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June 11 to June 17, 2001
C.O.R.N. 2001-17
In This Issue:
A) Unusual "White Corn" Problems
B) Callisto - A New Corn Herbicide
C) Height Restrictions of Postemergence Corn Herbicides and
Other Postemergence Reminders
D) Brown Leaf Spot on Soybeans
E) Modified Relay Intercropping Update
F) Scout Alfalfa for Potato Leaf Hopper Now
G) Watch for Signs of First Brood Corn Borer to Appear
H) Seedcorn Maggots in Soybeans
I) Slugs Activity Still Bears Watching
J) Corn Not Planted and You Have Crop Insurance?
K) Southern Ohio Agronomic Field Days - June 27 & 28
This past week we received a flurry of reports and samples of "white corn". Typically, several bleached out leaves characterized affected corn plants. This bleaching was most prominent on the middle leaves of plants, especially at the base of the leaf, whereas new leaf tissue in the whorl appeared green. The bleaching and whitish discoloration was not as pronounced or uniform as that which would occur as a result of certain pigment inhibitor herbicide damage (e.g. Command, Balance). Several explanations have been put forward to explain the problem including bacterial infections, micronutrient deficiency, herbicide injury, a hybrid specific reaction to weather, etc.
When I showed affected samples to Dr. Don Eckert (Don teaches and conducts soil fertility research in SNR), he indicated that white leaf discoloration resembled Zn deficiency. He attributed the problem to the recent three weeks of wet, cool weather, which have dramatically reduced root growth and function in corn. Some of the conditions associated with this white corn would support this assessment. White corn has often been associated with relatively high pH fields with high phosphorus soil levels, all conditions which promote Zn deficiency. Moreover within fields, topography, soil type, and tillage appear to contribute to the problem, with poorly drained areas exhibiting more of the affected plants. Don suggested that the Zn induced leaf discoloration would disappear as temperatures warmed, and soils dried allowing the resumption of normal root growth.
Corn producers should be aware that corn is growing rapidly
and may be physiologically more advanced than expected. This rapid growth may
limit herbicide choices. Aim, Buctril, Basagran, Callisto, Clarity (< 8 oz/A),
Distinct (up to 4 oz/A), Liberty on Liberty-Link corn, Permit, Resource, and
Roundup Ultra Max on Roundup Ready corn can be applied broadcast over the top
of corn beyond 20 inches tall or six-collar stage.
Herbicides can probably safely be applied to corn according to the herbicide label, because it should have recovered from the cold and wet stress. However, if the corn is still severely stressed producers may need to decide whether weed control or lack of corn injury is the most important goal. When temperatures are over 90 degrees, as is forecasted for the next several days, growth regulator herbicides can cause severe corn injury, especially when corn is rapidly growing.
We have received several calls this week with questions pertaining to a dark brown leaf spot on soybeans. A fungus caused the leaf spot on the samples we have received, Septoria glycines, which is more commonly found on older leaves later in the season. This is a residue borne fungus and was quite prevalent in soybeans at the end of last season. I expect that we have high inoculum levels, particularly in continuous bean fields combined with absolutely perfect environmental conditions, wet, wet and wet.
If it ever dries up, these plants will outgrow this. We are not recommending fungicides at this time. This is a highly unusual occurrence of this disease so early in the growing season as a result of the environmental conditions. There is no data to support any applications at this time, with the price of beans expected to drop - that will negate doing anything to the beans.
Additional information concerning Brown Spot of Soybeans can be found in Ohio State University Extension Factsheet - AC-0018-01 on Ohioline at: http://ohioline.ag.ohio-state.edu/ac-fact/0018.html
( Modified Relay Intercropping in Crawford County June 5, 2001.)
Modified Relay Intercropping (MRI) is the planting of soybeans into standing wheat. This system of intercropping does not use coated soybeans and wheat rows are typically 10 to 12 inches in width. Also, MRI planting occurs in late May or early June as opposed to planting in early to mid May for other systems of intercropping done in wider rows. Soybeans in the MRI system are generally sown into wheat around the pollination time period, with a grain drill or tool bar planter. The wheat has a tramline to facilitate soybean planting. Light or the lack of it, has a profound effect on the growth of intercropped soybeans. Soybeans planted too early into well tillered wheat often will become tall and spindly and result in weak plants that do not grow or yield well. The wheat plant, by virtue of its wide adaptability, is able to tolerate slightly wider row spacing and the stress of soybean planting with minimal yield loss. Most MRI soybeans are planted in the wheat in the Crawford county area and the soybeans are coming up.
