Corn Looking Good but Plenty of Problems (not just in corn)

Given the circumstances we all are living through, growers remain optimistic about the current planting/growing season. For the most part, corn is off to a very good start.  Yes, we have our share of problems and some we can solve.  Peanut and cotton planting have started and growers say conditions are good in most areas.  More on this a little later in this entry.

sting nematode injury
Wind damage on well managed corn

Over the last week, I’ve received emails and pictures from colleagues and growers relating successes and problems.  Some problems we can solve and some we can’t.  Some will cost yield and others are stressors that may cost you yield depending how you treat the crop from now on out to the end of the season.   So, I want to share what I’ve heard, seen and fields I’ve walked and provide potential impact thoughts.  The close up pic on your left shows a confirmed stubby root infestation in Seminole county.  Usually, where there is a root problem you will see young plants easily lodge with high winds such as that which occurs everyday now in the south. Certainly there isn’t any thing we can do now but manage the crop the best we can and hope that the plant can grow roots faster than they are damaged.  These pics were provided by Mr. Rome Ethredge, Seminole Co. and Dr. Bob Kemerait, UGA Plant Pathologist.

Speaking of wind damage, corn from emergence to about V7 will easily recover (unless it is a root problem).  It takes a little while the older it gets but I’ve seen little lasting results.  However, if wind damage occurs further along the growth curve (+V10-VT) then more lasting damage results such as green snap, or severe “goose necking”.  Here again, do the best you can with your management.  I will admit under the severest circumstances with good growth, pivots have actually turned over climbing up tangled corn.  Yes, that actually happens.  I recall several years ago, it happened twice in  one field. Given the storms that have occurred lately, I expect to see a little more of this in Georgia.  In the case of the this picture, the field has been well managed and growing rapidly.  It will recover in due time and should produce a very good crop.

     a bleaching herbicide symptom
Chlorotic leaves due to slow unfolding

The current crop looks good across the state so when a problem or symptoms of problems show up, it seems to stand out.  A couple of weeks ago, I was seeing the results of some of the very cold nights and warm days on the growth of corn.  It is not unusual to see leaves coming out of the whorl that are yellow due to “locking in the whorl” ( A bad descriptive term on my part). During cooler temps, leaves are slower to emerge out of the whorl and unfold which causes yellowing. It may also cause “goose-necking” of the plant which can be mistaken for herbicide damage.  Be careful in diagnosing environmental problems as it can lead to false conclusions.  Just recently, a consultant sent a picture where a grower sprayed a combinations of herbicides, one which included a bleaching herbicide just prior to colder, wet conditions.  A lot of times, when environmental stress occurs, the plant has greater difficulty in metabolizing the herbicide.  In these cases, symptoms will show up in some of the plants (pic on the right).  One other symptom that I am certainly seeing a lot of is the damage caused by broadcasting fertilizer over the top of corn particularly urea or potash.  In these cases, fertilizer falls into the whorl or in between emerging leaves and causes burn.  If this is a common practice for you and you have irrigation, I would certainly turn the pivot on immediately after leaving the field to melt or wash the fertilizer out of the whorl or off the plant to reduce the burn effects from the salt.  IF you don’t have irrigation or do not choose to apply a little water, then expect to see leaf damage in a week or so

.

It does cause plant stress and it is a quick way to get a lot of fertilizer out efficiently but if you are trying to be the most effective with your inputs, it can reduce the yield potential depending on the severity of the burn. The plants will grow out of the damage but remember it is additional stress that can be avoided if you have irrigation.

Lastly, I want to mention a few things about peanuts and cotton.  The following came from Dr. Bob Kemerait this week.  “The two images are of early-planted peanuts in Tift County (pics credited to Mr. Justin Hand, County Extension agent). These are classic symptoms of Aspergillus crown rot, note the rapid death, the shredded taproot, and the distinctive black, sooty sporulation. There is very little that can be done once the furrow is closed. Management to reduce this disease is 1) quality seed, 2) an effective fungicide seed treatment, 3) possible use of an in-furrow fungicide where Proline and Velum Total are surpassing azoxystrobin, and 4) timely irrigation or rain to cool hot and dry soils. Question What is my biggest concern with the stand loss from Aspergillus crown rot?? Answer: The stand loss can make severity of Tomato spotted wilt much greater. Bottom line- growers get one chance to fight both Aspergillus crown rot and Tomato spotted wilt.”

The other problem facing growers in corn, cotton and peanuts is the high levels of thrips being found.  In corn, they are very difficult to control and generally to not pose a threat particularly if we used a bt hybrid.  Most of the time corn will not suffer much but the evidence will be seen by the scarring of the leaf.  The same is not true for peanuts and particularly cotton.  Damage can be severe.

I had a quick chat with Dr. Phillip Roberts, UGA Cotton Entomologist and he addressed the issue by encouraging cotton growers to take advantage of the cotton thrip infestation predictor model: http://climate.ncsu.edu/CottonTIP

The current levels in the field being observed suggest that normal seed treatments (neonics) may not be enough right now and cutting corners by not using additional measures will hurt the bottom line.  He strongly suggest that the addition of other control methods are most likely warranted.  I encourage all cotton growers to consider this advice and if you are uncertain as to the best choice or option, contact your local county extension agent to review your options and make the most efficient and effective treatment that you can given your management time and equipment.  This is probably enough for today. Thanks for reading.

Right now, most of all…… is to stay safe and stay healthy.

2 thoughts on “Corn Looking Good but Plenty of Problems (not just in corn)

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