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Technical Report TR 21-6
Agricultural
Experiment Station
College of Agricultural Sciences Department of Soil & Crop Sciences Extension
Making
Better
Decisions
2021 Colorado
Sunflower
Variety
Performance
Trials
For the fastest access to up-to-date variety information and results visit us at: www.csucrops.com Research conducted by Colorado State University Crops Testing Program Department of Soil and Crop Sciences Colorado State University Extension Colorado Agricultural Experiment Station Disclaimer **Mention of a trademark or proprietary product does not constitute endorsement by the Colorado Agricultural Experiment Station.** Colorado State University is an equal opportunity/affirmative action institution and complies with all Federal and Colorado State laws, regulations, and executive orders regarding affirmative action requirements in all programs. The Office of Equal Opportunity is located in 101 Student Services. In order to assist Colorado State University in meeting its affirmative action responsibilities, ethnic minorities, women, and other protected class members are encouraged to apply and to so identify themselves. 2
Table of Contents
Authors.......................................................................................................................................................3
Acknowledgments....................................................................................................................................3
Summary of the 2021 Colorado Sunflower Hybrid Performance Trials...........................................4
2021 Irrigated Oil Sunflower Hybrid Performance Trial at Burlington............................................6
2021 Irrigated Confection Sunflower Hybrid Performance Trial at Burlington...............................7
2021 Irrigated Confection Sunflower Hybrid Performance Trial at Prospect Valley......................8
2021 Irrigated Oil Sunflower Hybrid Performance Trial at Prospect Valley....................................9
2021 Dryland Oil Sunflower Hybrid Performance Trial at Julesburg.............................................10
2021 Dryland Oil Sunflower Hybrid Performance Trial at Sheridan Lake.....................................11
White Mold of Sunflower........................................................................................................................12
Authors
Sally Jones-Diamond - Director - Crops Testing, CSU Department of Soil and Crop Sciences,
Phone: 970-214-4611, E-mail: sally.jones@colostate.edu
Ed Asfeld - Research Associate - Crops Testing, CSU Department of Soil and Crop Sciences,
40335 CR GG, Akron, CO 80720, Phone: 970-554-0980, E-mail: ed.asfeld@colostate.edu
Dr. Jerry Johnson - (Retired) Professor and Extension Specialist - Crop Production, CSU
Department of Soil and Crop Sciences, E-mail: jerry.johnson@colostate.edu
Dr. Robyn Roberts - Assistant Professor - Plant Pathology, Colorado State University,
Department of Agricultural Biology, Phone: 970-491-8239, E-mail: robyn.roberts@colostate.edu
Olivia LoGrasso - Student - Colorado State University, Department of Agricultural Biology,
E-mail: olivia.lograsso@colostate.edu
Acknowledgments
The authors wish to express their gratitude to the collaborating Colorado farmers who
voluntarily and generously contributed the use of their land, equipment, and time to facilitate
the 2021 sunflower hybrid performance trials: Josh Lechman at Julesburg, Jason Specht at
Sheridan Lake, Gerhard Heintges at Burlington, and Leon Zimbelman at Prospect Valley.
We thank Red River Commodities Inc. in Colby, KS, for doing the confection sunflower seed-
sizing analyses and the USDA-ARS Northern Crop Science Laboratory in Fargo, ND, for doing
the oil content analyses.
3
Summary of the 2021 Colorado Sunflower Hybrid Performance Trials
Sally Jones-Diamond
Colorado State University (CSU) conducts hybrid sunflower performance trials to provide
research-based, unbiased, current, and reliable information to Colorado sunflower producers
to make better planting decisions. Colorado State University promotes crop variety testing as a
service to crop producers and seed companies who depend on us for crop variety performance
information. The sunflower trials are made possible by funding received from company entry
fees, the Colorado Sunflower Administrative Committee, and Colorado State University.
Colorado State University personnel planted four irrigated and two dryland sunflower trials in
Colorado, including oil and confection type trials. Irrigated trial locations were Burlington and
Prospect Valley. The dryland trials were located at Julesburg and Sheridan Lake. Thirty-one
hybrids with diverse origins, maturities, and value-added traits were tested in our different
irrigated and dryland trial locations. Trial results are statistically analyzed and reported
shortly after harvest on our website at agsci.colostate.edu/csucrops/sunflower/.
Testing Methods
Hybrids were included in the test based on paid company entries where company
representatives select and enter hybrids and provide seed for planting. All trial entries were
randomized within each replication using a randomized complete block design. Plot sizes
were 2 rows wide for irrigated trials and 4 rows wide for dryland trials at 30” spacing by
35’ long. Both irrigated and dryland trials had four replicates. Cultural practices for each
trial location are included below the individual site tables when available and management
practices in the trial area match the rest of the grower’s field in most cases.
Plots at all locations were planted using a four-row Seed Research Equipment Solutions
(SRES) 2013 Classic Aire small plot vacuum planter equipped with Monosem seed meters.
