Category Archives: Corn

2016 Silage Trial Variety

CornSilageHarvest 012

It’s always long, hot day when many of us agents come together to help plant and harvest the Brooks County Silage Variety trials. I went to help them harvest a few weeks ago. County Agents Ben Shirley and Stephanie Hollifield did a great job coordinating the harvest. Ben and intern, Meghan were in the field cutting silage. Stephanie was in the weigh house taking tonnage. Lowndes County Agent Mihasha Dowdy and I were in ‘the pit’ collecting silage samples which are sent to receive milk producing capabilities. Below is the data shared by Brooks County Agent Ben Shirley on their Brooks County Ag Connection blog I wanted to pass along.

I want to share results obtained from the Brooks County 2016 Corn Silage Variety trial.  We planted this trial on April 25th and harvested 14 weeks later on July 27th.  This year’s trial included 69 replications, 23 varieties replicated three times each. There were no significant differences in yield among planted varieties. The varieties are ranked according to two different parameters, lbs. of milk/acre and green tons @35% moisture/acre. We conduct this trial annually, in order to assist our Dairymen and growers with variety selection and planting decisions pertaining to silage production.  We would like to thank our cooperators, sponsors, and seed companies for their support and assistance.  All data collected is available at (the Brooks County) office, please call or e-mail us if you would like additional copies or if you have any questions. Also, I have provided a link to view the data in its entirety.

2016-silage-results

Note* Keep in mind no significant differences were found between the varieties; ranking of varieties is from highest to lowest only.

Note* DKC67-88 only replicated 2 times, all others replicated 3 times.

Our view from the pit.

Our view from the pit.

Lowndes County Agent Mihasha Dowdy collects a silage sample

Lowndes County Agent Mihasha Dowdy collects a silage sample

2016SilageTrialHarvest 001

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Corn Denting

Corn-Denting (3)

R5 Growth Stage - Denting

R5 Growth Stage – Denting

Here is some corn that is now denting (R5). We are getting closer to physiological maturity. At this time, the crop is still needing water but less than before. Once the milk line progresses to the bottom of the kernel, we will see the ‘black layer’ form. We can then cut off irrigation. In the photo below, you will also notice the “milk line.” This is the separation between the softer doughy white portion close to the cob and the starchy, solid portion at the top.

When we stage kernels in R5, we look at the milk line: 1/4, 1/2, or 3/4. This is good for observing kernel development. Progression of the milk line varies due to temperature, moisture, and hybrid maturity. Here is a table from “Corn Growth & Development” that shows the expected trend:

R5-MilkLine

Milk line progression

Milk line progression

Southern rust can still hurt us until about 1/2 milk line. We have sprayed most everything for rust right now, but there are reports of rust in many fields still. This is a good time to evaluate the control we got from gungicides. We may also look for stinkbug damage on field borders. If the ears are curved, the damage from SB was early. If individual kernels are damaged, damage from SB occurred late.

 

 

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Southern Corn Rust In GA

Southern corn rust has been diagnosed thanks to Extension Agents Chase Hembree (Seminole County), Andy Shirley (Mitchell County) and consultant Rome Ethredge. Here is a photo below:

Raised postules of southern corn rust - Photo by Andy Shirley

Raised postules of southern corn rust – Photo by Andy Shirley

We’ve sprayed some of our corn in the county already as we are two weeks into tassel. Here are some comments from UGA Extension Pathologist Dr. Bob Kemerait:

  1. Southern corn rust is the most important disease affecting corn in Georgia.
  2.  Southern corn rust was found today in a very small amount in Seminole County on corn at the R2/blister stage (older than most corn in the state).
  3. The disease cab spread rapidly in storms and also with irrigation.  Conditions last week were favorable for development and spread.
  4.  I have recommended that growers hold off spraying until we find rust.  Now that we have found it, I have enough respect for the disease to say that growers in the southwestern part of the state whose corn has reached (or is about to reach) tassel growth stage an application of fungicide to protect the crop. Growers in other areas removed from extreme SW Georgia should consider to monitor the spread of the disease. Some may want to make fungicide application either as a 1) Safeguard or because 2) they are already making a trip across the field to spray something else.
  5. If northern corn leaf blight is not a problem in a field, then growers have many fungicide options, to include tebuconazole to manage rust. For longer protective windows or where NCLB is also a problem, growers should apply strobilurin or fungicides that include some combination of strobilurins, triazoles, and SDHI active ingredients.

ASIAN SOYBEAN RUST

As of today, Asian soybean rust has now been found in small amounts on KUDZU in the following counties: Miller, Baker, Grady. We can assume that soybean rust is present in low amounts throughout SW Georgia.

