Woolly cupgrass taxon

-Woolly cupgrass Outline (1996)
-Woolly cupgrass Bibliography (1996)
a. Eriochloa villosa
b. taxon: intraspecific variation Canada thistle taxon

 

4.22.96
Agronomy 517: Weed Biology and Ecology
Spring Semester, 1996
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Outline of Woolly Cupgrass
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Prepared by Kevin Adam
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I. Description of Woolly Cupgrass

A. Genus name from Greeks
erion means woolly
chloa means grass

B. Name and relatives
1. Woolly Cupgrass - Eriochloa villosa (Thumb.) Kunth

member of the Millet family
belongs to the Paniceae family
sub-family is Panicoideae
2. other relatives
Prairie Cupgrass
Southern Cupgrass
Wild Proso Millet
Fall Panicum
Crabgrass
Sandbur

C. Characteristics
1. annual growth habit
2. Identification of plant
plant grows .6 to 1.5 meters tall
culm, sheath and leaves have dense pubescence
leaf sheath open at top and overlaps at base
no auricle present
one or both leaf margins are wrinkled
wide leaf blade that is 90 degrees to stem
ligule a fine fringe of hairs up to 1.5mm
tillers profusely at base
3. Identification of seedhead
racemes and panicles have dense pubesences
several racemes per panicle
seeds form two lines on bottom side of the raceme
seeds shatter readily as they mature
4. Identification of seed
large seed - 3 mm by 5 mm
seed color ranges from light green to tan-brown to purple depending upon maturity
cuplike depression at the base of the seed - formed by hardened first glume
often appears to be striped

II. Geographical Distribution
A. origin in eastern Asia
B. spread to many countries
North and South Korea
Japan
China
Soviet Far East
United States of America - entered U.S. through a ship's ballast near Portland, Oregon in the 1940's
Illinois
Wisconsin
Minnesota
Pennsylvania
Iowa
first identified in Ringold County on August 8, 1957
In 1994, 77 counties infested
over 5% of cropland infested
III. Biology
A. Germination of seed
1. occurs at temps. between 15-40 degrees C.
2. dependent upon O2 concentrations
low germination at concentrations lower than 16% O2
may be function of depth in the soil profile - the lower in the profile the lower the O2 concentrations
3. non-photoblastic
no light needed to stimulate germination
seeds are able to germinate under dense row crop canopies throughout the season
4. depth of seed in the soil
seed able to emerge from deep in the soil profile
9 cm in field conditions
15.25 cm in greenhouse conditions
optimum between 2-4 cm
surface germination is variable
low surface germination (Bello, 1988)
high surface germination (Franzenburg, 1994)
5. germination season
can germinate throughout the growing season
if germinated by July 15, it will produce seed
germination occurs at temps up to 40 degrees C.
germinates in low light environments
B. Dormancy
1. Innate dormancy - completely dormant at maturity and loses dormancy during winter months
2. germination approaches 100% by March
3. stratification in soil profile
causes seed to break dormancy faster
seeds on the surface and deep in the profile slower to germinate
physical interaction between seed and soil reduces dormancy
wetting and drying cycles
freezing and thawing cycles
4. high temps and drought during seed production reduce dormancy

C. Seed Longevity

literature lacking info.
IV. Vegetative development
A. Light and temp.
C4 plant
few members of Millet tribe have C4 ability
very competitive with row crop plants
adapted to high temps.
B. Tillering - adventitious buds
environmental factor affecting tillering
water stress - decreases number of tillers
plant density
low populations = high number of tillers
high populations = low number of tillers
nutrient availability
Nitrogen most important factor
Phosphorus, Potassium and minor nutrients less important
temperature - up to 35 degrees C. cause increased tillering
light - more light leads to increased tillering
time of emergence
anytime in May - 30-59 tiller per plant
earlier and later emerging plants have fewer tillers
C. Root system
fiberous
adventitious root can form at base of plant
nutrient uptake
added support
V. Seed production
A. sexually reproduces
B. seeds
3mm by 5mm in size
light green to tan-brown to purple in color
often appear to be striped
C. production capacity in the field
4-59 tillers per plant
80-897 panicles per plant
4-8 racemes per panicle
12-34 seeds per raceme
2,600-164,000 seeds per plant
D. non-competitive environment
observed plants with 180 tillers per plant in optimal growth conditions
VI. Control and Economics
A. Mechanical control
cultivation
rotary hoe
B. Chemical control
Pre-plant and Pre-emergence - Suppression to control at high rates
EPTC
pendimethalin
alachlor
acetochlor
Post emergence
quizalofop
fenoxaprop-ethyl
fluazifop-P
sethoxydim
clethodim
85%-92% control with chemical in years with good growing conditions
43%-62% control with chemical in years with dry growing conditions
easy to control post in soybeans but hard to control anytime in corn
control reduced after onset of tillering
resistant to atrazine
C. Integrated Pest Management
split rate applications of herbicides
use of mechanical and chemical control - best choice for consistent control
D. Economics
can reduce row crop yields by 50%
highly competitive in row crops
about 5% of Iowa's row crop infested
increased herbicide rate
extra tillage passes needed for control
VII. Reasons for success
A. Ability to tiller adventitious buds
number of tillers range from 4 to 180
depend upon the environmental conditions
often escape effect of herbicides
B. Large seed
contains high amounts of energy
give it the ability to emerge from deep in the profile
C. Highly competitive
C4 plant
produces large number of seeds
germinates, emerges and establishes quickly
D. Resistant to chemical treatments
atrazine
requires full rates for adequate control
injured plants can initiate tillers