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Agronomic Crops Network

Ohio State University Extension

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C.O.R.N. Newsletter 2008-16

Dates Covered: 
June 2, 2008 - June 10, 2008
Editor: 
Jonah T. Johnson

Wheat Disease Update

Authors: Pierce Paul

With the exception of wheat spindle streak mosaic virus and powdery mildew in some fields planted with susceptible varieties, we have so far this year seen very little foliar diseases in wheat in Ohio. Even the risk of head scab continues to be low across the state. Cooler-than-usual temperatures over the last two weeks have contributed to minimizing disease development, in spite of the recent rains we have had. The crop is at early to mid grain fill in southern Ohio and approaching pollination (flowering) in northern counties. Foliar diseases are of greatest concern in terms of yield reduction when they occur and spread to the flag leaf before pollination and grain fill.

In the case of powdery mildew, for late-planted fields that are still at head emergence, growers should scout their fields. If pustules are present on the leaf just below the flag leaf, a fungicide application may be warranted if the variety is susceptible. However, for those fields in which pollination and grain fill occurred before the disease reached to the leaf below the flag leaf, powdery mildew should not be a concern. Most of the fungicides that are effective against powdery mildew cannot be applied after full head emergence. In addition, the warmer weather forecasted for the next few days will slow down the development and spread of powdery mildew.

As temperatures increase, however, the risk of other diseases such as Stagonospora leaf blotch and Stagonospora glume blotch will increase, especially if it rains as is forecasted for the next five days. However, infections occurring at the current growth stage (late heading to grain fill) will likely be too late to be of major concern. The leaf and glume blotch fungus, Stagonospora nodorum, requires six hours or more of leaf wetness to infect, and once infection occurs, it will take 5 to 7 days before lesions develop, and an additional 5 to 14 days before a new crop of spores is produced. The time taken from infection to spore production depends on the variety and the weather, being much shorter on highly susceptible varieties under warm (68 F to 81 F), wet conditions than resistant varieties under dry conditions. Now is the time for growers to scout those late-developing fields planted with susceptible varieties and if lesions are seen on the leaf below the flag leaf, a fungicide application may be warranted.

The warm, wet conditions forecasted for the next few days will also increase the risk of Fusarium head blight or head scab in central and northern Ohio where the wheat is flowering. As the wheat reaches the flowering growth stage, producers should refer to the Fusarium Head Blight Prediction Center www.wheatscab.psu.edu to evaluate the potential risk of head scab developing and to help guide fungicide decisions. Remember, head scab develops best when wet, humid conditions occur during flowering. Hence, fungicides are most effective against head scab and vomitoxin when applied at flowering, not before or after.

For more on managing wheat diseases with fungicides, please refer to the following C.O.R.N newsletter articles:http://corn.osu.edu/story.php?setissueID=227&storyID=1407 , http://corn.osu.edu/story.php?setissueID=228&storyID=1412


Very little soybean rust in the southern U.S.

Authors: Anne Dorrance

The first reports of soybean rust came in late last week (May 29) from the panhandle in Florida and Louisiana. These findings came for shady areas in kudzu patches and the incidence is very low. It will take some time for rust to begin to build again. Texas also is reporting very low levels of infection in only 1 or 2 kudzu patches. This again puts us at very low levels of inoculum going into this year’s production season. In order for rust to impact the soybeans that went in the ground over the last few weeks in Ohio, there will have to be highly favorable weather conditions in the south for the next month, moderate temperatures, and lots of rain. However, the high temperatures predicted for this week will not be good for rust. Our predicted risk for soybean rust in Ohio for 2008 is very, very, very low.

Ohio’s early planted sentinel plots are in and about half of the plots have emerged. No disease problems have been observed to date.

Some Fungicide Application Basics – how not to blow a great tool.

Authors: Dennis Mills, Pierce Paul, Anne Dorrance

We have learned of some interesting new practices for fungicide applications this season and while not directly “off-label” they are cause for concern. As plant pathologists that utilize these tools and depend on these tools at times to manage epidemics caused by fungi – we thought this would be a good time for a few reminders.

1. What is fungicide? This is a compound applied to crops to manage a multitude of fungal and fungal-like plant pathogens. Fungicides have been instrumental in managing late blight of potato, apple scab in apples, powdery mildews in wheat, cucurbits, and apples. Fungicides are primarily needed when a susceptible host is grown and the environment is highly favorable. Both conditions must occur at the same time. Better weather models, and now predictive models, disease scouting are all used to save producers monies in that the fungicides will be applied only as needed. Many crops now have resistance to many of these pathogens and so the use of these fungicides is not warranted.

