July 12, 2013

Good afternoon,

 

We’ve finally received some relief from the daily rains that have been going on.  This is good news for the Hardin County 4-H club members who are at Camp Ohio this week.  The constant rains though have done some damage to crops locally.  In addition, high winds have also blown over some corn in the area.  Wheat harvest continues to be delayed but if the weather stays clear, maybe there will be some farmers in the fields next week.  I have dedicated a big portion to this week’s email to the current crop problems that are going on so maybe this will help answer any questions you might have about the effect of the weather on the corn, soybean, and wheat crops. 

 

The most popular home owner problem this week has centered around the Japanese Beetles that are becoming very prevalent in the area.  I have also included information on this pest and some attached fact sheets on how to deal with this insect.  Also included in this email is information about Ridgemont School’s Environmental Education Day that I will be assisting with this coming week.  Finally, there is an article included as an attachment put together by Darke County OSU Extension Educator Sam Custer regarding the use of the Slow Moving Vehicle (SMV) sign and other items to consider when transporting farm equipment on the roadways.

 

I have added pictures this week for color to make this newsletter more appealing. I hope that you are able to view them with your email program as they are formatted.   Let me know if you have any questions.

 

Mark

 

 

Environmental Education Day at Ridgemont High School – Stephanie Jolliff

 

Ridgemont’s Second Summer Enrichment Program is Tuesday, July 16 at the High School! Please register by Friday for the Environmental Education Day. Lunch is included in the free educational event for youth grades 4-7!

The STEM Environmental Day will give youth hands-on experiences with stream sample analysis, soils core sample drilling, soil conservation practices, watershed impacts, and soil microbiology. Ridgemont Schools is collaborating with The Ohio State University, Hardin County Soil & Water District, The Ohio State University Extension – Hardin County, and Nutrients For Life Foundation for this educational event.

Registration can be completed by messaging Stephanie Jolliff on Facebook or calling or texting at 740.225.3955.

 

 

Japanese Beetle

 

There have been several calls and office visits this week regarding the Japanese Beetle and ways to control them as they invade trees, landscape plants, and gardens.  Remember that when it comes to controlling a pest, OSU recommends using integrated pest management (IPM).  IPM involves using various methods of control to receive the desired outcome if the pest is reaching the economic threshold or doing damage.  Methods of control that should be considered are cultural, mechanical, biological, and chemical.  Remember that effective control doesn’t end with the adult beetles, you also need to have a plan for the eggs that the females have laid which will become a problem later.  See the attached two files for more information on the Japanese Beetle.

Japanese Beetle

Control of Japanese Beetle Adults and Grubs in Home Lawns

 

Slow Moving Vehicle Emblem and Farm Equipment on the Roads – Sam Custer

 

 

The Slow Moving Vehicle (SMV) emblem celebrates its 50th Anniversary! This emblem, recognized for safety around the U.S., was developed in the Agricultural Engineering Department at The Ohio State University in the early 60’s. In 1963 this emblem was dedicated to the public by the OSU President Novice G. Fawcett. Testing was conducted by Ken Harkness, an OSU Ag Engineer, and his team of graduate students to determine the best shape and color for this roadway safety symbol. A 1/16 scale highway simulator was constructed to test human recognition rates of slow moving vehicles with most of the testing conducted outside of the Ives Hall Building (no longer standing on OSU campus).  See the attached file for further information.

SMV Emblem

 

 

Root Lodging and “Green Snap” in Corn (article written last year but has timely information)  – Peter Thomison

Scattered thunderstorms brought much needed relief to Ohio corn fields enduring blistering temperatures and drought conditions. However, the rains in some cases came at a cost. Strong winds associated with the storms caused localized crop injury – root lodging and “green snap”. The magnitude of the damage was influenced by other factors including crop stage of development and hybrid genetics.

Root lodging occurs when strong winds pull corn roots part way out of the soil. The problem is more pronounced when soil are saturated by heavy rains accompanying winds. If root lodging occurs before grain fill, plants usually recover at least partly by “kneeing up.” This response results in the characteristic gooseneck bend in the lower stalk with brace roots providing above ground support. If this stalk bending takes place before pollination, there may be little effect on yield. When lodging occurs later in the season, some yield decrease due to partial loss of root activity and reduced light interception may occur. If root lodging occurs shortly before or during pollen shed and pollination, it may interfere with effective fertilization thereby reducing kernel set. In a University of Wisconsin study, wind damage was simulated at various vegetative stages through silking (V10 to R1). Compared to hand harvested grain yields of control plants, grain yield decreased by 2 to 6%, 5 to 15% and 13 to 31% when the lodging occurred at early (V10-V12), mid (V13-V15) and late (V17-R1) stages, respectively.

Green snap or “brittle snap” are terms used to characterize pre-tassel stalk brakeage caused by wind . Corn plants are more prone to green snap during the rapid elongation stage of growth between V8 and tasseling, especially during the two week period prior to tasseling. Breaks in the stalk usually occur at nodes (along nodal plates) below the ear. When soil moisture and temperature conditions are favorable for growth during this stage of plant development, plants elongate rapidly but stalks are unusually brittle. Stalk brittleness is greatest in rapidly growing corn under high temperature, high soil moisture conditions. There is speculation that rapidly growing plants are more susceptible to snapping-off for several days during the few weeks before tasseling because there has been little time for plants to develop lignified tissues at the nodes.