Oil irrigated trials were planted at 25,000 seeds per acre and confection irrigated trials were
planted at 20,000 seeds per acre. The dryland oil trials were planted at 19,000 seeds per acre
and the dryland confection trial was planted at 15,000 seeds per acre. Grain yields for all trial
hybrids are reported in the tables.
Sunflower plots at all locations were harvested using a Case IH 1620 combine modified for
small plots and equipped with a H2 GrainGage weighing system (provides weight, moisture,
and test weight). All yields are calculated and adjusted to 10% moisture content. Oil seed
contents are also adjusted to 10% moisture. Confection seed sizing is evaluated by the percent
of seeds that go through or stay above different sizes of round-hole screens.
Data Results
The least significant difference (LSD) is provided at the bottom of the results table. The LSD
is used to help determine whether the difference in hybrid yields are statistically significant.
If the difference between two hybrid yields equals or exceeds the LSD value, the difference is
significant. Farmers should use the LSD (P
risk of false positive results. If two entries being compared have a difference in yield that is less
than the LSD value, those two entries are to be considered equal yielding. Hybrid yields in
bold are in the top LSD group. Hybrids in the table are sorted from highest to lowest-yielding.
Hybrid selection may be based on more than yield performance. Other factors to consider
when selecting a hybrid may include maturity, herbicide or pest tolerance traits, disease
resistance, standability, seed size, and seed quality.
5
2021 Irrigated Oil Sunflower Hybrid
Performance Trial at Burlington
Oil 3-Year Test Plant Oil
Brand Hybrid Typea Technology Traitsb Yieldc Avg. Yield Moisture Weight Height Population Contentc
lb/ac lb/ac percent lb/bu in plants/ac percent
CROPLAN by Winfield United CP7919CL NS Clearfield 3420 - 14 30 66 23,100 38
Nuseed N4H521 CL HO Clearfield, DMR 3330 2820 14 30 75 22,100 38
Dyna-Gro H49NS14CL NS Clearfield 2850 2750 15 31 70 20,300 36
Dyna-Gro H49HO19CL HO Clearfield 2730 2480 14 31 66 21,100 37
Nuseed N4H422 CL HO Clearfield, DMR 2700 2460 14 30 72 21,600 33
Nuseed Hornet HO Clearfield, DMR 2670 2670 14 30 71 19,200 35
Dyna-Gro XH81H52CP HO Clearfield 2640 - 16 32 78 24,800 37
CROPLAN by Winfield United CP455E HO ExpressSun 2520 2490 14 31 66 21,100 35
Nuseed N4H470 CL Plus HO Clearfield Plus, DMR 2520 2260 15 31 65 23,500 37
Nuseed Falcon NS ExpressSun 2490 - 14 32 73 21,900 36
Nuseed NHKE53359 HO ExpressSun, DMR 2220 - 15 30 70 22,700 33
Nuseed NLKE4002 NS ExpressSun, DMR 2070 - 15 33 76 23,100 35
Average 2680 2560 14 31 71 22,000 36
d
LSD (P
2021 Irrigated Confection Sunflower Hybrid
Seed Retained Over Screen
Technology 2-Year Test Plant Over Over Over Over
a
Brand Hybrid Traits Yieldb Avg. Yield Moisture Weight Height Population 24/64 22/64 20/64 16/64
lb/ac lb/ac percent lb/bu in plants/ac percent
Royal Hybrid RH609CLP Clearfield Plus 4320 3649 12 18 80 15,500 47.8 27.0 18.2 6.8
Valia Genetics Valia 95 N/A 3300 2963 12 18 68 16,700 42.5 28.1 19.7 9.4
Valia Genetics D2101EXP Clearfield 3120 - 13 20 80 19,200 6.7 4.5 5.8 44.2
Royal Hybrid 21-EXP01 ExpressSun 3030 - 12 18 63 17,600 26.7 28.8 28.3 15.3
SH Seeds SHS 46 IMI 3030 - 12 17 60 14,700 73.4 18.2 7.0 1.2
Red River Commodities RRC 2319 N/A 2880 2762 12 18 72 14,500 60.2 25.5 11.1 2.7
Red River Commodities RRC 2414 N/A 2820 3145 13 18 64 13,900 66.4 19.4 10.0 3.8
Nuseed 4334 Clearfield 2640 - 12 18 74 12,500 62.9 22.7 9.5 4.8
Valia Genetics Valia 92 N/A 2610 2714 13 19 72 17,300 22.8 25.8 30.1 18.4
