Approaches to Weed Control in Vineyard Driplines
Sarah Bowman Dept. of Plant, Soil and Agricultural Systems
Southern Illinois University
2015 IGGVA Annual Conference Springfield, IL
Importance of Weed Control
• Reduce competition with vines: – Water – Nutrients – Light
• Reduce vine canopy and fruit zone interference: – Light – Air flow – Pesticide spray – Increase difficulty of canopy management and harvest
• Reduce environment for pests: – Insects – Disease – Nematodes – Rodents
• Reduce injury/annoyance for workers: – Poison ivy skin irritant – Multiflora rose, horsenettle thorns
Poor or Lack of Weed Control Encourages:
• Competition with vines
– Small vine size – Reduced yield – Poor fruit quality
• Establishment of perennial weeds – Difficult to control
• Disease – Poor fungicide interception and coverage – Downy mildew – Late season fruit rot
Excessive Competition Problematic When:
• Vines are young, weak or over cropped – Small or shallow root system
– Short stature/small canopy size
• Droughty season – Less water and nutrient availability
• Low vigor site – Eroded, tight clay soil Limited rooting volume
– Excessively well drained with no irrigation
– Nutrient deficient soil
Grower Weed Control Goals
• Control perennial weeds during site prep
• Maintain weed free strip during vine establishment (years 1 through 3)
• Provide adequate weed control throughout growing season • Adjust weed control intensity in accordance with vine needs • Promote soil health
– Reduce erosion – Increase water/air infiltration – Increase biological activity
Considerations When Choosing Weed Control Approach
• Weed identification
• Problematic weed species
• Vine age
• Vine vigor
• Site vigor
• Training system
• Site susceptibility to erosion
• Soil type
• Precipitation
• Irrigation
Approaches to Weed Control
• Traditional: herbicide bare strip
• Chemical: herbicide bare strip as needed/weed mulch layer
• Mechanical: cultivation
• Cover Crop: annual or perennial
• Organic Mulch: compost or hardwood
• Other: permeable fabric or plastic, mowing, flame burning
• Spring and late summer → apply pre-emerge residual herbicide under row
– Rotation of Princep, Karmex, Solicam
Traditional: Herbicide Bare Strip
Traditional: Herbicide Bare Strip
Advantages Disadvantages • Eliminates competition
• Herbicide resistance
• Difficult application mid/late season
• Vine injury
• Increased soil erosion
• Reduced soil water/air infiltration
• Reduced soil biological activity
• Eliminates competition
• Ease of application early in season
• Low cost
• Pre-emerge residual activity
• Systemic herbicide provides good control of perennial weeds
• Broad spectrum control
• Specific control
Herbicide Bare Dripline Leads to Soil Erosion
• Spring →apply pre-emerge residual herbicide under row
– Rotation of Princep, Karmex, Solicam
– Use less than full rate
• Follow up (5-6 weeks later) apply mix of residual + burndown
Chemical: Herbicide Bare As Needed/ Weed Mulch Layer
Chemical: Herbicide Bare As Needed/ Weed Mulch Layer
Advantages • Reduces competition • Reduces damage to soil health • Increase soil air/water
infiltration • Increase soil water retention • Ease of application early in
season • Low cost • Pre-emerge residual activity • Systemic herbicide provides
good control of perennial weeds
• Broad spectrum control • Specific control
Disadvantages • Time sensitive
• Difficult application mid/late season
• Vine injury
• Herbicide resistance
• Rodent pressure
Choose and Apply Herbicides Wisely
• Pre-emerge with post-emerge activity can damage trunk renewals – Protect renewals with grow tubes, or use product with
no post-emerge activity
• Pre-emerge can damage vine roots on sandy, low organic matter, low clay soils
• Perennial weeds best controlled with systemic herbicide
• Grass weeds can be controlled with selective grass herbicide
• Always practice herbicide rotation to avoid resistance
• Always read herbicide label • Take the time to calibrate sprayer
• Cultivate when average weed height is 4 to 6” • Repeat as necessary
– Frequency of cultivation increases with frequency of precipitation
• Implement Options:
– Weed badger – Grape hoe – Weed knife
Mechanical: Cultivation
Mechanical: Cultivation
Advantages • Reduces competition
• Applied as needed
• Broad spectrum control
Disadvantages • Encourage weed seed
germination
• Requires special equipment
• Injury to vines
• Root pruning
• Damage to soil structure – Breaks aggregate structure
and increase soil susceptibility to erosion and crusting
• Decreased soil organic matter
• Light cultivation to prepare seedbed
• Annual, spring seeded: cereal rye, oats
• Annual, fall seeded: cereal rye, wheat
• Perennial, fall seeded: red fescue
• Grass cover crop species can be controlled with selective grass herbicide
• Fertilize and control weeds to encourage strong stand development
Cover Crops: Annual or Perennial
Cereal Rye
May June July
Red Fescue as Living Mulch
May July Aug. Nov.
