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AGR 549 (Weeds) > Exam 1 > Flashcards

Exam 1 Flashcards

2019

1
Q

What was White Snakeroot known to cause?

A

“Milk Sickness”

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2
Q

What well-known person was killed by White Snakeroot?

A

Abraham Lincoln’s mother (Nancy Lincoln)

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3
Q

Who identified White Snakeroot?

A

Dr. Anna

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4
Q

Where was White Snakeroot found identified at?

A

Rock Creek, IL

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5
Q

What method of weed control is still the most popular globally?

A

handhoeing

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6
Q

What did handhoeing previously cost per hour and acre?

A

$0.10/HR; $3.00/Ac

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7
Q

What does handhoeing cost not per hour and acre?

A

$9/HR; $270/Ac

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8
Q

What herbicides are currently approved for Hemp?

A

None!

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9
Q

What percent of plant species are considered “true weeds”?

A

Less than 0.1%/

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10
Q

What are the characteristics of true weeds? (2)

A
  1. Persistent- continually return

2. Pernicious- are a problem (highly destructive)

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11
Q

How many weeds are usually a major problem for any given crop?

A

25

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12
Q

What is the definition of a weed?

A

A plant that causes economic losses or ecological damage, creates health problems for humans, animals ,or is undesirable where it is growing.

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13
Q

What are some traits weeds display? (7)

A
  • the ability to grow in habitats disturbed by mankind
  • rapid seedling growth
  • quick maturation
  • dual modes of reproduction
  • highly adaptable
  • self compatible
  • seed dormancy
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14
Q

What do weeds cause in crops? (4)

A
  • loss of yield
  • added protection costs
  • Reduced quality of farm products
  • Reduced quality of animals
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15
Q

What percent yield loss are weeds responsible for?

A

12%

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16
Q

What is harbored in Johnsongrass?

A

Maize Dwarf Mosaic Virus

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17
Q

What weeds harbor nematodes? (2)

A

Polk weed

henbit

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18
Q

What does Johnsongrass do when it grows near Sorghum?

A

Hybridizes with to form Shattercane.

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19
Q

What weed results in docks when mixed with Wheat?

A

Wild Garlic (known at home as wild onion)

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20
Q

What weed must be cleaned from Soybeans?

A

Balloonvine

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21
Q

What weed is toxic to livestock and is common in KY?

A

Perilla Mint (Beefsteak Plant)

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22
Q

What weed is thought to cause extensive damage in rangeland out west but is not found here? How many acres does it take up?

A

Leafy spurge; 5mil.

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23
Q

What weed impairs the harvesting of corn and cotton?

A

Morningglory

24
Q

What weeds cause significant head, threshing, and separating loss? (2)

A

Redroot pigweed

Giant foxtail

25
Q

What were examples of weeds poisionous to humans?

A
  • poison ivy

- poison hemlock

26
Q

How do you calculate expected yield loss because of weeds?

A

You will be given the following information:

  • Expected yield of planted crop
  • Weed or weeds present and their loss percentage
  • current market price for your crop

You will plug your information into the following formula:

(Expected yield x loss percent as a decimal) x current market price= loss

27
Q

What are the 5 varieties of pigweeds that we went over?

A
  1. Redroot Pigweed
  2. Smooth Pigweed
  3. Spiny Amaranth
  4. Palmer Amaranth
  5. Waterhemp
28
Q

Which 2 pigweeds are known to be resistant to glyphosate?

A

Palmer Amaranth and Waterhemp

29
Q

How to ID the pigweeds?

A 
1. Does it have spines? (Y/N)
Y- Spined Amaranth
N-Go to 2.
2. Does it have fine hairs on the stem?
Y-Go to 3
N-Go to 4
3. are the sepals longer than the leaves?
Y-Redroot Pigweed
N-Smooth Pigweed
4. Are the petioles long and the leaves pointy?
Y-Palmer Amaranth
N-Waterhemp
30
Q

Define Winter Annual.

A

A plant that:

  • grows in the fall and through the winter
  • flowers the following spring
  • lifecycle is less than or equal to 1yr
31
Q

What are 3 examples of a winter annual?