Although we encounter green snap problems periodically in Ohio, it’s usually a more serious problem in the western Corn Belt. Vulnerability to green snap damage varies among hybrids. However, all hybrids are at risk from such wind injury when they are growing rapidly prior to tasseling. Once the crop tassels green snap problems generally disappear. Back in the 1990’s, Nebraska researchers observed that it was often the most productive fields with the highest yield potential that experienced the greatest green snap injury. They concluded that factors promoting rapid growth early in the growing season also predisposed corn to greater green snap injury.

According to Dr. Emerson Nafziger at the University of Illinois  “Yield effects of green snap depend on the number of plants snapped and where the breakage takes place. Stalks that break above the ear will usually produce an ear, but if nearby plants are intact, they will shade the broken-off plants and reduce ear size. When plants break at the node below the top ear, dormancy will break and allow the next ear down to develop, but it may not receive enough pollen to produce a lot of kernels. Plants that break near the ground won’t produce yield, of course, but will allow more light to reach intact plants, which in turn will produce more grain. Loss of plants thus typically reduces overall yield less than the percentage of broken plants might suggest.”

 

What can we expect after a week of rain? Is it Phytophthora, flooding or both?  – Anne Dorrance

Rainfall this past week around the Midwest was extensive.  We know that a week after a rain, we will start to see the above ground symptoms of Phytophthora root rot on susceptible varieties.  So, this week will be a good time to scout to see if the Rps genes in your varieties are still effective and if the field resistance/partial resistance levels are high enough.  From tours around the state last week, there was also ponding & flooding.  When soil is saturated for more than 3 days and anoxia – low oxygen, high carbon dioxide sets up, flooding injury occurs.  Some plants will die and others will be set back until new roots form.

To separate flooding injury from Phytophthora, dig up symptomatic plants.  Pull on the outer epidermis of the roots.  If it collapses between your fingers, it is Phytophthora or root rot caused by another watermold, Pythium.  If you can pull off the epidermis and the nodules on the root and find the white root stele, it is flooding injury.  

If it is Phytophthora, the final check to see if this is a highly susceptible variety is to look for the chocolate brown canker on the main stem.  Leaves will be yellow and wilted.  Go back to your seed catalogue and see what the field resistance levels were listed for that variety.  Make a note, because you will want a better score for the next time you plant soybeans in that field.  Read the fine print, every company has bit different scoring system.  Ohio State uses the score from 1 to 9 – 1 is for no root rot and 9 is dead.  Other companies use the reverse, in reality they are all close.  For scoring systems of 1 to 9 where 9 is dead, you want a score of 3 to 5; for scoring systems where 9 is best – you want 5 to 7.  The reason why I am not recommending scores of 1 to 2 or 8 to 9, is that this means the R-genes was expressed.  An effective R-gene will mask the presence of partial resistance.

Lots of flooding and ponding on our clay soils also indicate that it is time to have the field checked for drainage.  The longer the field is saturated that is also the amount of time available for the watermolds to infect plants.  The drier the field, the less time for infections to occur.    

For flooding injury, there will be yield loss, the plants will re-root and new nodules will have to form.  So the plants will look at bit yellow for a while.  But the plants will recover.  Phytophthora, those plants are gone.  If you decide to replant, take the time to pick a variety with better levels of partial resistance and use a seed treatment.

 

 

Late-season Rainfall, Late Harvest and Wheat Grain Quality –  Laura Lindsey, Pierce Paul, Ed Lentz

 

The month of June was fairly cool which resulted in an extended grain fill period. Combined with low disease levels and low grain contamination with vomitoxin, wheat quality is expected to be good this season. However, growers are now finding it hard to get their crop harvested. It has rained consistently across most of the state over the last two weeks and growers are understandably concerned about grain quality. Indeed, rain and late harvest can certainly reduce test weights, increase fungal colonization of the heads, and cause pre-harvest sprouting.      

What is test weight? Test weight is used to take into account varying densities (weight per given volume) of grain. It is an indicator of grain quality. Generally the higher the test weight the higher yields will be for flour and starch. The standard commodity weight for soft red winter wheat is 60 pounds per bushel at 13.5% moisture. If test weight is below the acceptable range (low test weight), the wheat sale could be “docked.” Depending upon the elevator, dockage for test weight generally does not occur unless the value is below 58 lb/bu. Some elevators will give a premium for test weights 60 and above. 

What causes low test weight? Grain density can vary based on weather, production practices, variety, and pests. Low test weights occur if grain is prevented from filling completely and/or maturing and drying naturally in the field. Rewetting of grain in the field prior to harvest can also reduce test weight.  When grain is rewetted, the germination process may initiate causing photosynthates (i.e., starch) to be digested. This leaves small voids inside the grain which decreases test weight. Additionally, grain will swell each time it is rewetted and may not return to its original size as it dries which will reduce test weight. Thus the enlarged kernels will take more space but weigh the same allowing fewer kernels to pack in the measuring container, lowering the test weight. If possible, for maximum test weight, it is best to harvest wheat on the first dry-down.  

