Corn Newsletter : 2018-22

  1. Overall Drier Pattern into Early August

    Author(s): Jim Noel

    The pattern change from wet to dry has arrived. For the remainder of July expect temperatures not too far from normal, some days above some days slightly below. Nothing real extreme to note in the temperatures. Humidity will also fluctuate from higher to lower to higher. Overall, moisture in the air will be typical for July. The one thing that will be different is the rainfall pattern. July has been a drier month for many areas. After a few showers or storms early this week, the next rain chance will be late this Friday into the weekend. It appears most should be 0.50-1.0 inches with the range being 0.25 to 3.00 inches. However, after this rain event it looks like rainfall will go back to being limited for the rest of July and possibly into early August.

    August is shaping up to be warmer than normal with a drier start and wetter finish.

    For the next two weeks the attached rainfall map from NOAA/NWS/Ohio River Forecast Center shows rainfall will average 0.75 to 2.75 inches across Ohio with isolated totals higher and lower than that. The heaviest rains will be to the south and east of Ohio.

    Two-Week Rain Forecast

     

  2. Western Bean Cutworm: Time to Scout (Scouting Video Included!)

    Author(s): Amy Raudenbush

    John Schoenhals, Mark Badertscher, Lee Beers, Amanda Bennett, JD Bethel, Bruce Clevenger, Sam Custer, Tom Dehass, Allen Gahler, Mike Gastier, Jason Hartschuh, Ed Lentz, Rory Lewandowski, Cecilia Lokai-Minnich, David Marrison, Sarah Noggle, Les Ober, Eric Richer, Garth Ruff, Jeff Stachler, Alan Sundermeier, Curtis Young, Chris Zoller, Andy Michel, Kelley Tilmon

    Western bean cutworm (WBC) adult moth catches in our trapping network are ticking up, with a noticeable increase from the week before. For week ending July 14, 24 counties monitored 88 traps (Figure 1). Overall, there was an average of 14.5 moths per trap (1116 total captured). This is an increase from an average of 3.4 moths/trap (217 total captured) the previous week.

    Figure 1. Average Western bean cutworm adult per trap in Ohio counties, followed in parentheses by total number of traps monitored in each county for the week ending July 14, 2018. Legend in the bottom left describes the color coding on map for the average WBC per county.

     

    Life cycle and feeding.  Adult moths (what we monitor in the traps) will be making their way into corn fields where females will lay eggs on the uppermost portion of the flag leaf. Eggs are laid in unevenly distributed clusters of 5–200, but averaging about 50 per cluster, and hatch within 5–7 days (Figure 2). Eggs first appear white, then tan and then a dark purple. Once eggs turn purple, they will hatch within 24 to 48 hours (Figure 3).  In pre-tassel corn, caterpillars will move to the whorl to feed on the flag leaf and unemerged tassel. Once the tassel emerges, larvae then move to the ear, while feeding on corn pollen, leaf tissue, and silks. Later they will enter the ear through the tip, or by chewing through the side of the husk.  Damage occurs from both direct feeding and from mold problems at feeding sites.

     

     

     

     

     

     

     

       Figure 2. WBC egg mass.

     

    Scouting and management. 

     

     

    Female moths prefer to lay eggs in pre-tassel corn approaching tassel, so check such fields first.  To scout for eggs or larvae, choose at least 20 consecutive plants in 5 random locations and inspect the uppermost 3–4 leaves for eggs, as well as the silks for larvae if tassel has emerged. Be sure to inspect different areas of the field that may be in different growth stages. For field corn, if 8% or more of the plants inspected have eggs or larvae, consider treatment. For sweet corn, consider treatment if eggs or larvae are found on >4% of plants for the processing market or on >1% of plants for fresh-market.  Bt corn with the Cry1F trait can no longer be relied upon for good western bean cutworm control, so these fields should be scouted too.  These include Herculex I, Herculex Xtra, SmartStax, and others.

      If infestations exceed threshold, many insecticides are available to adequately control western bean cutworm, especially those containing a       pyrethroid.  However, as with any ear-burrowing caterpillar pest, timing is critical. Insecticide applications must occur after egg hatch, or after tassel emergence, but before caterpillars enter the ear. If eggs have hatched, applications should be made after 95% of the field has tassel. If eggs have not hatched, monitor for the color change. Hatch will occur within 24–48 hours once eggs turn purple. To search for larval injury after it has occurred, search the corn for ears having feeding holes on the outside of the husks.                 

       Figure 3. WBC larvae hatching from egg mass. Size compared to US dime.                

     

  3. Keep Scouting for Potato Leafhoppers in Alfalfa

    If you grow alfalfa, now is the time to scout those fields for potato leafhoppers.  Integrated pest management (IPM) scouts are finding potato leafhoppers (PLH) widely distributed across a number of alfalfa fields.  PLH numbers have ranged from low to well above economic treatment thresholds.   In addition, alfalfa growers have been calling about yellow leaves on alfalfa, one of the classic PLH damage symptoms.  Alfalfa growers should consider regular field scouting for PLH because this is one of the economically significant pests of alfalfa. 