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Row Crop Disease Update – Corn & Soybeans

CornTasseling

We are starting to tassel (VT) and move into reproductive growth stage on corn (R1), when the silks emerge from the little ears and the pollen starts falling from the tassels. For Seminole Agent Rome Ethredge writes, “The greatest production of pollen from a field will occur over 4 days, with some pollen shedding for a week or more. Over 2 million pollen grains fall from each tassel.  Peak pollen shed is mid morning and then towards late afternoon more falls, but if it’s raining or a heavy dew the plant won’t shed pollen until it dries. Also, some research shows that when the temperature goes above 86 degrees there isn’t much shed. If it’s cloudy and slightly cool, pollen may fall most of the day. Extreme heat (100 degrees) can kill some of the pollen.”

CornEar-R1This is also a critical time in corn development where we don’t want stress on the plants. Stress during silking can reduce the number of kernel per ear. The number or rows will not be affected now as they were decided already. Disease is the main topic this week with corn, and here is an update from UGA Extension Pathologist Dr. Bob Kemerait on disease in CORN and SOYBEANS.

Here are a couple of notes on the current disease situation:

  1. Our scouts have found Asian soybean rust on kudzu in Miller County today (May 17th). This is the earliest we have found it since 2005, and it likely means rust will be problematic for our soybean producers this year. Current conditions favor spread of the disease within kudzu.
  2. Corn in the earliest planted fields is approaching the tassel growth stage and growers are beginning to ask questions about spraying fungicides.  Here are my thoughts:
  • Tassel stage (or just prior to tassel) is an appropriate time to consider applying a protective fungicide.  This is especially true if a) southern corn rust has been detected in the area, b) northern corn leaf BLIGHT is problematic in a field (typically with a less-resistant hybrid), c) conditions have been favorable for disease (very wet), d) the corn was planted LATE or e) the grower is aggressive in a disease management program and wants to make sure the crop is protected.
  • As of today (May 17th), we have not found SOUTHERN CORN RUST in Georgia and conditions have not been especially favorable for southern rust.
  • As of today, we have had one report of common corn rust from Mitchell County. Common rust typically forms pustules on both sides of the leaf and does NOT need a fungicide application.
Common Rust, Photo by Andy Shirley, Mitchell County

Common Rust, Photo by Andy Shirley, Mitchell County

  • As of today, I have only had a report of northern corn leaf BLIGHT from Ty Torrance in Decatur County. Northern corn leaf blight can be an important problem that requires a fungicide treatment IF it is severe (e.g., a susceptible variety and favorable weather). The NCLB in Decatur County was confined to the bottom leaves and there were only a few lesions on about one plant out of 15. The grower is right to be aware of the problem but I do not think a fungicide is needed for NCLB in that particular field.
Northern Corn Leaf Blight, Photo by Ty Torrence, Decatur County

Northern Corn Leaf Blight, Photo by Ty Torrence, Decatur County

  • Northern corn leaf SPOT has been found in Mitchell County by Andy Shirley.  Typically we do not spray for this disease, except in severe cases. The northern corn leaf spot in this field was confined to the lower leaves and did not appear to be spreading.
Northern Corn Leaf Spot - Photo by Andy Shirley, Mitchell County

Northern Corn Leaf Spot – Photo by Andy Shirley, Mitchell County

CORN:  We have not detected southern corn rust in Georgia yet. Conditions over the next few days are more favorable for disease spread, but (overall) conditions have been unfavorable. I would not argue with a grower who wants to apply a fungicide at this time (to corn) as it reaches the tasseling growth stage; HOWEVER I think the grower is better advised to DELAY a fungicide application at this point and wait at least a week or so.

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Irrigating Corn

Corn-V8-V10 002

Much of our corn is approaching the V6 to V7 growth stage. We really need rain at this time. This is an important time in development as corn is setting yields. Our water management is critical at this time. Here is a look at corn growth and development.

CornGrowthTimeling-UGA

Thanks to Mitchell County Ag Agent Andy Shirley for sharing the checkbook method from the 2016 UGA Corn Production Guide on his blog with Mitchell County Ag News. Many growers may be using moisture monitors or other technology to determine when and how much to irrigate.  If not, we need to consider using the checkbook method for scheduling irrigation. Below are tables:

EstimatedWaterUseInCorn-Table-10

WaterHoldingCapacities-Table-11

Here is an example of how to use the checkbook method:

ExampleofCheckBookMethod

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Early Planted Corn Growing

Corn-V2

Here is some of our earliest planted corn in the northeast part of the county. This corn is planted twin row at 8 inches.

Collar visible on fourth leaf

Collar visible on fourth leaf

Much of the corn is in the seedling stage with one or two leaves. But the oldest of this corn at v3. At this growth stage, the first three leaves are collared. This is how we tell our growth stage. Look for the collar on the back of the leaf sheath. All leaves are initiated at the growing point, which is still below ground. This is more important early on if temperatures were to drop. The photo on the right shows the collar.

