C.O.R.N. Newsletter 2009-25

Dates Covered: 
August 3, 2009 - August 10, 2009
Editor: 
Andy Kleinschmidt

Late Summer is a Good Time to Plant New Pastures & Hay Crops

Authors: Mark Sulc

Late summer can be an excellent time to establish new forage stands. It is also a good time to seed in bare or thin spots in stands established this spring. While we can’t control the weather, there are several things we can control that will improve the chances for successful forage stand establishment this time of year.

First, apply lime and fertilizer according to a recent soil test. Also control problem perennial weeds ahead of seeding. Be careful with herbicide selection because some have residual soil activity and will harm new forage seedings if proper waiting periods are not observed. Be sure to read the labels of any herbicides being considered.

If you are going to use tillage, don’t over-till and be sure to prepare a firm seedbed. Loose seedbeds dry out very quickly. Deep tillage is not ideal for late summer seedings. A cultipacker or cultimulcher is an excellent last-pass tillage tool. The soil should be firm enough that the your boot leaves a print no deeper than 3/8 inch (you can bounce a basketball on it).

No-till seedings conserve moisture and can be very successful provided weeds are controlled prior to seeding. Remove all straw from fields previously planted to small grains. Any remaining stubble should either be left standing, or clipped and removed. Do not leave clipped stubble in fields because it will form a dense mat that prevents good emergence.

Plant the seed shallow (1/4 to 1/2 inch deep) and in firm contact with the soil. Carefully check seeding depth, especially when using a no-till drill. Use a drill with press wheels for greatest success with summer seeding. Broadcasting seed on the surface without good soil coverage and without firm packing is usually a recipe for failure in the summer.

Use high quality seed of known forage-type varieties from reputable dealers. Cheap seed often results in lower yield and shorter stand life. Check out our variety performance trials and those of neighboring states at the following websites:

Ohio: http://oardc.osu.edu/forage2008/
Kentucky: http://www.uky.edu/Ag/Forage/ForageVarietyTrials2.htm
Pennsylvania: http://cropsoil.psu.edu/pdf/2008_forage_trials_report.pdf
Michigan: http://web1.msue.msu.edu/fis/

Make sure legume seed has fresh inoculum of the proper rhizobium to ensure nitrogen fixation.

If you plan to seed alfalfa, don’t plant new alfalfa immediately after an older established alfalfa stand. Autotoxic compounds are released by old alfalfa plants, which inhibit growth and productivity of new alfalfa seedlings. You can seed in alfalfa in late summer to thicken up a new alfalfa seeding that was made this spring. The autotoxic compounds are not present in young alfalfa plants. They are released from older, established alfalfa plants.

Recent rains have resulted in good soil moisture conditions across much of Ohio, which increases the chances for successful forage establishment. But do keep in mind that it is risky to place seeds into dry soil – there may be just enough moisture to germinate the seed but not enough to get the seeding established.

Plant new perennial forages as soon as possible here in August. Seedlings require at least 6 to 8 weeks of growth after emergence to have adequate vigor to survive the winter. Plant during the first two weeks of August in northern Ohio, and by August 30 in southern Ohio. Planting later than those dates may work, but there is more risk for establishment failure and the stand may have lower yield potential next year.

Slow establishing species should be planted this week. Fast establishing species like red clover, alfalfa, and orchardgrass can be seeded up to the dates listed above if moisture is present. Kentucky bluegrass and timothy can actually be seeded 15 days later than the dates listed above.

As the stand develops this fall, do not be tempted to harvest it. No matter how much growth accumulates, it is usually best to let the cover protect the new crowns during the winter. The only exception to the no fall harvest rule for late summer seedings is perennial ryegrass. If perennial ryegrass has tillered and has more than six inches of growth in late fall, clip it back to 3 to 4 inches in November or early December.

Finally, scout new seedings for winter annual weeds in October. Apply herbicides as needed. Winter annual weeds are much easier to control in late fall than they will be next spring.

By following these guidelines, and with a little cooperation from the weather, I trust you will have a vigorous and productive new forage stand next year that should yield the same as if it had been planted this past spring.

Kernel Development Well Underway in Early Planted Corn

Authors: Peter Thomison

Many Ohio corn fields received over an inch of rain last week. This rainfall in combination with good rainfall the previous week and unseasonably mild temperature have helped minimize the soil moisture deficits some areas were still experiencing. Brown silks are common and kernel development is well underway in corn fields that were planted in April and early May. Following pollination, kernel development (or grain fill) is the most critical period in the development of the corn plant for the determination of grain yield. Kernel development proceeds through a number of stages which have been characterized by such terms as blister, milk, roasting ear, soft dough, dent, etc. Since these descriptive terms can sometimes be difficult to interpret, alternative systems have been proposed. A staging system widely used by agronomists and crop consultants divides kernel development into six stages, designated numerically as R1, R2, through R6. Below lists kernel developmental stages in sequence and provides a brief description of each phase.

