Unit 4 12/5/22

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Total cards: 24•Content version: v4•Public deck•Updated: 8/1/2026

Card preview (24)

Front (Question)

Why is weed control important?

Back (Answer)

• Livestock producer • Home • Medical • Recreational • Aesthetic • Hort/turf/agronomic • Preserving native species

Front (Question)

Generally ______________ produce the most amount of seed in one year

Back (Answer)

Annuals

Front (Question)

How do we influence weeds?

Back (Answer)

• Annual weeds are adapted to growing in any soil with characteristics favorable for crop growth (most data indicates) • However, there are economically important weeds that are perennial • Dandelion, Canada thistle, curly dock, common milkweed, etc.

Front (Question)

one plant can produce how many seeds

Back (Answer)

60-80 thousand

Front (Question)

What are the tree main weed groups?

Back (Answer)

Annuals Biannual Perennials

Front (Question)

What is the annual weed group?

Back (Answer)

• Annuals (summer and winter) – Should be managed before they can produce seed for the following year

Front (Question)

Biennials

Back (Answer)

• Biennials – Reproduce by both vegetatively or by seed (seed not produced until the second year)

Front (Question)

Perennials

Back (Answer)

• Perennials – Survive for many years and produce seed. However, many primarily produce vegetatively by creeping stems (rhizomes and stolons). Hardest to control once established.

Front (Question)

How are weeds dispersed?

Back (Answer)

• Wind • Water • Animals • Humans • Equipment • Plant mechanisms (barbs, hooks, spines, awns, sticky secretion, cottony lint)

#10

Front (Question)

What is an example of a weed dispersed by animals?

Back (Answer)

Buckthorn, birds eat seeds and poop

#11

Front (Question)

What makes weeds so successful?

Back (Answer)

• Abundant seed production • Rapid population establishment • Seed dormancy • Long-time survival of buried seed • Adaption for seed dispersal • Vegetative reproductive structures • *Ability to thrive in disturbed soils

#12

Front (Question)

What do weeds compete

Back (Answer)

light water, nutrients space

#13

Front (Question)

Would you expect more dormancy for weeds or crops

Back (Answer)

Weeds

#14

Front (Question)

What are the two vegetative structures

Back (Answer)

Stolons and rhizomes

#15

Front (Question)

What is GDD

Back (Answer)

Growing Degree Day

#16

Front (Question)

Why is understanding Weed Emergence Sequence important?

Back (Answer)

*improve weed management by determining when to scout fields • GDD = are heat units required to reach 10% emergence • For some species, the majority of emergence occurs in a short time period (2-3 weeks). Other plant species may emergence over a prolonged period (8-10 weeks)

#17

Front (Question)

Emergence date of group 0

Back (Answer)

#18

Front (Question)

Emergence date of group 1

Back (Answer)

#19

Front (Question)

Emergence date of group 2

Back (Answer)

#20

Front (Question)

Emergence date of group 3

Back (Answer)

#21

Front (Question)

Emergence date of group 4

Back (Answer)

#22

Front (Question)

Do weeds grow more when they are younger or older

Back (Answer)

Weeds will grow more as they get older

#23

Front (Question)

How long can weed seeds survive?

Back (Answer)

5-10 years in soil Weeds in your field (seed bank) can go up to 142 years

#24

Front (Question)

Seed bank viability

Back (Answer)

• 142-year-old experiment at Michigan State University • Moth Mullein