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Silverleaf Whitefly Management Begins NOW! (Phillip Roberts):

Silverleaf whitefly (SLWF) is a sporadic and localized pest of cotton in Georgia. There are reasons for this localized infestation pattern and it is important we understand why this occurs. In Georgia SLWF infestations are most common in areas where both cotton and vegetable production occur. In these areas crops which serve as reproductive hosts are grown 12 months a year. SLWF infests brassica crops in the winter months, move to cucurbits in the spring, move to cotton in the summer, move to cucurbits in the fall, and back to brassica crops during the winter. This is a simplified view of movement and buildup of SLWF during the year. SLWF actually has many different hosts (both wild hosts and cultivated crops), but the crops mentioned are the drivers in SLWF population dynamics. What we do know is that it is important for all of agriculture to properly manage SLWF. Failure to properly manage SLWF in a crop will have negative consequences on the next crop SLWF infests. More information on SLWF and management can be found in the publication “Cross-Commodity Management of Silverleaf Whitefly in Georgia” (https://secure.caes.uga.edu/extension/publications/files/pdf/C%201141_1.PDF).
There are several risk factors influencing SLWF populations during the year. One important factor is winter weather. SLWF survive the winter months on both cultivated and wild host plants. Mild winters favor survival of SLWF. Although temperatures rarely are low enough in South Georgia to kill SLWF outright, freezing temperatures which kill host plants infested with immature SLWF effectively kills immature SLWF on those plants. Cold temperatures also slow development of SLWF. Higher survival and reproduction during winter months leads to higher populations in the spring and the opportunity for populations to rapidly build to damaging levels. To date we have only had 6 days in Tifton when the low temperature was below 32 degrees. When reviewing weather data for the last 15 years, this winter was tied for the fewest days below freezing. What does the lack of cold temperatures mean for cotton? The mild winter suggest our risk for SLWF in cotton is elevated. This does not mean we will have a SLWF problem in cotton, but we cannot ignore the lack of cold temperatures. Spring and summer weather will be the primary factor affecting SLWF populations from this point forward. Hot and dry conditions will favor SLWF population buildup. If you are in an area prone to have SLWF, NOW is the time to manage risk factors we can control.

Variety Selection: hairy leaf cottons are preferred by SLWF compared with smooth leaf cottons. There is a direct correlation of SLWF infestations in cotton based on the degree of leaf hairiness. Risk of SLWF is greatest on hairy varieties > light hairy > semi-smooth > smooth varieties. Smooth leaf varieties are the least preferred by SLWF. Plant Smooth Leaf Varieties

Planting Date: the risk of SLWF problems increases as planting dates are delayed. SLWF complete a generation in about 2 weeks during summer months and populations can increase rapidly. The impact of SLWF on yield is dependent on the growth stage of cotton when SLWF infest the crop. Potential yield loss is greater when infestations appear during squaring or early bloom compared with late bloom. The duration or time of control required to protect yield and quality from SLWF is also dependent upon
planting date. April and early May planted cotton is at lower risk for SLWF problems compared with late May and June planted cotton.
Avoid Late Planting

Location (proximity of SLWF infested crops): crops produced in a given area can be viewed as sources and sinks for SLWF populations. Spring vegetable and melon crops are a source of SLWF infesting cotton. In the fall cotton is a source of SLWF infesting fall vegetables. The nearness of cotton to a SLWF infested field increases the risk of SLWF. Minimize Planting Cotton Next to SLWF Infested Crops. If planting cotton near SLWF infested crops, be sure to avoid late planting and use a smooth leaf variety. Destroy SLWF host crops immediately after harvest; this includes vegetable and melon crops in the spring and cotton (timely defoliation and harvest) and other crops in the fall.