Stage, Description (Avg. No. Days/Stage, Avg. Days from Silking)
===============================================================
Silking (R1), fresh green silks, no visible blisters (4, --)

Pre-Blister, silks brown, not necessarily dry visible kernel pimples, contain little clear fluid (4, 8)

Blister (R2), visible blisters w/abundant fluid (4, 12)

Early Milk, mostly white kernels w/milky-white fluid, some yellow kernels (4, 16)

Milk (R3), mostly yellow kernels w/milky-white fluid, no solids yet, “Roasting Ear” stage (4, 20)

Late Milk to Early Dough, solids beginning to form, kernel pasty texture and barely edible (4, 24)

Soft Dough (R4), pasty or semi-solid, not edible, no visible denting (5, 28)

Late Dough to Early Dent, few kernels beginning to dent, especially near butt of ear (5, 33)

Dent (R5), majority of kernels dented or denting (8, 38)

Late Dent, essentially all kernels dented, milk line may just be visible (17, 52)

Black Layer (R6), maximum kernel dry weight, kernel moisture 27-32% (10, 62)
____________________________________________________________________
Note on R-Stages 1 through 6: specific number of days associated with each stage may vary from season to season, from location to location, and from hybrid to hybrid.

Keep in mind that the values for average number of days per stage and approximate days from silking in the table above are based on timely corn planting (e.g. early May). When corn is planted later, it generally requires fewer heat units to achieve R6, physiological maturity or “black layer”, and this may affect the number of days per stage and days from silking. For more on grainfill check out the following article that Dr. Bob Nielsen which excellent pictures and diagrams:

Nielsen, R.L. (Bob). 2008. Grain Fill Stages in Corn. Corny News Network, Purdue Univ. [online] http://www.kingcorn.org/news/timeless/GrainFill.html. [URL accessed 8/3/09].

Soybean Cyst Nematodes, Now is the Time to Scout

Authors: Dennis Mills

Soybean cyst nematode (SCN) is an important soybean pest that is often unnoticed. SCN can cause substantial yield loss without above-ground symptoms. An easy way to check fields this time of year for the presence of SCN is to dig soybean roots and gently shake off the excess soil. Examine the roots closely. The SCN females are small, round white to yellow objects on the roots about the size of a pinhead, much smaller than the nitrogen fixing nodules. They will be apparent now through early September. Although observation of the white females will confirm an SCN infestation it cannot tell you much about the level of infestation, if no nematodes are found that does not mean that SCN is absent. Soybean cyst nematodes will not be distributed evenly throughout a field therefore the best way to identify those fields and monitor populations is to soil sample in the fall following harvest and have the samples analyzed by a professional lab.
For more information:

http://www.oardc.ohio-state.edu/ohiofieldcropdisease/soybeans/AC_39_08.pdf

Soybean Aphid Update and Possible Alert

Authors: Bruce Eisley, Andy Michel, Ron Hammond

Last week we had the opportunity to check or get reports from numerous fields throughout Ohio on the situation with soybean aphids, and in general, the reports were about the relative lack of soybean aphids. However, late in the week, we got a report from Geauga County in northeast Ohio about fields having higher populations. A visit to that area this weekend supported those findings. We found numerous soybean fields that are nearly 100% infested. Numbers of soybean aphids per plant were not yet high, but nearly all plants had aphids, ranging from a few to 10-15 per plant. It was difficult to find a plant without aphids. Many of the soybeans in that area were later planted and are just now in growth stage R2. The Extension Educator from Geauga County, Les Ober, said that he is aware of one field that while not yet at threshold, will probably be within a week if the aphid population continues to grow. Thus, we would remind growers that we are not out of the woods yet when it comes to aphids. This is especially true for growers in north central and northeast OH, who should make an extra effort to sample their soybeans. If, and it is a big if, aphid populations starting doubling, these fields could be reaching threshold within next 1-2 weeks.

