Peanut Update – More on Boron

The following update was prepared by Clemson Peanut Specialist Dan Anco.

In a previous notice we mentioned the importance of Boron application to avoid Boron deficiency (and toxicity) in peanuts. There are lots of different products to choose from, and sometimes the difference from one to another is not as straightforward. Typically the best way to compare similar products is to look at the active ingredient concentration and base our application amounts on the desired amount of active ingredient we want. However, sometimes the unspecified or proprietary “inactive ingredients” can play an important role as well. As an example, a liquid boron product containing 10% boron would require about 2 qt/A (58 fl oz/A for products containing 1.1 lb boron/gal) to supply 0.5 lb boron/A. Some other products advertise a “low-use boron” formulation. For example, Boron X-treme contains less total elemental boron (7.5%), but the recommended rate to provide 0.5 lb Boron comes out to be 0.5 pt/A, which is quite a bit less than recommended for the product containing 10% elemental boron. The lower recommended rate is due to the “proprietary blend” that uses an auxin hormone and another compound to increase leaf solubility and plant uptake of the boron.

To put these rates into perspective, Boron X-treme runs around $32/gal ($2 per acre for a 0.5 pt/A application), whereas its Boron 10% counterpart runs around $12/gal ($6 per acre for a 2 qt/A application). In theory, this would favor the low-use product. Since we have not yet had a chance to examine Boron X-treme in our peanut trials, at this point all I can do is help clarify the labels. The proprietary components of Boron X-treme is supposed to mix well with most products with the exception of ammoniated zinc (which in most cases we don’t need to apply to peanuts anyway) and certain calcium products (this also shouldn’t be an issue since our calcium is spread separately). If uncertain about a specific mix compatibility, mixing up a small-scale batch in a jar test can help indicate if certain products are incompatible in the tank.

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Sugarcane Aphids Found in SC – 2017

For those growing grain sorghum, be aware that sugarcane aphids have recently been found in SC.  They are not known to overwinter in SC and travel North from Florida, Texas, and Louisiana each year.


Sugarcane aphids on grain sorghum leaf.

Sugarcane aphids can build up to damaging population levels very quickly, so growers need to scout carefully and often.  Use the threshold of 50-125 or more aphids per leaf when making spray decisions.  The two insecticides we have to control sugarcane aphids are Transform and Sivanto Prime.  You can view and download the labels below.

Transform Section 18_2017



Sugarcane aphids under microscope.

Take a look at this publication from Clemson Entomologists Francis Reay-Jones and Jeremy Greene for more info:  Clemson_Sugarcane_Aphid_2017

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Question of the Week: Pigweed

Last week the question was:  What are the weeds surrounding these young cotton plants?


This was an easy one.  These is pigweed, Palmer amaranth to be more specific.  There is not a single farmer in SC that hasn’t fought pigweed.  This is one of the most serious and frustrating weeds we deal with because resistance to several different herbicide modes of action have been found.  Take a look at the 2017 SC Pest Management Handbook for control recommendations in various crops.


Here is this week’s question:  What made this nearly perfect circle in this leaf?


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Cotton Squaring

We’ve had plenty of rain and warm weather over the past week and our fields are growing fast.  Some of our older cotton is squaring now.


Match-head square

Water availability becomes a little more important to the plants now that the reproductive structures are being developed.  Hopefully we will continue to get regular rainfall.


This is the time when we want to apply the remainder of our nitrogen.  Clemson Cotton Specialist Mike Jones recommends 70 total lbs of N per acre in dryland fields and 100 total lbs in irrigated fields.  We need to side dress now so the plant has plenty of N during bloom.


Cotton square.

Insect pressure has been low lately.  Clemson Entomologist Jeremy Greene cautions growers in his latest Cotton/Soybean Insect Newsletter to be scouting for tarnished plant bugs (TPB).  TPBs can cause squares to abort, so if we are seeing 25% square abortion and TPBs are present, treatment may be needed.  You can also use the threshold of eight or more plant bugs per 100 sweeps with a sweep net.  Take a look at Dr. Greene’s newsletter here for more info:  Newsletter #8 (22 June 2017)

2017 SC Cotton Growers Guide.

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Cucurbit Downy Mildew Found in SC

This past week cucurbit downy mildew was found in Charleston and Horry Counties.  Downy mildew blows in from the south in the summer and is a very serious disease once it is established.  Anyone growing cucurbit crops (cucumber, watermelon, squash, zucchini, cantaloupe, pumpkins, etc.) in SC should begin making preventative fungicide sprays now, if they have not already done so.


Downy Mildew symptoms on cucumber leaf.

The forecast shows a decent chance of rain every day this week.  This will be a good opportunity for downy mildew to spread.  We need to be diligent in our disease control programs for the remainder of the crop.  Take a look back at this blog post for detailed information on managing downy mildew.


Downy Mildew symptoms on cucumber leaf.

Downy mildew can make growing cucurbits in the late summer and fall a challenge.  Get on a strict spray schedule and stick to it.  You can look at updates on the latest reported cases of downy mildew on the Cucurbit Downy Mildew Alert System website.  If you need help scouting or identifying downy mildew, please contact your local Clemson Extension agent.

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Watermelon Field Day – 7/13/17


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Question of the Week: Turkey

Last week the question was:  What bird made this nest in the middle of a field?


These are Eastern wild turkey eggs.  This pea field was a great spot to make a nest until it was harvested.  It had a lot of thick cover 2-3 feet high, but now all the cover is gone and the nest is very exposed.  Hopefully they will still hatch.  Here is a good website with lots of info about the Eastern wild turkey.


Here is this week’s question:  What are the weeds surrounding these young cotton plants?


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Peanut Update – Corn Earworms

The following update was prepared by Clemson Peanut Specialist Dan Anco.

A producer recently found corn earworm larvae in a 30 day old peanut field. This is a little more than a month earlier than when we typically see them. Populations were still low, and if we get the rain that’s forecasted for the later part of this week and weekend it will both help peanuts recover from any remaining paraquat injury and produce more canopy, as well as help keep insect pest populations down. The general threshold we have for stressed peanuts that have not yet lapped the middle is 4 worms per row ft. This is the general guideline, and each situation and the condition of the peanuts can be a little different. The best way to know how your peanuts are doing, what pests might be in them and what if anything needs to be done, is to scout them.


Corn Earworm

If scouting reveals a developing worm population that requires action, this is a good time to also remember not to jump the gun with using pyrethroids.  Pyrethroids can flare spider mites populations, and they are difficult to manage with currently labeled products once they get going. On rain fed fields we don’t have the luxury of scheduling rain, and so everything we can do to avoid secondary problems (like avoiding pyrethroid use, particularly early in the season) is worth keeping on the radar.

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Cotton Marketing News – 6/13/17


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Question of the Week: Poor Pollination

Last week the question was:  What is wrong with the three cucumbers on the right?


These cucumbers are misshaped because of poor pollination.  Cucumbers need several hundred grains of pollen to be properly pollinated.  Pollen from male cucumber flowers is large and sticky; therefore, it requires several bee visits for the female flowers to obtain the appropriate amount of pollen.  If there are not enough bee visits then the fruit ends up looking like these cucumbers.  Check out this website for more detailed info.


Here is this week’s question:  This nest was found when a field of ESO peas was harvested recently.  What bird made this nest in the middle of a field?


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