Category Archives: Cotton

PGR Rainfast

We are 2nd and 3rd week into squaring now, and we’re starting to put out our plant growth regulators. I had an unexpected 1 inch rain at the house yesterday afternoon.With all the rain we are having, we need to keep in mind the ‘rainfast’ of our PGRs. Below has written out each of our mepiquat and mixed products. Generally, when a surfactant is used, we can cut the rainfast in half. Pentia is more expensive, but with a 2 hour rainfast (1 hr with surfactant), we may find it beneficial our current conditions.

 

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Aphid Fungus

For the first time, I am getting to see what ‘consistent aphids’ looks like in the field. Normally, aphid populations are sporadic, seen only in ‘hot spots.’ This season, they are prevalent in our oldest and youngest cotton. We looked at a field this week where every single plant was affected by aphids in the top 3 – 4 leaves (below). The only reason we don’t talk much about it is UGA research on treating aphids has never found a consistent yield response. The best thing is to limit stress on the plant, and our rainfall is helping us here.

Leaves of 8-leaf cotton curl due to stress of aphids

Classic symptoms of aphids in our cotton variety trial.

Aphid Fungus

But the real new is that yesterday, we confirmed the ‘aphid fungus’ in Thomas County. UGA Extension Entomologist Dr. Phillip Roberts already reported the ‘aphid fungus’ being spotted in Tifton this week. This means, aphids will soon crash.

We observed the aphid fungus, (Neozygites fresenii), which causes aphid populations to crash on the Tifton Campus on June 26, 2017.  We have also received some early observations from both north and south of Tifton.  The presence of grey, fuzzy aphid cadavers is indicative of the naturally occuring fungus (below).  Once observed in the field we would expect aphids to crash within a week.  We typically first observe the fungus in fields with high aphid infestations; and more specifically areas of those fields which were initially infested.  All scouts should be on the lookout for the fungus and be sure to report to growers.

Aphid fungus – Photo by Dr. Phillip Roberts

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Cotton Irrigation At Squaring

Some of our pivots have not been running these past few weeks thanks to steady rainy days. For being so dry at planting, this is hopefully going to get us off to a good start in the field. Below is a photo of rep 2 from our variety trial. We have some plants squaring already.

Remember, stressing cotton during squaring has more negative effects than we realize. Cotton does not rebound if stressed from no irrigation through squaring. Last year, we lost so many squares from drought stress. This is something UGA Extension Irrigation Specialist Dr. Wes Porter says we have to be careful about.

Data on this using the UGA Checkbook Method where pre-bloom irrigation was eliminated found no difference in non-irrigated cotton. The reason for this is that cotton grows vegetatively and reproductively at the same time. During its vegetative growth, cotton is setting nodes. If it is stressed during this time, less nodes are set.

ImpactofPre-BloomIrrigation-J.Whitaker-2012

Dr. Porter has been looking at soil moisture sensors and the irrigation apps we can download on our phone. Research does show that the Smart Irrigation App is keeping us from putting out more water than is needed during both drought and rainfall situations. This is interesting because these apps do not monitor soil moisture, and the Smart Irrigation App is no charge to download. We go one step further when we use soil moisture sensors.

UGACheckbookMethod

Aphids???

I saw some ants crawling up some plants. I then checked for aphids. The ants eat the ‘honeydew’ produced by the aphids, called ‘farming aphids.’ UGA Extension Entomologist Dr. Phillip Roberts says there are some aphid hot spots that may develop in fields now. We just need to watch.

Aphids under leaf of squaring cotton

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Cotton Market Update

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June 16, 2017 · 6:56 PM

Cotton Coming Up, Variety Trial Planted, Scout Thrips

Cotton is anywhere from just planted to cotyledon to 4 leaf at this time. Recent rains have growers planting and we hope to have more this weekend. It’s past our thrips date of May 10th and we have reason to believe thrips may crash soon this year – since we had a warm winter, they were active sooner. But remember, thrips live in the winter weeds along roadsides and move to our cotton and peanuts following germination.

From 0 to level 5, I’m seeing damage from none to about level 3, sporadic in most fields. Neonic seed treatments (imidacloprid, thiametoxam) are active on thrips for up to 14 – 21 days after planting. If we have no seed treatment, we need to be in the field checking the first true leaf. This is the best time when we need to apply a foliar application. Once we have 4 true leaves and the plant is growing fast, thrips foliar sprays are not economical.

Thrips injury on 1st true leaf

Threshold

Research has shown that foliar applications are still needed when thrips infestations are high. The best way to make this decision is based on current threshold of: 2 – 3 thrips per plant AND/OR presence of immatures. The immature (wingless) thrips will be yellow/green in color; the adult (winged) thrips are black. Take a white piece of paper and slap a plant on it. Give it a second for the thrips to start crawling. In this field, I have immature thrips present. This suggests are at-plant insecticides are no longer active, and reproduction is taking place.