Western Bean Cutworm Numbers on the Decrease

Authors: Bruce Eisley, Ron Hammond, Andy Michel

From July 27 to Aug 3, we saw a decrease in total trap catches across the state. This suggests that we have passed peak flight, but does not mean we are out of the woods yet. Inspecting corn should continue, although we are more likely to find larvae at this point than eggs. Since most of our corn has tasseled, look for larvae on the tip of the ear, feeding on the silks and eventually the ear tip. Larvae should not be found in corn with the Cry1F gene (Herculex I and Herculex Extra), so concentrate your efforts in the refuge or other non-Cry1F corn. Larvae are light tan in color and can be recognized by 2 broad, dark brown stripes immediately behind the head. In addition, you may find more than 1 larva per year, unlike corn earworms which are cannibalistic. Thresholds are the same: infestation of more than 5% of 20 consecutive plants in 5 different areas of the field. Please contact your local Extension Educator or an entomology specialist if you suspect the presence of Western Bean Cutworm larvae.

“Abnormal Corn Ears” Poster

Authors: Peter Thomison, Allen Geyer

Farmers frequently encounter abnormal corn ears in their fields when the crop experiences a major stress, such as drought, temperature extremes, disease and insect injury, or misapplied chemicals. These abnormalities can affect yield and grain quality adversely. We’ve prepared a poster highlighting ten abnormal corn ears with distinct symptoms and causes. The purpose of the poster is to help corn growers and agricultural professionals diagnose various ear disorders.

A reduced 11 x 14 inch version of the poster is available for online at:
https://agcrops.osu.edu/corn/documents/AbnormalCornEarsPoster_000.pdf

The OSU College of Food Agric. and Env. Sci. Communications & Technology section (contact information below) has 26 x 33 inch copies of the poster available for distribution. The poster is printed on plasticized coated paper for durability. Poster cost is $10 plus shipping. Ask for “Abnormal Corn Ears” poster” ACE-1.

The Ohio State University
College of Food Agric. & Env. Sci.
Communications and Technology
Media Distribution
216 Kottman Hall, 2021 Coffey Road
Columbus, OH 43210-1044
E-mail: pubs@ag.osu.edu
Order Online: http://estore.osu-extension.org/
Phone 614-292-1607
Fax 614-292-1248

For more help in diagnosing various corn and kernel anomalies, check out the following: “Troubleshooting Abnormal Corn Ears and Related Disorders” online at- https://agcrops.osu.edu/corn/EarAbnormalities.php
 

Soybean Nodulation Issues

Authors: Greg Roth

The following article was written by Greg Roth, Penn State Grain Crop Specialist, for the July 28, 2009 Penn State Field Crop News:

We have been receiving reports again from throughout the state on soybeans that did not nodulate or have variable nodulation across the field. Often these are first year soybean fields or fields without a recent history of soybeans. With our diverse cropping systems in Pennsylvania and occasional use of soybeans on some fields, this issue seems to be more prevalent for us than in other states.

Lack of nodulation is due to a lack of viable bacteria in the soil or inoculant or due to environmental conditions that are not conducive to nodulation. Very wet or very dry conditions can inhibit nodulation. High N fertility can also limit nodulation. Sandy or low pH levels in soils can reduce bacteria levels and cause parts of fields to show less than ideal nodulation. Viability of the inoculant bacteria can also be caused by exposing seed or inoculants to high temperatures prior to planting. Inoculants’ viability can also be reduced through extended exposure to the insecticide or fungicide seed treatment. Inoculant manufacturers have guidelines for the interval between treatment and planting.

Lack of nodulation can sometimes be confused with other issues like potassium deficiency. Potassium deficiency is characterized by yellowing on leaf margins.

To confirm a lack of nodulation, carefully dig out a few plants and examine the root system. The tap root should be strong, thick and rather long (12 in.) with a number of large secondary roots. Along the tap root, you should be able to find large numerous nodules that when cut open show a red or pink interior. The color develops from a reaction of oxygen with the compound leghemoglobin found in nodules that helps maintain reducing conditions (low oxygen levels) inside the nodule so the Bradyrhizobia can function. Non-functioning nodules can have white, green, or even black interiors as the nodule decays.

A well nodulated soybean plant should have around 5 to 7 nodules on the primary root. If they do not, and nitrogen deficiency has developed as evidenced by a pale green or yellow color, then up to 70 pounds of N could be applied. Ideally N should have been applied shortly after flowering, but should still be effective through early August.

Scrambled Silks, Anyone?

Authors: Bob Nielson

The following article was written by Bob Nielsen, Purdue University, and appeared in the July 31, 2009 issue of the Pest & Crop Newsletter. Please visit http://extension.entm.purdue.edu/pestcrop/2009/issue18/index.html#scrambled for the accompanying pictures.

This article is admittedly fearmongering on the part of your friendly neighborhood corn specialist, but I figure it is my prerogative and responsibility to do so when I believe conditions are ripe for the development of a potential crop problem. If the problem does not occur, then growers will be relieved and they will forget I said anything about it. If the problem does occur, then I will look pretty smart for having forecast its development.

