PEANUTS:  We are reaching a critical time in the management of white mold (stem rot) and leaf spot diseases in area peanuts.   Growers should be aggressive with appropriate fungicide programs.  Now is not the time to watch and wait.  Rainfall will create favorable conditions for diseases of peanut, but timely rainfall will also help to move the fungicides from the leaves of the plant to the crown of the plant for better coverage.  According to Bob Kemerait, UGA Plant Pathologist, peanut fungicides should have 8-12 hours of drying time before a rain or irrigation event.  If such occurs earlier, we can discuss what should be done to insure adequate protection.  If you would like more information about the Peanut Rx fungicide programs please go the link below

http://blog.extension.uga.edu/colquittag/2017/04/2017-peanut-rx/

I have been getting questions about three cornered alfalfa hoppers (TCAH) in Colquitt County peanuts.    Dr. Mark Abney, UGA Peanut Entomologist,  mentions that there will be a lot of interest in spraying TCAH, but there are several things to keep in mind when making management decisions. The first is that there are no valid economic thresholds, and opinions vary about whether or how it should be managed. While this is frustrating, it does provide some insight into the pest status of the insect. If TCAH routinely caused serious economic loss, we would know it. Can TCAH affect yield? Probably. Can you achieve high yields with lots of TCAH stem girdles? Yes.

Below is his blog that discusses his thoughts in the peanut insect situation.

http://blog.extension.uga.edu/peanutent/2017/07/peanut-insect-update-scout-your-peanuts/

Tankmixing Grass herbicides with fungicides on peanuts.  This has been a common question.  According to Dr. Eric Prostko, UGA Weed Specialist,   for optimum grass control, it not a great idea to mix POST grass herbicides with a fungicide due to the increased potential for antagonism.  Generally, Abound, Bravo WS, Headline, and Folicur have all reduced grass control at some point when tank-mixed with POST grass herbicides.  When a grass/fungicide interaction has occurred, grass control has been reduced by as little as 3% (Poast + Bravo WS – large crabgrass) or as much as 45% (Select + Bravo WS – large crabgrass).  It all depends upon the grass species and fungicide used.

Tank-Mixing Chemicals Applied to Peanut Crops:  Are the Chemicals Compatible?

http://www.peanut.ncsu.edu/pdffiles/004993/tank_mixing_chemicals_applied_to_peanut_crops.pdf

And how late is too late to apply boron to peanut?  According to Dr. Glenn Harris, peak pod fill for peanuts occurs 60 to 90 days after planting, once peanuts are 80 days old or older, the chances of applying boron and getting a yield increase decrease dramatically. And what about rate? The UGA recommendation for B on peanuts is 0.5 lb. B/a. This can be applied in one application or split into 2, 0.25 lb. B/a applications. Rates higher than 0. 5 lb. B/a in a single application can cause burn to the foliage.

How do I scout for whitefly in cotton?

Steps for Efficient Sampling of Whiteflies

1.Familiarize yourself with the general location of the 5th main stem leaf in each field.

2.Select plants at random at least 25 paces into the field and at least 10 paces apart, being careful to keep your shadow from passing over the plant you plan to sample.

3.Turn the 5th leaf over slowly by its tip or petiole and count the leaf as infested with adults if it has 3 or more adults on it.  Include in your counts any adults that fly up from the leaf as you turn it over.

4.Detach the leaf by the petiole from the main stem.  If it fails to snap off easily, you have likely sampled a leaf that is too high on the plant.  Recheck your leaf position to make sure you are sampling the 5th leaf.

5.Examine the bottom of the leaf for the presence of immature SLWFs.  Count the leaf as infested if it has 5 or more immatures on the underside of the leaf.  It is important that you are sampling the 5th mainstem leaf.  A hand lens will aid in counting immatures.

6.Sample at least 30 plants (leaves) per field.

7.Calculate the percentage of leaves infested with adults and the percentage of leaves infested with immatures.

Treatment is recommended when 50 percent of sampled leaves are infested with immature SLWFs

Here’s the UGA recommendations for applying foliar fertilizer to cotton:

Nitrogen: Feed grade urea is the most reliable, economical and proven foliar N material.  The standard recommendation is to apply 4.5 lbs of nitrogen/acre as urea in at least 5 gallons or more of water per acre (5 gal/acre assumes aerial application, 10 to 12 gallons of water is preferred for ground application).  Both liquid urea (23% N) and granular urea (46% N dissolved into water) can be used. 10 lbs of feed grade urea (granular 46% N) per acre will give you approximately the recommended 4.5 lbs of nitrogen per acre.

Potassium: Potassium nitrate is the most common material used for foliar K applications.  The standard recommendation is to apply 4.4 lb of potassium per acre in 5 gallons or more water per acre. (Again 5 gallons assumes foliar application, 10 to 12 gallons is preferred for ground application).  Both liquid and granular potassium nitrate can be used. 10 lbs of granular potassium nitrate (44% K2O) per acre will give you the recommended 4.4 lbs of potassium per acre. Keep in mind that there are other products out there available to use for foliar feeding cotton.  Some of these may not contain as much fertilizer as the products mentioned above and you may not be able to apply them at the same rates as mentioned above. Use caution with all fertilizer products as improper rates could cause leaf burn.

How late is too late to foliar feed cotton?

Foliar feeding is most effective when applied during peak bloom, or the first 4 weeks of bloom.  Foliar feeding during weeks 5-7 of bloom may or may not be effective depending on the variety grown.

Once you pass the 8th week of bloom, it is too late.  No foliar feeding is recommended after this point.

 Bermudagrass Stem Maggot Management Update

Will Hudson Extension Entomologist

Bermudagrass stem maggot has been a common issue in Colquitt County bermudagrass hay fields.  

The fall armyworm situation is much less severe this summer, but the stem maggot (BSM) is building in numbers in most of the southern 2/3 of the state.  We’ve seen this pattern before, and our standard recommendation is that hay producers everywhere in the state should be watching closely as they begin the July cutting for signs of BSM activity.  If there is damage in July, you can count on more in the August crop and a treatment may be warranted.  Continuing research with insecticide control of BSM has shown that spraying a pyrethroid (active ingredients that end in –thrin, like cypermethrin, cyfluthrin, etc) 7-10 days after cutting will reduce damage in the next crop.  Under good growing conditions and light to moderate pressure from the flies, one application may be enough.  Heavy pressure or poor growing conditions that slow the grass down may require a second application 7-10 days after the first.

At this point, we have no research results that show efficacy for any other insecticide active ingredients except the pyrethroids.  Materials like Dimilin or those containing spinosad or chlorantraniliprole are good choices for armyworm control but do not appear to affect BSM.  We have not found anything that provides residual control of the maggots, and nothing is more effective at killing the adult flies than the pyrethroids.  For best results, slow down and apply as high a spray volume as your equipment and situation allow.

 

Cotton Policy Update

Below are a few words from Don Shurley pertaining to a few recent Cotton Policy Developments

 https://blog.extension.uga.edu/colquittag/2017/07/cotton-policy-update-july-28-2017/

 

Update on Stored Corn Protectants..

Corn harvest has started in Colquitt County.  Insect management in the bin is important for profitability in corn production.  Dr. Mike Toews, UGA Entomologist, has given us a timely update for grain protectants.

http://blog.extension.uga.edu/colquittag/2017/07/update-on-stored-corn-protectants/