2. There are different classes of fungicides – basically this means that there are different chemistries and these have different features – ie: systemic movement in plants – some move up and down a few leaves, some don’t move at all. Some can be applied shortly after infection has started and have a “curative” effect – but none can be applied after the field has high levels of disease and lots of spore production. Know your chemistry so you know how to use it correctly. Don’t know what your chemistry is? Check out these resources for more information:

http://oardc.osu.edu/soyrust/ - Chapter 7 has a nice discussion on fungicide basics.


3. Do fungicides provide a “plant health” benefit? This is questionable for Ohio. Across the US from a number of University based studies in fields with out disease, there has been both a negative and positive response. For our data to get the dramatic yield results – disease was always present. Another fact hidden in some data was insect pressure. Many of the strategies that have been promoted are an insecticide/fungicide combination and again where most of the dramatic results come from pertains to fields where insects had become an issue. Remember those aphid years of 2003 and 2005?

4. Timing is critical. Fungi (including the water molds) only have certain life stages that are vulnerable to fungicides. If the fungicide is applied too early – it is not effective; if the fungicide is applied to late – it is not effective. The recommendations and guidelines are based on the most up-to-date compilation of studies to optimize the best timing. Read the labels – if the recommendation says to apply at flowering – then a week earlier will not work nor will a week later.


5. The other fact about fungicides – is they don’t last. Many fungi have developed resistance to these very important tools. Based on history – some things that favor fungicide resistance are i) overuse or repeated applications of one chemistry – constantly apply one type of chemistry repeatedly – even if it is a different product (a strobilurin is a strobilurin is a strobilurin no matter who makes it! And don’t forget the mixtures – a strobilurin combined with a triazole is still applying a strobilurin and not rotating) ii) half rates – we don’t know who came up with this idea but it is a really bad one. A half rate won’t be effective in killing the pathogens that you are trying to manage. The pathogens that survive this application have a high potential to be less sensitive to the fungicide the next time around; iii) applying fungicides when pathogen populations/disease levels are already high – this increases the chance that some will survive. You can’t rescue a bad field – let it go and learn the lesson to have better scouting and timing next time.

6. Fungicides don’t cure environmental problems – fungicides are not the answer for poor fertility, flooding, freeze, frost or hail damage, herbicide mistakes, or anything else. This is not the “take an aspirin” and it will feel better; fungicides are not placebos. If you’ve got a bad field – go home and forget about it, call the insurance guy and learn from it—don’t spray it.

Early postemergence considerations for corn

Authors: Mark Loux

Cool weather in May slowed crop and weed growth compared with most years, but the postemergence (POST) season is going into high gear. Expect weeds and crops to grow fast under the high temperatures and adequate soil moisture that will occur this week, and this is when the advantage of residual herbicides applied at planting often becomes evident. Fields in west central Ohio that were planted in late April or early May have progressed to the point that many summer annual weeds have reached a size of 2 to 4 inches where preemergence (PRE) herbicides were not used (giant ragweed plants can be larger than this, which is to be expected). Fields treated with residual herbicides at planting are likely to have much reduced weed populations, and weeds growing at a slower rate. Some guidelines for early postemergence applications in corn:

- In the absence of PRE herbicides (i.e in total POST herbicide programs), POST herbicides should be applied before summer annual weeds exceed 2 to 3 inches in height. This often corresponds to approximately 20 to 25 days after crop planting, but cool temperatures in May extended this somewhat. Allowing weeds to become larger than this size results in the risk of crop yield loss due to early-season weed interference. Applying POST herbicides to 6-inch weeds results in an average yield loss of 6%, compared to earlier applications, and the loss increases with weed size. We often use annual grasses as the indicator species for timing of early POST treatments, but many summer annuals grow at about the same rate for several weeks after they emerge. See the most recent article on the Iowa State Weed Science website for more information on timing of POST applications (http://www.weeds.iastate.edu ).

- Where an effective rate of a broad-spectrum PRE herbicide program was used, and it was initially active due to timely rain, POST application timing is less critical than in total POST programs. This is because the PRE herbicides reduce the weed population and slow the growth of emerging weeds. The end result – POST herbicides can often be applied a little later in the season, which works well for control of late-emerging weeds. So while total POST programs should usually be applied before corn exceeds the V3 to V4 stage, use of PRE herbicides allows application to corn that is substantially larger. However, with a few exceptions, POST herbicides should be applied before corn exceeds 18 to 20 inches in height. Weeds that become evident in corn later in the season have usually emerged by the time corn is this size, and corn out-competes weeds that emerge beyond this point.

