Welcome to the Georgia Tobacco Hotline
May 15, 2000
1-800-659-7288
J. Michael Moore,
Editor
University of Georgia
Extension Agronomist-Tobacco
Topics for this week include:
Georgia Weather
Plant Growth Problems
Disease
Curing Barn Retrofit Update
Insects
Bale Tags for 2000
2000 Georgia Tobacco Tour
Georgia tobacco received no rain for the last seven to ten days. Soil moisture continues to be short to adequate. Some irrigation has been applied, but most growers are choosing to save water until it is needed more. For the last week, evening temperatures have fallen only into the upper 60s and the daytime temperatures are running 5 degrees ahead of normal and reaching into the low 90s. This is a dramatic change from last week when evening temperatures were consistently in the low 50s and daytime temperatures only in the upper 70s. Considering the adverse weather conditions up to this point, tobacco growth has been good. Approximately 20 percent of the crop has been cultivated for the last time. Sixty percent of the crop has been cultivated only for the second time and fertilizer applied. A final 20 percent of the crop has been cultivated only once and is just now beginning to be established and grow.
A number of farm visits over the last week dealt with excessive fertilizer application, too close to the plants, too early in the growing season. Excessive fertilizer salts in the soil bed can cause stunting and injury to young seedlings as the salt pulls moisture from the plant roots and stems. One case involved heavy application of the complete fertilizer in two bands prior to transplanting, adequate rainfall to start the plant and moisten the fertilizer before a prolonged drying period. The other case involved a broadcast application of an excessive amount of complete fertilizer prior to soil preparation, shallow soil incorporation prior to bedding, adequate rainfall for start the plants and moisten the fertilizer before a continuing period of no rain. In both cases more than 40 pounds of nitrogen was applied prior to transplanting. Forty pounds of nitrogen is the rule-of-thumb application limit for young tobacco. Drying soils, poorly incorporated herbicides which wind up in the root zone, and cool weather all contributed to poor early establishment and growth of the seedlings. Irrigation was the recommended treatment.
The disease of the week has been a mix of viruses which now appear to be widespread across the production area and in addition to the plague of tomato spotted wilt virus.
Mosaic: Numerous fields have been found to contain up to 80 percent of the plants exhibiting severe mosaic mottling of the leaves and burning of the lower affected leaves as the virus infected thin leaves were exposed to the brightest sun and hottest temperatures of the season. Initial laboratory investigations have determined that a majority of the mosaic symptoms are the result of Tobacco Mosaic Virus (TMV) infection. However, some samples have been determined to contain Cucumber Mosaic Virus (CMV) or Potato Virus Y (PVY).
Infected tobacco seedlings were grown in both greenhouses and field plant beds. Severe infection levels have been observed in Colquitt, Lowndes, Echols, Lanier, Berrien, Appling, and Bacon Counties. Although scattered plants have been observed to contain mosaic symptoms in several other popular varieties, the majority of the severely infected fields are being reported to be planted in NC 71 and NC 72. Both NC 71 and NC 72 are new hybrids and together they probably comprise 70 to 80 percent of the planted acreage in Georgia. Never before have we seen the widespread distribution of mosaic symptoms such as we are seeing now. Tobacco Mosaic Virus is spread by mechanical means and the mowers used in greenhouses and plant beds are proven means of spreading this virus from a single infection. Cucumber Mosaic Virus and Potato Virus Y are vectored by numerous aphid species.
Cucumber Mosaic Virus: Reports from just across the border in Florida indicate another year of heavy infection from Cucumber Mosaic Virus in tobacco. Limited instances of CMV have been observed and reported in Georgia tobacco, with numerous reports of CMV in vegetables. Researchers at the Coastal Plain Experiment Station in Tifton are cooperating with Extension Specialists and County Agents to analyze plant samples and determine the cause of mosaic symptoms.
Tomato Spotted Wilt Virus (TSWV) continues to increase in most of the crop. Statewide average incidence levels are running 5 to 8 percent of plants. Some fields have significantly more plants affected, ranging from 20 to 40 percent. Fields planted in March appear to have a greater level of infection than those planted in through the month of April. Symptoms continue to appear with time. Tobacco receiving a treatment of Admire 2F either in the plant house or transplant water appears to have lower incidence of TSWV with the plant house treatment consistently resulting in greater control of TSWV.
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Above: Examples of the mosaic symptoms seen recently.
The proposed funding program to assist growers with the retrofitting of curing barns with heat exchangers still has not been signed and activated. Limited numbers of heat exchangers have been purchased in Georgia and only a few have actually been delivered and installed. Growers generally are waiting for the funding assistance program to be approved before placing heat exchanger orders. With the beginning of tobacco harvest less than eight weeks away the time for delivery and installation has really begun to come into consideration for retrofitting barns this season.
Grower concern appears to be increasing regarding the purchase of tobacco from non-retrofitted barns during the 2000 marketing season. However, the limited number of retrofits and the requirement for segregation of tobacco beginning at the farm level and carrying through to the warehouse and the processor seem to be reassurances of the likely lack of differentiation at the point of purchase. The original time frame of the retrofit program as proposed by the Tobacco Industry Leadership Group runs until July 1, 2001, when heat exchangers will be required in order to receive price support.
