 18:  Crop Management Diagnostic Clinic:  Soil Health, ARDC (now ENREC) near Mead
Aug. 2:  Crop Management Diagnostic Clinic:  Precision Ag Training, ARDC (now ENREC) near Mead
Aug. 8:  Soybean Management Field Days, North Platte
Aug. 9:  Soybean Management Field Days, Ord
Aug. 10:  Soybean Management Field Days, Auburn
Aug. 11:  Soybean Management Field Days, Tekamah
Aug. 23:  Crop Management Diagnostic Clinic:  Soybean Production Training, ARDC (now ENREC) near Mead
Aug. 24:  Crop Management Diagnostic Clinic:  Corn Production Training, ARDC (now ENREC) near Mead

Farm Finance Clinic Sites and Dates To sign up for a clinic or to get more information, call Michelle at the Nebraska Farm Hotline at 1-800-464-0258.

Cold and Freeze Effects on Crops:  This past week, we released a CropWatch article on the potential effects of chilling injury on germinating seeds.  The first 24 to 48 hours are critical periods for soybean and corn respectively in how quickly they imbibe (take in) water.  When seeds take in cold water (when soil temperatures drop much below 50F within that critical time period), cell membranes within the seeds can rupture, leak, or burst causing damage to the germinating seed.  The result can be anything from poor germination, poor vigor, reduced plant stands, and death of the seed/seedling.  The last week of April has contained these cold snaps since 2013.  While I don’t have research to prove this, I’ve observed how yield differences are potentially due to days planting occurred just prior to a cold snap.  It will be important to watch germination in fields this year and keep track of emergence and plant stands based on planting dates.

Freezing temperatures may have also affected alfalfa, wheat, and emerged corn in the area.  For all crops, it’s wise to wait several days to see how the plants proceed in growth.  The cold temperatures may also delay growth so we may need to wait closer to a week after the frost. 

For corn, evaluate your plant stands and slit open some corn plant stems.  The growing point is below the soil till 6 leaf stage.  However, it will be important to look at the growing point to ensure freeze damage didn’t occur down to the growing point.  The growing point should be firm and white/cream-colored and not rotted and brown.  Leaf tissue exposed to cold temperatures may have turned brown.  Sometimes wind can cause this dead/dying tissue to buggy-whip around the whorl.  Normally this dead tissue will eventually break off and there’s nothing you need to do for it. 

For wheat, critical temperatures are 24F for two hours during jointing and 28F for two hours during boot.  It will be important to monitor stems for any splitting and bending from ruptured cells as these symptoms of frost damage can impact yield.  It will also be important to monitor the developing head.  You can split the stems of wheat to find the growing point and developing head.  Frost damage to wheat heads will often show white awns and/or white heads/florets that became sterile due to the frost.  Sometimes the head will have difficulty emerging from the boot depending on how close that head was to boot stage during a freeze event.  Odor of decaying tissue can also be a symptom of frost damage to wheat. 

Also to note, I found low incidence of stripe rust in wheat in Nuckolls County last week.  Like last year, I’m noticing it is very variety dependent so it’s important to scout your fields when temperatures warm up again.  Powdery mildew at moderate to severe levels can also be observed in lower wheat canopies. 

Regarding alfalfa, it again will take time to assess damage.  The growing point is located inside a dense cluster of unfolded leaves at the top of the main stem.  Leaves around the growing point may be brown or wilted/dying while the growing point may or may not be affected.  You will know if new growth begins from the top of the main stem when warm weather returns.  If you don’t see new growth at the top of the plant, it may begin from the base of the plants.  Depending on how much growth you had, you may or may not be interested in taking an early harvest to stimulate regrowth.  Early harvest before plants were ready can stimulate new growth and can add stress to the plants.  It’s recommended to wait and see how plants recover at this time. 

Frost to Rhubarb and Asparagus:  While it may be a little late for some right now, it is important to note frost effects on rhubarb and asparagus as well.  Rhubarb stalks that have wilted/limp/frosted leaves are not safe to eat after a frost.  The reason is the rhubarb leaves contain a toxic compound that can move into the stalks when a freeze occurs.  If you have rhubarb stalks with leaves that are wilted/limp/affected by frost, it’s recommended to cut and discard those stalks.  Rhubarb stalks that had normal leaves would be safe to eat.  Asparagus, on the other hand, is safe to eat after a frost, even if the tops become wilted and bent over.  They may have an off-flavor, however. 

Chemical Application to Lawns:  A reminder of the importance to sweep or use a leaf blower to move chemical granules (whether fertilizer or pesticide) back into the lawn and not leave them on sidewalks, driveways, or other hard surfaces.  Rain moves particles lying on concrete into storm sewers or other non-target areas.  Pesticide granules lying on the sidewalk are a danger to pets, children, and wildlife, so please, take the time and clean up after chemical applications to your lawns!

Study Course for Drone (UAV) Pilot Exam:  If you are interested in earning your Part 107 Remote Pilot certificate so that you can fly unmanned aircraft (drones) for commercial purposes, a new Nebraska Extension home study course will be of interest to you. This home study course focuses on the knowledge you will need to successfully pass the computer-based Federal Aviation Administration (FAA) exam to earn your Remote Pilot certificate.  The home study course allows you to learn at your own pace while interacting with professional unmanned aircraft pilots and fellow course participants.  Experienced unmanned aircraft pilots affiliated with Nebraska Extension will be available to help with questions and provide coaching support as you progress through the home study course.

The first group of participants will start the course the first week in May. The course is expected to last approximately two months. If you’re interested in being in this class, it will be important to register as soon as possible.  Registration and more information are available on the NU-AIRE web site at http://nuaire.unl.edu.