Tolerance of Flowers Grown for Seed to Herbicides Laurel Moulton and Ed Peachey Horticulture Department, Oregon State University
Methods Fertilizer (12-29-10, 400 lbs/A) was broadcast and incorporated with the last tillage operation. Flower seeds of nineteen species (see table below) were planted on the OSU Vegetable Research Farm on June 20 and 21, 2011 into a moderately fine seedbed. Each species was represented by one row in each plot, and each plot was replicated three times. Herbicide treatments were applied in strips perpendicular to the seed row across each entire replication in a strip-plot arrangement. Plot width in the first replication was 20 ft to make viewing easier during the field day; plot width in replications 2 and 3 was 9 ft. Post plant surface (PPS) herbicides were applied on June 14 with a 5 nozzle boom powered by CO2 at 20 GPA. POST herbicides were applied on July 15. Crop emergence, visual injury, and weed control were evaluated periodically through August 26.
Table 1. Species represented in trial. Botanical family
Common name
Genus/species
Annual/ perennial
Asteraceae Asteraceae Asteraceae Asteraceae Asteraceae Asteraceae
Bachelor button Black eyed Susan Calendula Cosmos Prairie coneflower Purple cone flower
Centaurea cyanus Rudbeckia hirta Calendula officinalis Cosmos spp. Ratibida columnifera Echinacea purpurea
annual perennial annual annual perennial perennial
Boraginaceae Boraginaceae
Forget-me-not Phacelia
Myosotis spp Phacelia
annual annual
Caryophyllaceae
Baby’s breath
Gypsophila muralis
annual
Fabaceae
Lupine
Lupinus spp
perennial
Lamiaceae
Self-heal
Prunella vulgaris
perennial
Lythraceae
Cuphea
Cuphea spp.
annual
Onagraceae Onagraceae
Evening primrose Spike primrose
Oenothera biennis Epilobium densiflorum
biennial annual in Oregon
Papaveraceae
Shirley poppy
Papaver rhoeas
annual
42
Results ⊕ Weed control followed expected patterns. Rimsulfuron and halosulfuron did not control nightshade; dithiopyr missed pigweed; oryzalin did not control nightshade, and clopyralid was weak on most species present. Mesotrione, saflufenacil, oxyfluorfen, indaziflam, flumioxazin, and dimethenamid-p gave the best overall weed control (Table 2). ⊕ Spike primrose and selfheal seeds emerged very slowly and produced very few plants. In the case of spike primrose, the late planting date may have affected germination. ⊕ Selectivity among herbicides differed significantly among crops. A ratio was calculated that compared weed control to crop injury estimates (Table 5). ⊕ Phacelia was extremely tolerant of mesotrione whether applied PPS or POST ⊕ Forget-me-not was very tolerant to clopyralid POST, and moderately tolerant to saflufenacil. Phacelia, the other entry of the Boraginaceae family, was completely controlled by saflufenacil. ⊕ Baby’s breath was tolerant to oxyfluorfen. ⊕ Evening primrose was tolerant to a number of herbicides, most strongly tolerant to oxyfluorfen. ⊕ Bachelor button appeared to be very tolerant of pyroxasulfone, but not s-metolachlor, chemistries with the same mode of action and that often perform similarly. None of the other entries of the Asteraceae family tolerated pyroxasulfone. Bachelor button was the only entry that appeared to have some tolerance to indaziflam. ⊕ Lupine tolerated s-metolachlor and pyroxasulfone. ⊕ Cuphea had some tolerance to mesotrione PPS, but less tolerance to mesotrione applied POST. ⊕ Cosmos was tolerant to dithiopyr, dimethenamid-p, pendimethalin, oryzalin, and smetolachlor. Weeds of the Asteraceae family are often tolerant to moderately tolerant to these herbicides. Other species of this family did not follow this pattern. ⊕ A number of entries in this experiment were sufficiently tolerant to one or more herbicides to consider registration. The rates used in this trial were maximum use rates in many cases. Where crop tolerance was marginal or on the borderline of acceptability, lower rates may still give acceptable weed control and provide the crop safety needed to make these products useful.
