Dark Tobacco Update

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Dark Tobacco Update
UT Tobacco Agent Training March 6, 2009 Highland
Rim Res Educ Ctr Springfield, TN
Andy Bailey Tobacco Extension Specialist Univ. of
KY / Univ. of TN Princeton, KY
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Dark Tobacco Topics

• 2008-2009 crop outlook
• Dark Variety update
• Curing

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Total KY/TN Dark Tobacco2008 Crop
ProjectionCounty Agent Survey
USDA estimate for total 2008 dark crop 87.5
million lbs.
Probably lost 1.5 million lbs of dark-fired and
0.1 million lbs dark air-cured to Hurricane
Ike. 2009 crop down from 2008 -- Reductions in
buying intentions from all companies 2009 crop
more like 2005 crop (40 to 45 million lbs
dark-fired, 12 to 14 million lbs air-cured).
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2009 Dark Tobacco Variety Guide
F or A refers to use as fire-cured or air-cured
variety. F/A indicates either use, with
predominant use given first. Relative yield and
quality scores given on a 0-10 scale, with 10
being best for the predominant use. Dash (-)
means that resistance level is unknown or not
rated at present.
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KT D6 LC

• First hybrid dark tobacco released from KY-TN
  breeding program
• KT D4LC x TN D950
• Leaf texture more like TN D950
• Maturity should be later than TN D950?
• Available for growers in 2007
• Black shank and black root rot resistance
• Improved curing and leaf quality over KT D4LC
• Yield potential slightly less than KT D4LC

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DT 538 LC

• Released from Newton Seed in 2006
• Black shank resistance similar to KT D4
• Maturity similar to KT D4
• Yield potential slightly less than KT D4
• Excellent leaf quality
• Cured leaf quality superior to KT D4
• Lugs tend to fade in color
• May fire up from bottom more
• Some curing problems in 2008?
• Restrictions against DT 538 by some buyers for
  2009

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KT D8LC

• Sister line to KT D4LC
• Same genetics, disease resistance, and high yield
  potential as KT D4
• Different seed selection
• Medium Race 0 and Race 1 black shank resistance
• No black root rot, TMV, or wildfire resistance
• Medium maturity
• Same potential quality problems as KT D4
• Restrictions by some buyers against KT D4 and KT
  D8 in 2009.

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PD 7302LC

• Rickard, 2008
• Similar to KY 171
• Good quality
• Good yield potential
• Race 0 BS resistant
• No Race 1 BS resistance
• Black root rot resistant

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PD 7309LC

• Rickard, 2008
• Similar to NL Mad
• Good quality
• Good yield potential
• Race 0 BS resistant
• No Race 1 BS resistance
• No Black root rot resistance

10
PD 7318LC

• Rickard, 2009
• Similar to NL Mad
• Good quality
• Good yield potential
• Race 0 BS resistant
• No Race 1 BS resistance
• Black root rot resistant

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2008 Dark Air-Cured Variety TrialYield - HRREC,
Springfield, TN
LSD0.05 67 321
296 249 (total)
Total Yield/A (lbs) 3181 2973 3087 3129
3101 3306 2739 2974 3270 3252 3290 3187
2991 3167 3292
Yield (lbs/A)
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2008 Dark Air-Cured Variety TrialQuality Grade
Index - HRREC, Springfield, TN
LSD0.05 11.5
Grade Index (0-100)
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2008 Dark Fire-Cured Variety TrialYield - HRREC,
Springfield, TN
LSD0.05 39 445 419
372 (total)
Total Yield/A (lbs) 3211 3254 3116 2997
3490 3931 3757 3752 4081 3426 3207 3060
3102 3948 3799
Yield (lbs/A)
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2008 Dark Fire-Cured Variety TrialQuality Grade
Index - HRREC, Springfield, TN
LSD0.05 14.2
Grade Index (0-100)
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Evaluation of Dark Tobacco Varieties under Black
Shank PressureChristian Co. Kent Boyd Farm
Hopkinsville, KY - 2008

