weed identification and control · weed identification and control kurt hembree farm advisor, ucce...

Weed Identification

and Control

Kurt Hembree

Farm Advisor, UCCE Fresno County

October 28, 2015

Kurt Hembree, UCCE, Fresno County Oct 28, 2015

• To determine which method of control to use

• To slow down reproduction

• To determine the best chemical (herbicide)

Weed identification is very important!


Weed Growth Cycle Summer annuals – live and die in <1 year

• pigweed

• purslane

• puncturevine

• crabgrass

• junglerice

• nightshade

• horseweed

• knotweed

• lambsquarters


***Active (plant)

Dormant (seed)

Winter

Summer

Fall Spring

Weed Growth Cycle Winter annuals – live and die in <1 year


Dormant (seed)

***Active (plant)

Winter

Summer

Fall Spring

• cheeseweed

• mustard

• nettle

• sowthistle

• filaree

• shepherd’s-purse

• annual bluegrass

• groundsel

• ryegrass

• horseweed 1,000,000

• mullein 223,200

• redroot pigweed 117,400

• purslane 52,300

• Shepherd’s-purse 38,500

• sunflower 7,200

• wild oats 250

Annuals can produce lots of seed!


Pigweed - 117,400 seeds


Purslane (verdolaga) - 52,300 seeds


Wild oats - 250 seeds


• Biennials - Live 2 years

• Perennials – Live more than 2 years

Weed Growth Cycle, con’t


Fall Spring

Summer

Winter

Dormant (roots, rhizomes, tubers)

***Active (plant)

Spring

• yellow nutsedge - 1 tuber= 1,918 plants in 1 year

• johnsongrass – one plant produces 85’ of stems underground in 14 weeks

• bermudagrass, dallisgrass, bindweed, nutsedge, johnsongrass, others

Perennials reproduce from plant parts and from seeds


Johnsongrass- 85 feet rhizomes underground stems


Nutsedge - purple and yellow 1, 918 plants in 1 year


• Field Equipment - rototiller, disc, hoe, plow, lilliston

• Plastic - black, brown, blue, green

• Transplants - cover the soil making shade

• Crop rotation - sudangrass, clover

• Other - water, wait, then cultivate (or spray)

• Solarization - clear plastic 4-6 weeks (in summer)

• Herbicides- pre-emergents, post-emergents,

and fumigants

Methods of control



Equipment and hand labor

http://www.google.com/url?sa=i&rct=j&q=hand+pulling+weeds+uc&source=images&cd=&cad=rja&docid=ajpWc5_U9yxVsM&tbnid=WtHNpRdye4b6gM:&ved=0CAUQjRw&url=http://heavytable.com/farm-journal-13-the-dog-days-of-summer/&ei=RUJbUbv_DuL5igKI1ICwDw&psig=AFQjCNEqqqd56WD4OxOfmfqnV7bljDgzig&ust=1365021525209090

http://www.google.com/url?sa=i&rct=j&q=hand+weeding+in+garden&source=images&cd=&cad=rja&docid=CZXUQpFpDJNBLM&tbnid=UjKZ8d_nghiXPM:&ved=0CAUQjRw&url=http://gentle-k.blogspot.com/2012/07/weeds.html&ei=XXdcUb6-DaqYiAL5wIH4CQ&bvm=bv.44770516,d.cGE&psig=AFQjCNEwPJCMsg8kbUUVN2UbEtrXAjz6dQ&ust=1365100478258880

http://www.google.com/url?sa=i&rct=j&q=rototill+garden+uc&source=images&cd=&cad=rja&docid=I66pJeYgdNkZcM&tbnid=7OVeP7ceCNEMFM:&ved=0CAUQjRw&url=http://gardenlightsguru.com/category/landscaping-diy/gardens/page/3/&ei=JUFbUaP5OKr1iwL9goHwDQ&psig=AFQjCNFI4Fn0p9oEca90Hl_4x86KXr6GVA&ust=1365020660151623

http://www.google.com/url?sa=i&rct=j&q=pulling+nutsedge&source=images&cd=&cad=rja&docid=URLXC_sjIaddnM&tbnid=ejZZlMJHekGapM:&ved=&url=http://firstrootfarm.com/2010/05/15/meet-our-weeds-yellow-nutsedge/&ei=HXlcUbq_EOmpigLlqoCADQ&psig=AFQjCNF2L7BlGS3Tf5wwQ27xPq1d0B_KuA&ust=1365101213620004

