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Weed and Vegetation Management in Grape Production
Jeffrey Derr
Professor of Weed Science
Virginia Tech
Charlottesville VVA talk 1/30/14
2014 Pest Management Guides
Horticultural and Forest Crops
• http://pubs.ext.vt.edu/456/456-017/456-017.html
Weed control section for grapes
• http://pubs.ext.vt.edu/456/456-017/Section-3_Grapes-3.pdf
Weed identification Books and Websites
• Weeds of the Northeast – Cornell Press
• Weeds of the South - University of Georgia Press
• Virginia Tech weed identification website:
http://oak.ppws.vt.edu/weedindex.htm
Vegetation Management Plan
Cover crop between the rows- Erosion control, ability to drive through vineyard soon after a rain
Initially bare ground within the grape row- weeds, cover crops suppress vine growth
Weed control in row middles
Few options after planting grapes
• Aim (carfentrazone) -contact herbicide that will control small annual broadleaf weeds.
• Establish cover crop, control broadleaf weeds, kill cover crops in strips prior to planting
Perennial Cover Crop Evaluation for Enhanced Vineyard Floor Management
Funded by the Virginia Wine Board/ VVA/VDACS
Trials in Virginia Beach, Blacksburg, and cooperating vineyards
Evaluate cool- and warm-season perennial grasses for use between rows of grapes
Project Goals
• Evaluate ease of establishment and persistence for cool- and warm-season cover crops between vine rows.
• Evaluate weed suppression for each perennial cover crop.
• Determine crop suitability criteria such as: traffic, drought, and cold tolerance, as well as maintenance requirements.
• Evaluate cover crop influence on overall soil health.
Cool-season Establishment - Blacksburg
All good establishment
‘Bighorn GT’ Sheep /Hard Fescue
‘DTT-43’ Dwarf Tall Fescue
‘DTT-20’ Dwarf Tall Fescue
‘Rough and Ready’ Microclover mix*
‘Companion Grass ‘ Cover Crop Mixture**
‘Applaud’ Perennial Ryegrass
‘Fawn’ K31
‘Midnight’ Kentucky Bluegrass
‘Silverlawn’ Creeping Red Fescue
Cool-season Establishment - Blacksburg
‘Rough and Ready’ Microclover mix* -
34% Quatro Sheep Fescue, 30% Eureka II Hard
Fescue, 30% PR8821 Perennial Ryegrass, 5 %
Microclover
‘Companion Grass ‘ Cover Crop Mixture** - 80% PR8821 Perennial Ryegrass, 20% Creeping Red Fescue
Warm-season Establishment - Blacksburg
Poor with blue grama
Uneven with bermudagrass, zoysiagrass and
their combinations with cool-season grasses
- Weed competition
Establishment – Virginia Beach
Good – tall fescues (Fawn, DTT 43, DTT 20, Justice), zoysiagrass + Gotham hard fescue
Poor – Kentucky bluegrass, hybrid bluegrass, Bighorn GT, Companion grass, Rough and Ready, Perennial ryegrass, zoysia + perennial; ryegrass, blue grama
Traffic tolerance
Good with the tall fescues, Companion grass, Rough and Ready
Fair with Kentucky bluegrass
Poor to fair with Bighorn GT, creeping red fescue
Cover crops – Cool-season glyphosate tolerant
• Big Horn GT – sheeps fescue• Aurora Gold hard fescue
• Compared to Gotham hard fescue
Weed life cycle
Annuals
Summer - grass, broadleaf, sedge, other monocots
Winter – grass, broadleaf
Biennials – broadleaf
Perennials – grass, sedge, other monocots, broadleaves
Summer annual grasses
Large crabgrass
Giant foxtail
Goosegrass
Winter annual grasses
Italian (Annual) ryegrass Annual bluegrass
Annual broadleaves
Summer common lambsquarters, smooth pigweed, common ragweed, ivyleaf morningglory
Winter vetch, horseweed, fleabane, common chickweed, henbit
Summer annual broadleaves
Common ragweed tall morningglory
Common lambsquarters Smooth pigweed
Winter annual broadleaves
Vetch
Common chickweed Horseweed
Henbit
Biennials
Musk thistle Wild carrot
Perennial Monocots
Perennial grasses• clump - tall fescue, orchardgrass• creeping - quackgrass, bermudagrass,
johnsongrass
Perennial sedges – yellow nutsedge
Other perennial monocots – wild garlic
Bermudagrass
Perennial grasses
Quackgrass
Johnsongrass
Yellow and Purple NutsedgePerennial sedges (rhizomes, tubers)
Other monocots
Wild garlic (perennial)
Perennial broadleaves
• Simple – dandelion, buckhorn plantain
• Creeping - bindweed, brambles, poison ivy, horsenettle, hemp dogbane
Dandelion Buckhorn plantain
Simple perennial broadleaves
Creeping perennial broadleaves
Poison ivy Horsenettle
Hedge bindweed
Perennial broadleaf weeds
Hemp dogbane Black locust
Grape Weed Control
• Biological – little available
• Cultural
• Chemical
Vegetation Management Plan
• Killed strip within the row to reduce weed competition
• Mowed (grass) alleyways for erosion control, drivability soon after rain
Site PreparationGoal is to reduce weed populations, especially for perennial weeds
• Cover crops - cropping with competitive or allelopathic crops, such as rye or sudangrass, for 1 to 2 to two years before planting
• Grow alternative crops like corn where troublesome weeds like yellow nutsedge or broadleaf weeds can be controlled using herbicides that cannot be used in fruit.