- Where PRE herbicides have not been completely effective due to an initial scarcity of rain, it may be more difficult to determine the timing of POST applications. Where the PRE has largely failed and there is a fairly dense weed population, it is essential to apply before weeds exceed 3 to 4 inches in height to avoid yield loss. Where the PRE herbicides have been somewhat active, it may be a possible to apply POST herbicides later and still not suffer crop yield loss.

- The above guidelines all pertain to management of weeds to avoid yield loss, but timing should also be based on the limitations of the herbicides with regard to weed size. The size of annual grasses is often a determining factor for POST application timing, because large grasses are more difficult to control than large broadleaf weeds with conventional POST corn herbicides. Labels for most POST grass herbicides (Option, Steadfast, etc) specify application when grass weeds are 4 inches tall or less. For these herbicides, the previous discussion about POST application timing, based on the competitive nature of weeds, becomes unnecessary because they have to be applied when grasses are small to obtain adequate control. So, for those growers evaluating options where PRE herbicides have not been completely effective, the real question may be whether to apply when grasses are less than 2 inches tall in order to reduce costs, or apply when grasses are about 4 inches tall to try to improve control of late-emerging weeds.

- Making the choice to plant Liberty Link or glyphosate-resistant corn (is there still a choice?) can pay off in a year when PRE herbicide activity is so-so. Liberty and glyphosate both have broad-spectrum activity, although there is less flexibility in timing of Liberty application with regard to weed size. Liberty controls giant foxtail up to 6 inches tall, while glyphosate can control grasses well over 6 inches tall. Keep in mind, however, that in total POST programs or where a lack of rain has resulted in a complete failure of PRE herbicides to reduce early-season weed populations, Liberty and glyphosate should be applied when weeds are less than about 4 inches tall to avoid corn yield loss. Impact and Laudis fit well into POST programs in conventional corn where PRE herbicides have not been completely effective, due to their activity on small grass and broadleaf weeds. Impact and Laudis should be applied with atrazine and methylated seed oil (MSO) for most effective control of grasses and certain broadleaf weeds.

- University research has shown that the critical period of weed control in corn occurs between approximately 20 and 45 days after planting. Controlling weeds during this period is essential to avoid crop yield loss. So, total POST herbicide programs applied at about 20 to 25 days after planting will minimize competition from weeds that emerge with the corn, but these programs should also contain a residual herbicide component to control weeds for another 2 to 4 weeks. Weeds likely to reinfest a field following early POST herbicide application include giant ragweed, annual grasses, shattercane, burcucumber, morninggglory and waterhemp. Fields with a history of weed control problems are likely candidates to have major infestations of these and other weeds emerge within this 20 to 45 day after the planting window.

- In fields where giant ragweed was not well controlled in previous years, and the seedbank for this weed is well stocked, we have observed substantial new emergence in mid June. This corresponds to about the end of the critical period of weed control in many fields, and the residual herbicides included in early POST applications should be robust enough to control as much of these late emergers as possible. High rates of atrazine may provide effective control of late-emerging broadleaf weeds (as long as they are not triazine-resistant), but often fail to adequately control late-emerging grasses. In those fields that have not been treated with PRE herbicides, our suggestion would be to take a more broad-spectrum approach when adding residual herbicides to early POST applications of glyphosate, Liberty/Ignite, etc. Including an atrazine premix product in early POST applications at rate equivalent to at least 70% of the typical PRE rate is more likely to provide the desired longevity of grass and broadleaf control than atrazine alone. In fields with a history of giant ragweed problems, an even better approach would be a mixture of atrazine with products such as SureStart or Halex GT. This approach should ensure better late-season giant ragweed control and allow use of lower atrazine rates, compared with trying to achieve this with atrazine alone.

