CFAES Give Today
Agronomic Crops Network

Ohio State University Extension


C.O.R.N. Newsletter 2006-31

Dates Covered: 
September 18, 2006 - September 24, 2006
Andy Kleinschmidt

Prepare Grain Bins Now for Fall Harvest

Authors: Curtis Young

Grain harvest is fast approaching and it is time to prepare storage facilities and harvest equipment for the coming corn and soybeans. Grain quality will never be any better than when it first comes out of the field, it can only deteriorate over time if it is allowed to do so. There are several measures one can take prior loading grain into storage structures to reduce the chances of the deterioration of stored grain quality. These measures include: facility inspection and repair, sanitation, and empty-bin insecticide treatments.

The condition of the grain facility can be as important as the potential of insects infesting the stored grain. Facilities should be inspected closely for sign of deterioration, especially for leaks and holes through which insects, birds or rodents can gain easy access to the stored grain. While inspecting for physical problems, one should also test aeration fans and driers for functionality. Seal all leaks and make repairs to the equipment before you need them to manage the grain.

Sanitation can prove to be a very valuable tool in reducing the potential of new grain coming into contact with grain that may be infested with grain damaging and contaminating insects. Grain that accumulated or got stuck in equipment and stayed there throughout the summer months had a great potential of becoming infested with several species of insects. Pieces of equipment that need to be cleaned thoroughly before they are used again include the combine, truck beds, grain wagons, augers, bucket lifts, and grain dumps. Other sources of grain infesting insects include livestock feeds, old seed bags, spilled grain, old contaminated grain that was not disposed of properly and other cereal products. And the number one rule in grain storage is, NEVER LOAD NEW GRAIN INTO A BIN ON TOP OF OLD GRAIN.

Another area of sanitation that is frequently overlooked is the clearing of all vegetation growing around the bases of storage bins. This vegetation can harbor grain infesting insects and provide concealment for rodents. It is advisable to clear all vegetation within 10 feet of the bases of the bins. It would be even more preferable to have the whole storage area cleared of vegetation and be covered with gravel. Follow up the vegetation removal with a residual herbicide application to the cleared area to prevent regrowth.

And last, but not least, the interiors of the storage bins should be thoroughly cleaned. Walls, ceilings, ledges, rafters, braces, ladder wrongs and handling equipment should be swept, brushed or vacuumed clean of all debris, dust and grain. Fans, aeration ducts, exhausts and when possible, beneath slotted floors should be cleared of debris as well. Dispose of all debris in a lawful manner and away from the storage facility. Once all cleaning has been completed, an empty-bin application of an appropriately labeled insecticide is advisable, especially in bins with difficult to clean areas and/or in bins with a history of insect problems. For empty-bin insecticide treatments that are applied as a liquid, allow a minimum of 24 hours for the sprays to dry before loading grain into the bin.

Registered empty-bin insecticides include: Diacon II (methoprene (an insect growth regulator that only impacts immature insects)), Tempo (cyfluthrin), Storcide II (chlorpyrifos methyl plus deltamethrin), and Insecto, Protect-It, Perma-Guard and others (diatomaceous earth and/or silicon dioxide). Refer to the individual product labels for lists of insects controlled and application directions. If a bin is known to be heavily infested with insects, an empty-bin fumigation may be required to knock down insect populations before applying one of the above insecticides. The most readily available product for this purpose is phosphine gas producing materials such as aluminum phosphide and magnesium phosphide. Phosphine is an extremely toxic material and fumigations should be conducted by trained, experienced, licensed applicators.

Finally, one last measure one might take to reduce the chance of insect infestation is to apply a perimeter spray around the base and up the outside walls of the bin about 15 feet. This may only be necessary in areas where grain infesting insect movement has been observed on the outsides of the storage bins. There are several synthetic pyrethroids (cyfluthrin, deltamethrin, permethrin, resmethrin, etc.) that can be used for this purpose as long as they do not come in contact with the grain.

