Post on 23-Apr-2018
Integrated Pest Management Strategies for Tobacco Production in the United States
T. David Reed
Virginia Tech Southern Piedmont Center
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Objective
Discuss the use of integrated pest management by U.S.
tobacco growers
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Concept of Integrated Pest Management
1. Implies an integration of pest management approaches and methods
2. Considers the crop and pest ecology and relevant interactions that pest management practices may have on the environment
3. Considers the interaction of the pest and the crop in the overall cropping system
4. Minimizes the economic risks of pest populations and the potential impact of control measures on the environment
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Approaches to Pest Management
1. Prevent a pest outbreak from occurring
2. Suppress a pest outbreak that has occurred
(remedial control)
3. Eradicate a pest
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Pest Management Methods
1. Biological
2. Cultural / Mechanical
3. Chemical
4. Regulatory or Legal
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Biological Control
1. Classical
2. Augmentation
3. Natural
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Examples of Natural Biological Control 2011
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Cultural Pest Control in Tobacco Crop rotation
Resistant varieties
Row cultivation
Fertilization level
(nitrogen)
Planting date
Reducing weed hosts
Plant spacing
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Tobacco Host Plant Resistance Black shank
Bacterial wilt
Tobacco mosaic virus
Aphid transmitted viruses
Blue mold in burley tobacco
Root knot nematode resistance
Black root rot
Budworm resistance / tolerance
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Cultural Practices for Disease and Nematode Control
Early stalk and root
destruction
Crop rotation
Resistant varieties
Priming for target spot
Plant spacing for blue
mold
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Chemical Control
Preventative and Remedial or Curative
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Pest Management Thresholds
Economic threshold – pest population level at which
the economic benefit of a pesticide application
exceeds the cost
Based on quantitative models
Remedial control action
Action threshold – management decision based more
on practical experience and judgment than a
quantitative model
Both preventative and remedial control
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Insect Thresholds Insect Action Threshold
Aphids 50 or more on any upper leaf of
10% of the plants
4 wks after planting until
final harvest
Budworms 10 plants with 1 or more
budworms per 50 plants
3 wks after planting until
1 week prior to topping
Hornworms 1 in. long = 5 per 50 plants
< 1 in. long = 1 per plant
Do not count parasitized worms.
3 weeks after planting
through harvest.
May continue to eat on
air-cured tobacco.
Flea beetles 4 per plant when less than 2 wks
old
8 per plant when 2 to 4 wks old
> 60 per plant when plants are
more than 4 wks old
Transplanting to 4 wks
after planting and from
topping through harvest
Cutworms 5 of 100 plants with recent
damage
1 to 4 wks after planting
Grasshoppers 10 grasshoppers per 50 plants 6 wks after planting
through harvest
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Root-Knot Nematodes
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Root-Knot Nematode Thresholds
Risk of
Crop Loss
Galled Roots
(%)
Nematode per
500 cc of soil Control Options
Very Low 1 to 10 1 to 200 Crop rotation and/or
use a resistant variety
Low 11 to 25 201 to 1,000
Crop rotation and a
resistant variety and/or
a nematicide
Moderate 26 to 50 1001 to 3000
Increase crop rotation
interval and use a
resistant variety and a
nematicide rated
“Good” or better
High > 50 > 3000
Increase crop rotation
interval and use a
resistant variety and a
fumigant nematicide
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Thresholds for Other Nematodes
Use of a nematicide is warranted if:
Lesion nematode = 50 to 100 per 500 cc of
Tobacco cyst nematode = 1000 eggs per 500 cc of soil
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Black Shank Management Decisions
Resistance Index
(1 to 100) Management Systems
90 or above
Satisfactory against black shank in most situations without the
use of a fungicide. Varieties are susceptible to Pythium and
other races of black shank
81 to 89 Use with 3 applications of a fungicide in fields with a history of
black shank and a short rotation interval.
80 or below
Use in fields with little to no history of black shank.
Lengthening rotation interval and use of fungicide will minimize
any losses.
2005 Flue-Cured Tobacco Production Guide (Virginia)
Heavy reliance on host plant resistance (Ph gene)
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Black Shank Management Decisions
Resistance Index
(1 to 100) Management Systems
90 or above Growers planting Ph gene varieties in infested fields
should assume the presence of race 1 black shank and
consider use of a fungicide in fields where previous
disease losses have occurred.
81 to 89 Use with 3 applications of a fungicide in fields with a history of
black shank and a short rotation interval.
80 or below Use in fields with little to no history of black shank.
Lengthening rotation interval and use of fungicide will minimize
any losses.
2011 Flue-Cured Tobacco Production Guide (Virginia)
Emphasize a combination of host plant resistance and fungicide use
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Tomato Spotted Wilt Virus in Georgia
1. Transplant after April 7
2. Use greenhouse transplants and treat in the
greenhouse with imidacloprid
3. Treat transplants in the greenhouse with
Actigard
4. Use transplant setter water Strip-tillage into small a grain cover has been demonstrated
to reduce the incidence of TSWV
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Do we employ IPM strategies in U.S. tobacco production?
Answer is yes.
Extension education stresses the principles of IPM
Growers utilize an assortment of IPM practices
Most growers utilize crop rotation and resistant varieties
Pest control include a combination cultural and chemical strategies
Very few true IPM “programs” (TSWV in Georgia)
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IPM Needs
Increased host plant resistance options
budworms, race 0 and 1 black shank, bacterial wilt, TSWV, etc.
reduced sucker pressure
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IPM Needs
Increased host plant resistance options
Better understanding of foliar diseases and management options
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IPM Needs
Increased host plant resistance options
Better understanding of foliar diseases and management options
Strengthen the concepts of field scouting and thresholds
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IPM Needs
Increased host plant resistance options
Better understanding of foliar diseases and management options
Strengthen the concepts of field scouting and use of thresholds
Address the aspect of pesticide residues on the cured leaf
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IPM Needs Increased host plant
resistance options
Better understanding of foliar diseases and management options
Strengthen the concepts of field scouting and use of economic thresholds
Address the aspect of pesticide residues on the cured leaf
Biological control options
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IPM Needs Increased host plant
resistance options
Better understanding of foliar diseases and management options
Strengthen the concepts of field scouting and use of economic thresholds
Address the aspect of pesticide residues on the cured leaf
Biological control options
Greenhouse disease management
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Will the future level of applied land grant university
research be sufficient to address pest management
challenges?
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Integrated Pest Management
Consider and take advantage of interactions between pest populations and
management / cultural practices
Ph gene for black shank resistance
Near immunity to race 0 black shank
Tolerance to tobacco cyst nematode
Result of the use of Ph gene varieties for black shank has been to significantly reduce TCN populations
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Integrated Pest Management
Consider and take advantage of
interactions between pest populations and
management / cultural practices
Impact of mechanical topping and harvesting
on the spread of bacterial wilt
Result is the demonstration of the need to
reduce the mechanical spread of the
bacterial wilt pathogen
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Biological Control of Aphids
Release of lady beetles
Aphid fungus
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Cultural Practices for Insect Management 1. Early plowing in the spring
2. Use recommended nitrogen rate
3. Transplant early (+ aphids and hornworms – budworms and flea beetles)
4. Destroy unused transplants in greenhouse
5. Manage field borders to reduce insect habitat
6. Top tobacco in button to early flower
7. Control suckers
8. Destroy crop residue after harvest
9. Rotate with crops to reduce soil insects
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