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Row Crop Disease Update

Below is some information that Dr. Kemerait recently shared with county agents:

Though we are still generally early in the season, there are a few things I want to make sure that you are aware of:

  1. We have been allowed to continue our survey of kudzu old growth/regrowth in Georgia.  Last week we surveyed from Midville/Burke County in the east to Plains in the west and numerous locations in-between and south.  The first thing to note is that (no surprise) kudzu is rapidly breaking dormancy across the Coastal Plain.  Caleb (Kemerait’s technician) was able to find it most anywhere he looked.  Most importantly, he only found “old growth” infected with rust and “new growth” infected with rust in a single kudzu patch- extreme southwest Georgia in the Donalsonville/Seminole County area.  We have been finding old-growth kudzu and infected new-growth kudzu throughout much of the winter, but now we only found soybean rust at the single location.  We will continue our survey efforts on a bi-weekly basis for now.
  2. Peanut seed quality issues and related issues with Aspergillus flavus, use of fungicide seed treatments, and in-furrow fungicides continue to be an issue.  Watch for more updates on this as Dr. Brenneman shares his research.  (I’ll update the blog.)
  3. PLANTING DATES:  Temperatures have been nearly “summer-like” recently and many are likely feeling the urge to put seed in the ground – perhaps making plans to plant earlier than usual. The importance of picking a “best” or even a “better” planting date can have a tremendous impact on the threat of disease and nematodes to any crop.  Here are a few pointers:
  •  Planting into warm soils supports rapid germination, rapid growth, and early-season vigor.  All of these things are helpful in the battle against seedling diseases and also to establish a root-system to minimize damage from nematodes.
  • Planting in cooler, especially cooler and wetter soils, not only slows germination and development of the seedlings, but also gives the pathogens, mostly fungal pathogens in my row-crop world, and upper-hand in infecting and even killing seedlings.
  • Planting earlier than normal because “the ground is warm enough and there is plenty of moisture” could easily back-fire.  Sure, it has been beautiful weather to plant for the past could of weeks.  But look what is coming – cold rain and cooler temperatures, I wouldn’t want to have anything but corn in the ground now.
  • Planting date can affect disease severity in ways other than “colder soils” or “warmer soils”.  For example, when using “Peanut Rx”, note that planting prior to 10 May, especially when peanuts are planted in April, increases risk to Tomato spotted wilt, as does planting later in May and into June.  Conversely, planting a bit later can reduce risk to white mold.  (See Peanut Rx)
  • Planting dates are important to other crops as well.  For example, earlier-planted corn and soybeans are much less likely to be affected by southern corn rust and Asian soybean rust, than are later planted corn and soybeans.  Planting date can also have a significant impact on the likelihood of storms and wetter weather later in the season, particularly at harvest.  Whether we recognize it or not, some important reasons why we plant the varieties we plant and the dates when we do are to minimize boll rots in our cotton and late-season losses due to wet weather in our corn and soybean crops.
  • The bottom line is that careful selection of an optimal planting date can have tremendous impact on the risk to diseases early in the season and throughout the season until harvest.  Sometimes, especially when a grower doesn’t have irrigation, you have to plant “into moisture”, whenever that might be.  However, recognizing the impact of planting date and the choice of planting dates, can make a world of difference.

 

 

 

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Liu: Cotton Outlook under Worldwide Coronavirus Outbreak MARCH 20, 2020 / GEORGIA COTTON COMMISSION

Along with the life-and-death struggle and the rising cases of Covid-19, financial markets worldwide have lurched lower. The sell-off of the U.S. stock market started on Feb. 21, 2020. Since then, the great coronavirus crash has been frightening in its speed. Even U.S. Treasury bonds and gold, traditionally a safe harbor in times of crisis, have come under pressure. Crude Oil May 2020 (CLK20) future prices slide to the lowest point at $20.52 per barrel on Mar. 18, 2020.

As investors’ recent pessimism over a coronavirus-induced business slowdown, the cotton market also shadows the pandemic of the coronavirus as well. May 2020 cotton futures for old crop closed at 54.93 cents per pound, and new crop December futures closed at 56.10 cents on Mar. 19, 2020.

