Exam

Question 1

What do weeds compete for? What is allelopathy?

Answer 1

4 things - light, water, nutrients, and space.

Allelopathy - the production of phytotoxic compounds that reduce the germ of other plants.

Question 2

What is the key environmental condition required for biennial plants to begin reproductive development? How does this relate to time of control?

Answer 2

30 days of below 0 degrees
Control in the fall before this cold period

Question 3

5 types of vegetative reproductive structures for creeping perennials.

Answer 3

Rhizome - horizontal underground stem
Tuber - enlarged tip of a rhizome
Bulb - piece of stem tissue surrounded by modified leaves
Stolon - horizontal, aboveground stem
Creeping Root - horizontal and vertical roots

Question 4

What are the shared characteristics of grasses and grass-like weeds?

Answer 4

elongated leaves
stems enclosed in leaf sheaths

Question 5

What problems does weed interference cause?

Answer 5

competition for light, nutrients, space, and water

Question 6

What three factors determine the competitiveness of a weed?

Answer 6

Time of emergence relative to the crop.
Growth form of the weed.
Weed density.

Question 7

What is the critical weed free period that most plants need to avoid a reduction in growth?

Answer 7

Depends on the crop but during germination.

Question 8

Is weed density more important in competitive or non-competitive crops? (graphs)

Answer 8

non-competitive

Question 9

What is the importance of a weed seed bank?

Answer 9

A reservoir of new individual plants.
Seed bank can be depleted or added to each year.
Overwintering.

Question 10

What mechanisms of dormancy are found in weeds. Describe.

Answer 10

Immature embryos - time required after release to develop and germ (cow parsnip)
Physiological - cold or warm strat, light strat (common groundsel)
Physical - hard seed coat (ragweed or cocklebur)

Question 11

How long can lamb’s quarters and velvetleaf remain in the soil? Why? How does this influence management?

Answer 11

40 years
Hard seed coat, resistant to moisture loss and rot
will have to deal with it for a while, don’t let it go to flower

Question 12

Why are veg reproductive structures so effective at carrying out overwinter survival, rapid establishment, and spreading quickly?

Answer 12

Produce buds that over winter.
Large roots or veg pieces store a lot of carbs.
Get moved by equipment to different places.

Question 13

How do you distinguish burcucumber and wild cucumber?

Answer 13

BC - shallow lobes and deep petiole lobe, cluster of flowers on stalk, cluster of fruit
WC - deep lobes and shallow petiole lobe, flower in leaf axil, one fruit

Question 14

How does virginia creeper and poison ivy look different

Answer 14

VC - palmately compound
PI - trifoliate

Question 15

What are the life cycle, method of reproduction and key environmental requirement of Canada goldenrod?

Answer 15

CP
seed and rhizome
shade avoidance

Question 16

Life cycle and reproductive method of garlic mustard

Answer 16

biennial and seed

Question 17

Implications of garlic mustard for nursery production?

Answer 17

Mytotoxic, limits uptake of nutrients by deciduous trees

Question 18

Which weeds grow in compacted soil (C), dry gravelly soil (D), saturated soils (S)?

Answer 18

C - common knotweed, bicknell’s geranium
D - pineappleweed, toadflax, common mullein
S - common burdock, bull thistle, cattail

Question 19

Weed management in residential landscapes

Answer 19

cultural management
soil amendments, nutrition, irrigation
mulches
weed free nursery stock
bio weed control

Question 20

How can crop selection be used to suppress weeds?

Answer 20

most appropriate crop for the area, planting densities, and variety

Question 21

What is the biennial lifecycle and best time to control?

Answer 21

First year is vegetative, second year is reproductive. 30 days below 0 degrees
control in fall of first year

Question 22

Glyphosate resistance and dispersal of Canada fleabane

Answer 22

Can travel up to 500km and we cannot effectively used herbicides against it

Question 23

Name a weed that acts as an alternate host for cucumber mosaic virus and how does it enter ghs?

Answer 23

Curled dock
insects with mouth sucking parts (aphids)

Question 24

What soil condition does lambsquarter tolerate and how?

Answer 24

Saline soils, possesses salt glands to expel salt

Question 25

Why is horsetail hard to kill with herbicides?

Answer 25

The phloem are not arranged in long strands, they are broken up

Question 26

Why is velvetleaf hard to kill at night?

Answer 26

Leaves droop, poor coverage

Question 27

Describe appearance of two types of leaves in henbit

Answer 27

Lower leaves are petiolated and upper leaves are sessile

Question 28

Three features that enhance the invasiveness of field bindweed

Answer 28

vining growth rhizomes seeds

Question 29

What type of soil and light conditions does eastern black nightshade grow best in?

Answer 29

high nitrogen and full sun

Question 30

what soil conditions are plantains well adapted to and what features help with that?

Answer 30

compacted soils taproots

Question 31

Rough cinquefoil looks like strawberries, how to tell apart?

Answer 31

RCF - serrated all of the margin S - serrated on half

Question 32

How does seed dispersal allow for creeping woodsorrel to exist in ghs?

Answer 32

Explosively discharged with mucilage, can stick on windows

Question 33

What soil conditions does sweet violet live in and reproduce?

Answer 33

high OM and low pH seed and rhizome

Question 34

What effect does early planting have on weed populations and what are two disadvantages of planting early?

Answer 34

relative time of emergence 1 frost damage 2 too wet = compaction

Question 35

How can soil amendments with high C:N ratios negatively affect crop competitiveness and microbial activity?

Answer 35

The amendments add WHC and nutrients, but high C:N will reduce MOO activity

Question 36

For how long and at what temperature do soil amendments need to be composted to keep them as weed free as possible?

Answer 36

30 days at 30 degrees and for field bindweed 50 degrees

Question 37

How can excess fertility negatively affect crop competitiveness and microbial activity?

Answer 37

Root injury and reduced growth of microbes

Question 38

How do frequency of irrigation and amount of water used influence weed emergence and growth?

Answer 38

– Light, frequent irrigation favours germination of small seeded annual weeds. – Heavier, less frequent irrigation favours germination of larger seeded weeds from deeper in soil.

Question 39

In general what range of depth and when should mulches be applied?

Answer 39

4" in the fall

Question 40

Mulch types and advantages and disadvantages of each

Answer 40

Degradable A- cheap and adds OM D- apply more frequently Persistent A- apply less often, consistent D- expensive, no OM