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Agronomic Crops Network

Ohio State University Extension


C.O.R.N. Newsletter 2013-14

Dates Covered: 
May 21, 2013 - May 28, 2013
Debbie Brown

NOAA Late May Weather Update

A weather pattern change is coming!!!

Another round of showers and storms will affect Ohio through Thursday May 23. After that a pattern change will mean limited rainfall for Ohio until about June 10. The exception may be the northern tier of counties that get clipped by rains from time to time. All indications are planting will be able to be completed in the next few weeks.

For the week of May 21...temperatures will be a few degrees above normal with rainfall also slightly above normal. Temperatures will go from the 80s for highs through mid week to the upper 60s and 70s by late week and early into the holiday weekend. Rainfall will average 0.5 to 1.5 inches with normal being 0.75 to 1 inch.

For the week of May 27...temperatures will average 5 to 10 degrees above normal and rainfall below normal. By the end of the month of May temperature highs will reach well into the 80s for highs with a few lower 90s possible.

For the week of June 3...temperatures will continue to average 5-10 degrees above normal with below normal rainfall. Highs will be in the 80s and some 90s are possible.

The 16-day average rainfall outlook can be found on the NWS Ohio River Forecast Center page at:

This outlook is an average of 21 weather models.


Wheat Disease Update: Week of May 20

Wheat Disease Update: Week of May 20

Wheat heads are beginning to emerge or emerged over the weekend in some locations across the state. Early-planted fields and early-maturing varieties will likely reach anthesis (flowering) this week, but most of the crop will likely reach this critical growth stage during next week (the week of May 27). The next 7 to 10 days will be very important for making decisions regarding fungicide application for scab and Stagonospora control, and once pollination occurs, the next several weeks will be critical for grain-fill. The forecast is for temperatures in the upper 80s early in the week, cooling down to mid-60s and lower-70s over the weekend and early next week. Cool temperatures during the weeks after flowering will make for excellent grain-fill as well as reduce the risk for disease development.

There is a 30-60% chance for rain on Tuesday, Wednesday, and Thursday of this week, followed by drier conditions for the next 7 days or so. The risk tool ( is currently indicating low risk for scab across the state. This is due in part to the fact that it has been cool and dry in most areas. However, if it becomes warm and humid and rains over the next several days, as the weather forecast indicates, the risk for scab will likely increase for wheat flowering later this week and over the weekend. Check the risk tool regularly and be prepared to apply Prosaro or Caramba if the risk for scab increases in your area. Remember, both of these fungicides are most effective against scab and vomitoxin when applied at flowering. If you are unable to apply the fungicide at flowering, our data suggest that applications made 2-4 days after flowering will still provide some level of scab suppression. For more on fungicide efficacy, rates, and pre-harvest intervals, go to:

Corn Planting Nearing Completion – Time to Troubleshoot Emergence Problems

According to the USDA/NASS ( for the week ending May 19, corn was 74 percent planted, which was 19 percent behind last year but 16 percent ahead of the five-year average. In some areas, producers were able to start and complete their corn planting within the week. Corn emergence has generally been rapid and many fields planted in early May are now easily rowed from the road.

Troubleshooting emergence problems early is critical in identifying solutions and developing successful replant plans, if needed. Here's a list of a few common things to look for if you encounter an emergence problem in corn this spring.

(Some of this information has been adapted from a newsletter article written by Dr. Greg Roth, my counterpart at Penn State several years ago).

 -No seed present. May be due to planter malfunction or bird or rodent damage. The latter often will leave some evidence such as digging or seed or plant parts on the ground.

 -Coleoptile (shoot) unfurled, leafing-out underground. Could be due to premature exposure to light in cloddy soil, planting too deep, compaction or soil crusting, extended exposure to acetanilide herbicides under cool wet conditions, combinations of several of these factors, or may be due to extended cool wet conditions alone.

 -Seed with poorly developed radicle (root) or coleoptile. Coleoptile tip brown or yellow. Could be seed rots or seed with low vigor. Although corn has just started to emerge, or has not yet emerged in many fields, growers should carefully inspect seedlings for symptoms of disease, especially in lower lying areas of fields where ponding and saturated soils were more likely.  Seeds and seedlings that are brown in color, are soft, and fall apart easily while digging, are obviously dead or dying. Seeds and seedling roots or shoots with white to pinkish mold growing on them are likely victims of fungal attack and will likely die. Pythium and Fusarium are common fungi that attack plants and cause these damping-off or seedling blight symptoms under wet, cool conditions. It is more difficult to diagnose disease damage on plants that also show abnormal growth caused by cold soil conditions or by crusting of the soil surface. However, dark, discolored roots and crowns, instead of a healthy creamish-white appearance, are typical symptoms of seedling diseases problems. So, it is best to check these seedlings very closely for dark brown or soft areas on seedling roots and shoots. Any discoloration will indicate a problem that could worsen if the soils remain cold or wet.  