Cotton growers need to be aware of the rising volatility and uncertainties in the cotton market. Since the disease outbreak, the cotton supply chain has been severely interrupted. Countries worldwide are implementing social distancing or lockdown, hoping to slow down the spread of the virus. The cotton industry suffers tremendously as the temporary closedown of factories to control the virus.

The long-term impact of the virus is also expected. The aftermath of the coronavirus pandemic is highly likely to result in a global economic slowdown or recession. Cotton products are discretionary items. Thus, the consumption of cotton goes up or down with the economy. Cotton demands are likely to continue decreasing due to the slowing down of the global economy. The world cotton demand is currently forecasted at 118 million bales, down 5 million bales from the last peak in 2017.

On top of everything discussed so far, the U.S. dollar appreciates during the time of crisis as investors are seeking a safety harbor. This appreciation of the U.S. dollar further hinders the export opportunity for cotton. In 2019, 83 percent (16.5 million bales) of cotton produced in the U.S. were exported and traded in the global market. U.S. cotton relies on the global market and international trade to consume excess supply and support domestic prices. The decline in oil prices is likely to increase the competition of synthetic fiber down the road, similar to what we observed after the drop in oil prices during the 2008 financial crisis.

The uncertainties in trade make cotton profitability more challenging. The signing of the Phase 1 trade deal between the U.S. and China on Jan. 15 gave the cotton market a short period of optimism. China agreed to purchase at least $40 billion worth of agricultural products for each of the next two years. However, no details are released so far about how China will be able to fulfill this large purchase of agricultural products. The outbreak of the coronavirus further increased the uncertainty in trade.

USDA Farm Service Agency announced the weekly average adjusted world price (AWP) and loan deficiency payment (LDP) rate every Thursday in the Upland Cotton Announcement. The AWP is currently at 49.95 cents per pound. The LDP rate of 2.05 cents per pound is available from Mar. 20 through Mar. 26. The LDP rate is the difference between the base loan rate of 52.00 cents and the AWP. If taking the LDP, the producer should be aware that there is no further protection from prices going even lower. Producers can wait until Mar. 25 or Mar. 26 in poping their cotton to see what the prices hold for next week. If a producer is willing to take the risk and feels that cotton prices are going to improve, then the producer could take the LDP and market the cotton later.

Looking ahead, producers need to be aware of the continuous risk of down-side price weakness and volatile cotton prices. It might take a while before we see a recovery of cotton prices. Strategies to improve productivity or cutting costs are highly recommended during the time of low cotton prices.

Additional Information

Georgia Department of Public Health reports daily of the confirmed cases of Covid-19 in Georgia (https://dph.georgia.gov/covid-19-daily-status-report ). The latest news about the Covid-19 in the U.S. can be found on the CDC’s website (https://www.coronavirus.gov/). Keep your distance, and stay safe.

This article was written by UGA Extension Cotton Economist Dr. Serinna Liu.

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Example Fungicide Program for 2020

Below is some information from our UGA Pecan Blog (Lenny Wells):

I hope you all are staying safe amid the coronavirus concerns out there right now. Unfortunately as many of you know we have had to cancel our last four county meetings of the year (Wilcox, Jenkins, Brooks, and Dougherty) as well as the Georgia Pecan Growers Assoc. Conference. We will be getting the county meeting presentations up on our website soon. I will send out a quick blog post to provide the link for those if you need them.

Usually this time of year, as bud break is nearing (I began to see budbreak on Cape Fear last week), I send out an example fungicide program. Again, there are many such programs that one could put together. Based on Dr. Tim Brenneman’s research results, I feel that the following would be good choices. You will see one program for highly scab susceptible varieties (think Desirable, Pawnee, Cunard) and another for more moderately susceptible varieties.

The important thing to remember is to rotate chemistries and use the fungicides to their strengths. Group 3 + Group 11 materials are excellent on leaf scab when combined and work well on nut scab too. Phosphites make a great leaf scab material and can be used alone at the 2 qt rate. Miravis Top is a superb new material that provides an additional chemistry to throw in the mix and should be focused on nut scab. Elast and Tin both work better on nut scab than on leaf scab and when combined are an excellent choice for nut scab.