http://www.google.com/url?sa=i&rct=j&q=hula+hoe&source=images&cd=&cad=rja&docid=RTAThtgogvENbM&tbnid=3_RvG22YjYFR9M:&ved=0CAUQjRw&url=http://www.acehardware.com/family/index.jsp?categoryId=1305554&ei=dkpbUY-jBIL5igKy_IDwBg&psig=AFQjCNFHCRr18XYYq1Snw3MdJCwYGpHStw&ust=1365022727895904

http://www.google.com/url?sa=i&rct=j&q=hula+hoe&source=images&cd=&cad=rja&docid=xMKai5sBRgSCTM&tbnid=GQ5OVVLWXW5Z4M:&ved=0CAUQjRw&url=http://www.gardeners.com/on/demandware.static/Sites-Gardeners-Site/Sites-CATALOG_Gardeners/default/pwr/product-reviews/Gardening/Gardening-Tools/Shovels-Hoes/p/38__926-Hula-Hoe.html&ei=0UhbUcv_MsK2iwLq9IGQBA&psig=AFQjCNFHCRr18XYYq1Snw3MdJCwYGpHStw&ust=1365022727895904


Colored plastic mulch to stop weed seed germination

Keep in place

4-6 weeks

during summer

to reach a temp

of 140 ºF.


Soil Solarization (to kill weed seeds)

http://www.google.com/url?sa=i&rct=j&q=soil+solarization+uc&source=images&cd=&cad=rja&docid=5-gUq86IkaetbM&tbnid=iNbUvgrwDmtZ8M:&ved=0CAUQjRw&url=http://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=3609&ei=fk5bUd-0AqjtigL0voHIAg&psig=AFQjCNHPsoMb2CpMSoToXmfLS7htCGheOQ&ust=1365024753602849

http://www.google.com/url?sa=i&rct=j&q=soil+solarization+uc&source=images&cd=&cad=rja&docid=5-gUq86IkaetbM&tbnid=iNbUvgrwDmtZ8M:&ved=0CAUQjRw&url=http://www.cattletoday.com/forum/viewtopic.php?f=18&t=65818&ei=1U5bUZKAH4rriwLy84D4AQ&psig=AFQjCNHPsoMb2CpMSoToXmfLS7htCGheOQ&ust=1365024753602849

– Water and/or mechanical incorporation is needed to activate

– Lasts for 3-6 months in the soil

Devrinol

Treflan

Prefar

Herbicides – Pre-emergents (applied to soil to control weed seed in the soil)


• Needs to be mixed in to soil before planting

• Registered for:

– Broccoli, cauliflower, others

– Eggplant, pepper

– Tomatoes

Devrinol – Pre-emergent (to control weed seed in the soil)


http://www.google.com/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0CAcQjRxqFQoTCK_E8-i85cgCFUnyYwodi0gAqw&url=http://www.agrimarket.fi/main.cfm?iA%3D251900&psig=AFQjCNFDSLLIg_aTCORHLdcaBcODO3ENow&ust=1446132289111165

• Controlled

Blegrass, foxtail, barnyardgrass, junglerice, other grasses, cheeseweed, purslane, sowthistle, pigweed lambsquarters

Not controlled

Groundcherry, nightshade, fleabane, groundsel, others

Devrinol – weed seeds killed


– No water is needed to activate, to remain dry

– Lasts 0 months in the soil

Roundup

Gramoxone

Poast

Fusilade

Herbicides – Post-emergents (to control growing plants)


Poast– Post-emergent (to control growing plants)

• Kills grass plants but does not hurt broadleaf plants, so can be sprayed over the top of most vegetables.

• Applied 7-30 days before harvest

• Registered for:

– Most vegetable crops



http://www.google.com/url?sa=i&rct=j&q=funny weed management&source=images&cd=&cad=rja&docid=wrlbq9giRKAEkM&tbnid=-6YoA7846VmExM:&ved=0CAUQjRw&url=http://www.agweb.com/blog/Rubes_Cartoons_-_Tales_from_a_Twisted_Mind_263/?Year=2010&Month=3&ei=Job5UbanF4eGiQK0moDQCg&psig=AFQjCNFuLuzxUy6dy-21XrLrp-BYvDWNbQ&ust=1375393607109386

weed identification and control · weed identification and control kurt hembree farm advisor, ucce...

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