Soil Sampling Time Again

Authors: Robert Mullen

Here it is fall again in Ohio and that means three things – 1) Saturday football games at the Shoe, 2) yard work (raking leaves), and 3) soil sampling to determine soil nutrient needs for next growing season. Make sure you follow the good rules of thumb when collecting your soil sample to ensure the information you get is as accurate as possible.

1) Collect 15 to 20 random samples from representative areas of the field. Representative areas are those areas that best representative soil conditions across the field landscape. Areas at different landscape positions or “problem” areas should be sampled separately. Make a composite sample of the 15 to 20 samples and make certain that is well mixed. Take a small sample of the composite and submit it to a reputable lab. Labs available in Ohio can be found at the following webpage:

2) Collect soil samples to a depth of 8 inches. Tri-State Fertilizer Recommendations are based on soil samples collected to a depth of 8 inches. If sampling no-till fields, 4 inch samples should also be collected. This is for determination of lime recommendations.

3) Do not dry soil samples at temperatures higher than 120 degrees F. Typically semi-moist samples can be submitted directly to analytical labs.

4) Avoid contamination. Use clean probes for sampling and clean buckets for mixing.

Remember, the lab you are submitting your sample to can control error much better than you can, so do your part and collect a good soil sample. Keep in mind that Ohio State University does not operate a soil testing lab.

Synopsis of the 2006 Field Crop Insect Situation

Authors: Ron Hammond, Bruce Eisley

We have seen almost everything in our crop fields in the way of insect pests this past year, with the possible exception of soybean aphid (which we would remind growers that we had predicted their low numbers). Prior to getting into our winter meetings and what to expect in 2007, we thought it would be helpful to discuss what happened this past summer.

Spring was fairly normal, with problem calls received on slugs and the regular group of soil pests including seedcorn maggots and grubs. Of interest, slug problems appeared to be more numerous than normal on the eastern edge of Ohio and also around the Springfield-Dayton area. Does this mean that slugs are spreading in terms of their economic problems? We are not sure, but will keep an eye on it.

Soon after crop emergence, we began getting more calls than usual on cutworms and stalk borers on corn. Perhaps this is related to the heavier weed pressure that is occurring in field crops, perhaps because of favorable environmental conditions. The cutworm situation was of special concern because we received many calls from growers that had treated their corn with low rates of either Cruiser or Poncho and still had economic problems with cutworms in their fields. We will need to continue to examine these seed treatments as to whether they offer acceptable control of black cutworms.

During May and early June, we began receiving reports from southern states of adult armyworms being collected in high numbers. We then began trapping them in high numbers in our traps in Ohio. Soon thereafter, armyworm became a big concern in various crops including wheat, corn adjacent to wheat and corn planted into rye cover crops. Both these latter situations were severe enough to require insecticide applications.

For the first time in a quite a few years, we also saw more cereal leaf beetle, or should we say their larvae, on wheat and other cereal grasses requiring treatment in some instances. Normally this insect is held down by parasitoids; whether this is a sign of coming problems is not known. It will, however, also require further monitoring. On alfalfa, we received the usual reports of alfalfa weevil causing problems in some areas of Ohio. Not too many problems were evident on early soybeans, although overwintering bean leaf beetles did show up in some fields.

As we moved into summer, numerous problems began, including one of the worst years for potato leafhopper on alfalfa in recent memory. It was not unusual to see completely yellow alfalfa in fields that had not been treated. Of note was that the newer, glandular-haired leafhopper resistant varieties held up very well, although in fields with extremely high leafhopper densities, the numbers exceeded the 3X treatment threshold that was established for resistant alfalfa. Even some of these fields might have benefited from a treatment. However, the resistant alfalfa performed admirably. On other field crops, the usually cast of characters were around, including European corn borers and flea beetles on corn, defoliators on soybeans, and Japanese beetles on both.