• Establish permanent cover
Site prep - Chemical control
• Glyphosate
- apply in strips in fall for fescue, orchardgrass control
- plant into killed strips
Cultural control
• Cultivation (mechanical) – suppress perennials, break crusts, soil erosion, root damage
• Cultivation (flame) – tree injury, fire hazard• Black plastic, fabrics – habitat for rodents,
cost• Organic mulches – improve moisture
penetration, habitat for rodents, cost
Chemical controlPreemergence herbicides
• Match to weed problems• Apply prior to weed germination (clean
soil or add a postemergence)• Apply proper rate for soil type (organic
matter, soil texture)• Need rain or irrigation for activation• Shorter residual under wet conditions
Preemergence herbicides for grapes – annual grasses and small-seeded
broadleaf weeds
• Surflan (oryzalin), Prowl (pendimethalin), Devrinol (napropamide) – annual grasses, some broadleaves
• Can be used at planting after soil settles
Preemergence control – small-seeded broadleaf weeds
• Trellis (Gallery) (isoxaben)• Combine with Surflan (oryzalin), Prowl
(pendimethalin), Devrinol (napropamide) – annual grasses, some broadleaves
• Can be used at planting after soil settles• 165 day PHI
Preemergence herbicides for grapes – annual grasses, small-seeded broadleaf weeds, suppression of yellow nutsedge
• Solicam (norflurazon)• Vines must be established 2 years
Pre and early POST control – annual grasses, small-seeded broadleaf weeds,
suppression of yellow nutsedge, dandelion
Matrix (rimsulfuron)• Vines must be established 1 year• Short residual• Combined with Surflan, Prowl, etc. for
broader-spectrum control• 14 day PHI
Pre and early Post control – annual broadleaf weeds, annual grasses
Goal, GoalTender (oxyfluorfen)
• vines established 3 years unless on trellis wire at least 3 feet above soil surface
• combine with Surflan, Prowl, etc. for improved annual grass control
Chateau (flumioxazin) – grapes
• Dormant applications preferred• Treat in early spring and fall• Could add a preemergence grass herbicide,
especially under high annual grass pressure or lower rates
• Add a postemergence herbicide for control of emerged weeds
• Use directed sprays, do not apply overtop of grapes
Chateau (flumioxazin) – grapes
• 6 to 12 ounces of product per treated acre, which equates to 0.19 to 0.38 pounds active ingredient per acre.
• Maximum use rate per year is 24 ounces of product.
• Use of 6 ounces of Chateau per acre when applications are made to very sandy/gravelly soils and tree or grape vines are established less than 3 years.
Pre and early Post control – annual broadleaf weeds, annual grasses
Chateau (flumioxazin)• Vines established at least 2 years unless
vines protected with grow tubes, waxed containers, etc.