• Trial set June 11
• 42 rows, 30 plant spacing
• 4978 plants/A
• Predominantly Race 0 black shank
• Plant mortality evaluated throughout season
• 2, 4, 6, 9 wks after setting
• Preharvest
• Yield data collected using preharvest stand
  counts
• Fire-cured
• 2 fires over 22 days

• 8 varieties tested
• Randomized complete block design with 4
  replications
• 2-row plots, 80 ft. long
• Varieties
• Narrowleaf Madole LC
• DT 538LC
• KT D4LC
• KT D6LC
• PD 7302LC
• PD 7318LC
• D2602 (experimental)
• PD 305H (experimental)

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Evaluation of Dark Tobacco Varieties Under Black
Shank Pressure Christian Co. Kent Boyd Farm
Hopkinsville, KY - 2008
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Evaluation of Dark Tobacco Varieties Under Black
Shank Pressure Christian Co. Kent Boyd Farm
Hopkinsville, KY - 2008
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Evaluation of Dark Tobacco Varieties under
Intensive Black Shank PressureDaviess Co. - Tony
and Joe Fischer Farm Owensboro, KY - 2008

• 2 quarts/A Ultra Flourish applied PreTr Inc. to
  entire trial area.
• Trial set June 4
• Plant mortality evaluated throughout the season
• 2, 4, 6, 9 weeks after setting
• Preharvest
• Trial harvested September 9
• Air-cured
• Stripped November 13

• 9 varieties tested
• Randomized complete block with 4 replications
• 2-row plots, 60 ft. long
• Varieties
• Narrowleaf Madole LC
• VA 359
• KT D6
• KT D8
• PD 7302LC
• PD 7309 LC
• PD 7318LC
• PD 305H (experimental)
• D2602 (experimental)

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Evaluation of Dark Tobacco Varieties under
Intensive Black Shank PressureDaviess Co. - Tony
and Joe Fischer Farm Owensboro, KY
2008 Black Shank Resistance Levels of Varieties
Tested
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Evaluation of Dark Tobacco Varieties under
Intensive Black Shank PressureDaviess Co. - Tony
and Joe Fischer Farm Owensboro, KY
2008Stand Counts throughout the season and
final yield/A
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NL Madole LC No black shank resistance
VA 359 Low Race 0, Low Race 1
22
PD 305H R0 R1
D2602 R0R1
PD 7309LC Race 0 resistance, no race 1 Daviess
Co. 2008
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PH-gene Dark Varieties and Race 12 months after
setting Owensboro, KY 2008
PD 7302LC
PD 7309LC
PD 7318LC
Black Shank Variety Trial - Tony and Joe Fischer
Farm Owensboro, KY 2008
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Holdability and Harvest Timingof Dark Tobacco
Narrowleaf Madole
Little Crittenden
PD 7312LC
PD 7302LC
PD 7309LC
PD 7318LC
DT 538LC
TR Madole
KT D8LC
KT D4LC
KT D6LC
TN D950
Burley
VA 309
VA 359
KY 171
DF 911
Weeks After Topping
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Dark Air-Curing

• Curing process similar to burley
• Requirements for dark air-cured
• Better air-cured barns (no outdoor structures)
• Not as open as some burley barns
• Wider stick spacing (12)
• Open firing? (heat and no smoke) may not be
  needed
• Dark more prone to sweat/houseburn and mold
• Control with stick spacing and ventillation

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Air-Curing Tobacco

• Harvest mature tobacco, but dont cut late.
• Weather dictates air-curing
• Barn management has some effect
• Requires slow chemical reactions to change
  tobacco from green to uniform brown
• Slower for dark than for burley
• Optimum conditions
• 65 to 90 F (mean daily)
• 65 to 70 RH (mean daily)
• 15 ft/min air velocity