A situation on corn that was different than normal was the higher levels of rootworm injury we saw, including more injury in corn following corn that had been treated with soil insecticides and seed treatments. This injury was then followed by higher numbers of adults feeding on silks in August. Although we did not receive many reports of first year corn problems, our yellow-sticky trap sampling in soybeans in August indicated some fields reached the established threshold of 5 beetles/trap/day and will need treatment for corn rootworm larva if the fields are planted to corn in 2007. Many fields did not reach the threshold and will not need to be treated for rootworm in 2007. We are currently formulating our recommendations for rootworm control in 2007, including the use of transgenics and seed treatments in continuous and first year corn. As soon as we gather all the data from our efficacy tests and the yellow-sticky trapping in soybeans, we will publish our thoughts on 2007 in an upcoming CORN newsletter.

As the summer came to an end, we began receiving calls of heavier bean leaf beetle pod feeding in some late maturing soybean fields. Although pod feeding occurs somewhere every year in Ohio, these reports suggested very high densities. This was especially evident in very late maturing fields that were still green in mid September.

As mentioned in the first paragraph, the one pest that that did not show up at damaging levels was the soybean aphid. Populations, while present, came nowhere near the 250 per plant threshold. However, observations so far suggest that the soybean aphid will be back next year, so keep abreast of the situation through this newsletter.

That, in a nutshell, was the season of 2006. Two major issues for the 2007 season will be whether corn rootworms are indeed more damaging in corn following corn and first year corn, and the expected come-back of the soybean aphid. Keep reading this CORN newsletter and attend one of extension meetings that will be held throughout the state to keep abreast of the potential insect problems and management options!

Scouting for Weeds at Harvest

Authors: Mark Loux

Scouting fields for weeds during harvest can provide useful information as you put together weed management programs for next year’s crops. While many growers are maintaining effective weed control in Roundup Ready soybeans, we have observed a steady erosion in control of certain weeds in some Roundup Ready fields over the past several years. We had a banner year for giant ragweed, pokeweed, poison hemlock, and marestail, among other weeds. Current problems with weeds are due in part to mismanagement and oversimplification of herbicide programs. However, we are observing the continued spread of glyphosate-resistant marestail, and we suspect a number of giant ragweed populations may be developing a low level of resistance to glyphosate. We conducted field research this year on several such giant ragweed populations. In brief, the results of this research demonstrated the importance of 2,4-D and residual herbicides for management of giant ragweed in soybeans, along with proper glyphosate rate and application timing. Many cornfields are also infested with late-season populations of giant ragweed this year, especially where growers attempted control with total preemergence herbicide programs. We’ll be providing more detailed recommendations on giant ragweed management later this year after we have a chance to fully digest the data from our 2006 research. However, it appears that we are assured of much replenishment of giant ragweed in the soil seedbank this fall, which will make problems worse next year.

The bottom line: 1) take time during harvest to make a note of fields where weed control was less than adequate or where one or more weeds are becoming more prevalent (yield monitors may also provide useful information on the impact of weeds); 2) take time to revisit your 2006 weed management program with the goal of determining why these weeds escaped; 3) consult future issues of C.O.R.N., the Ohio/Indiana Weed Control Guide, and other sources for the latest information and recommendations from OSU weed scientists; and 4) as you plan next year’s weed management strategies, make the necessary adjustments to improve control and prevent another year of weed seed production.

Tips for Assessing Corn Hybrid Demonstration Plots

Authors: Peter Thomison

This is the time of year when many farmers visit and evaluate hybrid demonstration plots planted by seed companies and county Extension personnel, among others. When checking out these plots, it’s important to keep in mind their relative value and limitations. Demonstration plots may be useful in providing information on certain hybrid traits, especially those that are usually not reported in state corn performance summaries. The following are some hybrid characteristics to consider while checking out hybrid demo plots.

PLANT/EAR HEIGHT. Corn reaches it maximum plant height soon after tasseling occurs. Remember that although a big tall hybrid may have a lot of "eye appeal," it may also be more prone to stalk lodging in the fall. Unless your interest is primarily silage production, increasing plant height should not be a major concern. Generally later maturity hybrids are taller than earlier maturity hybrids. Big ears placed head high on a plant translate to a high center of gravity, predisposing a plant to potential lodging. The negative effects of stalk rot on stalk lodging in the fall may be worsened by high ear placement.