Cover Crops: Annual or Perennial
Advantages • Reduced erosion
• Increased soil water/air infiltration
• Increased organic matter
• Increased soil biological activity
• Grass cover crops can reduce broadleaf weed pressure
Disadvantages • Competition with vine
• Time sensitive management
• Intensive management – Establishment
– Stand maintenance
• Escape weeds require spot treatment
• Composted winery waste
• Hardwood bark mulch
• Shredded or composted corn stalks
• Straw
• Grow your own
• Carbon to nitrogen ratio and thickness of mulch layer influences mulch persistence
• Adjust fertility to reduce negative impact of nitrogen immobilization
Organic Mulch
Bark Mulch + Composted Winery Waste
June October
Organic Mulch
Advantages • Reduced competition with
vine for soil water
• Increased moisture retention
• Reduced erosion
• Increased organic matter
• Increased rooting volume
• Increased root zone cooling
• Utilization of winery waste
• Source and slow release of N,P,K,
Disadvantages • Weed seed in mulch source
• Nitrogen immobilization
• Increased rodent pressure
• Impact on fruit chemistry
Other Forms of Weed Control
• Inorganic Mulch: Permeable fabric or plastic
• Mowing
• Flame Burning
Weed Control as a Vine and Soil Health Tool
• Eliminate, reduce, or encourage competition to promote or reduce vine vegetative growth
– Eliminate competition: young or weak vines, drought
– Promote competition: extremely vigorous vines, wet seasons
– Reduce competition: balanced vine growth, adequate but not excessive rainfall
What to Look For: The Visual Symptoms of Healthy, Balanced Vines
• Leaf color: Deep green
• Shoot length: 3 to 4 ft.
• Shoot Diameter: Pencil size
• Leaf number: 12 to 20 leaves/shoot
• Lateral length: Less than 1 ft.
• Tendril length: Extending just past growing tip
Weed Control as a Vine and Soil Health Tool
• Eliminate, reduce, or encourage competition to promote or reduce vine vegetative growth – Eliminate competition: young or weak vines, drought – Promote competition: extremely vigorous vines, wet – Reduce competition: balanced vine growth, adequate but not
excessive rainfall
• Allow moderate weed growth (8 to 10”) before burndown application to create mulch layer – Protect soil from erosion – Increase soil water/air infiltration – Maintain or increase soil organic matter
Grower Weed Control Goals
• Control perennial weeds during site prep
• Maintain weed free strip during vine establishment (years 1 through 3)
• Provide adequate weed control throughout growing season • Adjust weed control intensity in accordance with vine needs • Promote soil health
– Reduce erosion – Increase water/air infiltration – Increase soil biological activity
Summary
• Rigorous weed control is necessary for young or weak vines, or during drought conditions
• Avoid using herbicide bare culture just for aesthetics
• Remember to scout for symptoms of vine stress, balance, or excessive vigor and use weed control as a vine growth tool
• Use weed control practices that promote soil health – Reduce erosion
– Promote soil water/air infiltration
– Increase soil biological activity
Approaches to Vineyard Weed Control Sources:
• Midwest Grape Production Guide, Bulletin 919, OSU Extension
Authors: I. Dami, B. Bordelon, D.C. Ferree, M. Brown, M.A. Ellis, R.N. Williams, D. Doohan
• Wine Grape Production Guide for Eastern North America, NRAES-145, Virginia Tech
Editor: T.K. Wolf
• Midwest Small Fruit and Grape Spray Guide, Bulletin 861, OSU Extension
Thank You For Your Attention!
Acknowledgements:
Illinois Grape Growers and Vintners Association
Conference Attendees