43
Table 2. Weed control in flowers grown for seed on July 26, 2011 before plots were cultivated (n=3). Herbicide
Product
Timing
Rate
Weed Control Black nightshade
lbs ai/A
Pigweed
Common purslane
Composite rating
--------------------- % ---------------------
1
Dithiopyr
Dimension
PPS
0.18
95
33
100
77
2
Dimethenamid-P
Outlook
PPS
0.63
96
99
97
95
3
Ethalfluralin + clomazone
Strategy
PPS
1.05
98
99
100
96
4
Flumioxazin
Chateau
PPS
0.191
99
99
100
99
5
Halosulfuron
Sandea
PPS
0.035
0
100
100
72
6
Indaziflam
Alion
PPS
0.026
98
100
97
97
7
Isoxaben
Gallery
PPS
0.66
98
98
100
93
8
Mesotrione
Callisto
PPS
0.094
99
100
92
94
9
Oryzalin
Surflan
PPS
1
66
83
100
88
10
Oxyfluorfen
Goal 2 XL
PPS
0.25
100
100
100
98
11
Pendimethalin
Prowl
PPS
0.75
95
100
90
92
12
Prodiamine
Barricade
PPS
0.5
93
100
99
95
13
Pyroxasulfone
Zidua
PPS
0.067
90
97
100
90
14
Saflufenacil
Treevix
PPS
0.044
100
100
100
99
15
S-metolachlor
Dual Magnum
PPS
0.95
92
98
100
92
16
Rimsulfuron
Matrix
POST
0.031
33
100
87
70
17
Clopyralid
Stinger
POST
0.125
50
10
17
33
18
Halosulfuron
Sandea
POST
0.035
0
82
33
50
19
Mesotrione
Callisto
POST
0.094
100
100
20
96
21
26
36
23
FPLSD (0.05)
44
lbs ai/A 1
Dithiopyr
2
Dimethenamid-P
3 4
Ethalfluralin+clomazon e Flumioxazin
5
Prairie cone flower
Black eyed Susan
Cosmos
Cuphea
Selfheal
Lupine
Bachelor button
Eve primrose
Baby’s breath
Obs
Forget me not
Rate
Calendula
Timing
Spike primrose
Product
Poppy
Herbicide
Phacelia
Level
Purple cone flower
Table 3. Herbicide effects on seedling emergence, July 18, 2011, approximately 1 month after planting.
---------------------------------------------- no/m of row----------------------------------------
Dimensio n Outlook
PPS
0.18
3
6.0
1.3
1.0
0
6.0
2.7
0.3
6.0
6.0
4.3
0
5.0
6.0
6.0
6.0
PPS
0.63
3
0
0
0
0
6.0
6.0
5.0
0
6.0
6.0
0
0
6.0
0
0
Strategy
PPS
1.05
3
0.3
0
0
0
6.0
3.3
2.0
6.0
6.0
1.7
0
2.3
6.0
0
0.3
Chateau
PPS
0.191
3
0
0
0
0
0
2.0
0
0
2.7
0
0
0
1.7
0
0
Halosulfuron
Sandea
PPS
0.035
3
0
0
0
0
2.0
2.0
0.3
4.0
4.7
6.0
0
0
4.0
0
0
6
Indaziflam
Alion
PPS
026
3
2.7
0
0
0
0
4.0
2.0
0
6.0
6.0
0
1.0
6.0
1.0
0
7
Isoxaben
Gallery
PPS
0.66
3
1.7
0
0
0
4.0
4.3
2.3
6.0
6.0
3.0
0
1.7
5.7
0
0
8
Mesotrione
Callisto
PPS
0.094
3
6.0
0
6.0
0
6.0
2.0
2.0
0
0
0
0
6.0
3.3
0
0
9
Oryzalin
Surflan
PPS
1
3
2.3
2.0
0
0
6.0
0
0
5.0
6.0
5.3
0
3.0
6.0
6.0
3.7
10
Oxyfluorfen
Goal 2 XL
PPS
0.25
3
0
0
0
0
3.3
4.0
6.0
2.3
5.3
5.0
0
0.7
6.0
0
0
11
Pendimethalin
Prowl
PPS
0.75
3
1.3
4.0
0
0
6.0
2.0
0
6.0
6.0
6.0
0
1.7
6.0
6.0
4.0
12
Prodiamine
Barricade
PPS
0.5
3
4.0
0
0.3
0
6.0
0.7
2.0
6.0
6.0
5.7
0
3.3
4.3
3.3
0.3
13
Pyroxasulfone
Zidua
PPS
0.067
3
4.3
1.0
0
0
6.0
4.0
2.0
0.3
6.0
6.0
0
2.7
5.7
0
0
14
Saflufenacil
Treevix
PPS
0.044
3
0
0
0
0
2.3
5.0
3.7
0
5.3
1.3
0
0.7
1.0
0
0
15
S-metolachlor
PPS
0.95
3
4.0
0.3
0
0
5.3
5.3
4.0
4.0
6.0
6.0
0
0
6.0
0
0.3
16
Rimsulfuron
Dual Magnum Matrix
POST
0.031
3
2.0
1.3
2.3
0
3.3
4.0
6.0
6.0
6.0
2.3
0
0
4.0
4.0
4.0
17
Clopyralid
Stinger
POST
0.125
3
6.0
1.0
2.7
0
0.7
4.0
4.0
6.0
0
4.3
0
3.7
6.0
2.0
2.0
18
Halosulfuron
Sandea
POST
0.035
3
2.0
0.7
4.3
0
1.3
6.0
2.3
6.0
2.0
2.3
0
0.7
4.0
1.7
0.7
19
Mesotrione
Callisto
POST
0.094
3
6.0
0
5.3
0
6.0
2.0
0.3
0
4.7
0
0
4.7
6.0
0
0
20
Check
-
-
3
6.0
2.0
3.0
0
6.0
4.0
4.0
6.0
4.3
6.0
0
4.3
6.0
4.3
3.0
3.1
2.3
2.3
0
2.3
4.7
4.0
2.0
2.2
2.4
0
2.9
2.3
2.5
2.6
FPLSD (05)
-
45
Table 4. Percent growth reduction in flowers grown for seed on August 26, 2011.
