Photosynthesis inhibitors

1
Photosynthesis inhibitors

• Often translocated
• chlorosis
• loss of green color
• yellow
• necrosis
• dead tissue

2
Atrazine
soybean
3
Bladex
cotton
4
Cotoran
cotton
5
Pigment Inhibitors

• Zorial (norflurazon)
• Command (clomazone)
• Balance (isoxaflutole)

6
Pigment Inhibitors

• Translocated
• bleaching
• whitening
• lack of orange green pigments
• may see some purple pigment

7
Pigment Inhibitors

• chlorosis
• loss of green color
• veinal vs. interveinal

8
Command
rice
corn
9
Lipid inhibitors

• Select (clethodim)
• Poast Plus (sethoxydim)
• Fusilade (fluazifop)
• Assure II (quizalofop)
• Hoelon (diclofop)

10
Lipid inhibitors

• chlorosis
• purpling
• necrosis of newest leaf tissue emerging from the
  whorl
• rotten neck
• can be easily pulled from plant

11
Select / Poast Plus injury
milo
12
Select / Poast Plus injury
corn
13
Amino Acid Synthesis Inhibitors

• EPSP synthase inhibitors
• Roundup (glyphosate)
• Touchdown (sulfosate)
• Glutamine synthetase inhibitor
• Liberty (glufosinate)

14
Amino Acid Synthesis Inhibitors

• ALS inhibitors
• Classic (chlorimuron)
• Accent (nicosulfuron)
• Permit (halosulfuron)
• Scepter (imazaquin)
• Pursuit, Newpath (imazethapyr)
• Cadre (imazapic)
• FirstRate (cloransulam-methyl)

15
Amino Acid Synthesis Inhibitors

• Translocated
• chlorosis to necrosis
• growing point dies first
• purpling
• stacking of nodes
• shortened internode length

16
Regiment 1X
17
Roundup drift
corn
18
Roundup
sicklepod
19
Accent
corn
20
Classic Staple
southernpea
soybean
21
Cadre/Scepter/Newpath
cotton
22
Roundup on Rice increasing problem.
23
Cell Membrane Disruptors

• Gramoxone Max (paraquat)
• Buctril (bentazon)
• Blazer (acifluorfen)
• Reflex, Flexstar (fomesafen)
• Aim (carfentrazone-ethyl)
• Resource (flumiclorac-pentyl)

24
Cell Membrane Disruptors

• Contact Injury!
• necrosis
• brown spots on leaves
• dead tissue
• bronzing
• early stage of necrosis

25
Gramoxone Max
corn
26
Gramoxone Max..what else could it be?
corn
27
Blazer
southern pea
28
Growth Regulators

• 2,4-D
• Grandstand, Garlon (triclopyr)
• Banvel, Clarity (dicamba)
• Facet (quinclorac)
• Stinger (clopyralid)
• Tordon (triclopyr)

29
Growth Regulators

• leaf strapping
• elongation of leaves
• epinasty
• upper surface grows faster
• cupping
• leaf margin curls upward

30
Growth Regulators

• fused brace roots
• malformed
• brittle stalks
• susceptible to wind damage
• callus tissue
• broadleaves

31
2,4-D
corn
32
2,4-D
soybean
33
2,4-D
soybean
34
2,4-D leaf strapping/epinasty
cotton
grape
35
2,4-D
Soybean leaf puckering
36
Dicamba - Clarity
Soybean - cupping
37
Seedling growth inhibitors

• Root inhibitors
• Prowl (pendimethalin)
• Treflan (trifluralin)
• Shoot inhibitors
• Dual II (s-metolachlor)
• Lasso (alachlor)
• Outlook, Frontier
• Eptam, Eradicane (EPTC)

38
Root inhibitors

• clubbed roots
• swollen root tips
• cellular swelling
• around hypocotyl
• brittle stems

39
Treflan / Prowl
Restricted root growth Bottle Brush Roots
corn
40
Treflan / Prowl
Cotton Brittle stem cotton
41
Treflan / Prowl
Soybean Brittle Bean Syndrome
42
Shoot inhibitors

• heart-shaped leaves
• mid-vein shorter than normal
• buggy whipping
• in grasses
• rolled leaves
• Top leaf caught in whorl

43
Dual / Lasso / Outlook
soybean
44
Dual / Lasso / Outlook
Corn - Buggy Whip
45
Respiration inhibitors

• MSMA
• DSMA

46
Respiration inhibitors

• purpling
• grasses
• chlorosis
• yellowing
• necrosis
• dead

47
MSMA
cotton
48
MSMA
southern pea
corn