                The potato leafhopper is a small bright green wedge shaped insect that arrives in our area each year on storm fronts from the Gulf Coast region.  PLH is a sucking insect.  PLH feeding causes stunting of alfalfa plants resulting in yield loss.  Excessive stress on plants by heavy PLH feeding can result in yield reductions in the current as well as subsequent cuttings.  A common symptom of PLH feeding is a wedge-shaped yellowing of leaf tips.  If you are noticing these symptoms, some damage has been done.  Regular scouting can help to detect PLH earlier and determine if there is a need for a rescue treatment.

                Scouting involves the use of a sweep net.  There is no other way to properly and accurately scout for PLH.  The procedure is to take three to five samples for each 25 acres from random areas within the field.  One sample consists of 10 pendulum sweeps.  After the 10-sweep sample, carefully inspect the net contents and count the number of PLH adults and nymphs.  For non-PLH resistant alfalfa varieties, treatment is warranted if the number of PLH adults and nymphs is equal to or greater than the average height of the alfalfa in inches. 

    An OSU Extension fact sheet on PLH is available on-line at https://ohioline.osu.edu/factsheet/ENT-33.  A short video clip on how to scout for PLH and use a sweep net to sample for PLH is available at http://tiny.cc/PLHscouting featuring Mark Sulc, OSU Extension Forage Specialist.

  4. NW Ohio Precision Planter Field Day – Come See All the Colors Plant in the Same Field

    Author(s): Eric Richer, CCA

    The Fulton County OSU Extension Office will be holding a Northwest Ohio Precision Planter Field Day on Tuesday, August 14th from 8:00 am to 3:30 pm at the Fulton County Fairgrounds, 8514 St Rt 108 in Wauseon. 

    This year the event will focus on precision planter technology and will feature discussions and demonstrations from leading equipment, seed and technology professionals.  Learn about variable rate seeding, precision placement with your planter (John Fulton, OSUE), variable rate seeding and other soybean trials (Mike Staton, MSUE), planter downforce options and high speed planting (Nate Douridas, OSU’s Farm Science Review). Then in the afternoon see planter demos—All the Colors Plant in the Same Field!

    Additionally, participants will hear the most recent changes to the Tri-State Fertility recommendations (Greg LaBarge, OSUE) and how to calibrate your solid manure spreaders (Amanda Douridas, OSUE).  Five hours of Certified Crop Advisor credits will be offered and those participating in the nutrient management rotations will earn a 1 hour ‘fert-recert’.

    Major sponsors for this planter focused event are Kenn-Feld Group—John Deere, Redline Equipment— CaseIH & Kinze, Paul Martin and Sons— Horsh Planters, Ohio Ag Equipment—White Planters and Davis Farm Services —Mycogen Seeds.   

    Registration is $20 if paid before August 3 and $30 after this date.  For a registration form, complete agenda and a list of all sponsors and exhibitors, see www.fulton.osu.edu. The Fulton County Fairgrounds are located at 8591 State Route 108, Wauseon, OH 43567.

About the C.O.R.N. Newsletter

C.O.R.N. Newsletter is a summary of crop observations, related information, and appropriate recommendations for Ohio crop producers and industry. C.O.R.N. Newsletter is produced by the Ohio State University Extension Agronomy Team, state specialists at The Ohio State University and the Ohio Agricultural Research and Development Center (OARDC). C.O.R.N. Newsletter questions are directed to Extension and OARDC state specialists and associates at Ohio State.

Contributors

Bruce Clevenger, CCA (Defiance County)
Chris Zoller (Tuscarawas County)
Clifton Martin, CCA (Muskingum County)
David Dugan (Adams County)
Dean Kreager (Licking County)
Garth Ruff (Henry County)
Glen Arnold, CCA (Field Specialist, Manure Nutrient Management )
Greg LaBarge, CPAg/CCA (Field Specialist, Agronomic Systems)
Harold Watters, CPAg/CCA (Field Specialist, Agronomic Systems)
Lee Beers, CCA (Trumbull County )
Les Ober, CCA (Geauga County)
Mark Badertscher (Hardin County)
Mary Griffith (Madison County)
Mike Estadt (Pickaway County)
Mike Gastier, CCA (Huron County)
Sam Custer (Darke County)
Trevor Corboy (Greene County)
Wayne Dellinger (Union County)

Disclaimer

The information presented here, along with any trade names used, is supplied with the understanding that no discrimination is intended and no endorsement is made by Ohio State University Extension is implied. Although every attempt is made to produce information that is complete, timely, and accurate, the pesticide user bears responsibility of consulting the pesticide label and adhering to those directions.

CFAES provides research and related educational programs to clientele on a nondiscriminatory basis. For more information, visit cfaesdiversity.osu.edu. For an accessible format of this publication, visit cfaes.osu.edu/accessibility.