Agronomy Zone 15

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• Aaron Ahrenholz (11)
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• Jacob Evans (11)
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• Rich Howe (3)
• Bill Kessinger (6)
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• Tony Lenz (14)
• Mike McKibben (8)
• Keith Niemeier (11)
• Tony Plenggenkuhle (7)
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• Jim Rowley (8)
• Kevin Ryan (11)
• Thom Schreeg (10)
• Brenton Schwab (9)
• Louis Sutton (12)

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Across Central Indiana and Ohio we have a wide range in corn maturity from tasseling to knee-high to bare soil.  The corn that did not get damaged by the heavy rains in May and June is tasseling and looks tremendous.  With the rapid growth experienced in June and wet field conditions, some growers struggled to get nitrogen applied and had to revert to using drops.  Farm programs with high amounts of N as starter and preplant N are suffering from denitrification, with many corn fields already showing signs of nitrogen deficiency.  Above-normal levels of Grey Leaf Spot and rust have the planes out spraying in full force.  As a whole, the corn looks good but most fields still show signs from water damage.

Soybeans are in the same condition as corn.  Some of the soybeans planted in April look excellent, but many fields were replanted or planted for the first time over the July 4th weekend.  We have experienced ideal conditions for seedling diseases this spring, with Phytophthora still causing plant death, especially in Southern and Central Ohio.  Due to the wet conditions, rapid growth, and increasing herbicide resistance, weed control has been another tough issue growers are trying to overcome.  The soybeans planted a couple weeks ago are beginning to take off.  With some luck--and rain--in July and August, a decent soybean yield is still possible.

As I have made my way around central Indiana the past couple of weeks, I have been noticing Sudden Death Syndrome beginning to show up.

Sudden Death Syndrome (SDS) is caused by Fusarium solani f. sp. glycines.  Foliar symptoms occur at mid-to-late season due to advancing decay that was initiated much earlier in the growing season.  Noticeable symptoms appear suddenly around flowering but become most pronounced from full pod to seed development.  Symptoms begin as small yellow spots on upper leaves expanding to interveinal chlorosis, followed by complete necrosis.

Brown Stem Rot (BSR) also will show these symptoms, but there are subtle differences.  Split the stem at the base.  The pith of a plant infected by SDS will maintain healthy white, while the pith of BSR will be browning.  Late in the season a blue color may also be visible on the surface of the root when soil is moist on a plant infected by SDS.

The fungus will over winter in crop residue or freely within the soil.  Soybeans can be infected as early as one week after crop emergence.  Around R4-R6 when the soil is wet the fungus produces toxins in the roots that are translocated in the leaves. The fungus actually never leaves the roots.  Soybean seeds become small, abort, or entire pod could fall off. 

There are no soybeans resistant to SDS but only levels of resistance.  Problems are most common on early planted soybean fields and wet areas within a field.  The problem intensifies with abundant moisture during flowering and pod development.  Fungicides will not control Sudden Death Syndrome.

Frogeye leaf spot is beginning to show up again.  Cercospora sojina is the fungus that causes Frogeye leaf spot, and can be absolutely devastating to a soybean crop.  If you live south of US 70 in Ohio or Indiana and you want to have some soybeans to harvest this fall, you need get out and start scouting now. 

Symptoms

Frogeye leaf spot can attack a plant at any growing stage, so check all your fields.  The fungus will start out as small yellow spots on the upper leaves.  Then those spots will enlarge to roughly ¼ inch with a gray/brown center and purple/red margins.  Stem and pod lesions can also occur, but the leaf spots are a better diagnostic indicator.  As long as weather is favorable, spots will continue to multiply covering green leaf area greatly reducing yield potential.

Infection

The fifteen day forecast is calling for worm humid weather with a couple thunder storm possible, ideal climate for the spread of frogeye leaf spot.  Cercospora sojina over winters in plat debris and infected seeds from last years infected crop.  Wind will readily transport the spores from the infected host plant at any time, but infection requires warm and humid weather.  Young leaves are more susceptible than older more mature leaves.  With the late planting this year, plants are younger and doing more vegetative growing than normal this time of year, increasing their susceptibility.

