All posts by Sebe Brown, IPM Extension Specialist

2022 UT Soybean Scout Schools

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UT’s Soybean Scout Schools will be held in July (see details below). These field-side programs cover the basics of soybean growth, scouting, pest identification, and general management. Pesticide recertification and CCA CEU points will be available. Scout Schools are offered free of charge with sponsorship from the Tennessee Soybean Promotion Board. Registration is not required. Participants will receive a scouting notebook and a sweep net while supplies last.

West TN – Madison County, July 11th, 9:00 AM – 11:30 AM. This school will be at the West TN Research and Education Center, 605 Airways Blvd. Jackson TN, 38301. Signs will be up at the station to direct you to the field.

West TN – Henry County, July 12th, 9:00 AM – 11:30 AM. This school will be at Norwood Farms, 645 Norwood Rd, Mansfield, TN.

Middle TN –  Lincoln County, July 13th, 9:30 AM – Noon. This school will be at H&R Agri-Power, 11 Highland Rim Road, Fayetteville, TN 37334.  Lunch will be provided courtesy of H&R Agri-Power. A head count is required for the meal,  please contact Bruce Steelman of the UT Lincoln County Extension Office at (office) 931-433-1582 or (cell) 615-542-1364 if you plan to attend.


Spider Mite Numbers Increasing in Cotton

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I’ve received several phone calls about spider mites increasing in cotton around West Tennessee. Spider mites favor hot, dry weather and will often become an issue after plant bug applications are initiated. UT recommends treatment when 30-50% of plants are showing signs of injury and spider mites are still present.  This may be too aggressive under low stress conditions, but most of the crop is currently under substantial heat and drought stress. Treatment options are fairly limited and most are mite specific. Abamectin based products are typically the first option because they are economical and effective. There are a couple different formulations of abamectin that are different lb/ai per gallon products.  Below is a rate conversion of 0.15 lb ai/gallon formulations (Willowood Abamectin 0.15 EC, etc)  to 0.7 lb ai/gallon formulations (Agri-mek SC 0.7, Willowood 0.7 SC, etc).

5.0 fl oz/a = 1.0 fl oz/a

7.0 fl oz/a = 1.5 fl oz/a 

8.0 fl oz/a =1.75 fl oz/a

10.0 fl oz/a = 2.0 fl oz/a

Abamectin rates below 7.0 fl oz/a or 1.5 fl oz/a should be avoided due to potential resistance issues and the increased likely hood of retreatment.

Other mite products such as etoxazole (Zeal, Stifle) are mite growth regulators that work very well but are more expensive and somewhat slower than traditional miticides.  Fenpyroximate (Portal) is a contact miticide that has a shorter residual than abamectin or etoxazole but  works very well. Bifenthrin alone is not an adequate miticide and should be avoided.

Products used for controlling plant bugs, bollworms and stink bugs (OPs, pyrethroids) exacerbate mite populations and their use, especially during hot dry conditions, should be delayed until after bloom if possible. Mite populations can rebound quickly after miticide applications so diligent scouting is critical to slowing the spread of mites across a field.

 

 


2022 UT Soybean Scout Schools

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UT’s Soybean Scout Schools will be held in July (see details below). These field-side programs cover the basics of soybean growth, scouting, pest identification, and general management. Pesticide recertification and CCA CEU points will be available. Scout Schools are offered free of charge with sponsorship from the Tennessee Soybean Promotion Board. Registration is not required. Participants will receive a scouting notebook and a sweep net while supplies last.

West TN – Madison County, July 11th, 9:00 AM – 11:30 AM. This school will be at the West TN Research and Education Center, 605 Airways Blvd. Jackson TN, 38301. Signs will be up at the station to direct you to the field.

West TN – Henry County, July 12th, 9:00 AM – 11:30 AM. This school will be at Norwood Farms, 645 Norwood Rd, Mansfield, TN.

Middle TN –  Lincoln County, July 13th, 9:30 AM – Noon. This school will be at H&R Agri-Power, 11 Highland Rim Road, Fayetteville, TN 37334.  Lunch will be provided courtesy of H&R Agri-Power. A head count is required for the meal,  please contact Bruce Steelman of the UT Lincoln County Extension Office at (office) 931-433-1582 or (cell) 615-542-1364 if you plan to attend.