An educational program of the land grant universities in the tobacco growing area has been planned to assist growers who have existing barns without direct flame curing with the assurance that their heat exchangers do not emit nitrous oxide into the barn during the curing process. Additionally, it is hoped that the same processes will be used to reassure growers and the industry that retrofitted barns are performing as desired. However, initial attempts to quantify the nitrous oxide levels in the circulated barn air have been less than successful. The gas analyzers evaluated were not capable of determining nitrous oxide levels of less than one ppm. Gas analyzers which are more sensitive are available at a much greater cost, but do not seem to be suitable for use outside the laboratory. We continue to believe that barns equipped with properly installed heat exchangers which provide for venting the exhaust gases of combustion outside the barn will significantly reduce the resulting nitrosamine levels in tobacco and are the approach which must be taken to maintain the desirability of U.S. flue-cured tobacco.
A variety of insects have been found affecting this year's tobacco crop. Budworms have arrived and growers have begun treatments. Limited aphids and flea beetles have been observed, probably as a result of the high level of usage of Admire 2F among tobacco growers. One report of adult vegetable weevils causing damage in field tobacco has been received.
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Above: Cotton Bennett Farm, Ware County; Soil Insect Test; David Jones, Extension Entomologist; Tony Otts, Ware County Extension Agent. Left: Pink flags indicate cutworm damaged tobacco plants. Right: Admire 2F planthouse drench with Orthene in the transplant water and in 5 foliar sprays.
Cutworms and mole crickets have also caused some losses. In fact, one of David Jones's soil insect tests happened to be in a hot spot for granulate cutworm and he has accumulated a great deal of data on a number of soil insecticides. Outstanding control was provided by Admire 2F when compared with Lorsban. Better control resulted from rates of Admire greater than one ounce per 1000 plants, with better control from the plant house drench treatment compared with the transplant water treatments. Control was further improved for Admire plant house treated plants which received Orthene in the transplant water and as 5 foliar sprays in the field. No Admire transplant water treatments received the Orthene treatments at this location. Admire is not currently labeled for cutworms. Control obtained with transplant water treatments of Platinum, yet to be labeled from Novartis, was intermediate between Admire and Lorsban.
The Flue-Cured Tobacco Bale Tag Corporation announced this past week two important changes in the procedure for obtaining bale tags for the 2000 marketing season. 1.) Bale tags ordered by August 15, 2000 will be supplied without charge. After August 15, tags will cost 15¢ each. 2.) All tag request forms must be submitted by mail. No orders will be taken by fax or phone.
Other rules and procedures remain essentially unchanged from 1999.
Information on "Rules and Procedures Governing Flue-Cured Tobacco Bale Tags: 2000 Marketing Season", the "Bale Tag Request Form for Growers," and the "Bale Tag Request Form for Warehouses/Dealers" may be found on the Georgia Tobacco Web Page at the following address:
http://www.griffin.peachnet.edu/caes/tobacco/BaleTags2000.htm
If you have questions about bale tags, please contact: J.T. (Tommy) Bunn (919) 782-5151
The tour will begin with a Kick-Off Supper on Tuesday, June 13, and end mid-afternoon on Thursday, June 15, 2000. The Florida Tobacco Tour will start in Gainesville, Florida at 8:00 am and will end at the Shoney's Inn in Valdosta, Georgia (Exit 16, GA Hwy 84 east of I-75) in time for the Kick-Off Dinner.
Contact Ben Whitty (352-392-1817, extension 211) for information regarding the Florida Tour.
After finishing the Florida Tobacco Tour, headquarters for Tuesday evening June 13, will be the Shoney's Inn (912-244-7711) in Valdosta, GA located at Exit 16 off I-75. Identify yourself as part of the "Georgia Tobacco Tour" for Special Rates. The Kick-Off Supper will be held at the Lowndes County Civic Center on Hwy 84 East at 7:00 p.m.
The tour will leave Shoney's Inn at Exit 16 at 7:30 a.m. on Wednesday, June 14, and visit farm sites and the Coastal Plain Experiment Station. In the afternoon we will visit on-farm demonstration sites. We will spend the night of June 14, in Waycross. Supper will be served at 7:00 p.m. at Mixon's pond on Hwy. 82, west of Waycross, near Waresboro. A block of rooms has been reserved at the Holiday Inn (912-283-4490) in Waycross. Identify yourself as part of the "Georgia Tobacco Tour".
Thursday morning, June 15, the tour will leave from the Holiday Inn parking lot at 7:30 a.m. to visit on-farm demonstrations in Ware and Bacon. Lunch will be in Alma. In the afternoon we will visit several additional on-farm demonstration sites in Appling, Jeff Davis and Evans Counties and ending in the middle of the afternoon.
Register on-line for the Georgia Tobacco Tour by clicking on the web site below. Additional scheduling information and directions to tour stops will be added to the Tobacco Tour Web Page as the date gets closer.
http://www.griffin.peachnet.edu/caes/tobacco/TobaccoTour.htm
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