Estimated Water Use

At this point, corn is using 0.07 – 0.09 inches of water per day. This is between 13 and 22 days after planting. Here is a table from the UGA Corn Production Guide showing the irrigation scheduling through checkbook method.

EstimatedWaterUseInCorn-Table-10

Leaf Tissue Sampling

At this stage, we may pull some leaf tissue samples to make sure we’re taking up our nutrients from pre-plant. Sidedressing is coming soon when corn is 12 to 16 inches tall. In terms of leaf tissue sampling, we consider anything less than 12 inches seedling stage. We need to sample all above ground portions of the plant:

Corn

  1. Seedling stage (less than 12″) – All the above ground portion
  2. Prior to tasselling – The first fully developed leaf below the whorl
  3. From tasselling and shooting to silking – The entire leaf at the ear node (or immediately above /below it)

*We need 15 – 20 samples at each stage.

We have not been able to get in the field this week with rain last weekend.  I’ve driven on a pasture and around woods edge making calls the last two days, and you can still hear the water under the tires. With projected rain coming, it’ll be another few days before fields dry out. We had a good sunny day yesterday, but it takes a few sunny days to dry things out. Some reports of rain 5 inches. Here is picture from yesterday.

WetField

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2016 Corn Short Course & Annual Meeting – Feb 2nd

UGAextensioncmykDate: February 2, 2016

Location: UGA Tifton Campus Conference Center

HOW TO REGISTER:

By Mail or Online. Mail your completed registration form with payment to Conference Office, UGA Tifton Campus Conference Center, 2360 Rainwater Road, Tifton, GA 31793-5766. Make checks payable to UGA TCCC/Corn.

You may also register on-line at www.ugatiftonconference.org – click on registration for the Corn Short Course.

REGISTRATION FEE:

The registration fee includes instruction, refreshment breaks and registration. The fee is $5. Registration at the door will be $10.

SUBSTITUTIONS AND CANCELLATIONS:

You can have someone substitute for you at any time – just call and let us know. If you must cancel, please notify the Tifton Campus Conference Center Office by January 22th at 229/386-3416.

WE WANT TO HELP:

Special arrangements for people with disabilities will be made if requested in advance. For these arrangements or more information, call the Conference Office at 229/386-3416.

FOR ADDITIONAL INFORMATION:

Contact your county Extension Office or the Conference Office

at 229/386-3416.

 

Schedule

V8-TasselCorn-StinkBugs 0198:10 a.m.     Registration-Coffee, Juice, Pastries, Fruit

8:30 a.m.     Welcome and Introduction of Program

Dr. Laura Perry Johnson, Associate Dean,Cooperative Extension, UGA, Athens

Program Moderator: Dr. Dewey Lee, Professor, retired – Grain Crops

State Exec., Georgia Corn Growers-UGA, Tifton Campus

8:45 a.m.     Managing Nematodes and Foliar Diseases in Corn.

                                Dr. Bob Kemerait, Plant Pathologist, UGA, Tifton Campus

9:10 a.m.     Stress Effects on Growth Rate, Yield and Yield Components of Corn

                                Dr. Mark Westgate, Professor, Iowa State University, Corn and Soybean Physiologist

10:00 a.m.   Refreshment Break: Please Visit w/Exhibitors

10:20 a.m.   Current Weed Control Topics in Corn

                                Dr. Eric Prostko, Weed Scientist, UGA, Tifton Campus

10:45 a.m.   Irrigation Strategies for Profitable Return in Corn

                                Dr. Wes Porter, Ag Engineer and Irrigation Specialist, UGA, Tifton Campus

11:30 a.m.   Sources and Timing of Sulfur and  Magnesium in Corn

                                Dr. Glen Harris, Soil Scientist, UGA, Tifton Campus

11:50 p.m.   Lunch- Visit with Exhibitors – Provided by the Agricultural Commodity Commission for Corn

1:00 p.m. Georgia Corn Growers Associations                         Business Meeting

Mr. Rodney Harrell, President

Agricultural Commodity Commission for                       Corn Update

                                Mr. Robby Brett, Corn Commission

Recognition of Georgia High Yield Producers

                      Dr. Dewey Lee, UGA Tifton Campus

1:30 p.m.   Market Strategies to Improve Profit Opportunities

Dr. Nathan Smith, Ag Economist, Clemson University, Columbia S.Car.

