Monthly Archives: December 2015

December 18, 2015 · 9:21 PM

Herbicide Timing In Small Grain

Wild Radish

Though little to no wheat is planted this season, we are still looking at other small grains and forages for winter weeds. Yesterday, we were looking at wild radish in oats that need to be treated. Sometimes we have injury reported after using broadleaf herbicides in small grain, particularly oats. There are many things that influence herbicide injury, but the timing of our broadleaf products, such as 2,4-D and MCPA is critical in small grains.

UGA Extension Weed Scientist Dr. Stanley Culpepper says we do not need to use 2,4-D and MCPA until we have full tiller and before jointing.

Growth Stage

What is full tiller? Following emergence and the spike stage, small grain crops begin to tiller. These are essentially stems that will produce a grain head in the future. When we have 4, 5, or 6 tillers on a plant, it is considered full tiller. Depending on growing degree days, it will generally take between 20 and 35 days to reach full tiller.

We looked at two oat fields yesterday – one planted in October and one in November. The later planted field had just 3 tillers per plant (above) where the older field had 5 tillers. The difference here and in other small grain is that these oats are planted for grazing only. Therefore, we have less concern over injury. It will be fine to go ahead and treat both fields.

With the same herbicides, we don’t want to treat once crop enters the jointing stage. Just before jointing, the stems will elongate. At the base of the stem, you will feel a swelling of the stem (almost like a bee bee inside the stem) which is the first node or joint. The joint is the growing point. The plants have now moved into the reproductive growth stages. Here is a shot of growth development from the 2015-2016 UGA Wheat Production Guide.

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Filed under Forages, Grain, Weed Science

December 17, 2015 · 8:18 PM

Winterizing Irrigation Systems

From Gary Hawkins, Ph.D. Water Resource Management Specialist Crop and Soil Science Department, UGA.

‘Twas the night before harvest, when all through the fields not a creature was stirring, not even a mouse.  The harvesters were greased by the farmer with care,  in hopes that good harvest soon would be there.

But before you “spring from your bed to see what’s the matter or settle in for a long winters nap”, take some time to think about your irrigation system and get it ready for a long winter’s nap as well.

Now that the harvest is over, have “irrigation geysers” been dancing in your head? Where were they? Which ones needed to be repaired and which nozzles were worn? At this time of the year, I realize you are tired, want to go to the house for a nap and dream of next years planting, but prepare your irrigation system now so it will also be ready for the spring. Water is a commodity that is needed by the plants to produce the crop you dream of and getting the water to the fields is the purpose of the irrigation system.

So before you whistle and shout them by name: “Now Case! Now Valley!  Now, John and Deere!  On, Reinke! On, Rainbird!  On, Cotton and Peanut!  To the top of the Field!  To the top of the shed!  Now Winter -ize! Winter -ize! Winter -ize! all!”

-Get everything winterized prior to settling in so next year will be a good year on many different fronts. In the Regional Water Plans (can be found at http://www.georgiawaterplanning.org) there are many activities suggested by the Water Councils to help conserve water in the specific water regions and in the State of Georgia.

In the Southern portion of Georgia some of these are:

Continue to improve agricultural water use efficiency through innovation.
Implement water conservation practices.
Improve implementation of nonpoint source controls.
Conduct irrigation audits By winterizing your irrigation system you can improve your irrigation system efficiency, increase uniformity and better utilize water resources.

Through the process of conducting an irrigation audit this time of the year when it is easy to get into the field, around the pivots and under them for repairs you are also performing the check of your irrigation systems efficiency required by the Flint River Drought Protection Act (http://www.legis.ga.gov/legislation/en-US/display/20132014/SB/213).

After efficiency and uniformity tests are “nestled all snug in their beds,” winterize your system. Briefly, that is the process of removing water from the spots prone to freeze in the winter, cleaning the engines, and preparing the system for a new beginning in the spring. A complete checklist for both center pivot and drip systems can be found in the “Winterizing your Irrigation System” publication (http://extension.uga.edu/publications/detail.cfm?number=B1439).

