4.11.96
Agronomy 517: Weed Biology and Ecology
Spring Semester, 1996
Unit 4: Weed Species Reports
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Velvetleaf
Abutilon theophrasti

Prepared by Kerry Taylor
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I. Description

A. Annual
1. reproduces by seed
2. overwinters as seed

B. Physical appearance
1. height = 1-4 meters
3. highly branched
4. leaves
a. alternate
b. broadly heart shaped
c. 'velvety' feel
1. flowers
d. small
e. color = yellow to yellow-orange

II. Economic Importance
B. Detrimental
1. weed in maize, soya, sorghum, cotton
a. 1982 cost of control in U.S. = $342 million
b. causes losses in soya yield due to competition
c. up to 70% reduction in maize yield infestation of 6
weeks
1. possible alleopathy
2. host for crop pests
a. insects
1. scentless plant bug (Niesthrea louisianica)
2. early season larval generation of tobacco bud and boll
worm (Heliothis virescens and H. zea)
3. alternate host for flea beetle (Systena frontalis)
a. host of major fungal pathogens
2. Verticillium
3. Cladisporium
4. Cercospora
5. Macrophomina
6. Phomopsis
7. Fusarium
A. Beneficial implications
2. grown in China for bast fiber
3. introduced as potential fiber crop in U.S.
4. seeds contain 15 - 30% lipids: suitable for food
5. plants contain 23% crude protein (dry weight basis)

III. History
C. About 150 species of Abutilon
1. several ornamental
a. Chinese lantern
b. Parlor maple
1. native origin India or China
b. research suggests not tropical or sub- tropical
A. Introduction North America: mid 1700's
2. purpose: commercial fiber production (attempted for +
100 years)
3. current infestations originate from 1.

IV. Biology
D. Seed
1. germination throughout growing season
2. production at @ 700 - 1700 per plant
3. hard seed coat
a. antibiotics
1. 80% bacteria within the seed antagonistic to fungi on
seed surface
2. tannin-like compounds are inhibitory to microorganisms
4. Dormancy
a. known to remain dormant for over 50 years
b. mostly due to hard seededness?
A. Plant
2. leaves
a. stay perpendicular to the sun all day
b. pubescent (hold moisture away)
c. very photosynthetically efficient
1. response to shading = reduced branching and increased
elongation
2. root exudates inhibit fungi growth
A. Habitat
3. widespread between 32 and 45 degrees north ( North
America)
4. found in disturbed areas

V. Success as a Weed
E. Large seed production
F. High viability of seed
G. Prolonged dormancy
H. Continuos germination
I. Good ability to produce seed under competition

VI. Management
F. Cultural
1. seedling survival reduced under high nutrient
concentrations
2. emergence reduced by burial greater than 5 cm
3. crop rotations
A. Chemical
2. PRE
a. anything with metribuzin
b. atrazine
1. POST
b. atrazine
c. 2,4-D
d. bentazon
e. bromoxynil
f. cyanazine
g. dicamba
h. metribuzin
i. linuron
1. resistance
c. triazine
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