Herbicide Groups

NACTA. Damage and modes

Mode of Action

How the herbicide interacts with the plant

Site of Action

Where on the plant the herbicide interacts with.

Group 1

ACCase inhibitors (fatty acid synthesis). Works on grasses. Systematic

1

Group 2

ALS inhibitors. Block enzyme that synthesize branched chain amino acids. Some grasses and broadleaves. Systematic

2

Group 3

Microtubule Assembly Inhibitors. Stop cell division. Grasses and small seeded broadleaves. Not systematic

3

Group 4

Auxin mimics. Disrupts cell division and growth. Broadleaves. Systematic.

4

4

Group 5 and 6

Photosystem 2 Inhibitors. Stop photosynthesis. Some grasses and broadleaves. Xylem

5 or 6

5 or 6

Group 9

EPSP Synthase Inhibitor. Blocks synthesis of essential AAs. (glyphosate). Non-selective. Systematic

9

Group 10

Glutamine Synthetase Inhibitor. Inhibits nitrogen metabolism. Non-selective. Not systematic

10

10

Group 13

DOXP synthase inhibitors. Inhibits pigment production. Systematic

13

13

Group 14

PPO inhibitors. Affects chlorophyll biosynthesis. Broadleaves. Not systematic

14

14

Group 15

Very long chain fatty acid synthesis inhibitors. Grasses and small seeded broadleaves. Not systematic

15

15

Group 22

Photosystem 1 electron diversion. Diverts electrons away from PS1, which rapidly degrades lipids and destroys membranes. Not systematic

22

Group 27

HPPD inhibitors. Inhibits HPPD in pigment synthesis. Some grasses and broadleaves. Systematic

27

27