Cotton Defoliation Timing

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With so much attention on peanuts this week, cotton is starting to be defoliated in the county. We were looking at some fields this morning to make decisions on defoliating. There are a few different methods from the 2014 UGA Cotton Production Handbook we could check to make decisions.

  1. Counting bolls – We can defoliate when 60%-75% of bolls are open. This method focuses mainly on the “open” portion of the bolls, but ignores the “unopen” portion.
  2. CottonBoll 009Slicing bolls – Slice the boll in half with a knife. Bolls are mature and ready for harvest aid applications when they cannot be sliced with “stringing” the lint. Also, bolls are mature when the seed embro contains only tiny folded leaves (no ‘jelly’ within developing seed) and the seedcoat begins to turn yellow or tan.
  3. Nodes Above Cracked Boll (NACB) – This is determined by counting the number of nodes between the uppermost first position cracked boll and the uppermost 1st position boll that is expected to be harvested. Once NACB reaches 4, we are generally safe to defoliate.

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Pecan Nut Development

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Nut development has really progressed over the last few weeks. We’re not seeing shuck split in this orchard yet, but there are some ‘Pawnees’ starting shuck split. UGA Extension Pecan Specialist Dr. Lenny Wells says, “‘Pawnee shuck split starting in South Georgia means that nut maturity is still about 10 days or so behind normal. The calendar date of nut maturity for a given variety varies from one year to the next because the date of fruit maturity is dependent upon the accumulation of heat units in the early spring. Our spring in Georgia was cooler in 2014 than in 2013.”

PecansThe photo on the right shows nut development of ‘Stuart’ on September 16th. The kernels are filling well and almost complete.  Dr. Wells says, “‘Stuart’ nut maturity and shuck split is more prolonged and staggered, while that of ‘Schley’ is a little more uniform.  Nut maturity in Schley normally precedes that of ‘Stuart’ by about 2 days on average. We had a pretty cold winter last year and this causes nut maturity of ‘Stuart’ and ‘Schley’ to be similar. Following mild winters ‘Stuart’ nut maturity may be delayed another 10-14 days due to its high chilling requirement, while ‘Schley’ maturity will remain roughly the same. ‘Desirable’ nuts (are) still mostly in the late water stage, although I did see some gel forming in some of them. From this point forward ‘Desirable’ nut maturity should develop rapidly. They always seem to linger in the water stage and then fill all of a sudden.  I would expect that it will be late October or early November (depending on location) before harvest begins in earnest on these varieties.”

Economic Outlook- Dr. Lenny Wells

Chinese demand for pecans at this time seems strong. Size will play a large role in export prices offered to growers and our size is highly variable this year, largely as a result of scab pressure early and dry weather during nut sizing. Two weeks ago early contract offers I heard from various growers were at $2.20-$2.35 in-shell  for ‘Stuart’ and $2.75 for ‘Desirable’. Over the past week, these prices seem to have gone up to around $2.40-$2.50 for ‘Stuart’ and $2.85-$2.95 for ‘Desirable’. I have heard blends priced in the $2.40-$2.45 range. Again, size will be the determining factor in price. Small nuts will not bring high prices.

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Dryland Peanut Digging Considerations

We checked quite a few more peanut hull scrape samples yesterday, and almost all of these were dryland fields. Many of the these fields a considerable time without rain and are now flowering and have recently set pods. The profiles show this later crop. We’ve had rain, but also cloudy days. Daylight time is getting shorter also. How long can we hold out in these situations? Here is some information from UGA Extension Agronomist Dr. Scott Tubbs:

A month ago, I was telling a few county agents there was a decent chance we would be looking at a late crop with recommendations to leave the peanuts in the ground longer than usual in order to progress maturity to optimum.  There were several reasons behind this rationale:

  1. The crop was planted later than usual because of  too much rain.  When late planting occurs, it usually means a slightly longer growing season, because as the crop is nearing the 135-140 mark, it is also when day length is getting shorter and temperatures are dropping, thus requiring a little extra time to accumulate “Growing Degree Days” and advance to full maturity.
  2. The month of June would have constituted the period when much of the crop was setting its first pods, usually representing the densest and highest grading peanuts, but there was very little rainfall from June 20 through July 10 and thus there was a delay in flowering. And the lack of moisture was slowing movement of Calcium into the early forming pods, further pushing the crop behind in terms of maturity advancement.  Then, with some mid-July moisture, the largest flush of flowers was set later in the season than normal, so advancing this steeper part of the curve further into the brown/black region on the maturity board would be worth the risk of losing a few early pods since they were slower to establish.  However, the continuation of dry conditions through July and large chunks of August has changed things considerably.  Having heard of reports and seen fields where kernels are turning loose in the hull, delaying harvest to progress the remainder of the pods that are behind may not be possible without risking sprouting on the vine once those seed break dormancy.