STALK SIZE. Generally speaking, a thicker stalk is preferable to a thinner one in terms of overall stalk strength and resistance to stalk lodging. As you inspect a test plot, you will see distinct differences among hybrids for stalk diameter. However, also check that the hybrids are planted at similar populations. As population increases stalk diameter generally decreases.

LEAF DISEASES. During the grain fill period, leaf diseases can cause serious yield reductions and predispose corn to stalk rot and lodging problems at maturity. The onset of leaf death shortly after pollination can be devastating to potential yield, since maximum photosynthetic leaf surface is needed to optimize grain yield. Hybrids can vary considerably in their ability to resist infection by these diseases. Demonstration plots provide an excellent opportunity to compare differences among hybrids to disease problems that have only occurred on a localized basis. Look for differences in resistance to northern corn leaf blight and gray leaf spot. Check to see if foliar fungicides have been applied and what crop rotation has been followed. Typically you’ll encounter more severe foliar disease problem in no-till, continuous corn.

STALK ROTS. Hybrids will likely differ widely when faced with strong stalk rot pressure. Begin checking plants in late August or about 6 weeks after pollination by pinching lower stalk internodes with your thumb and forefinger. Stalks that collapse easily are a sure indicator of stalk rot. Remember that hybrids with thicker stalks may be in plots having thin stands.

LODGING. Perhaps as important as stalk rot resistance is the stalk strength characteristics of a hybrid. Sometimes, superior stalk strength will overcome the effects of stalk rot. If your variety plot is affected by stalk rot in late August and early September, be certain to evaluate the stalk lodging resistance of the different hybrids. Most agronomists characterize plants with stalks broken below the ear as ‘stalk lodged’ plants. In contrast, corn stalks leaning 30 degrees or more from the center are generally described as ‘root lodged’ plants; broken stalks are not involved. Root lodging can occur as early as the late vegetative stages and as late as harvest maturity. Both stalk and root lodging can be affected by hybrid susceptibility, environmental stress (drought), insect and disease injury.

Root lodging is frequently attributed to western corn rootworm injury. However, much root lodging in Ohio occurs as the result of other factors, i.e. when a hybrid susceptible to root lodging is hit by a severe windstorm. A hybrid may be particularly sensitive to root lodging yet very resistant to stalk lodging. A cornfield may exhibit extensive root lodging in July but show little or no evidence of root lodging at harvest maturity in September (except for a slight “goose necking” at the base of the plant).

Demonstration plots also provide a good opportunity to evaluate another stalk related problem, green snap (a.k.a. brittle snap). Green snap damage in Ohio has usually been limited to localized areas where severe windstorms occur prior to pollination. Although green snap is not a major problem in Ohio, as it is in the western Corn Belt, there are differences in susceptibility among hybrids that growers may want to consider to avoid risks.

TRANSGENIC TRAITS: Because damage from European corn borer (ECB) and western corn rootworm (RW) can be very localized, strip plot demonstrations may be one of the best ways to assess the advantages of ECB Bt and RW Bt corns. The potential benefit of the ECB Bt trait is likely to be most evident in plots planted very early or very late; the potential benefit of the RW Bt trait is likely to be most evident in plots planted following corn or in a field where the western corn rootworm variant is present.

HUSK COVERAGE/EAR ANGLE. Hybrids will vary for completeness of husk coverage on the ear as well as tightness of the husk leaves around the ear. Ears protrude from the husk leaves are susceptible to insect and bird feeding. Husks that remain tight around the ear delay field drydown of the grain. Hybrids with upright ears often associated with short shanks may be more prone to ear and kernel rots that those ears that point down after maturity. Under certain environmental conditions, some hybrids are more prone to drop ears, a major problem if harvesting is delayed.