lbs ai/A
Prairie cone
Black eyed Susan
Cosmos
Cuphea
Selfheal
Lupine
Bachelor button
Eve primrose
Baby’s breath
Forget me not
Calendula
Spike primrose
Rate
Poppy
Timing
Purple cone
Product
Phacelia
Herbicide
------------------------------------------------ % stunting ------------------------------------------------
1
Dithiopyr
Dimension
PPS
0.18
43
90
100
87
27
100
99
7
7
47
100
27
0
23
40
2
Dimethenamid-P
Outlook
PPS
0.63
100
100
100
100
37
80
50
100
23
23
67
100
10
100
100
3
Ethalfluralin+ clomazone
Strategy
PPS
1.05
100
100
100
100
67
97
97
7
83
100
100
73
20
100
100
4
Flumioxazin
Chateau
PPS
0.191
100
100
100
100
100
100
100
100
88
100
100
100
83
100
100
5
Halosulfuron
Sandea
PPS
0.035
100
100
100
100
100
100
100
100
92
50
100
100
85
100
100
6
Indaziflam
Alion
PPS
0.026
80
100
100
100
100
73
93
100
7
23
100
87
13
83
100
7
Isoxaben
Gallery
PPS
0.66
73
100
100
93
57
85
73
7
57
50
100
70
40
83
100
8
Mesotrione
Callisto
PPS
0.094
0
100
30
100
37
100
100
100
100
100
100
10
95
100
100
9
Oryzalin
Surflan
PPS
1
77
67
100
83
40
100
100
70
7
17
100
63
0
20
30
10
Oxyfluorfen
Goal 2 XL
PPS
0.25
100
100
100
83
87
63
0
83
53
53
100
90
23
100
100
11
Pendimethalin
Prowl
PPS
0.75
98
33
100
67
17
93
100
33
40
17
100
87
7
7
33
12
Prodiamine
Barricade
PPS
0.5
90
100
100
100
10
100
67
0
10
20
100
97
33
80
50
13
Pyroxasulfone
Zidua
PPS
0.067
37
93
100
100
33
83
53
100
0
0
100
52
40
100
100
14
Saflufenacil
Treevix
PPS
0.044
100
100
100
100
90
17
60
100
70
92
100
90
87
100
100
15
S-metolachlor
Dual Magnum
PPS
0.95
63
93
100
100
23
50
0
50
23
0
100
100
0
100
73
16
Rimsulfuron
Matrix
POST
0.031
97
93
97
100
100
93
93
40
53
97
100
100
97
83
43
17
Clopyralid
Stinger
POST
0.125
0
100
80
83
100
0
13
40
97
70
100
47
93
100
100
18
Halosulfuron
Sandea
POST
0.035
80
100
80
100
100
90
70
73
97
100
100
93
90
100
67
19
Mesotrione
Callisto
POST
0.094
17
100
37
67
23
97
98
100
85
100
100
30
77
100
100
FPLSD (05)
46
Table 5. Relative selectivity of flower crop tolerance to post plant surface and postemergence herbicides. Value in each cell is the ratio of crop injury sustained by the herbicide divided by the weed control provided. Shaded cells indicate treatments that provided acceptable weed control without damaging the crops. Prairie cone flower
Black eyed Susan
Cosmos
Cuphea
Selfheal
Lupine
Bachelor button
Evening primrose
Baby’s reath
Forget me not
Calendula
Spike primrose
Timing
Poppy
Product
Purple cone flower
Herbicide
Phacelia
Level
----------------------------------------------------- ratio of % herbicide injury to weed control-------------------------------1