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Air-Curing Problems

• Low humidity/high temperature
• Drying, not a cure
• Low humidity/satisfactory temperature
• Variegated, piebald or green tobacco
• Low or high humidity/low temperature
• Green tobacco
• High humidity/high temperature
• Houseburn/sweat, microbial growth and excessive
  weight loss

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Manipulating Air-Curing Conditions

• Barn management has most effect on humidity
• Low humidity ? ventilation (2007)
• Could add moisture to barn floor to increase
  humidity
• Beware of excessive moisture and mold growth
• High humidity ? ventillation
• Dark air-cured Could add heat to ? humidity, ?
  drying
• Dry heat from wood or coke fires

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Barn Management for Air-CuringGeneral Practices

• Housing
• Burley 6 spacing in barns 4 in structures
• Dark 9 to 12 in barns
• No overlap between tiers shingle or skip tiers
• Normally need greatest ventilation/air movement
  during first 3 to 4 weeks after housing
• Exception dry curing seasons of 2007 and 2008
• Low temperature (60 F) and/or low humidity early
  in cure
• Casty green dark tobacco, light/high-colored
  burley
• Barn doors/vent open except during inclement
  weather
• Less ventilation needed once color is set in
  lamina

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Air Curing Structures

• Barns
• Inefficient use of labor
• Inconsistent conditions
• Long term storage
• Stick spacing and airflow management critical
• Other structures
• Facilitate air movement
• Cycle in/out of order
• Curing not storage
• Risk of weather damage
• Manage covers more than barn vents and remove
  when cured

Outdoor structures not recommended for dark
tobacco
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Low Cost Air-Curing Structures

• Interest in building non-traditional barns
• Advantage substantial cost savings
• Disadvantages
• Lower capacity?
• Leaf quality?
• Options
• Outdoor curing structures various styles
• Tarp barns
• Sheds

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Tarp Barns
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Tarp Barns

• Ends open lots of ventillation
• Life of tarp 10 to 15 years
• Heath Thurby Henderson Co.
• 40 ft. x 120 ft.
• 2 tiers high scaffolding, wood or pipe
• 5,000 sticks (5-6 acres dark)
• Cost 18,500 for metal and tarp
• 6,000 lumber for tiers
• 25,000 (35,000 for conv. barn)

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Curing Sheds
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Curing Sheds

• Versatile house tobacco or store equipment
• Excellent ventilation
• 24 ft. x 36 ft., closed on ends
• 3 cantilever beams per shed
• Limited housing space (1 tier)
• Sticks can blow out on ends, need some protection
  (trees)
• Dark 80 sticks per beam (40 sticks/side), 240
  sticks/shed
• Burley 120 sticks per beam (60 sticks/side),
  360 sticks/shed
• 3 sheds house 1 acre of tobacco
• Cost less than 1,000 per shed

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Variations on Barn Designs
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Removable Tiers
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Fire Curing

• Tobacco housed 5-8 days prior to 1st firing
• Fired 2 to 6 times with hardwood slabs/sawdust
• 3-4 days to 2 wks/fire
• Initial fires (yellowing/colorsetting)
• 95 to 110 F
• Drying 120 to 135 F
• Finishing 110 to 120 F

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Fire-Curing

• Curing stages for dark fire-cured tobacco
• Yellowing the leaves
• Setting leaf color
• Drying down stalks and leaves
• Applying smoke finish to leaves
• Yellowing done with ventilation and no fires
• Open vents and/or use fans for 5 to 8 days
• Fires started when yellow spots begin to appear.
• All vents closed except those in the top of the
  barn.
• Hardwood slabs covered with sawdust.
• Initial fires increase barn temperature to 95 to
  100?F,
• RH 85 to 90.