 - Seed has swelled but not sprouted. Often poor seed-to-soil contact or shallow planting: seed swelled then dried out. Check seed furrow closure in no-till. Seed may also not be viable.

 -Skips associated with discolored and malformed seedlings. May be herbicide damage. Note depth of planting and herbicides applied compared with injury symptoms such as twisted roots, club roots, or purple plants.

 -Seeds hollowed out. Seed corn maggot or wireworm. Look for evidence of the pest to confirm.

 -Uneven emergence. May be due to soil moisture and temperature variability within the seed zone. Poor seed to soil contact caused by cloddy soils. Soil crusting. Shallow planting. Other conditions that result in uneven emergence already noted above, including feeding by various grub species.

Note patterns of poor emergence. At times they are associated with a particular row, spray width, hybrid, field or residue that may provide some additional clues to the cause. Often two or more stress factors interact to reduce emergence where the crop would have emerged well with just one present. Also, note the population and the variability of the seed spacing. This information will be valuable in the future.

Don’t forget that corn may take up to 3 to 4 weeks to emerge when soil conditions are not favorable (e.g. temperatures below 55 degrees F, inadequate soil moisture). This was widely observed in many fields in 2005 when corn planted in mid April did not emerge until the first or second week of May. As long as stands are not seriously reduced, delayed emergence usually does not have a major negative impact on yield. However, when delayed emergence is associated with uneven plant development, yield potential is often reduced.

Factors to Consider for Modified Relay Intercrop Soybeans

Factors to Consider for Modified Relay Intercrop Soybeans

Modified Relay Intercropping (MRI) is the planting of soybeans into standing wheat. Wheat is a flexible, adaptable plant with a growing season that starts with planting in the fall and ends with harvest in the early summer.  This adaptability allows farmers to capture some 66% of the traditional growing season in Ohio — May 25 to September 30 — to produce a second crop through the inter-planting of soybeans into wheat in late May or early June.

Long-term research at The Ohio State University's Ohio Agricultural Research and Development Center (OARDC) in Crawford County, Ohio and other locations in Indiana has shown that MRI or Relay intercropped wheat can yield at least 90 percent of conventional wheat.

Because of the high probability of growing wheat in an MRI system at 90% or better of conventional wheat, farmers may hedge their crop production and market risk in an MRI system through the opportunity (option) to grow and harvest a crop of soybeans.  Soybean production in an MRI system is more speculative than wheat production due to the need for adequate rainfall in July and August.  Last year’s very dry weather represented the perils of interseeding, in that soybeans were not harvested in the 2012 trial. 

Vyn et al, found that relay intercropping of soybeans yielded better than double cropping of soybeans north of I-70 in Indiana (  In 14 years of replicated trials in North Central Ohio on the MRI system, yields have averaged 76 bu/acre for wheat and 28 bu/acre for soybeans (86 bu/wheat and 0 bushel soybeans in 2012). Wheat yields in favorable growing seasons have exceeded 90 bushels per acre  while soybeans have yielded well over 45 bushels per acre.

To successfully MRI soybeans into wheat, wheat row spacing modification to allow soybean planting equipment to pass without running down plants should be made in the fall.  Wheat Row spacing for MRI has ranged from 10 to 20 inches. As wheat row spacing widens, wheat yields may decline .

There have been various row configurations used to allow soybean planting equipment.  For example, some wheat producers will slide row units together to a 6 inch row spacing and leave a 14 inch planting strip for soybeans. Many producers wish to utilize the corn or soybean planter to sow wheat and this normally is a 15 inch row configuration.  For 2012 data on 15 inch row wheat go to  Row spacing data would suggest that wheat is an adaptable plant that will yield well over various row spacings up to 15 inches.

To accommodate soybean planting and allow for better wheat management via fertilizer, herbicide, and/or fungicide applications, a tram line is essential. Generally, the tram line will be set up for the  MRI  tractor tires. If necessary, planter equipment tires are moved to follow tractor tires.

Finally, wheat culture for MRI, outside of row spacing modification, should remain the same as for monoculture wheat. 

Some Follow-Up from Last Week . . .

(From the article by Ron Hammond and Andy Michel)

Continue to scout for Black Cutworm . . .  Because of the small size of the corn for the next few weeks, the crop will be very susceptible to injury by cutworms if they are present. Growers are urged to scout their corn for the next month and take action if cutworm cutting is present at the appropriate levels for the size of your corn.  See the fact sheet for more information, and for insecticide choices.

Pierce Paul introduced a new system to forecast wheat scab . . .

There is now a direct link to The Wheat Scab Forecasting System on the Agronomic Crops Network homepage:



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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.