The following are some additional points to consider during your plot evaluations:

1. Field variability alone can easily account for differences of 10 to 50 bushels per acre. Be extremely wary of strip plots that are not replicated, or only have "check" or "tester" hybrids inserted between every 5 to 10 hybrids. The best test plots are replicated (with all hybrids replicated at least three times).

2. Don't put much stock in results from ONE LOCATION AND ONE YEAR, even if the trial is well run and reliable. This is especially important this year given the tremendous variability in growing conditions and crop performance across the state. Don't overemphasize results from ONE TYPE OF TRIAL. Use data and observations from university trials, local demonstration plots, and then your own on-farm trials to look for consistent trends.

3. Initial appearances can be deceiving, especially visual assessments! Use field days to make careful observations and ask questions, but reserve decisions concerning hybrid selection until you've seen performance results.

4.Walk into plots and check plant populations. Hybrids with large ears or two ears/plant may have thin stands.

5. Break ears in two to check relative kernel development of different hybrids. Use kernel milk line development to compare relative maturity of hybrids if hybrids have not yet reached black layer. Hybrids that look most healthy and green may be more immature than others. Don't confuse good late season plant health ("stay green") with late maturity.

6. Differences in standability will not show up until later in the season and/or until after a windstorm. Pinch or split the lower stalk to see whether the stalk pith is beginning to rot.

7. Visual observations of kernel set, ear-tip fill ("tip dieback"), ear length, number of kernel rows and kernel depth, etc. may provide some approximate basis for comparisons among hybrids but may not indicate much about actual yield potential.

8. Find out if the seed treatments (seed applied fungicides and insecticides) used varied among hybrids planted, e.g. were the hybrids treated with the same seed applied insecticide at the same rate? Differences in treatments may affect final stand and injury caused by insects and diseases.

Certified Nutrient Plan Providers Course in November

Authors: Greg LaBarge

Technical Service Providers and those who would like to become providers of certified nutrient management plans for landowners in Ohio, Michigan and Indiana are encouraged to sign up for the CNMP Provider’s Course being offered by Ohio State University Extension, Purdue University Extension and Michigan State University Extension. The course will be offered at the Holiday Inn in Lima, Ohio on November 7, 8 and 9. The three day course has been approved by NRCS in Ohio, Michigan and Indiana.

The course is an important first step on the road to gaining the status as a Certified Nutrient Management Planner. The course will help the participants become familiar with the process of developing an approved plan, tools available to assist in the planning and become more familiar with options to manage nutrients on today’s farms. The course will have state specific components as well as cover general best management practices.

A six module course has been designed to cover the topics to be considered and include:

  • The CNMP Process
  • Livestock Operation and Resource Inventory
  • Land Treatment
  • Feed Management
  • Other Manure Utilizations Options
  • Nutrient Management

Certified Crop Advisors will receive a total of 17 pre-approved continuing education credits with 7 credits in Nutrient Management, 9 credits in Soil and Water plus 1 credit in Crop Management.

The cost to register for the program is $375 prior to October 6. Between October 7th and 31st the cost is $450. Registrations must be received prior to October 31st. More information including a draft agenda for the three day program and registration materials can be found at:


Archive Issue Contributors: 

State Specialists: Ann Dorrance and Pierce Paul (Plant Pathology), Peter Thomison (Corn Production), Mark Loux and Jeff Stachler (Weed Science), Ron Hammond and Bruce Eisley (Entomology), Robert Mullen and Maurice Watson (Soil Fertility). Extension Educators: Harold Watters (Champaign), Glen Arnold (Putnam), Roger Bender (Shelby), Harold Watters (Champaign), Curtis Young (Allen), Todd Mangen (Mercer), Howard Siegrist (Licking), Mark Koenig (Sandusky), Greg LaBarge (Fulton), Ed Lentz (Seneca), Alan Sundermeier (Wood), Mike Gastier (Huron), Greg La Barge (Fulton), Gary Wilson (Hancock), Jonah Johnson (Clark) and Keith Diedrick (Wayne).

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.