Should I be concerned about sprouting? Rain and harvest delay may lead to pre-harvest sprouting in some varieties in some areas. Sprouting is characterized by the swelling of kernels, splitting of seed coats, and germination of seeds (emergence of roots and shoots) within the wheat heads. Some varieties are more tolerant to sprouting than other, and for a given variety, sprouting may vary from one field to another depending on the duration of warm, wet conditions. Sprouting affects grain quality (test weight). Once moisture is taken up by mature grain, stored reserves (sugars especially) are converted and used up for germination, which leads to reduced test weights. Even before visual signs of sprouting are evident, sugars are converted and grain quality is reduced. Since varieties differ in their ability to take up water, their drying rate, the rate at which sugars are used up, and embryo dormancy (resistance to germination), grain quality reduction will vary from one variety to another.

Why are heads turning black? In addition to sprouting, the growth of mold is another problem that may result from rain-related harvest delay. To fungi, mature wheat heads are nothing more than dead plant tissue ready to be colonized. Under warm, wet conditions, saprophytic fungi (and even fungi known to cause diseases such as wheat scab) readily colonize wheat heads, resulting in a dark moldy cast being formed over the heads and straw. This problem is particularly severe on lodged wheat. In general, the growth of blackish saprophytic molds on the surface of the grain usually does not affect the grain. However, the growth of pathogens, usually whitish or pinkish mold, could result in low test weights and poor grain quality. In particular, on scab-affected heads, molds may produce toxins such as deoxynivalenol (DON), leading to further grain quality reduction and dockage. While DON contamination is generally higher in fields with high levels of wheat scab, it is not uncommon to find DON (above 2 ppm) in late-harvested fields that have been exposed to excessive moisture. Even in the absence of visual scab symptoms, the fungi that produce DON may still colonize grain and produce toxin.

 

 

Impact Of Ponding and Saturated Soils On Corn  – Peter Thomison

Persistent rains during the past two weeks have resulted in ponding and saturated soils in many Ohio corn fields and led to questions concerning what impact these conditions will have on corn performance. 

The extent to which ponding injures corn is determined by several factors including: (1) plant stage of development when ponding occurs, (2) duration of ponding and (3) air/soil temperatures. Corn is affected most by flooding at the early stages of growth. Once corn has reached the late vegetative stages, saturated soil conditions will usually not cause significant damage. Since most corn in Ohio is approaching the silking stage, this bodes well. Although standing water is evident in fields with compacted areas, ponding has usually been of limited duration, i.e. the water has drained off quickly within a few hours, so the injury resulting from the saturated soil conditions should be minimal. Moreover temperatures have been moderate.

However, under certain conditions saturated soils can result in yield losses. Although plants may not be killed outright by the oxygen deficiency and the carbon dioxide toxicity that result from saturated soils, root uptake of nutrients may be seriously reduced. Root growth and plant respiration slow down while root permeability to water and nutrient uptake decreases. Impaired nutrient uptake may result in deficiencies of nitrogen and other nutrients during the grain filling stage. Moreover, saturated soil conditions can also result in losses of nitrogen through denitrification and leaching.

Past research at Iowa State University evaluated flood damage to corn that was inundated for variable periods of time at different stages of growth (including silking). Two different N levels (“high” N   350 lb N/ac vs. “low” N 50 lb N/ac) were also considered to determine how N affected corn response to flood injury. Low N plots yields were reduced by 16% at silking when plots were flooded for 96 and 72 hours. In the high N plots, flooding at silking had little or no effect on yields.

According to Dr. Emerson Nafziger at the University of Illinois  (http://bulletin.ipm.illinois.edu/?p=1240) “…At the time the crop reaches stage V13 (about head-high), it still has to take up 110 to 120 lb of N, and in years when June is wet, a common question is whether or not the crop might run out of nitrogen, leaving the crop short. While the need for 20 or more lb of N per week would seem to raise the possibility of a shortage, the production of plant-available N from soil organic matter through the process of mineralization is also at its maximum rate in mid-season. For a crop with a good root system growing in a soil with 3 percent organic matter, mineralization at mid-season likely provides at least half the N needed by the crop on a daily basis. This means that normal amounts of fertilizer N, even if there has been some loss, should be adequate to supply the crop.”

 

References

Nafziger, E. 2013. Corn roots, wet soils, and nitrogen. The Bulletin. University of Illinois, Urbana-Champaign. http://bulletin.ipm.illinois.edu/?p=1240

Ritter, W.R. and Beer, C.E. 1969. Yield reduction by controlled flooding of corn. Trans. ASAE 12:46-47.

 

The Ohio State University

Mark A. Badertscher

Agriculture and Natural Resources Educator

OSU Extension Hardin County

1021 W. Lima Street, Suite 103, Kenton, OH 43326

419-674-2297 Office

hardin.osu.edu

 

 

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