Weed Test 4 Flashcards
Planting Corn
plant on beds mid mar-apr 30,000-35,000 plants per acre emergence 7-10 days replanting not uncommon high fertility and water requirements grows rapidly in warm weather count collars to describe stage of growth
Plant back restrictions
be aware of previous crops and herbicides
be aware of rotation restrictions after corn
Major weed control considerations
burndown or clean at planting
early competition causes yield loss
late germinating weeds cause harvest problems
late germinating weeds increase weed seed in soil seed bank
weeds interfere with irrigation
Major weeds in corn
moringglory (#1) pigweed prickly sida velvetleaf cocklebur barnyardgrass broadleaf signalgrass crabgrass Johnsongrass nutsedge
Bicep II
Premix
Dual II + Atrazine
Bicep Magnum
Premix
Dual Magnum + Atrazine
Guardsman Max
Premix
Outlook + Atrazine
Fulltime
Premix
Surpass + Atrazine
Harness Extra
Premix
Harness + Atrazine
Roundup ready corn
alllows total POST program
allows late season applications
protects from glyphosate drift
Major Herbicides in corn
Atrazine Glyphosate Metolachlor Rimsulfuron Mizotrium Halosulfuron Nicosulfuron
Preemergence Options
Chloroacetamides (good on grasses), rainfall dependent
Atrazine (good on broadleaves), not long residual, can’t be applied past 12in corn
Tank mixes or or premixes
Why roundup ready corn
3 applications up to 1 qt/A/app 30in height V8 convenient good varieties adapted to Arkansas
best technology available for corn
roundup ready + liberty link corn
can spray with glyphosate or glufosinate
best over the top
best weed program for corn
burndown clean at planting metolachlor 1.5 pts behind planter atrazine 1.5 qts when stand confirmed glyphosate + 3 oz Callisto when atrazine breaks
Latest application reminders
12in - atrazine
24in - callisto
12in - lexar (contains atrazine)
late season morningglory control
atrazine + dual mag (pre or early post)
roundup + callisto (late to post at 20-24in)
best weed program for grain sorghum
metolachlor at planting
atrazine or atrazine + metolachlor when stand established
must have protected seed before using chloroacetamides
Paramount
barnyardgrass, crabgrass, signalgrass
5.3-8oz pre or post to 12in
do not apply by air
Peak
wide spectrum broadleaf herbicide (not pigweed)
5-30in sorghum, 2in weed
0.5-.75 oz/A
Paraquat
annual grasses and broadleaf weeds 1-2pts/A (use surfactant) sorghum must be 12in or taller must be direct sprayed under hoods spray cannot touch more than lower 3in of stalk cause injury
Prowl
prowl 3.3EC 4in to layby 1.8-2.4 pts/A cultivate prior to application cover base with soil incorporate after application requires more management but cheaper
Inzen grain sorghum
game changer
new mode of action
product used: Zest (nicosulfuron)
Forage weed problems
lack of management (fertility, lime, overgrazing)
no weed control (only 5-10% AR pastures sprayed)
lack of weed control knowledge (part-timers, hobbyists)
Spray first or fertilize
Spray. SO weeds don’t take up the nutrients intended for the grasses. Control your existing weeds then have soil-test done to know the best lime and fertilizer program
Economic threshold of pasture
spray when weeds are more than 20% of pasture
Grazing for weed control
keep weeds small (more palatable)
many weeds have same protein levels as forages
have to have good fencing and enough livestock to work
Mowing for weed control
reduces seeds
mowing 3x year for 2 years provides 80-90% control in most species
too late to prevent competition
no selectivity
perennials regrow
consistency is the key for effective weed control
Easy to control pasture weeds
broadleaf weeds in grass pastures
winter weeds in dormant bermudagrass
Hard to control pasture weeds
summer grasses in bermudagrass
broadleaf weeds in legumes
sedges
fescue in bermudagrass
Spray winter annuals
(henbit, chickweed, buttercup, thistles)