- Finally, some discussion about the merits of mixing other POST corn herbicides with glyphosate, or substituting other POST herbicides for glyphosate. POST mixtures or glyphosate replacements start to make more sense when the price of glyphosate rises, but the price of other herbicides remains relatively constant. Where a substantial rate of a PRE herbicide program was applied at planting, it’s possible that the POST glyphosate will be applied to small weeds, and there can be little need to mix with other POST herbicides. This may still be the most inexpensive approach, but when the cost of glyphosate is $10 to 12 per acre, it’s possible to apply Impact or Laudis for about the same price. The advantages of using Impact or Laudis would be a reduction in the selection pressure for glyphosate-resistant weeds, control of glyphosate-resistant weeds, and the possibility of a little residual control. Primary disadvantages would be the need to include atrazine to ensure the effectiveness of these herbicides on certain weeds (a limiting factor where corn is more than 12 inches tall), and the need for grasses to be less than 2 inches tall at the time of application. In fields that have a history of poor broadleaf control with glyphosate, or where the broadleaf weeds are large or old, consider mixtures of glyphosate with a dicamba-containing product. This is likely to be a more consistently effective approach than increasing the glyphosate rate, at about the same price in many cases. Use of dicamba products that contain safeners (Status, Require Q) will reduce the risk of injury to larger corn. It’s possible to make a case for mixtures of glyphosate with POST herbicides other than those mentioned here, where the other herbicide have a strength on a specific weed problem.

"Patching In" Poor Corn: Guidelines to Consider.

Authors: Peter Thomison

Various emergence problems associated with frequent rains and cold, wet soil conditions (including corn seedlings leafing out underground, soil crusting, soilborne insect and disease damage) have reduced corn stands in many Ohio corn fields. In affected fields, the remaining plants are often unevenly spaced within rows and not developing uniformly. Questions often arise as to whether to patch-in these poor stands, replant stands with poor emergence, or to protect late emerging plants during row cultivation. The following are some guidelines to consider in these situations based on findings of Illinois and Wisconsin research. A good source for more information on this subject is North Central Regional Extension Pub. No. 344. “Uneven Emergence in Corn” available on-line at http://learningstore.uwex.edu/pdf%5CNCR344.pdf.

WHEN SHOULD YOU PATCH-IN A POOR STAND?
Growers will sometimes attempt to plant over or "patch in" a poor stand rather than kill the existing plants and replant at a full population. However, "patching in" is generally of limited benefit unless the surviving plant population is less than one half that of the original. The success of such an approach is even less likely late in the planting season (i.e. after June 1). Later planted corn cannot compete effectively with the remnants of the original plant population for sunlight, water, and nutrients.

• If you replant within 2 weeks of planting the original, patching-in may be a viable option. Yields will be similar to those from a uniform-emerging replanted stand, if you can get relatively uniform plant spacing within the row between the old and new plants. However, within 2 weeks of planting, it probably will be too early to determine what the final stand will be (and whether patching will be needed).

• If you replant within 3 weeks after the initial planting, yield potential is about 10% greater if you tear up the field and start over with an even emerging stand rather than just patch-in the original stand. Balance this possible yield increase against the additional cost of tillage, seed, and dryer fuel.

SHOULD YOU REPLANT STANDS WITH UNEVEN EMERGENCE?
• If the delay in emergence is less than 2 weeks, replanting will have a minimal effect on yields, regardless of the pattern of unevenness.
• If one half or more of the plants in the stand emerge 3 weeks late or later, then replanting may increase yields by up to 10%. To decide whether to replant in this situation, estimate both the expected economic return of the increased yield compared to your replanting costs and the risk of emergence problems with the replanted stand.
For more information on replanting corn, check last week’s CORN newsletter (May 27-June 2, 2008 C.O.R.N. 2008-15 ("Replant Issues in Corn") available on-line at http://corn.osu.edu/#B.

SHOULD LATE EMERGING PLANTS BE PROTECTED DURING ROW CULTIVATION?
• If the delayed plants emerge only 1 1/2 to 2 weeks late, use shields and avoid burying the late-emergers during cultivation.
• Protect plants emerging 3 weeks late if one half or more of the plants in the stand are late-emergers.
• If less than 1/4 of the stand emerges 3 weeks late or later, it probably will not pay to encourage their survival. Yields will be about the same whether or not these delayed plants are buried during cultivation.