 


Threecornered Alfalfa Hoppers in Vegetative Soybeans

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I’ve received several phone calls over the past few days about threecornered alfafa hoppers  in V-stage beans.  Many of the questions are related to the recent cotton injury that was observed in West TN where cotton was planted behind a legume cover crop. Hopper injury in beans  is not the same as hopper injury in cotton. Hopper injury in seedling (less than 6 nodes) cotton often results in a girdle on the main stem.  Over time the girdle swells, the cotton stops growing, the leaves turn red and the cotton dies.

Hopper injury in beans results in a girdled main stem, when plants are less than 8-10 inches tall, that doesn’t result in plant death like cotton.  Girdled beans are at increased risk for lodging late season when neighboring plants don’t have time to compensate.  Yields of girdled plants won’t be affected unless they break over during the season. Hopper damaged beans tend to be worse in thin stands and poorly growing soybeans. Hoppers are typically easy to control with pyrethroids or acephate. Insecticide seed treatments provide some protection against hoppers during the seedling stage, although levels of protection can be highly dependent on environmental conditions. For more information on thresholds and control options please visit: https://guide.utcrops.com/soybean/soybean-insect-guide/threecornered-alfalfa-hopper/

Soybean stem with multiple girdles
Soybean stem with multiple girdles (S. Stewart)
Hopper damaged seedling cotton. (S. Stewart)
Hopper damaged seedling cotton. (S. Stewart)

Rice Stink Bugs in Wheat

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I’ve received several phone calls over the past few days with concerns about rice stink bug in wheat. Rice stink bugs have to be present in extremely high numbers to cause  economic damage to wheat. There is no sweep net threshold for stink bugs in wheat and once the crop hits the hard dough stage injury potential is significantly reduced. Keep in mind that stink bugs are transient in wheat and can often be found in high numbers one week and disappear the next.  Stink bugs will often congregate on the edges of field crops and wheat is no different. High numbers of stink bugs will often be found on borders and diminish the further you move into a field. Since we normally do not treat for stink bugs in wheat, large numbers can move into seedling corn in adjacent fields. Corn smaller than 24 inches is at risk for stink bug injury and seedling corn with 10% or more infested plants should be treated.  Rice stink bugs are not a cause for concern in corn, brown stink bugs are the primary species that injury seedling stage corn.

Brown Stink Bug Wheat adult - UT Crops Pest Guides Rice Stink Bug 1 - UT Crops Pest Guides


UT Cotton Scout School

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The UT Cotton Scout School is scheduled for the last Friday of the month, May 27th, at the West Tennessee Research and Education Center (605 Airways Blvd, Jackson). There is no fee, and preregistration is not required. Registration begins at 8:00 AM with the program starting at 8:30. Content will include classroom and hands-on training with an optional go-to-the-field session after lunch. Topics covered will include cotton development and identification and symptoms of insect pests, plant diseases, and weeds.


Thrips Control in Cotton

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I’ve received several phone calls over the past few days about thrips in seedling cotton. Thrips pressure is variable by location with some areas reporting treatable numbers and others finding a few adults scattered around.  Application timing is critical for the best control.  Our research has shown that applications made early, before the second true leaf, provides the most benefit.

Options for foliar oversprays are limited to organophosphates  (Acephate, Bidrin, Dimethoate) and Intrepid Edge. OP resistance is present in West TN and while Acephate may provide some relief a more consistent option is 3.0 oz of Intrepid Edge. Also, increasing the rates of OPs may help some but overcoming resistance with higher rates often doesn’t provide consistent control and can be an expensive mistake.

The take home message, use acephate or other OPs with caution especially if you received questionable control last year and higher rates often aren’t the answer. Intrepid Edge, although the most expensive, is most consistent option that won’t flare spider mites or aphids. Surfactants aren’t required for Intrepid Edge but are highly recommended. Application with a herbicide such as Roundup or Liberty will work.

Side note: I’ve got word that Bidrin is in short supply so if you don’t have what you need for thrips I would think about making other arrangements.

 


UT Cotton Scout School (Friday, May 27, 2022)

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The UT Cotton Scout School is scheduled for the last Friday of the month, May 27th, at the West Tennessee Research and Education Center (605 Airways Blvd, Jackson). There is no fee, and preregistration is not required. Registration begins at 8:00 AM with the program starting at 8:30. Content will include classroom and hands-on training with an optional go-to-the-field session after lunch. Topics covered will include cotton development and identification and symptoms of insect pests, plant diseases, and weeds.