Six years of replicated field trials on the MRI system in Crawford County have resulted in favorable average soybean and wheat yields (73 bu/acre for wheat and 30 bu/acre for soybeans). Wheat yields in good years have exceeded 80 bushels per acre and soybean yields over 40 bushels per acre in the MRI system
The MRI system offers producers many benefits. Because two crops with vastly different growing seasons and cultural requirements are produced in the same field in the same year, MRI offers producers both a production and marketing hedge. Thus farmers in the MRI system utilize their time, equipment, land and labor during a period (normally early June) to grow a second crop. The MRI system is also very favorable from an environmental perspective in that soil erosion is minimized with the small grain crop and often very little herbicide is needed to grow soybeans sown into the standing wheat.
A fact sheet about PLH on alfalfa can be viewed on the web at:
http://www.ag.ohio-state.edu/~ohioline/ent-fact/0033.html
Adults moths of the spring flight of European corn borer (ECB) may be observed at this time in corn and wheat fields. Foliar feeding symptoms such as shot holes and windowpane feeding may be observed in cornfields that are almost knee high (i.e. V6 or V7 stage of development). Egg masses may be found on the underside of corn foliage if one searches long and hard. However, to date, I have not found any early stages of 1st brood ECB larvae feeding in whorl stage corn. In whorl stage corn that is almost knee high, signs of early larvae activity may be found if one inspects a significant number of plants. However, the central whorl is generally lacking any signs of larvae activity and inspection of the inner whorls draws a blank.
Most of the corn in central Ohio remains in early V3 or V4 stages of development and is unlikely to attract or support development of 1st brood ECB. Cornfields that were planted early and currently approaching mid-whorl stage should be inspected for possible economic infestations of 1st brood ECB. If whorl injury (shot holes and window-pane feeding) appears abundant, then about 20 plants should be inspected at 5 locations in the field to determine the proportion of stand exhibiting whorl injury. In the inspection process, a number of whorls should be pulled and opened to determine presence or absence of ECB larvae. When larvae are found, the average number of larvae per plant may be estimated based on the proportion of stand exhibiting whorl injury and the proportion of injured plants actually having larvae present. If the number of larvae found exceeds an average of one or more per plant and the larvae have not yet begun to burrow into the stalks, the infestation may warrant a rescue treatment.
The first generation of seedcorn maggot adults have emerged in heavy numbers, and large densities of flies are being seen in fields. These flies will be capable of ovipositing eggs in fields that will be tilled and planted over the next few weeks. In the past, we have observed significant injury to soybeans planted in June, especially in situations where a heavy weed growth was disked. Thus, fields that remain to be planted because of the wet conditions might warrant a seed treatment for protection against this insect. This is especially true if the fields are to be tilled prior to planting, and if heavy weed growth is present.
Numerous reports of slug injury have been received this past week. Historically, this is the time when most damage occurs to field crops. Slugs are growing and increasing their feeding. With the cool and wet weather the past few weeks, growers are advised to check their fields.
The planting season, during the last month, has been a struggle in most areas of Ohio. Producers that were able to get crops in the ground in late April and early May were fortunate. Since then it has been touch and go between showers, if at all. Producers that did purchase crop insurance on corn have an option to planting the crop at this late date.
Federal crop insurance provides a payment for "prevented planting." In the language of the insurance policy, the "final planting date" for corn in Ohio is June 5th. That means that after June 5th (beginning June 6th), if because of weather (and that is the case in Ohio) the corn crop is unplanted, an insured corn crop is eligible for a "prevented planting" insurance payment. To be eligible no other harvestable or substitute crop can be planted on the unplanted acres that would normally have planted to corn.
The payment calculations would be as follows:
135.0 APH proven yield per acre (proven by producer for policy)
x .75 75% yield guarantee (elected by producer in policy)
= 101.25 guaranteed production per acre
x .60 60% "prevented planting" yield guarantee (spec. in policy)
= 60.75 "prevented planting" yield guarantee
x $2.05 APH price guarantee (specified in policy)($2.46 if CRC policy)
= $124.54 "prevented planting" payment per acre
The critical question for producers facing this situation is to decide if planting the corn late will net them (from this time forward) more cash than the $124.54 "prevented planting" payment per acre. That means any costs already incurred or committed to, regardless if you plant or not, are irrelevant.