dec-mar
Spray summer annuals
(spiny amaranth, bitter sneezeweed)
apr-july
Legumes
est after good weed control 1-2 years
2,4-D amine safe on white clover and lespedeza
2, 4-D amine
most common pasture weeds
buttercup, thistle, ragweed, pigweed
cheapest ($35 for 2.5gal)
$3.50/A (1 qt rate)
Banvel + 2, 4-D
(dicamba + 2, 4-D) controls most common pasture weeds buttercup, thistle, ragweed, pigweed, red sorrel, plantain $69 for 2.5gal $5.25/A (1.5 pt rate)
Grazon P+D
controls most common pasture weeds
buttercup, thistle, ragweed, pigweed, red sorrel, plantain
$81 for 2.5gal
$6/A (1.5 pt rate)
GrazonNext
(aminopyralid + 2, 4-D) broadleaf weed control 7 day haying control 1.5-2.6 pt/A damages legumes restricted use
Prowl H20
BASF pendimethalin apply only to dormant bermudagrass should not be applied less than 60 days prior to hay harvest or 45 days to grazing 2.1-3.2 qt/A
Pastora
metsulfuron + nicosulfuron
stunt bermudagrass temporarily
use on est bermudagrass only
tank mix with 2, 4-D amine to improve thistle, ragweed, and plantain control
buttercup
treat seedling stage (late winter- early spring)
1-2pt/A 2,4-D
grazon P+D
weedmaster
pigweed
treat when small (2-4in) early may ally/cimarron grazon P+D 2,4-D germinates all summer repeat as needed
thistle
late fall or early spring treat at rosette leaf stage 2,4-D ester weedmaster grazon P+D
outrider
johnsongrass control use surfactant 18-24in spray after regrows after first cutting (june) must be actively growing good temps and good moisture don't spray big, tough, full seedhead, drought stressed if not actively growing it won't kill it
keys to weed control turf
learn to identify and know weed life cycle
good turf maintenance
prevent weed introduction
start control program
identifying weeds
read textbooks and periodicals
keep diagnostic tool kit (hand lens etc)
know biology of the weed
confirm identification and diagnosis
grasses
monocot
hollow stem
leaves in 2 vertical rows
sedges
triangular solid stem
leaves in 3 vertical rows
broadleaves
dicot
showy flowers
monocots that are not grasses or sedges
wild garlic (lily family) path rush (rush family) star or bethlehem (lily family)
summer annuals
germinate in spring soil temp 55 flower in summer die in fall- first frost ex: crabgrass, goosegrass, shephard's purses
winter annuals
germinate in fall
grow until spring
die late spring or early summer
ex: henbit, chickweed, spurges
biennials
completes life cycle in 2 years
flowering and seed production second year
ex: wild carrot, bull thistle
perennials
capable of living more than 2 years by producing rhizomes or tubers
ex:cool- dandelion, clover
warm- nutsedge, dallisgras
good turf practices
use adapted turfgrass fertilization watering mow correctly disease and insect control drainage compaction relief
mow at correct height
mowing shorter tends to take out crabgrass in tall fescue
fertilize correctly
excess nitrogen promotes common chickweed, ryegrass, annual bluegrass
low nitrogen leads to clovers, lespedeza, mosses, speedwell
high phosphorus encourages annual bluegrass
low soil pH and general fertility favors red sorrel and broomsedge
weed prevention in turf
- eternal vigilance- do not let weeds go to seed- 1 year’s seedling= 7 years of weeding
- use weed free planting material
- weed-free top soil
- clean equipment
- clean borders (ditches, fencerows)
where it can go wrong
herbicide error is 99% human error calibration errror wrong herbicide wrong timing wrong weed identification formulation error failure to make follow up applications bad product weather surfactant know the product
compatibility in the tank
physical- can it clabber in the tank (2,4-D amine and MSMA)
chemical- loss of activity due to tank mix interaction (certainty with amine and 2,4-D)
mode of action- rapid burn product with slow acting translocated product (Roundup and Reward or Finale)