Management

Management for soybeans already infected by frogeye leaf spot is simply a fungicide application.  Many fungicides on the market do a fairly good job of controlling frogeye leaf spot.  Do not wait to see if the problem gets worse.  The fungicides will help prevent the spread of new or already infected areas, but will not cure or repair the infected area.

Several different genes for frogeye resistance have been discovered.  If you live in southern Indiana or Ohio, make sure to talk with your Stine representative to ensure you are planting a resistant variety on your farm.

Hopefully none of you out there have this problem, but I have seen several infected plants over the past week.  While your out their, feel free to flip a leaf over and check for aphids and pull a plant or two out of the ground and look for cysts.  Better yet give your local Stine Agronomist a call and we would be glad to go with you.  It is more enjoyable and profitable for the both of us to talk about what we can do verse what we could have done.

Soybean farmers, if you have been waiting for a new in-crop soybean weed control option, with no yield lag or drag, your day is here!  Stine Seed Company, in conjunction with Bayer CropScience, is pleased to now be offering new LibertyLink soybeans, which offer high yields and tolerance to Ignite herbicide. 

Ignite is a newly formulated version of Liberty (glufosinate).  Next to glyphosate (Roundup), Glufosinate is the only other non-selective herbicide available in soybeans.  With no known weed resistance to glufosinate, Ignite has post emerge control of more than 120 broadleaf weeds and grasses, including velvetleaf, marestail, foxtail, morningglories, waterhemp, ragweeds, and even ALS- and glyphosate-resistant weeds.  According to the International Survey of Herbicide Resistant Weeds, glyphosate-resistant weeds have been confirmed in 19 states.  LibertyLink soybeans will give farmers an option to control even the most difficult and resistant weeds, while helping to incorporate a different mode of action, which will help prevent weed resistance. 

Because glufosinate has a different mode of action than glyphosate,  some farmers are going to have to tweak there application strategy slightly to make the most of this new technology.  Glufosinate is a membrane disruptor, meaning it inhibits the activity of the glutamine synthesis enzyme.  Put simply, application of glufosinate causes ammonia build up in the cell, which in turn destroys the cell membrane. 

Glufosinate is a contact herbicide, which means that it kills only what it touches.  This is different than glyphosate, which translocates throughout the plant.  What this means for growers is glufosinate's contact action results in a quick kill--in just a couple of days--versus a week or more with glyphosate. 

Of course, with a contact herbicide the name of the game is coverage.  Therefore, it is recommended that growers use between 15 to 20 gallons of water per acre.  Growers will also want to use sprayer tips that create medium-sized spray droplets.  Flat fan tips work great to get the coverage you need.  Drift has not been problem, just don’t spray in winds that will blow the hat off your head and you will be fine. 

Another very important factor in many herbicide systems is proper timing of application, and glufosinate is no different.  The number to remember is 22--  22 oz of Ignite roughly 22 days after planting, and another 22 oz in another 22 days if a rescue treatment is needed.  This is done to get a complete kill before the weeds get too large to control.  In some cases, growers spraying glyphosate have simply upped the rate to account for some larger weeds in a late spray situation.  Remember, though, that Ignite is a reformulated, more concentrated version of Liberty, and increasing rates is not usually recommended.  Consult your local Bayer representative before increasing rates.  In our seed production fields last summer, growers had no problem getting a complete kill with no burn using a recommended rate. 

LibertyLink soybeans are fully approved for food, feed and cultivation in the United States and Canada. Additionally, import approvals have been obtained in key soybean export markets including the Eropean Union, Mexico, Japan, China and Australia.  This makes LibertyLink soybeans an excellent addition to a farmer's tool box of options.  It will help control resistant weeds, help prevent resistance, help control volunteer VT3 and conventional corn, and keep your soybean fields clean. 

Good luck this spring, and remember that, when it comes to soybeans, you are no longer tied down to a specific herbicide program, you now have options.  And having options is always a good thing.