Program for Highly Scab Susceptible Varieties

Absolute

Phosphite (2 qt/acre rate)

Absolute

Phosphite (2 qt/acre rate)

Miravis Top (this should be about the time nut sizing begins)

Elast/Tin

Miravis Top

Elast/Tin

Miravis Top

Elast/Tin

(Continue with Elast/Tin or rotate with Absolute if additional sprays needed beyond this point.)

Moderately Susceptible Varieties

Phosphite (2 qt rate)

Absolute

Phosphite (2 qt rate)

Group 3 +Tin

Absolute (or Miravis Top if pressure is high)

Tin (full rate)

Group 3 + Tin (or Elast/Tin if pressure is high)

Tin (full rate)

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Clarification on Phosphite Materials

Written by Lenny Wells

Based on conversations I have had with a number of growers it sounds as if there is a need for some clarification regarding phosphite materials. Phosphite has become a very valuable tool for us in the battle against pecan scab. Dr. Tim Brenneman first began testing phosphite materials on pecan primarily for efficacy on some of our minor foliar diseases like anthracnose a number of years ago (since at least 2009).

In the course of Dr. Brenneman’s research he began to notice that phosphite also had a significant effect on scab—especially leaf scab. As his research continued, he developed a large data set on phosphite over several years, using many different phosphite products. UGA Extension recommendations for phosphite use are based solely on Dr. Brenneman’s research. Initially it was only recommended for use in combination with other products, never as a stand-alone. Dr. Brenneman now has the data to show that at rates of at least 2 qts per acre, phosphite can be used alone for leaf scab during the pre-pollination stage. It is an excellent leaf scab material and this is where its best use lies. It can be used during nut sizing as well but in high scab pressure situations, should be tank mixed with another fungicide for nut scab.

Now, what exactly is phosphite? Phosphite (H3 PO3 ) is derived from Phosphorous acid, NOT Phosphoric acid (H3PO4) which is a fertilizer. Phosphorous acid dissociates to form the phosphonate ion (HPO3 2-), also called phosphite. Phosphites are highly systemic and very stable in plants. There is evidence that phosphite may stimulate host defenses .

Phosphite or Phosphorous acid is not converted into phosphate, which is the primary nutrient source of P for plant. There are bacteria capable of transforming phosphite into phosphate, but this process is so slow that it is of no practical relevance. To date, no plant enzymes are known to convert phosphite into phosphate. Therefore, any claims that phosphite can contribute to P nutrient requirements for plant growth should be taken with much caution.

As a matter of fact, phosphite can trick plants into thinking they have enough P, which may potentially contribute to P deficiency when phosphite is over-used.

There is apparently some concern out there about the salts present in many phosphite products. If purity of product is of specific concern to you, then you should use a phosphite product that does not have salts present (bear in mind, that your soil applied potash [KCl] is also a chloride containing salt). However, Dr. Brenneman’s research has shown no negative effect from phosphite products containing salt in his research going back at least 10-11 years. There is no evidence for greater toxicity risk in phosphite products containing salt than for those without salt.

If you are concerned about the long term effects of products containing salt, you may also want to consider the fact that phosphite itself is not metabolized by the plant and we also do not know what the long-term ramifications of that may be. Let me be clear, we do not have any evidence that would lead us to believe this will cause any detrimental effects to pecan trees. Nor do we have any evidence to suggest the salts present in some phosphite products will cause any detrimental effects. If independent research on either topic leads to more information on this, we will let you know.

In short, Dr. Brenneman’s research trials have shown that as far as efficacy is concerned, all the phosphite products Dr. Brenneman has tested (which include most of those we currently use in pecan—I won’t list them because there are too many to be named) work equally well on pecan scab and the other minor diseases from which phosphite provides protection and there is no more risk of toxicity with one phosphite product than there is with another.

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Office Closure and UPW Update

Thomas County’s Extension Office will be closed to the public until further notice.  Please call or text my cell (12292258952) with any questions.

