Farmers and Agribusiness,
Busy week, some got rains and some didn’t, we’re praying for more. Field corn looks very good and is moving along towards maturity.
2011 Drought and Cotton Planting/Replanting Decisions
Don Shurley, UGA Extension Agricultural and Applied Economics, has some good info at our Cotton web page link below. Look under Breaking News.
Peanuts with leaf burn and some leaves falling off due to phorate or thimet systemic insecticide burn. This looks bad for a little while but will soon be gone and is an indication of the insectcide moving through the plant to do its job killing thrips.
We use a lot of good herbicides at planting but we often get an early flush of Coffeeweed (Sicklepod). Many times at this point in the season it will be the only weed present. Now’s the time to scout fields for weeds to get them while they’re young.
Cotton Herbicide Issues Seem Overwhelming This Season
Dr Stanley Culpepper, UGA Extension Crop Scientist,
This year has simply been a nightmare when it comes to herbicides and cotton injury, if you are lucky enough to have cotton up. Therefore, lets attempt to address some of the more common and challenging questions.
1. Why am I getting so much herbicide injury in a drought?
In most situations, the level of injury from at-plant herbicides is directly related to the time in which rainfall (irrigation) occurs and the specific herbicides used. In cotton, herbicide injury from at-plant products often takes two forms.
The first type of injury is observed when the herbicide is moved into the soil profile (rain/irrigation) where the herbicide is surrounding the germinating seed. As the seedling is emerging, herbicide uptake by roots and shoots are occurring. This type of injury most often results in stand loss, stunted (slower emerging) plants, and or plants that exhibit chlorosis. Obviously, stand loss can influence cotton yield but in most cases where cotton plants are slightly stunted, yield loss is not observed. However, slower growing cotton increases the likelihood that growers will delay postemergence herbicide applications. Delayed postemergence applications will likely reduce pigweed control and increase management costs.
The second type of injury is observed when the herbicide is sitting on the soil surface and rainfall or irrigation occurs at or near emergence (usually 1 day before emergence through 5 days after emergence). In this situation, the herbicide injury is a result of foliar uptake as the herbicide often splashes onto the emerging plant or is taken up as the cotyledons (crook) push through the soil surface. Injury (necrosis, malformed leaves etc…) of this sort can vary widely depending on the herbicides applied.
The level of injury noted this season is likely a response to the increased number of irrigations being required to get a stand of cotton. Multiple irrigations are essentially making herbicides much more available, thus more active. There is no good solution as growers must provide water for the cotton but understanding the relationship of irrigation and herbicides can be beneficial.
2. Herbicide injury is killing us, we have to stop with these at-plant herbicides.
There is essentially no way to produce Roundup Ready cotton in our state without at-plant herbicides. In fact, for a Roundup Ready system, growers will need either a Reflex mixture or a mixture of Prowl + Staple + Diuron (or Cotoran) behind the press wheel. Ignite-based programs do allow much more flexibility in selecting at-plant herbicides but we strongly encourage growers apply at least one residual herbicide at planting.
3. In Roundup Ready cotton, I have half a stand up and I am waiting on the rest of my cotton to emerge but weeds are up?
For a Roundup Ready producer, three valid topical options exists including 1) Roundup + Dual Magnum (or other Dual products), Roundup + Warrant, or Roundup + Staple. In this situation, Dual is out of the question as it could severely injure the cotton that has not emerged. Our 2011 research with Warrant is very intriguing, but for now we would still encourage growers to avoid this application to cotton seeds that have not emerged.
Thus, the best option would be Roundup + Staple as Staple can be applied both preemergence or postemergence safely to our cotton crop.
4. I have not decided if I am going to replant or keep the stand I have. While I am deciding, weeds are emerging and I need to spray…..what should I spray.
Again our topical applications in Roundup Ready cotton include Roundup + Staple, Roundup + Dual, or Roundup + Warrant. If we don’t replant, all of these options are valid. But, if we do re-plant, then this herbicide application would be made prior to re-planting, essentially being a burndown treatment. None of the residual herbicides (Dual, Warrant, Staple) are labeled for a burndown and therefore are not recommended; however, research suggests the greatest potential for injury to re-planted cotton would be Dual, with Staple being the least concerning.
In an Ignite-based program, simply apply Ignite and then decide if you are going to replant or keep the stand that is present. Apply residual herbicides in the system once the final decision is made.
Grasshopper damage in cotton seen this week. I’ve never seen grasshoppers take out a stand of cotton . It’s rare but I saw it this week in a small dryland field. Many areas of the field just had stems left.
Learn about all kinds of insects to look out for at these scout schools.
Cotton Scout Schools: Tifton June 13, and Midville June 21, 2011
Cotton insect scouting schools are annually held at various locations in Georgia. These programs offer general information on cotton insects and scouting procedures and will serve as a review for experienced scouts and producers and as an introduction to cotton insect monitoring for new scouts. The annual Cotton Scout School in Tifton will be held on June 13, 2011 at the UGA Tifton Campus Conference Center. The Midville Cotton Scout School will be will be held on June 21, 2011 at the Southeast Georgia Research and Education Center. The training programs at each location will begin at 9:00 a.m. and conclude at 12:30 p.m. No pre-registration is required.
Stinkbugs haven’t been very bad so far this year but this week we’re starting to see more of them like this one and I’ve seen some egg laying in the edges of corn fields. Mostly brown and rice stink bugs have been found. Also a few more fields have a little NCLB showing up but disease is overall low.
Question Of The Week
Last week I had a photo for you of some sick looking corn. It was getting too much of a good thing. It was in a spot near the irrigation well where extra water ran to and it stayed too wet . Roots need oxygen and won’t do well if it’s too wet also we probably leached away somer nutrients from that area.
This week’s question also has to do with corn and I want to know what’s wrong with these corn plants?