Weed IPM in Grape Production

Jeffrey Derr

Professor of Weed Science

Virginia Tech

IPM workshops 2014

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

• Weeds of the Northeast – Cornell Press

• Weeds of the South - University of Georgia Press

Additional Information

http://oak.ppws.vt.edu/weedindex.htm

www.ppws.vt.edu/ipm/weeds_container_nurseries.html

Virginia Tech Weed ID websites

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

Site PreparationGoal is to reduce weed populations, especially for perennial broadleaf 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 grape production

• Establish permanent cover before planting

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

Site prep - Chemical control

• Glyphosate

- apply in strips in fall for fescue, orchardgrass control

- plant into killed strips

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

Proposed new research – evaluate cover crops within the row, continue evaluating between row cover crops

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.

Cover crops – Cool-season

• Tall fescue – standard + dwarf types

• Creeping red fescue

• Hard fescue

• Perennial ryegrass

• Kentucky bluegrass

• Hybrid bluegrass

Cover crops – Cool-season

Prepackaged Combinations

• Companion grass – dwarf perennial ryegrass + creeping red fescue

• Rough and Ready- dwarf perennial ryegrass + turf type fescues + microclover

Cover crops – Cool-season glyphosate tolerant

• Big Horn GT – sheeps fescue

• Aurora Gold hard fescue

• Compared to Gotham hard fescue

Cover crops – Cool-season glyphosate tolerant

• Big Horn GT – sheeps fescue

• Aurora Gold hard fescue

• Compared to Gotham hard fescue

Cover crops – Warm-season

• Zoysiagrass

• Bermudagrass

• Blue grama

• Combinations with perennial ryegrass or hard fescue

Results – Warm season trials

Difficult to establish in existing grape plantings due to the lack of safe herbicides for both the perennial grass and grapes Bermudagrass establishes much better from seed than zoysiagrass but will be more competitive

Blue grama did not do well in our trials

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 Combination Seed Mixes

‘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

‘Southern States Premium Tall Fescue with Eco-Green’ -

DTT 20 + DTT 43 tall fescue cultivars

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

Grass species

Cultivar Seeding rate lb/1000 sq ft

Establish rate 1-10

Weed Supp 1-10

Hard fescue Bighorn GT 2 2 6

Dwarf tall fescue

DTT20/DTT43 blend

2 4 6

(mix) Rough and Ready

5 7 8

(mix) Companion grass

1 5 8

Perennial ryegrass

Applaud 5 9 6

Tall fescue Fawn 2 8 6

Kentucky bluegrass

Midnight 1 1 4

Creeping red fescue

Silverlawn 2 5 10

Grass species

Cultivar Traffic tol-erance 1-10

Appearance 1-10

Height inches

Hard fescue Bighorn GT 3 9 20

Dwarf tall fescue

DTT20/DTT43 blend

10 8 27

(mix) Rough and Ready

10 8 21

(mix) Companion grass

10 8 25

Perennial ryegrass

Applaud 9 7 20

Tall fescue Fawn 9 4 55

Kentucky bluegrass

Midnight 6 7 16

Creeping red fescue

Silverlawn 3 5 33

Why control weeds?

Reasons to Manage Weeds

Competition- leading to reduced crop growth and yield

(quantity, quality)

• for water (drought years)• nutrients (especially nitrogen) –cannot

correct with extra N• light (viny weeds)

Reasons to Manage Weeds

• Harbor insect and disease pests (dandelion and tomato ringspot virus, buckhorn plantain/aphids)

• Attract bees (problem for those allergic to bee stings, concern when insecticides are being applied)

• Interfere with harvest (rash - poison ivy, spines - brambles)

• Allelopathy (natural herbicides) - juglone – black walnut

• Provide cover for rodents

Tomato ringspot virus and grapes - http://www.grapes.msu.edu/ringspot.htm

Transmission of tomato ringspot virus from dandelion via seed and dagger nematodes. Mountain, W.L. et al. 1983. Plant Disease 67:867-868.

When seedlings from 5 TmRSV-infected Taraxacum officinale plants were assayed, an av. 24% were infected, but germination was unaffected. Xiphinema rivesi (nematode) acquired the virus from infected plants and transmitted it to healthy seedlings. Dandelion is a major natural reservoir of the virus in Pa. and the potential importance of this weed in the epidemiology of TmRSV-induced orchard diseases (especially Prunus stem pitting in peach and apple union necrosis in apple) is discussed

Distribution of tomato ringspot virus in dandelion in Pennsylvania. Powell, C. A. et al. 1984. Plant Disease 68:796-798. The percentage of dandelion infection with Tomato ringspot virus was higher in orchards with Peach stem pitting (29%) than in either orchards without PSP (7%) or non-orchards (5%). Results support the hypothesis that TmRSV is initially introduced in an orchard via either infected nursery stock or dandelion seed and subsequently becomes established in dandelion and other weeds over a period of years. 

Vegetation Management Plan

• Killed strip within the row to reduce weed competition

• Mowed (grass) alleyways for erosion control, drivability soon after rain

Grape Weed Control

• Biological – little available

• Cultural

• Chemical

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

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

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 broadleaf weeds, annual grasses

Goal (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

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.

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.

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

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.• Do not control yellow nutsedge or any

broadleaf weed• Poast (sethoxydim), Fusilade DX (fluazifop)

– 50 day PHI, Select Max – nonbearing • Need to 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, or fruit of fruit trees.

• Can also be used for control of suckers – see label for rates and directions for this use.

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

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)

• Rapid acting contact

• No effect on underground tissue – rhizomes, roots, bulbs, etc.

• 3-10% solution, use high spray volumes 75-200 gallons spray per acre

• Can be used for 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

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-Resistant Weeds in Virginia• atrazine - corn – smooth pigweed, redroot pigweed,

common lambsquarters• Simazine (Princep) – turf – annual bluegrass• diclofop – wheat – Italian ryegrass• sethoxydim – soybean - johnsongrass• ALS inhibitors (IMIs, Sus – imazethapyr, nicosulfuron,

etc.) – row crops - shattercane, smooth pigweed, common chickweed

• glyphosate – row crops - horseweed, Palmer amaranth• others?