OTHER CONSIDERATIONS
The researchers who conducted the study which is the basis for these recommendations noted that uneven stands yielded less than even stands due to direct competition of plants at two different stages of growth next to one another (i.e. older plants generally out-compete younger plants for light, water, and nutrients). They acknowledged that in some cases (which I’ve seen frequently in Ohio), that late-emerging plants are more vulnerable to silk clipping by corn rootworm beetles. Severe silk clipping that occurs early in the pollination process can interrupt pollination and reduce kernel set on the ears.
Other observations by the researchers included the following: Late-emerging plants had higher grain moisture content at harvest. This could result in harvested grain with varying moisture levels, which would increase kernel damage and drying costs. Late plants also lodged more due to smaller stems, had weaker stalks and fewer brace roots. During harvest, adjusting settings on combines for variable ear sizes between early and late plants is difficult. These problems would be minimal with a 1 1/2 -week delay, but could be serious with a 3-week delay.
REFERENCES
Carter, Paul, Emerson Nafziger, and Joe Lauer. Uneven Emergence in Corn. 2002. North Central Regional Extension Pub. No. 344. [On-Line]. Available at http://learningstore.uwex.edu/pdf%5CNCR344.pdf. (URL verified 6/2/08).

Cereal Leaf Beetle Problems in Cereal Grains.

Authors: Ron Hammond, Andy Michel, Bruce Eisley

During the past week we received reports of wheat fields with cereal leaf beetle populations starting to cause noticeable feeding injury, some requiring treatment. These reports have also come from spelt. As readers of this newsletter remember from a month ago, we thought this might happen. We would recommend that growers of wheat and other cereal grain crops scout their fields if not already doing so. It is the larvae that will cause the significant feeding on the flag leaf that causes economic yield loss. The current threshold for treatment is two larvae per stem. With the current high prices of these crops, you might want to be conservative in your decision to spray and treat if close to the actually threshold. See the following web sites for more information on the cereal leaf beetle along with a list of labeled insecticides http://ipm.osu.edu/ib/w-3.htm and http://entomology.osu.edu/ag/545/sgiclb.pdf.

Organic growers who experience problems with cereal leaf beetle on wheat and other cereal grain crops should be aware that they have an OMRI listed, an organically approved product, Entrust, made by Dow. Entrust contains spinosad, which is produced through the fermentation of living organisms. There are two formulations of spinosad available from Dow, with Entrust being the one that is OMRI listed.

Bean Leaf Beetle on Soybean.

Authors: Ron Hammond, Andy Michel, Bruce Eisley

Having mentioned bean leaf beetle on soybean a few weeks ago in this C.O.R.N. newsletter, we are now receiving reports of populations and some defoliation. Remember that it takes significant defoliation, well over 50%, before economic concerns, which is seldom seen. However, because of the scarcity of emerged soybean fields, fields that are already emerged, should be scouted for the possible presence of larger than normal numbers of bean leaf beetle. Without a lot of other soybean fields for the beetles to spread their numbers over, the few fields that are emerged might be getting more adult beetles than usual.

Potato Leafhoppers Have Arrived.

Authors: Ron Hammond, Andy Michel, Bruce Eisley

Potato leafhoppers have made their way north to Ohio. With alfalfa fields being harvested, growers should plan on scouting the regrowth for the leafhopper as soon as the alfalfa reaches sufficient height for sweep-net sampling. Sampling is done using a sweep net and taking 10 samples throughout a field. Each sample should consist of 10 sweeps with the net. Count all potato leafhopper adults and nymphs, though at this time of the year, mostly adults will be seen. When the average number of leafhoppers in a single sample (10 pendulum sweeps) is equal to or greater than the average height of the alfalfa stand, insecticide treatment is warranted for varieties not resistant to the potato leafhopper. For example, if the alfalfa is 6 inches tall and the average number of leafhoppers per 10-sweep sample is 6 or higher, insecticide treatment is warranted. If the average is lower, the grower should re-sample in a few days to check for populations above threshold. For potato leafhopper-resistant varieties of alfalfa, the economic threshold established from research is three leafhoppers per inch of growth (30 leafhoppers for 10” tall alfalfa, for example). With the current high prices of hay, you might want to be conservative in your decision to spray and treat if close to the actually threshold. Pictures of potato leafhopper adults and nymphs can be found on the WEB at: http://ohioline.osu.edu/icm-fact/images/112.html, http://ohioline.osu.edu/icm-fact/images/113.html. This site lists those insecticides labeled for PLH on alfalfa: http://entomology.osu.edu/ag/545/aiplh.pdf. While monitoring the alfalfa after cutting, it would also be worthwhile to keep an eye out for alfalfa weevil that might be limiting alfalfa regrowth. There is the possibility that alfalfa weevils are staying around longer because of the cooler temperatures we have been experiencing. Although weevil injury to regrowth is rare, it does require mentioning at this time.

