Lecture 16 - Group 11

Question 1

group 11 mode of action

Answer 1

carotenoid biosynthesis inhibitors

Question 2

what groups are termed carotenoid biosynthesis inhibitors

Answer 2

groups 11, 12, 13, and 27

Question 3

what is another name for group 11

Answer 3

bleachers

Question 4

group 11 herbicides

Answer 4

amitrole (triazole family)

Question 5

symptoms of group 11

Answer 5

bleaching, wilting, and chlorosis

Question 6

group 13 mode of action

Answer 6

DOXP inhibitors

Question 7

peculiarities of group 13

Answer 7

• inhibit plastid isoprenoid synthesis
• selectivity not based on metabolism

Question 8

symptoms of group 13

Answer 8

bleaching and stunting

Question 9

most popular herbicide on group 13

Answer 9

clomazone

Question 10

how is clomazone typically applied

Answer 10

soil applied, pre emergent

Question 11

how is clomazone taken up and translocated

Answer 11

• absorbed by roots and emerging shoots
• translocated in xylem

Question 12

t/f: clomazone has high volatility

Answer 12

t

Question 13

symptoms of clomazone (group 13)

Answer 13

susceptible seedlings emerge but are bleached and after a few days become necrotic

Question 14

group 14 mode of action

Answer 14

PPO inhibitor

Question 15

how is group 14 applied

Answer 15

pre and post-emergence with contact-like injury

Question 16

what does group 14 work on

Answer 16

selective herbicide with control and suppression of broadleaf, some grasses and sedges

Question 17

sulfentrazone requires ________ for activation

Answer 17

light and moisture

Question 18

what does carfentrazone control

Answer 18

most broadleaf weeds pre emergent (can cause chlorosis of monocot crops)

Question 19

carfentrazone-ethyl (group 14) symptoms

Answer 19

• crispy leaves
• burn off of newest leaves
• lesions on contact points

Question 20

how should saflufenacil be applied

Answer 20

post emergence to weeds, pre emergent to crops and must be tank mixed with glyphosate for burnoff

Question 21

what is flumioxazin used on

Answer 21

pre-emergence of crops and weeds (annual dicots)

Question 22

flumioxazin symptoms

Answer 22

emerging seedlings become necrotic shortly after exposure to light

Question 23

target site of PPO

Answer 23

protoporphyrinogen oxidase enzyme that inhibit carotene and chlorophyll biosynthesis

Question 24

how does PPO (group 14) mode of action work

Answer 24

inhibits heme and chlorophyll synthesis and inhibit steps in a complex chain of reactions and cause buildup of toxic O2 radicles

Question 25

symptoms of PPO (group 14)

Answer 25

- appear very rapidly - water soaked appearance - wilting and necrosis - yellowed leaves

Question 26

basis of selectivity of PPO (group 14)

Answer 26

rapid metabolism to inactive compounds

Question 27

peculiarities of group 14 (PPO)

Answer 27

- strongly absorbed to soil - rapid breakdown - requires moisture for activation and root uptake - burndown of RR canola

Question 28

group 13 mode of action

Answer 28

inhibitor of very long chain fatty acid biosynthesis (block growth metabolic pathways)

Question 29

types of thiocarbamates (group 13)

Answer 29

EPTC and Triallate

Question 30

properties of thiocarbamates (group 13)

Answer 30

- soil applied - placement at correct depth is critical for control

Question 31

what does triallate control

Answer 31

wild oats when applied pre-emergence in cereals

Question 32

soil persistence of triallate

Answer 32

- has high microbial degradation (82 days) - volatilization loss can be high if not properly incorporated

Question 33

target site of triallate

Answer 33

fatty acid synthase (prevent formation of waxes and suberin)

Question 34

mode of action of triallate

Answer 34

inhibit synthesis of very long chain fatty acids (stop cell elongation and division)

Question 35

symptoms of triallate (group 13)

Answer 35

- shoestring in grassy weeds - failed emergence - swollen, bright green shoots - shoots often emerge from sides of coleoptile and form loop

Question 36

thiocarbamates (group 13) basis of selectivity

Answer 36

- potentially differential uptake (not really sure)

Question 37

what does thiocarbamates control

Answer 37

broadleaf and grass control in monocot and dicot crops

Question 38

peculiarities of group 13

Answer 38

- resistance to triallate

Question 39

group 15 modes of action

Answer 39

- inhibit lipid synthesis at point other than ACCase - some inhibit other metabolic processes (phenylpropanoid and gibberallic acid biosynthesis

Question 40

group 15 herbicides does not affect seed germination but does have a potent effect on ______ _______ in the emerging seedling

Answer 40

shoot formation

Question 41

pyroxasulfone (group 15) has _________ soil persistence

Answer 41

moderate

Question 42

pyroxasulfone (group 15) symptoms

Answer 42

- weeds fail to emerge - if emerged, monocots appear twisted, malformed, and crinkled - broadleaf seedlings have cupping/crinkling, and shortened leaf midribs

Question 43

selectivity of pyroxasulfone (group 15)

Answer 43

- conjugation (metabolism of conjugates)