The potential problem of which I speak is a phenomenon traditionally called ‘silk balling’. I prefer the name ‘scrambled silks’ because I think it is more descriptive. The problem is one in which silk elongation, prior to their emergence from the husk leaves, is interrupted or altered, resulting in a mass of scrambled silks near the tip of the cob that never fully emerge from the husk. Obviously, any silks that fail to emerge from the husk will not exposed to any pollen and consequently will not contribute to the formation of kernels on the cob. The net result is some degree of barrenness on the cob and, consequently, lower yield.

Scrambled silks is a relatively infrequent problem and its causes are not well understood. Some believe that the occurrence of cool nights (low 60’s or cooler) prior to silk emergence plays a role in the development of scrambled silks. Others believe that rapid changes in temperature patterns (e.g., very warm to very cool) prior to silk emergence encourages the problem. Hybrids with naturally tighter husks seem to be more susceptible to developing scrambled silks.

Given these opinions on temperature factors that may contribute to the problem, one could speculate (some would say fearmonger) that recent unusually cool nights throughout the central and northern parts of Indiana, plus the current forecast for more of the same, may lead to an increased occurrence of scrambled silks this year.

Unfortunately, there is nothing you can do about preventing or avoiding the problem. Nonetheless, it would be prudent to walk some of your fields during or after pollination and look for evidence of the problem. Typically, the severity of the resulting poor kernel set is low and concentrated near the tip end of the cob. However, I’ve seen situations in the past where scrambled silks resulted in severe barrenness in nearly 1/3 of the plants in a field.

If you don’t have time to walk your fields right now, any affected plants will likely raise red flags later on in the grain filling process. By this, I mean that any plants severely afflicted with barrenness will eventually develop purpling or reddening of leaf midribs, leaf sheaths and other plant parts.

The reasons for this discoloration are similar to those for purple corn earlier in the growing season. An otherwise healthy plant whose ear is highly barren of kernels is a plant that is overproducing photosynthate (source) relative to the demands of existing kernels (sink). The excess sugars in the leaves and stalk trigger the formation of anthocyanin pigments in the plant tissues, especially in those hybrids with quite a few of the purpling genes. The similarity to early season purple corn is in the connection between excess plant sugars and anthocyanin production. Early in the season, excess plant sugars often result when root development is hindered for some reason.

Cover Crop Field Day

Authors: Tim Fine

The Miami and Darke SWCD and the Agriculture for a Clean Environment (ACE) group will be holding a cover crop field day on Wednesday, September 2nd from 4:00 to 8:00 PM. This event will be held at Batdorf Farms, located at 9291 North State Route 48, just north of Covington, Ohio.

With a grant provided by the Conservation Tillage Conference, these cover crop demonstration plots will be used to determine how well cover crops utilize nutrients. The agenda for the evening consists of presentations by Matt Deaton, ODNR soil scientist, Dennis Brown from Byron Seeds, and Jim Hoorman from OSU Extension. A free meal will also be provided to participants. Registration is requested by August 28.

For more information and to register, please contact either the Darke SWCD (937) 548-1715, or the Miami SWCD (937)335-7645.

Agriculture and Clean Energy Summit

Authors: Alan Sundermeier

Join Senator Sherrod Brown, the Ohio Corn Growers Association, and American Farmland Trust for a day long summit on agriculture and clean energy.

10:30am-2:00pm
Thursday, August 13th
(Registration begins at 10am)
Owens Community College
Audio Visual Center, Rooms 121-128
30335 Oregon Road
Perrysburg, OH 43551

Learn more about how proposed clean energy legislation will impact agriculture in Ohio. The USDA, agriculture professionals, and economists will discuss opportunities for Ohio’s farmers in clean energy legislation and be available to answer your questions. A light lunch will be served. Please RSVP with Senator Sherrod Brown’s office by Monday, August 10th to (216) 522-7272.

Visit the webpage to see agenda, and background papers, as they are posted. http://www.farmland.org/ohio

Archive Issue Contributors: 

State Specialists: Dennis Mills (Plant Pathology), Ron Hammond, Andy Michel, Bruce Eisley (Entomology), Peter Thomison (Horticulture and Crop Sciences). Extension Educators and Associates: Glen Arnold (Putnam) Roger Bender (Shelby), Bruce Clevenger (Defiance), Tim Fine (Miami), Mike Gastier (Huron), Wes Haun (Logan), Jonah Johnson (Clark), Ed Lentz (Seneca), Les Ober (Geauga), Howard Siegrist (Licking), Alan Sundermeier (Wood), Harold Watters (Champaign), Suzanne Mills-Wasniak (Montgomery)

Crop Observation and Recommendation Network

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.