Armyworm and Cover Crops

Authors: Ron Hammond, Andy Michel, Bruce Eisley

We received a couple of calls concerning armyworm on crops planted into rye cover crops. Although this is the common scenario we often see, (armyworm outbreaks on corn) these calls illustrate other factors that need to be taken into account. The first was in a field where a pyrethroid insecticide had been sprayed in early to mid April along with the herbicide used to kill the rye. The insecticide was applied as a preventive spray for possible armyworm larvae. However, in this field, larvae are now present, multiplying and getting bigger. The early, preventive insecticide did not last long enough to protect the corn from armyworm. Thus, growers who used a preventive treatment earlier in the spring might want to scout their fields to make sure that armyworm larvae are not becoming a problem. The second situation was from a field where soybean was planted into the rye cover. Although soybean is not a suitable host plant for armyworm, larvae will nibble along the edges of soybean leaves given the appearance of feeding. However, past experiences says that this feeding will not increase, and that the armyworm larvae will move out of the field because no suitable host plants will be present. The point is that soybean should not be sprayed because of armyworm. If soybean fields are found to have significant feeding, please inform us because this would probably be the first instance of a real armyworm problem in soybeans.

Regional Crop Report Availability Update.

Authors: Harold Watters

With the variable conditions this spring, sometimes it helps to have a more localized report of conditions and pest pressure in your county or region.
Many of the county Extension professionals and Agronomic Crops Team members include their local crop, insect, disease and weather scouting information on their county or regional websites. This information can be used to fill in the gaps that can occur when a state specialist makes a report and recommendations to cover the entire state. Additional new regional blogs have been added during the month of May to help with crop problems and pest issues during the growing season.

Blogs and websites with local Ohio crop progress, pest updates and weather information:
• West Central Ohio – covering the counties of Darke, Auglaize, Miami. Mercer, Champaign, Clark, Logan and Shelby: http://westohcropweather.blogspot.com
• Northwest Ohio – from Fulton, Williams, Defiance and Paulding Counties: http://nwohcropweather.blogspot.com/
• Van Wert County: http://agvanwert.wordpress.com/
• Northeast Ohio, covering Geauga, Ashtabula and Trumbull Counties: http://neohiocropweather.blogspot.com/
• Coshocton County and east central Ohio: http://eastohiocrop.blogspot.com/
• South central Ohio – Fayette, Pickaway and Ross Counties: http://southcentralohioagnewsblog.blogspot.com/

Weather Update

Authors: Jim Noel

May summary: It was a cool and damp month in most locations. Temperatures averaged several degrees below normal reducing evapotranspiration rates (which was a significant reduction). Rainfall was close to average with a tendency toward above normal rainfall in the south and normal in the north. There were pockets of below average rainfall in central Ohio and far northwest Ohio and far northeast Ohio. Toledo and Columbus and Pittsburgh stations were below average, Dayton and Cleveland were near average and Cincinnati was above average. The cool weather which is very “La Nina” like made it seem much wetter of a month with little evapotranspiration.

June outlook: A change toward above normal temperatures is expected for June. Rainfall will be near average but that will come with high variability. It appears above normal rainfall is on tap in northern Ohio while a little below normal may occur in the south and average in between. This week will see the best chances for rain especially north of I-70 on Tuesday & Wednesday. Temperatures will reach 85-93 degrees on Thursday and Friday. The high soil moisture content will keep temperatures from getting too high (a good thing). Next week we will see highs mostly in the 80s, with a few 90s far south. A few rain chances early and late in the week again especially in the north. The following week will see more isolated storms with warm weather.

Archive Issue Contributors: 

Pierce Paul, Anne Dorrance, and Dennis Mills (Plant Pathology), Ron Hammond, Andy Michel and Bruce Eisley (Entomology), Peter Thomison (Corn Production), Mark Loux (Weed Science), Florian Diekmann (Subject Matter Specialist) and Jim Noel (NOAA). Extension Agents and Associates: Roger Bender (Shelby), Howard Siegrist (Licking), Glen Arnold (Putnam), Greg LaBarge (Fulton), Harold Watters (Champaign), Mike Gastier (Huron), Mark Koenig (Sandusky), Wes Haun (Logan), Marissa Mullett (Coshocton), Les Ober (Geauga), Steve Bartels (Butler), Steve Prochaska (Crawford), Alan Sundermeier (Wood), Gary Wilson (Hancock), Todd Mangen (Mercer), Jonah Johnson (Clark), Woody Joslin (Shelby), Suzanne Mills-Wasniak (Montgomery) and Tim Fine (Miami).

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.