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Fire-Curing

• Color set when leaf midrib is still green but
  leaf lamina is uniform brown color.
• 6 to 8 hrs to several days
• Leaf drying
• Increase ventilation (all vents open)
• Heat increased to approx. 135?, RH decreased to
  75 to 80
• Lamina will crack when touched, bottom half of
  midrib brown (7 to 14 days).
• Tobacco allowed to absorb moisture and then
  firing repeated until uniform color is achieved
• Applying finish
• Smoke deposits on the leaf add aroma and texture
• Sequential low fires with no ventilation to
  maximize smoke levels and minimize temperature in
  barn.

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Tobacco Specific Nitrosamines(TSNAs)

• 4 major TSNAs NNN, NNK, NAT, NAB
• Formed from nitrosation of tobacco alkaloids
  nicotine, nornicotine, anatabine, anabasine
  during curing
• Carcinogenic compounds in tobacco products

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Effect of Seed Source and N Fertility on TSNA
Trends During Fire-CuringUKREC, Princeton, KY -
2006
PPM Total TSNA
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Double-Crop CuringCuring 2 crops of tobacco in 1
barn

• Disadvantages
• More management required
• Tighter window of opportunity
• Operations must be timely
• All barns will not work
• Curing conditions may not be ideal, particularly
  2nd crop.
• Steamers or misting systems must be available for
  takedown
• Still need 2 barns worth of sticks
• Where to store 1st crop during second curing

• Advantages
• Major cost savings for barns
• Fewer needed
• Easier to keep labor force occupied
• Barns can be consolidated closer to tobacco
• Companies receiving earlier to accommodate early
  crop stripping

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Double Crop Curing

• Curing 2 crops of dark fired tobacco in the same
  barn and season
• Increased stick spacing requirements on some
  contracts limits barn space
• Major savings in barn capacity

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Double Cropping

• Time management
• Set 1st crop early May, second crop mid-June
• Try to cure 1st crop in 5 weeks
• Aggressive curing

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Double Crop Curing

• 2 Crops
• 5 weeks between transplanting dates
• 1st crop set early May, 2nd crop set mid-June
• 2 crops managed separately throughout season
• Neither crop set at ideal time
• 200 to 300 lb/A yield reduction compared to
  single crop set at optimum date

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• Must manage 2 crops separately
• when double cropping
• Variety selection (maturity characteristics)
• Management practices
• Weather

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Double Crop Curing Experiment HRREC,
Springfield, TN 2005-2006

• Objective
• Discover Best Management Practices for curing and
  managing two crops of dark-fired tobacco in the
  same barn and crop year.
• Treatment comparisons
• Conditioning method
• Steaming or misting
• Takedown method
• Scaffold wagon or bulk
• Time of stripping for 1st cure
• Stripped at takedown or 3 to 4 weeks later

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Best Management Practices for Double-Crop Curing

• Conditioning / ordering
• Overhead misting may be preferred over steaming
• Takedown
• Scaffold wagon may be preferable to bulking
• Time of stripping
• Strip tobacco as soon as possible following
  takedown
• Deliver tobacco as soon as possible following
  stripping
• See new publication online AGR-196

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Fire Curing and Sawdust

• Sawdust shortages in 2008, will probably continue
• Interest in developing contact list of sawmills
  to help growers in sourcing.
• Charlotte, TN Wood grinding unit that can grind
  wood into sawdust specifically for dark
  fire-curing.
• Can reduce sawdust requirements by 50 or more by
  using wood chips if available
• Still need sawdust for stem drying

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Use of Wood Chips in Fire-Curing
2008 Princeton, KY 35 Reduction in sawdust usage
Fires 1 and 2 End of yellowing Color
setting Slabs/Sawdust
Fire 4 Finishing Slabs/chips/dust
Fire 3 Drying Slabs/Sawdust
Fire 5 Finishing Slabs/woodchips
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Websites Dark Tobacco http//ces.ca.uky.edu/da
rktobacco Dark Tobacco Agents
site http//ces.ca.uky.edu/darktobacco/Agent.htm
Burley Tobacco http//www.uky.edu/Ag/Tobacco
Burley Tobacco Agents site http//www.uky.edu/A
g/Tobacco/Agent.htm