A
  1. Cheat
  2. Henbit
  3. Annual Bluegrass
32
Q

Define Summer Annual

A

A plant that:

  • germinates in the spring
  • grows through the summer
  • flowers and dies in the fall
  • lifecycle is less than or equal to 1 year
33
Q

What are 3 examples of a summer annual?

A
  1. Pigweeds
  2. Goosegrass
  3. Cocklebur
34
Q

Define Biennial

A

A plant that:

  • has a lifecycle that is longer than 1 year but less than 2 years.
  • If often vegetative during its 1st year and reproductive during its last. (will bolt and flower the 2nd)
35
Q

What are 3 examples of a biennial?

A
  1. Bull Thistle
  2. Musk Thistle
  3. Common Burdock
36
Q

Define Simple Perennial

A

A plant that:

  • usually progresses like a summer annual but returns yearly
  • lifecycle is more than 2 years
  • these are non-spreading and non-creeping
37
Q

What are 3 examples of simple perennials?

A
  1. Dandelion
  2. Polkweed
  3. Buckhorn Plantain
38
Q

Define Creeping/Spreading Perennial

A

A plant that:

-follow same life as simple perennial and summer annual but has a method of creeping or spreading

39
Q

What are the 6 methods that creeping/spreading perennials may spread? What is an example of each?

A
  1. Rhyzomes
    - Johnsongrass
  2. Stolons
    - Bermudagrass
  3. Tubers
    - Yellow Nutsedge
  4. Bulb/Bulbets
    - Wild Garlic
  5. Creeping Roots
    - Horsenettle
  6. Taproot Reproduction
    - Dandelion
40
Q

What are 3 examples of parasitic weeds?

A
  1. Dodder
  2. Witchweed
  3. Mistletoe
41
Q

When was witchweed introduced into the Carolinas?

A

1957

42
Q

How does witchweed attack its hosts?

A

By attacking the host plants roots.

43
Q

What does dodder use to “tap” into host? What is it?

A

Haustoria- a simple branched projection that grows into host plant cells and acts as absorbing organ.

44
Q

How do the following 3 tillage methods affect weed seed dispersion?
(moldboard plowing, chisel plowing, no-till)

A

Moldboard plowing- distributes weed seed evenly throughout soil depth
No-till- keeps weed seed at soil surface
chisel plowing- is intermediate between the other 2

45
Q

What is the most common tillage method today?

A

Chisel plowing

46
Q

What is a “weed seed bank”?

A

The number of viable weed seedin the top 6in. of the soil.

  • it is different for every field
  • every field has one
47
Q

You can never eliminate all of weed seed population. (T/F)

A

T as evidenced by 1984 study. remaining 3% of pop reestablished infestation

48
Q

What is the percent range of dead weed seed as determined by a study? What was still the count of viable weed seed per square foot?

A

50-90% dead; 60-1500 viable seeds per sq. ft.

49
Q

What is fatal germination?

A

When seeds germinate at a depth that is too deep for emergence to occur.

50
Q

What is the dominant factor that determines the species composition of weed seed bank?

A

cropping sequence

51
Q

What type of weed does no-till favor?

A

Perennials

52
Q

How many seeds per plant does palmer amaranth produce?

A

Up to 600k, rumored up to 1M.

53
Q

What are the characteristics of Redroot Pigweed?

A
  • No spines
  • Fine hairs on stem
  • Short and thick branches
  • sepal 2x the length of the seed
54
Q

What are the characteristics of Smooth Pigweed?

A
  • No spines
  • fine hairs on stem
  • can have longer branches
  • sepals same length as seed
55
Q

What are the characteristics of Spiny Amaranth?

A
  • has spines on stem
  • no hairs on stem
  • can appear with green or purplish stems
56
Q

What are the characteristics of Palmer Amaranth?

A

-no spines
-no hairs on stem
-long petioles and oval shaped leaves
is dioecious
-RR resistant

57
Q

What are the characteristics of Waterhemp?

A
  • no spines
  • no hairs on stem
  • dioecious
  • long slender leaves and shorter petioles
  • RR resistant

AGR 549 (Weeds) (3 decks)

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