It will take a careful look at the number of small, underdeveloped pods to determine whether peanuts should be dug early or late.  I am currently of the opinion that the maturity profile board for non-irrigated peanuts is going to be highly inaccurate this year, and we’re probably going to see very few peanuts actually dug “on-time”.  Most peanuts are going to need to be dug early or late.  If they do not have a lot of small pods on the plant, then the majority of the yield potential is already set. In those situations, there may be some opportunity for at least improving grade, but timing digging with enough moisture to put the digger in the ground (especially in heavier, higher silt and clay-fraction soils) is probably more important than taking the risk to further advance the TSMK, so early digging is justified in these type of situations.

In the case of plants that have a large number of smaller pods currently in development (swelling pods approaching the size of a dime, and the plants are around 100 days old), there is still an opportunity to bring those pods along if the plants are allowed to stay in the ground longer than usual.  Remember that it takes in the neighborhood of 40 to 60 days for a pod to develop to a size large enough to be harvested and be maintained in the basket.  Consider that about half of the peanut crop was planted after May 17 this year, and a peanut planted on May 17 would be 111 days old at the time of this writing (Sept. 5).  Adding 40 days to those peanuts would put them at 150 days old on Oct. 11.  I believe there is still time to advance a limb crop of small, currently forming pods to the point that they could be harvestable.  If there are very few larger pods on the plant currently, this may be worth hanging on a bit longer.  But it will require more frequent and consistent rains, and holding onto this hope will also require a decision to make the necessary inputs to carry the crop for a longer period of time, so there is certainly risk associated with the decision to continue maintenance or to cut losses and take what is there.  Thus, the decision to go early or late will be on a case-by-case basis.

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Spider Mites In Peanuts

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We’ve had spider mites come through in the northwest part of the county. This is usually the hardest hit part of the county, which corresponds to dry weather conditions. These fields have been sprayed, but you can see how much damage has been left behind. With harvest in mind, we’ve been answering lots of questions related to disease. We still need to be mindful of spider mites. Below is information from UGA Extension Peanut Entomologist Dr. Mark Abney:

“Peanuts with two or more weeks to go before digging are still at risk of losing yield to a late infestation of mites. We really need to be watching our non-irrigated peanuts and the dry corners of our irrigated fields for the initial signs of mite infestation. Mite “hotspots” will show up first as yellow circles in the field. These spots will then turn brown, and the yellowing will spread out from the source as the mites migrate to new plants.

Because mite populations can explode rapidly, damage can go from barely noticeable to severe in only a few days. No one wants to make another pest spray this late in the season, but we cannot afford to let fields with good potential get defoliated with three weeks to go before harvest. Management decisions will need to be made on a field by field basis taking into account profit potential, mite densities, and time to digging. Keep in mind that catching mites early is important for good control, but spotting signs of infestations is complicated when plants are suffering from drought stress.”

In photo below, the brown and yellow coloration in the top of the rows is due to spider mite feeding.

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Late Season Fungicide Considerations In Peanuts

With some peanuts a few weeks from digging and white mold present with rain, we’ve been discussing disease control options and if/when we can cut off fungicide sprays. Here is an update from UGA Extension Pathologist Dr. Bob Kemerait on these options:

Peanuts-WhiteMold 012Conditions remain very warm; however increased rain has moved into our peanut production region over the past week and it looks like this trend will continue for the near future. Conditions now are favorable for increased development of leaf spot, white mold and other diseases.  However, most growers are within weeks, to a little more than a month away from harvest. It is unlikely that diseases will have time to develop and affect yields in fields where diseases are currently well managed.

Below are some typical situations that peanut growers may find themselves in and suggestions for control:

  1. Grower is 4 or more weeks away from harvest and currently has excellent disease control.
    1. Suggestion – I recommend the grower apply at least one more fungicide at least for leaf spot control.
    2. Suggestion – Given the low cost of tebucoazole, the grower may consider applying a tan-mix of tebuconazole  + chlorothalonil for added insurance of white mold and leaf spot.
    3. NOTE: If white mold is not an issue, then the grower should stick with a leaf spot spray only.
  2. Grower is 4 or more weeks away from harvest and has disease problems in the field.
    1. If the problem is with leaf spot – Grower should insure that any fungicide applied has systemic/curative activity. If a grower wants to use chlorothalonil, then they mix a product like thiophanate methyl (Topsin M), cyproconazole (Alto), propiconazole (Tilt, Bumper) with the chlorothalonil. Others may consider applying Headline.
    2. If the problem is white mold – Grower should continue with fungicide applications for management of white mold. If they have completed their regular white mold program, then they should extend the program, perhaps with a tebuconazole/chlorothalonil mix.  If the grower is unhappy with the level of control from their fungicide program, then we can offer alternative fungicides to apply.
    3. If the problem is underground white mold – Underground white mold is difficult to control.  Applying a white mold fungicide ahead of irrigation or rain, or applying at night, can help to increase management of this disease.
  3. Grower is 3 or less weeks away from projected harvest and does not currently have a disease issue. Good news! This grower should be good-to-go for the remainder of the season and no more fungicides are required.
  4. Grower is 3 or less weeks away from harvest and has a problem with disease.
    1. If leaf spot is a problem and 2-3 weeks away from harvest, a last leaf spot fungicide application may be beneficial. If leaf spot is too severe, then a last application will not help.
    2. If white mold is a problem and harvest is 3 weeks away, then it is likely beneficial to apply a final white mold fungicide. If harvest is 2 weeks or less away, then it is unlikely that a fungicide will be of any benefit.
    3. NOTE:  If harvest is likely to be delayed by threat from a hurricane or tropical storm, then the grower may reconsider recommendations for end-of-season fungicide applications.

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Transform WG Insecticide Section 18 For Sorghum Approved For GA

White Sugarcane Aphids are a pest of grain sorghum that showed up in the county a few weeks ago. Thomas County has just over 1,000 acres of sorghum with high populations of WSCA. Brooks County Agents Ben Shirley and Stephanie Hollifield confirmed WSCA in Brooks County this week. The EPA has approved a Section 18 request for use of Transform insecticide on sorghum. See White Sugarcane Aphids blog post below for more information on WSCA.

Here is information from David Buntin, UGA Grain Crop Entomologist:

A Section 18 Emergency Use Exception for Transform WG insecticide on sorghum has been approved for the state of Georgia as of September, 11, 2014. Transform WG may be applied to grain and forage sorghum for control of sugarcane aphid from now until November 30, 2014. Additional details of the product use are as follows:

Foliar applications may be made by ground or air at a rate of EITHER 0.75-1.5 oz of product (0.023-0.047 lb a.i.) per acre with a maximum of 2 applications per acre per year OR 1.0 oz of product (0.03 lb a.i.) per acre with a maximum of 3 applications per acrew per year; resulting in a seasonal mazimum application rate of 3.0 oz of product (0.09 lb a.i.) per acre per year.

The minimum application retreatment interval of 14 days and a restricted entry interval (REI) of 24 hours must be observed.

A 7-day pre-harvest interval (PHI) for forage and a 14-day PHI for grain or stover must be observed.

A maximum of 50,000 acres of sorghum fields (grain and forage) may be treated in Georgia.

This product is highly toxic to bees exposed through contact curing spraying and while spray droplets are still wet. This product may be toxic to bees exposed to treated foliage for up to 3 hours following application. Toxicity is reduced when spray droplets are dry. Risk to managed bees and native pollinators from contact with pesticide spray or residues can be minimized when applications are made before 7:00 am or after 7:00 pm local time or when the temperature is below 55 degrees F at the site of application.

The registered product, Transform TM WG (EPA Reg. No. 62719-625; 50% sulfoxaflor), manufactured by Dow AgroSciences, may be applied. All applicable direction, restrictions, and precautions on the EPA-registered Section 3 label, as well as those outlined in the Section 18 use directions, except as modified by this authorization must be followed.

 

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Checking Peanut Maturity

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We checked many peanut samples yesterday from all around the county. Peanuts are looking a lot better with rain. It rained more while we were sampling. Some parts of the county have had 7 inches in the last week and a half. We are having more reports of white mold, and seeing some pod rot as result. We need to observe vine strength. Most profiles are showing a 130-140 day maturity. Last year, 150 days was average. Looking at maturity last week, we noticed wider rangers. We normally start sampling at 120 days, however with more variability in maturity, UGA Extension Peanut Agronomist Dr. Scott Monford recommends evaluate fields that are 90 DAP or older. We are seeing a large variation of peanuts on the vine. Several fields have shut down around 105 DAP and are now coming loose in the hull. If the growers are not checking them until 135 DAP or more, they may indeed lose what they have.

Segregate Dryland Corners

With dryland maturity differences, one thing to consider is dryland areas of the field. Here is a note from Terrell County Ag Agent Nick McGhee:

Once harvest begins, growers need to consider segregating the peanuts they harvest in the dryland corners (or areas that received poor irrigation) from the peanuts that are harvested from irrigated areas. It does not take many poor quality pods to cause a load of peanuts to be graded as Seg 2 or worse. Growers need to consider separating these areas using a disk harrow and keeping them separate as they are loaded onto trailers. Do not let a few bad pods from a dryland corner affect the grade on an entire load of otherwise good quality peanuts.

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