So, before you exclaim “Happy Harvest, to all and to all a good winter”, get your irrigation systems ready for the winter so when you start the Deere or Case or IH for planting in the spring, the irrigation system will also be ready to provide the water needed for a good harvest next year while efficiently and uniformly applying the water resources needed for growth.

Remember to check in with the weekly Water Blog where we will put articles and links to water related issues across Georgia and the world. Blog.extension.uga.edu/water I hope you have a Merry Christmas and a very Happy Holiday Season!

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December 16, 2015 · 9:26 PM

Fall Broccoli Close To Harvest

We have a few vegetables planted in the county this fall. Here is Brandon Barnes with some bare ground broccoli that was transplanted back in October. This variety is Emerald Crown which is a mid-season variety in Georgia and North Carolina. The heads are coming on now, and some will probably be ready to pick in a week to ten days. The overall plants and color look good across the field. He has a pivot in this field, and we want to make sure we’re putting on an inch more or less of water each week.

Caterpillars are a common insect pest of cole crops. We have been checking for diamond back moths which is part of the cabbageworm complex. Populations are low in the field right now which is good since management is a challenge with resistance. When scouting, we note the ‘window pane’ effect that is common from diamondback moth feeding.

Some disease is showing up but not causing real problems. Alternaria is usually observed with concentric ring on a leaf. Another pathogen we may check for is black rot, which is a bacteria in the Xanthamonus genera. Below is a photo of black rot in red cabbage. With black rot you generally see yellowing at the leaf margin, and you will see ‘black veins’ running through the yellow/necrotic area through the light. Lesions are usually characteristic of V-shape. Upcoming cool nights will hold back the bacterium. So far, a good fungicide program has proved to be effective.

Black Rot of red cabbage

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Filed under Disease, Entomology, Irrigation, Vegetables

December 14, 2015 · 3:38 PM

Australian Report – Peanut Planting Time

Seminole Crop E News

Our weather is warmer than normal but we aren’t planting peanuts like they are in Australia, although it feels like we could.

I have an Australian fellow agronomist friend, Neil Halpin, who does research concerning peanuts and other crops. It’s funny that emails from there are often dated tomorrow’s date. Even right now it’s 9:19 in the morning here on Dec 14th, in his town of Bundaberg it’s already tomorrow, 12:19 am, Dec 15th.

He visited us here several years ago. He was kind enough to send us this report concerning what’s happening there at planting time down under.

“The Coastal Burnett cropping area is located around the towns of Bundaberg, Childers and Maryborough in Queensland Australia. The cropping is dominated by sugarcane. We have around 47,450ha (117,201 acres) of sugarcane. We also have about 5,800 ha of macadamia trees and about 1,000 ha of avocado trees as well in…

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December 11, 2015 · 9:32 PM

Cotton Response To Preemergent Herbicides In A Sandy Soil Environment

Earlier this season UGA Extension Weed Scientist Dr. Stanley Culpepper and I did a herbicide injury trial here in the county. With some of our sandy soils, we often wonder about injury in different field situations. Much injury from at-plant herbicides have been observed for many years through 2013. We put out a this trial to observe different rates and combinations. Though much of our crop in the county is not under pivot, we observed the difference under irrigation to make sure we had proper water timing. This is one of many plots Dr. Culpepper will have this year, but it still provided good information as we are continuing to learn about injury with preemergence.

Treatment

We set up plots behind planting of DP 1252 on May 23rd. Each plot was treated with equivalent of 15 gallons of water per acre at rates and herbicides listed below. Irrigation ran 0.5 inch two days following planting. Cotton was not irrigated again until it was completely emerged. We then rated three times: 5, 11, and 21 days after treatment.