2:00 p.m.    Update on Current Topics in Corn Insect Management

Dr. David Buntin, Entomologist, UGA, Griffin Campus

2:30 p.m.    Stored Grain Protectant Efficacy in Corn and Returns on Investment

Dr. Michael Toews, Entomologist,UGA, Tifton Campus

3:00 p.m.    Industry Door Prizes

                         Adjourn – Have a Safe Trip Home

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Corn Progressing Through Milk Stage

Milk Stage (R3)

Milk Stage (R3)

Here is dryland corn in Pavo that does look good. We’ve had more rain on the east side of the county. This corn is in the early milk stage (R3) of growth. Plants defined as R3 have kernels with a “milky” interior and explode easily when a kernel is mashed.

We were looking for southern rust.  Southern rust overwinters on corn in Mexico, Caribbean and Central America. Rust has not been found much since the location in Mitchell County two weeks ago. This could be because of not having tropical storms yet, and corn that is being protected with fungicide. This is helping us stay ahead of rust in 2015 unlike last year. Still, we need to be alert after the find of southern rust. We do have increase chance of rain next week and warm temperatures which is more conducive for disease.

What Stage of Growth is Corn Safe?

Much of the corn crop though, is silking to early ear development (R2/R3) which adds roughly 2 to 3 weeks of time to our potential spraying. UGA Extension Pathologist Dr. Bob Kemerait and Agronomist Dr. Dewey Lee say that a crop is likely to benefit from protection from southern rust until the ears reach the hard dough (R4) growth stage. Southern rust is less likely to adversely affect the cron crop if it occurs after the corn has reached the dough stage. Here is a blog post from Mitchell County Agent Andy Shirley of Corn Denting.

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Southern Corn Rust Identified In Area

R3-Corn

Southern corn rust has been identified in Mitchell County by Agent Andy Shirley. This is our most destructive disease in corn. Our current weather patterns do increase the risk. Any corn that is approaching or even passed tassel growth stage is worth protecting if yield potential is there. Below is an update from UGA Extension Agronomist Dr. Dewey Lee:

“Even though this southern rust infection is earlier than usual, most of our corn crop is a little head of schedule. While this might not be much comfort, it does mean we might have saved at least one spraying. Last year, it was extremely difficult to stay a head of southern rust because the infectious time was longer than normal due to favorable conditions for infection.  Some corn in the southern areas of the state is as far along as the R3/R4 stage. This makes it easier to control rust and reduce the impact since it is much closer to maturity.  Much of the corn crop though, is silking to early ear development (R2/R3) which adds roughly 2 to 3 weeks of time to our potential spraying.

If you have good yield potential (and most irrigated growers do), I would consider spraying a combination of fungicides to provide both a curative and preventative type of action. There are great choices today from lots of sources. You may not have a current infection taking place, but spores are active and an application of a combination of fungicides will be great insurance and likely prevent yield loss. As long as southern rust is active, I would consider staying on a 14 day spray schedule or shorter. This disease can certainly undermine all your efforts this year and significantly reduce corn yields.”

Southern Rust

Southern Rust

Common Rust

I have seen some common corn rust in some fields. This is NOT the bad rust that causes yield losses. This rust is a cooler season rust that most likely infected during cool nights a few weeks back. It causes damage on BOTH sides of the leaf whereas southern rust shows up primarily on the tops of leaves. This rust is darker  brick red as well in color. Southern rust is a more orangish color.

Common Rust - Photo by Rome Ethredge

Common Rust – Photo by Rome Ethredge

 

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Stink Bugs In Corn

V8-TasselCorn-StinkBugs 019

Our earliest planted corn has tasseled and silking at this time. I’m seeing stink bugs move into corn as wheat is being harvested. Stink bugs can cause the greatest amount of damage when the ear first pollinates. With piercing mouthparts, they feed through the husk and damage kernels. Their feeding injury usually deforms ears into a C or boomerang shape. The ears do not develop properly and may be more susceptible to infection by diseases. Here is a hatch out of brown stink bugs I found on a leaf this week.

1st Instar Brown Stink Bug

1st Instar – Brown Stink Bug

We usually see southern green, green, and brown stink bugs. Each of these species have similar behavior at hatching. They tend to remain clustered on the egg mass unless disturbed. They do not feed on plant tissue at first instar. Immature brown stink bugs are yellow to tan, with brown spots down the middle of the abdomen.

1st Instar - Brown Stink Bug

1st Instar – Brown Stink Bug

Adult - Brown Stink Bug

Adult – Brown Stink Bug

Threshold

UGA Extension Grain Entomologist Dr. David Buntin says, “Treat during the ear elongation / tassel state (VT) if 1 stink bug per 2 plants is present. During pollination to blister stages (R1 – R2), control is warranted if populations reach 1 bug per plant. Use pyrethroid insecticides if southern green and green stink bugs are prevalent. If brown stink bugs are present, a high rate of bifinthrein will provide about 75-90%.”

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