Here is a note from UGA Extension Entomologist Dr. Phillip Roberts from 2016. It may still answer some question today:

Should we follow with a second acephate spray? Dr. Roberts has conducted trials with 1 +3 leaf sprays, and they showed no difference from a 1 leaf ONLY spray. Something I noticed rating our thrips trials (2016) is not only the effectiveness of 1 leaf sprays, but also how fast the plants grow in 14 days. If we have a timely insecticide spray, AND growing conditions are good, cotton will outgrow potential thrips issues. The only reason to consider a second foliar application is if 1) cotton is not growing fast 2) thrips are still highly active. It would be a judgment call at best.

How long does this foliar spray of orthene last? Research entomologist Dr. Michael Toews, and Dr. Roberts have data on this that hasn’t been totally put together, but the best analysis is maybe 3 -4 days. Pyrethroids, on the other hand, photodegrade fast. Dr. Roberts says pyrethroids will kill thrips, but the reason we do not recommend them is 7 days after treatment, thrips populations are higher where pyrethroids were sprayed than where orthene was sprayed.

We were able to plant our variety trial last Friday. I visited the field today, and cotton is just now coming up. The field is at the end of Centennial Road where it touches Airline Road. It is the one on the right. We ended up participating in the UGA On Farm Variety Trial. Most of the varieties I asked for were in the trial. We were able to get in all varieties I wanted plus these for a total of 15. We replicated three times in the field; reps are actually stacked on top of each other.

2017 UGA On-Farm Variety Trial

We got done real fast, thanks to Brandon’s precision planting. Thanks to growers Mike, Brandon and Chandler Barnes for planting the trial this year and Jodie Stringer (Boston Gin) for helping and Jessica Jones, owner of Barbaritoes, for feeding us in the field.

Jodie and Brandon fixing flags

Brandon Barnes, Mike Barnes, Chandler Barnes, Jodie Stringer, Andrew Sawyer

 Jodie and Brandon fixing flags

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Cotton Market Update

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2017 Glyphosate-Resistant Palmer Amaranth Control

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Filed under Cotton, Weed Science

Thrips Infestation Predictor For Cotton

At our cotton meeting, UGA Extension Entomologist Dr. Phillip Roberts talked about a new model to help predict thrips infestation. The Thrips Infestation Predictor for Cotton tool can be found at http://climate.ncsu.edu/cottonthripsrisk/ . Dr. Roberts has this to say about the model and scouting:

Thrips are the most consistent insect pest of cotton in Georgia and the southeast.  Near 100 percent of the cotton planted in Georgia will be infested by thrips each year.  Preventive insecticides applied as a seed treatment and/or infurrow application at planting for thrips control provide consistent yield responses.  In some situations supplemental foliar insecticides may be needed in addition to preventive treatments at planting. 

Plant injury from thrips is a function of thrips pressure and seedling growth.  The Thrips Infestation Predictor for Cotton (TIP) tool uses planting date, temperature, precipitation, and knowledge of when and how intense thrips infestations will be to predict risk of thrips injury to cotton.  The TIP model can be used to identify planting dates which are at greatest risk for thrips injury.  The TIP tool will give the best predictions within 10-14 days after you use it, so use at multiple times during the planting and thrips management season would be beneficial.  Dr. George Kennedy has prepared the webinar “Thrips Infestation Predictor for Cotton: An Online Tool for Informed Thrips Managment”.  The webinar includes an overview and how to use the TIP tool and can be found at http://www.plantmanagementnetwork.org/edcenter/seminars/cotton/ThripsInfestationPredictor/

High risk planting dates will require more aggressive thrips management compared with low risk planting dates to achieve acceptable thrips control.  Management options for high risk planting dates would include the use of infurrow liquid insecticides such as acephate, imidacloprid, or aldicarb or the use of a neonicotinoid seed treatment plus a supplemental foliar application at the 1-leaf stage.  In low thrips risk environments neonicotinoid seed treatments will generally provide acceptable control.  The TIP tool should allow proactive decisions to be made relative to thrips managment.

How confident should I be using this TIP tool?  My thoughts are exactly as those of my colleague at NC State who answered this question very well.  Any forecast will have some uncertianty.  However, this tool is based on many years of data from across the Southeast US Cotton Belt and has been validated several years since.  We are very confident that this tool, when used as instructed, will accurately forecast thrips risk in cotton.

The TIP tool will not replace scouting and sampling for thrips and thrips injury in cotton.  But it does provide information which will improve our thrips management programs.

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UGA Cotton Market Update

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Cotton Efficiency Survey

Professor Jeff Dorfman has helped develop a cotton survey from a research project funded by the Georgia Cotton Commission designed to help Georgia cotton farmers improve their production efficiency. Producer involvement in this research project only involves filling out a questionnaire on various cotton inputs, farm qualities, and personal experience.

You can find the survey at http://www.georgiacottonfarmers.com/.

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