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Corn Newsletter : 2018-32
Wetter Than Normal Pattern into OctoberAuthor(s): Jim Noel
There is no change from last week as an overall wetter than normal pattern will persist into the October harvest season.
The one thing that has changed is that temperatures after last week's hot weather do not look as warm into October. Temperatures are now more likely to be normal or maybe a degree above normal.
It still looks like the first freeze is on track with a near normal arrival. Most places tend to be in the October 10-20 range in Ohio from northwest to south.
Looking further ahead in November, indications are for a warmer and not as wet period. Rainfall will likely be normal or possibly slightly below normal.
Rainfall over the next two weeks will average 2-5 inches. Normal is about 1.5 inches.
Evaluation of Adapt-N and FieldView Corn N Fertilizer Tools in OhioAuthor(s): Steve Culman
NutrientStar, an independent evaluator of nutrient management tools, has just released results testing the performance of two web-based tools that provide customized corn nitrogen fertilizer rates: Adapt-N and Climate FieldView. Both tools are available for farmers in Ohio to use for a fee.
NutrientStar conducted 61 trials over 3 years evaluating Adapt-N and 21 trials over 2 years evaluating FieldView in Ohio. A summary of findings is presented below.
Summary of Performance of Adapt-N and FieldView Compared to Farmer Normal Practices.
Change in Yield (bu/A)
Range of Change in Yield (bu/A)
Average return to N ($/A)
-91 - -2
-31 - 3
-42 - 33
-19 - 3
-25 - 0
Compared to ‘farmer normal practice’ using the tools produced a range of yield differences across trials and years in Ohio. Some trials yielded more grain using the tools (positive values) and some yielded less grain (negative values). When all trials within a year were averaged, both tools resulted in lower yields compared to farmer normal practices (8 – 41 bushels/acre less). Depending on the year, farmers lost on average between $6 – $131/ acre on their return to N fertilizer.
The results varied by state, with some states benefiting from the tools and other states not benefiting from the use of the tools. Unfortunately, these tools have not performed well in Ohio to date.
An alternative approach to deciding corn N fertilizer rates is to use the economic model that Ohio State University Extension endorses. This simple calculator is based on maximizing farmer profitability. It uses 3 inputs to determine at what point will additional N fertilizer not pay for itself with more yield. This free, publicly-available tool was recently updated with extensive on-farm trials in Ohio and can be found here: http://go.osu.edu/corn-n-rate
More information on Adapt-N evaluation: http://nutrientstar.org/tool-finder/adapt-n/
More information on FieldView evaluation: http://nutrientstar.org/tool-finder/climate-fieldview/
Corn Earworm Making an Unpleasant Late-Season Appearance; Watch for Molds
Although western bean cutworm numbers were low this year, we have recently seen and also received reports about high corn earworm populations in late-planted corn and field peas. Corn earworm is a pest with many hosts including corn, tomatoes and certain legumes. In Ohio, it is typically considered a pest of sweet corn rather than field corn, but this past week substantial populations have been found in certain field corn sites in the northwest and northeast in late-planted fields. It is open to debate how well corn earworm can overwinter in most parts of Ohio, and the majority of our population probably immigrates each summer from more southern states. Dr. Celeste Welty, OSU vegetable entomologist, reports unusually heavy trap catches of corn earworm from early August through early September.
Corn earworms are damaging as caterpillars laid by moths on target plants. They vary quite a bit in color – with individuals that are dark brown, brown, tan, green, or even pinkish. Typically only one caterpillar is found per ear, but more may be found in heavy infestations. They enter corn ears at the tips where the majority of feeding occurs. This also opens the corn ear up to the potential development of ear rots. Chemical control of corn earworm in corn is virtually impossible once they have entered the ear, so at this point the scouting emphasis should be on assessing mold and disease levels in infested corn.
Feeding sites or exit holes when the caterpillar matures and leaves the ear leave holes in the corn husk, which provide a potential entry wound for pathogens like Fusarium and Gibberella. Some of these organisms can then be a further source for mycotoxins, including Fumonisins and deoxynivalenol, also known as vomitoxin. In some cases, damaged kernels will likely be colonized by opportunistic molds, meaning that the mold-causing fungi are just there because they gain easy access to the grain. However, in other cases, damaged ears may be colonized by fungi such as Fusarium, Gibberella and Aspergillus that produce harmful mycotoxins. Some molds that are associated with mycotoxins are easy to detect based on the color of the damaged areas. For instance reddish or pinkish molds are often cause by Gibberella zeae, a fungus know to be associated with several toxins, including vomitoxin. On the other hand, greenish molds may be caused by Aspergillus, which is known to be associated with aflatoxins, but not all green molds are caused by Aspergillus. The same can be said for whitish mold growth, some, but not all are caused by mycotoxin-producing fungi.
So, since it is not always easy to tell which mold is associated with which fungus or which fungus produces mycotoxins, the safe thing to do is to avoid feeding moldy grain to livestock. Mycotoxins are harmful to animals – some animals are more sensitive to vomitoxin while others are more sensitive to Fumonisins, but it is quite possible for multiple toxins to be present in those damaged ears. If you have damaged ears and moldy grain, get it tested for mycotoxins before feeding to livestock, and if you absolutely have to use moldy grain, make sure it does not make up more than the recommended limit for the toxin detected and the animal being fed. These links provides more information on ear molds and mycotoxin contamination and identification:
About the C.O.R.N. Newsletter
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.
The information presented here, along with any trade names used, is supplied with the understanding that no discrimination is intended and no endorsement is made 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.
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