Dithiopyr
Dimension
PPS
0.6
1.3
1.4
1.3
0.5
1.4
1.4
0.1
0.1
0.7
1.4
0.2
0
0.3
0.1
2
Dimethenamid-P
Outlook
PPS
1.1
1.1
1.1
1.1
0.4
0.8
0.5
1.1
0.2
0.3
1.1
1.1
0.1
1.1
1.1
3
Strategy
PPS
1.0
1.0
1.0
1.0
0.7
1.0
1.0
0.1
0.9
1.0
1.0
0.8
0.2
1.0
1.0
4
Ethalfluralin+ clomazone Flumioxazin
Chateau
PPS
1.0
1.0
1.0
1.0
1.0
1.0
1.0
1.0
0.9
1.0
1.0
1.0
0.8
1.0
1.0
5
Halosulfuron
Sandea
PPS
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.4
0.5
1.5
1.5
1.2
1.5
1.5
6
Indaziflam
Alion
PPS
0.8
1.0
1.0
1.0
1.0
0.6
1.0
1.0
0.1
0.24
1.0
0.9
0.1
0.9
1.0
7
Isoxaben
Gallery
PPS
0.8
1.1
1.1
1.0
0.6
0.9
1.1
0.1
0.6
0.5
1.1
0.8
0.6
0.9
1.1
8
Mesotrione
Callisto
PPS
0
1.1
0.3
1.1
0.4
1.1
1.1
1.1
1.1
1.1
1.1
0.1
1.0
1.1
1.1
9
Oryzalin
Surflan
PPS
0.9
0.8
1.2
1.0
0.2
1.2
1.2
0.8
0.1
0.2
1.2
0.7
0
0.3
0.3
10
Oxyfluorfen
Goal 2 XL
PPS
1.0
1.0
1.0
0.8
0.9
0.6
0
0.8
0.5
0.5
1.0
0.9
0.2
1.0
1.0
11
Pendimethalin
Prowl
PPS
1.1
0.4
1.1
0.7
0.2
1.0
1.1
0.3
0.4
0.2
1.1
0.9
0.1
0.1
0.4
12
Prodiamine
Barricade
PPS
0.9
1.1
1.1
1.1
0.1
1.1
1.1
0
0.1
0.2
1.1
1.0
0.4
0.8
0.5
13
Pyroxasulfone
Zidua
PPS
0.4
1.0
1.1
1.1
0.4
0.9
0.6
1.1
0
0
1.1
0.4
0.4
1.1
1.1
14
Saflufenacil
Treevix
PPS
1.0
1.0
1.0
1.0
0.9
0.2
0.6
1.0
0.7
0.9
1.0
0.9
0.9
1.0
1.0
15
S-metolachlor
PPS
0.7
1.0
1.1
1.1
0.3
0.6
0
0.7
0.3
0
1.1
1.1
0
1.1
1.1
16
Rimsulfuron
Dual Magnum Matrix
POST
1.5
1.4
1.5
1.5
1.5
1.4
1.4
0.6
0.8
1.5
1.5
1.5
1.5
1.3
0.9
17
Clopyralid
Stinger
POST
0
2.0
1.7
2.0
2.0
0
0.4
0.8
1.9
1.7
2.0
1.4
1.8
2.0
2.0
18
Halosulfuron
Sandea
POST
1.7
2.3
1.6
2.3
2.3
1.9
1.4
1.7
2.2
2.3
2.3
2.2
2.1
2.3
1.7
19
Mesotrione
Callisto
POST
0.2
1.0
0.4
0.7
0.2
1.0
1.0
1.0
0.9
1.0
1.0
0.3
0.8
1.0
1.0
47
Table 6. Herbicide application data. Planted June 21-22 herbicide application date Crop stage Weeds and growth stage Application timing Start/end time Air temp/soil temp (2")/surface Rel humidity Wind direction/velocity Cloud cover Soil moisture Plant moisture Sprayer/PSI Mix size Gallons H20/acre Nozzle no. and type Nozzle spacing and height Soil inc. method/implement Other
Thursday, February 24, 2011 some cotyledons present (stale seedbed) PPS 5:30-9 AM 63/68/70 55% 0 at start and finish, up to 3 mph for trts 10-13 100 Dry BP30PSI 7000 mls 20 5-XR8002 20/20 Irrigation after 4 hours
48
Friday, July 15, 2011 3 WAP some 4 in or bigger EPOST 6-8AM 61 75% SW 0- 0.2 0 Damp Heay dew BP25PSI 8000 mls 20 4-XR8003 20/20 Irrigate on Monday Cultivated wheel tracks
Figure 1. Research farm plot showing effect of treatment on different flower species, Sept 2, 2011.
49