Results withChateau
• Strength is annual broadleaf control
• Excellent control – common lambsquarters, pigweed, velvetleaf, jimsonweed, common ragweed, prickly sida, bittercress
Buckhorn plantain, yellow woodsorrel from seed
• Good control – annual morningglories, cocklebur
Results with Chateau
• Fair to excellent control of annual grasses:
Large crabgrass, yellow foxtail, giant foxtail, johnsongrass from seed
• No control of yellow nutsedge or bermudagrass at use rates
Preemergence control - annual broadleaf weeds, annual grasses
Princep (simazine), Karmex (diuron)
• Vines established 3 years• Inexpensive broadleaf control• Match rate to soil type• Combine with a grass herbicide
Preemergence herbicides for grapes – winter applied – cool-season grasses,
winter annuals
Kerb, Casoron – winter-applied, cools season perennial grasses, winter annuals
• For control of quackgrass, tall fescue, orchardgrass, plus winter annuals
Pre – annual grasses, annual broadleaf weeds
Alion (indaziflam)
• Vines established at least 5 years
Alion (indaziflam)
-sprayable form 1.67 lb/gal caution label
- Preemergence with significant post activity
- different mode of action (cellulose biosynthesis inhibitor)
-directed spray
-use rate 5 fl oz/acre (0.065 lb ai/A) (only 1 appl/year at that rate)
Alion (indaziflam)Strength – controls annual grasses (crabgrass, goosegrass, foxtails, annual bluegrass, annual ryegrass)
- many annual broadleaf weeds (jimsonweed, pigweed, horseweed, lambsquarters, velvetleaf, eclipta, spurge, henbit, chickweed, speedwell, bittercress)
- Long residual
Weakness Does not control morningglory or yellow nutsedge
Postemergence herbicides for grapes
Chemical controlPostemergence herbicides
• Match to weed problem• Apply to actively growing weeds (no
drought stress)• Apply under warm temperatures (60 –
85 F)• See if a surfactant is needed (nonionic
versus crop oils)
Postemergence Grass herbicides
Perennial grasses – johnsongrass, quackgrass, bermudagrass
Annual grasses – crabgrass, foxtails, etc.• Poast (sethoxydim), Fusilade DX
(fluazifop) – 50 day PHI • Select Max – nonbearing • Add a nonionic surfactant or crop oil
Aim (Carfentrazone)• a 1.9 lb/gallon EW or as a 2 lb/gallon EC• postemergence control of small annual broadleaf weeds.• 1 to 2 fluid ounces per acre. • Apply when annual broadleaf weeds are less than 6 inches
in height and actively growing. • does not control grasses. • can be tank mixed within other postemergence herbicides
for broader-spectrum control or with preemergence herbicides.
• Adding a crop oil concentrate or nonionic surfactant may improve weed control.
• Do not allow spray to contact green stems, leaves, flowers • Can also be used for control of suckers – see label for rates
and directions for this use.• 3 day PHI
Rely (glufosinate)
Nonselective
• Contact with some translocation• Less effective on perennial weeds than
glyphosate but lower risk of crop injury• Apply as a directed spray when weeds are
small and actively growing • 14 day PHI
Alternatives to Rely (glufosinate)
Nonselective
paraquat (Gramoxone)• Rapid acting contact• No effect on underground tissue –
rhizomes, roots, bulbs, etc.• Restricted use due to toxicity• Apply this contact herbicide as a directed
spray when weeds are small and actively growing
Alternatives to Rely (glufosinate)
Nonselective
Scythe (pelargonic acid)
Acetic acid (Weed Pharm) – organic production• Rapid acting contact• No effect on underground tissue – rhizomes,
roots, bulbs, etc.• sucker control
Alternatives to Rely (glufosinate)
Nonselective
Glyphosate (Roundup, others)• more effective on weeds (systemic)• but poses greater risk of systemic damage• apply using a shield spray or wiper
application• Keep off grape foliage, green stems• 14 day PHI
Glyphosate
• Off patent, available under a variety of trade names (Roundup WEATHERMAX, Touchdown, etc.)
• Check label for pounds glyphosate acid/gallon• Check label for need for a surfactant• Check spray water for calcium content (hard
water) – add ammonium sulfate 8-17 lb/100 gal
Herbicide Resistance
• Refers to a weed that used to be controlled but no longer is controlled
• Separate from tolerance where a weed species was always hard to control with that herbicide
Horseweed (Conyza canadensis)
Weed shifts
(Weeds less sensitive to glyphosate)
• Bengal dayflower/tropical spiderwort
• Doveweed
• Dayflower
• Morningglory
Dayflower
Cutleaf evening primrose
White clover