Injury was only observed once on the 2nd rating. The injury was just 8% with our Direx + Warrant mixture. Once we got to the third rating, no difference in injury was observed. Looking at the results below, note each column under “% injury.” Where the letters change is where difference in injury was observed. This gives us more confidence in our preemergents that we may be safer than we originally thought. Lack of injury is likely due to well-timed irrigation program and better understanding of how and when to irrigate. We’re going to share this info at our cotton meeting this year, along with other data Dr. Culpepper has from other trials. If you want to read more, I have a screen shot of a poster at the bottom.

Early evaluation

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Filed under Cotton, Weed Science

December 11, 2015 · 8:41 PM

UGA Wheat Weed Control 2015-2016

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Filed under Grain, Weed Science

December 11, 2015 · 8:08 PM

Crown Rust In Oats?

I was asked about rust in some oats east in the county. These oats are coming along, getting closer to graze. It has been a little dry here, and many aphids are present. Tip burn is showing up where temperatures dropped. Once we started looking through the field, it was apparent spots on the leaves were the result of aphid feeding. We still need to scout for aphids since they vector barley yellow dwarf virus (BYD). Many times, aphids feeding will leave a small, circular red spot. This appears different than rust since the rust postule is raised from the leaf.

Aphid feeding

Aphids

Crown Rust

Crown rust is something we see more in our area south. Like rust we see in wheat and corn, the spores are carried by wind and move long distances easily. The spores overwinter in warmer southern climes and come back to our region in the summer. Rust is identified on the leaf by the small pustules which contain orange-yellow spores. Though grazing and grain are managed differently, UGA Extension Forage Scientist Dr. Dennis Hancock says rust can reduce yields in grazing. If rust is present, it is recommended to grave heavily to reduce the amount of fungal inoculant on the oat crop. We would also have to monitor this close grazing.

The key to differentiating rust from leaf spot or aphid feeding is the orange powder spores on your finger after rubbing the leaf. Here is a photo of rust from Seminole County Agent Rome Ethredge:

Crown Rust – Photo by Rome Ethredge

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Filed under Disease, Forages

December 1, 2015 · 12:08 AM

Too Late To Treat Pond Weeds?

Today I asked about duckweed taking over a pond around Meigs. On the way up, I passed another pond that was nearly 100% infested with duckweed. When we look at weeds like duckweed, we need to make sure another weed called watermeal is not also present. If that is the case, our treatment options change. To see more on these two weeds, click on my blog post titled Pond Weeds – Duckweed & Watermeal.

This pond is almost 100% full of both duckweed and watermeal. Some large bass have died as result of low oxygen. This pond needs to be treated, but we are very late in the season to do it. I’m getting this question more this year since temperatures are so warm. There are few general rules we can follow, but every situation is different depending on weed present, water temperature, who treats, chemical availability, etc.

When is too late?

UGA Extension Aquatic Scientist Dr. Gary Burtle says our water is borderline for treatment right now. 70 degrees F is when we are generally safe to treat ponds. We still need to consider, however, that some compounds work better at 80 degrees F though 70 is our cutoff. Right now, plants are not growing as fast, and chemical reaction is slower.

What does this mean? Some of our compounds are systemic and others contact. Diquat, cutrine and clipper are contact herbicides. Sonar, which is good on watermeal and duckweed, is systemic. Systemic chemicals needs 3 – 4 weeks of actively growing plants to be effective. We are certainly too late in the season for this kind of treatment. Clipper also works good on duckweed when watermeal is mixed. But the issue with contact herbicides is though they may provide a kill with borderline temperatures, timeliness is key. If we do not already have a plan, water temperature could drop to 60s in a short time.

We must to also consider pond converge. Dr. Burtle reminds us that if the pond is 80-100% covered, two treatments of a contact herbicide would be needed. Considering the cost, one application of a systemic herbicide (for a small pond < one acre) would be less expensive – which we are too late to apply.

Conditions now are essentially the same as conditions will be in late Febrary. At this time in the season oxygen in a pond is actually higher. This will keep us from losing too many fish and should also be considered. Cooler weather will also slow weed growth. Dr. Burtle says it is not totally bad to treat during these conditions; however, once all factors are considered, waiting until spring would be more beneficial.