From Worth County’s ANR Agent, Scott Carlson-  All in-person Using Pesticides Wisely (UPW) classroom trainings have been cancelled. For those still needing to be trained, UGA Extension and the Georgia Department of Agriculture are currently developing an effective approach that will fulfill training requirements. Look for future updates.

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Potential Peanut Seed Quality Issues

Below is some information from Dr. Kemerait, our UGA Extension Row Crop Plant Pathologist:

We have received many questions in recent days pertaining to the quality issues facing our peanut seed supply in 2020 and relative performance of seed treatments Dynasty PD and Rancona.  Below is the information that you need to know now; as more information is developed we will pass it to you quickly.  As you know, Rancona and Dynasty PD both contain several fungicides; however they do not contain the same fungicides.  This is noteworthy in 2020 when Aspergillus flavus seems to be especially important.

  1. We have multiple years of data showing that Dynasty and Rancona are both very good seed treatments for peanuts.
  2. There has been a tendency for Rancona being stronger on Aspergillus than Dynasty. This was with Aspergillus niger which has been our primary seed pathogen in recent years.
  3. UGA grad student Brian Jordan’s work showing that the mutation for high level resistance to QoI’s can occur in niger supports the clearly reduced efficacy of azoxystrobin (Abound) in furrow, and also on seed (although fludioxinil in Dynasty on seed would help moderate that effect).
  4. Those differences in control may or may not have been enough to make a difference in yield, although the pattern was there for that in some trials

The biggest issue we face with seed quality in 2020 is that this is a different scenario with Aspergillus flavus (a related, but different, pathogen).

Here is what we know now:

1)  Last season was extremely hot and dry.  There is a much higher frequency of Aspergillus flavus in our peanut seed from last year than we usually see.  A. flavus produces aflatoxin, but it can also be an important seedling pathogen.

2)  Culturing the pathogens from seed shows a huge difference in the efficacy of Dynasty and Rancona on this seed borne A. flavus, at least in some seed lots which were identified as being of lower germination.

3) Rancona has considerably less incidence of A. flavus growth in these seed lots.  The difference in seed treatments for inhibition of A. flavus is believed to help explain some of the differences in germination observed, with Rancona producing significantly higher germinations.   Again, this is on some seed lots and not others.  Preliminary evidence is that the later-harvested seeds, which were exposed to the most heat and drought, are the most likely to have high Aspergillus levels.

 What does all of this mean?  Are the differences observed this year due to A. flavus being resistant to QoI fungicides as sometimes occurs in A. niger?  That issue is not known, but is being evaluated as quickly as possible.  There is much we still need to learn, but for now we can say the following:

  • Rancona and Dynasty have both been very good seed treatments.  This year, with the emergence of flavus, Rancona will probably be more effective treatment on those lots with elevated A. flavus populations.  (Elevated A. flavus populations seem to be linked to seed lots with lower germination).
  • High quality seed with similar germinations on the Rancona and Dynasty will probably be fine with either product as the seed treatment.
  • Either seed treatment will likely benefit from the addition of an in furrow spray. Proline and Velum Total have been the most consistent in recent years.   Abound should not be paired with Dynasty, as it duplicates the chemistry most prone to resistance.  Abound would add an additional chemical class where Rancona is being used, and may help with other seed pathogens other than QoI-resistant Aspergillus.
  • If seed that is to be planted has (or is suspected to have lower germination rates), and the seed has been treated with Dynasty PD, then there is a greater need to consider use of additional infurrow applications of Proline or Velum Total to protect stands.

NOTE: We cannot become too narrowly focused as many different pathogens can affect peanut seed!

Research (including grow out tests in the greenhouse) is seeking to answer more of these questions prior to planting season, and we will keep you updated as those results come in.  It should be noted that these issues are being seen in commercial seed that have been produced, handled and stored with great care.  Farmer saved seed are sometimes exposed to less than ideal conditions, and may have even more issues this season.

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