Assume you decide to plant late anyway. Here is a quick way to determine your net cash from this point forward:
Cash Costs $/Acre:
Seed 30 (seed not yet used)
Fertilizer 10 (lost and/or side-dress N)
Chemicals 10 (yet to be applied)
Fuel 30 (yet to be used)
Repairs 10 (yet to be spent)
Misc. 5 (yet to be spent)
Interest 5
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Total $ 100/A (money yet to spend to plant, harvest and dry the crop)
Receipts:
Yield 97.5 (75% of normal yield)
Price $1.85 (current harvest contract price)
Sale $ 180.38 (income from sale of corn)
LDP $ .10 (estimate per bushel)
LDP $ 9.75 (Estimate per acre)
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Total $ 190.13 (income per acre)
Net Cash $ 90.13 (per acre from late planted corn - from today forward)
Now compare the two options.
Net Cash $124.54 (per acre from "prevented planting" payment)
Net Cash $ 90.13 (from late planted corn)
Gain $ 34.41 (added net cash from "prevented planting" payment
Calculate your own numbers. They may be different from those above. But there is no reason to forego more net cash with zero risk if your numbers look like those above. Harvest price would have to rise to $2.30 to make it a breakeven decision to plant late corn.
People interested in the latest news and research in crop production should attend the Southern Ohio Agronomic Field which will be held at the Fayette County Farm, on Wednesday, June 27 and Thursday, June 28, from 9 a.m. to 3 p.m. each day. The farm is north of Washington C.H. off of state Route 38 at the Fayette County Airport. Access to state Route 38 is found from Interstate 71, Exit 75. Signs will be posted on state Route 38.
Speakers will include state specialists, industry researchers and Extension agents covering topics such as weed control, corn health, soybean diagnostics, tillage practices, insect management, soil and water quality, and precision agriculture technology.
These field days provide practical, science-based information in an environment where producers and agribusiness people can engage in "hands-on" activities, ask questions on current and cutting-edge issues, and learn from specialists about common crop characteristics.
The program on June 27 is intended for farmers, while June 28 is geared toward agribusiness people. The same agenda will be covered both days, although the information on June 28 will be slightly more detailed and technical. All are welcome to attend either day, although each day is tailored for the particular professions.
Certified Crop Advisors can get at least five hours of credit by attending one day of the event, including two hours of Crop Management and one hour each of Nutrient Management, Soil and Water Management, and Pest Management.
Admission is $10 for farmers on June 27 and $25 for agribusiness representatives on June 28. Registration is required by June 21.
For more information about the Field Days, call the Fayette County Extension
Office at (740) 335-1150
Readers can subscribe electronically to this newsletter by sending an e-mail message to: corn-out-on@postoffice.ag.ohio-state.edu. A successful subscription message will receive by an automatic reply from the listserv. Contact your local Ohio State University Extension Office or e-mail labarge.1@osu.edu if you have problems subscribing.
Past versions of C.O.R.N. can be found on the World Wide Web at: http:/www.ag.ohio-state.edu/~corn/archive/
C.O.R.N. is a summary of crop observations, related information, and appropriate recommendations for Ohio Crop Producers and Industry. C.O.R.N. is produced by the Ohio State University Extension Agronomy Team, State Specialists at The Ohio State University and Ohio Agricultural Research and Development Center. C.O.R.N. Questions are directed to State Specialists, Extension Associates, and Agents associated with Ohio State University Extension and the Ohio Agricultural Research and Development Center at The Ohio State University.
Contributors to C.O.R.N. this week include:Editor: Clark Hutson Web Editor: Tom Rosati
Information presented above and where trade names are used, they are supplied with the understanding that no discrimination is intended and no endorsement 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.
All educational programs conducted by Ohio State University Extension are available to clientele on a nondiscriminatory basis without regard to race, color, creed, religion, sexual orientation, national origin, gender, age, disability or Vietnam-era veteran status.
Issued in furtherance of Cooperative Extension work, Acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture, Keith L. Smith, Director, Ohio State University Extension.
TDD # 1 (800) 589-8292 (Ohio only) or (614) 292-1868
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