Valia Genetics Valia 41 N/A 2490 2593 12 19 64 10,000 23.8 29.6 33.9 12.5
SH Seeds Express IMI 2460 - 11 18 60 12,200 11.7 29.3 29.8 26.9
Red River Commodities RRC 2310 N/A 2430 2511 13 20 73 14,700 70.3 17.2 10.1 1.8
Nuseed NSKM15788 Clearfield 2130 - 13 17 72 16,400 11.9 25.2 38.5 23.0
Nuseed NDKM16761 Clearfield 2070 - 12 19 60 16,700 56.7 22.5 13.6 6.6
Nuseed NJKE15790 Clearfield 1500 - 11 19 54 14,500 32.5 24.8 24.8 16.4
Average 2720 2905 12 18 68 15,100 41.1 23.2 19.4 12.9
c
LSD (P
2021 Irrigated Confection Sunflower Hybrid
Seed Retained Over Screen
Technology Test Over Over Over Over
Brand Hybrid Traitsa Yieldb Moisture Weight 24/64 22/64 20/64 16/64
lb/ac percent lb/bu percent
Royal Hybrid RH609CLP Clearfield Plus 3390 13 17 90.6 6.5 2.5 0.0
Royal Hybrid 21-EXP01 ExpressSun 3330 12 17 78.3 15.3 4.9 1.1
Nuseed NSKM15788 Clearfield 3270 12 15 56.0 31.0 10.4 2.0
Red River Commodities RRC 2414 N/A 2940 12 16 94.2 3.7 1.1 0.5
SH Seeds Express IMI 2160 12 16 83.6 11.8 3.4 0.7
SH Seeds SHS 46 IMI 2160 12 16 89.6 7.5 1.9 0.8
Red River Commodities RRC 2319 N/A 2130 13 16 77.4 15.2 5.0 1.8
Nuseed 4334 Clearfield 1920 12 16 90.6 5.9 2.9 0.0
Red River Commodities RRC 2310 N/A 1830 11 17 60.0 27.0 11.4 1.1
Nuseed NJKE15790 Clearfield 1710 13 18 35.1 31.1 22.5 10.5
Nuseed NDKM16761 Clearfield 1650 11 16 63.1 26.8 8.5 1.1
Average 2410 12 17 74.4 16.5 6.8 1.8
c
LSD (P
2021 Irrigated Oil Sunflower Hybrid
Performance Trial at Prospect Valley
Oil 2-Year Test Plant Oil
Brand Hybrid Typea Technology Traitsb Yieldc Avg. Yield Moisture Weight Height Contentc
lb/ac lb/ac percent lb/bu in percent
CROPLAN by Winfield United CP7919CL NS Clearfield 3210 - 15 26 57 37
Dyna-Gro H49NS14CL NS Clearfield 2700 2950 17 26 43 32
Nuseed N4H521 CL HO Clearfield, DMR 2700 2700 16 26 48 38
Nuseed Hornet HO Clearfield, DMR 2490 2410 15 26 58 33
Nuseed N4H422 CL HO Clearfield, DMR 2490 2590 14 26 54 33
CROPLAN by Winfield United CP455E HO ExpressSun 2340 2690 14 28 63 35
Nuseed Falcon NS ExpressSun 2280 - 13 28 56 34
Dyna-Gro H49HO19CL HO Clearfield 2160 2410 13 27 47 34
Nuseed N4H470 CL Plus HO Clearfield Plus, DMR 2070 2130 15 28 59 36
Dyna-Gro XH81H52CP HO Clearfield 2040 - 16 28 56 34
Nuseed NHKE53359 HO ExpressSun, DMR 1830 - 16 25 56 31
Nuseed NLKE4002 NS ExpressSun, DMR 1740 - 13 26 56 31
Average 2340 2550 15 26 54 34
d
LSD (P
2021 Dryland Oil Sunflower Hybrid
Performance Trial at Julesburg
Oil 2-Year Test Plant Oil
a b c c
Brand Hybrid Type Technology Traits Yield Avg. Yield Moisture Weight Height Content
lb/ac lb/ac percent lb/bu in percent
CROPLAN by Winfield United CP7919CL NS Clearfield 1590 - 12 28 50 38
Dyna-Gro H49NS14CL NS Clearfield 1410 - 12 30 42 38
Nuseed N4H422 CL HO Clearfield, DMR 1380 1320 12 29 50 36
Nuseed N4H521 CL HO Clearfield, DMR 1380 1380 12 29 43 37
Nuseed N4H470 CL Plus HO Clearfield Plus, DMR 1350 1200 12 30 42 38
Nuseed Falcon NS ExpressSun 1290 - 12 30 50 37
Dyna-Gro H49HO19CL HO Clearfield 1230 - 12 29 42 36
Nuseed Hornet HO Clearfield, DMR 1230 1200 12 29 38 36
Dyna-Gro XH81H52CP HO Clearfield 1200 - 12 30 46 37
CROPLAN by Winfield United CP455E HO ExpressSun 1140 1240 12 29 50 36
Average 1320 1270 12 29 45 37
d
LSD (P2021 Dryland Oil Sunflower Hybrid
Performance Trial at Sheridan Lake
Oil 2-Year Test Plant Oil
Brand Hybrid Typea Technology Traitsb Yieldc Avg. Yield Moisture Weight Lodging Height Population Contentc
lb/ac lb/ac percent lb/bu percent in plants/ac percent
CROPLAN by Winfield UnitedCP7919CL NS Clearfield 1200 - 11 27 33 39 17,700 33
Nuseed Hornet HO Clearfield, DMR 1140 941 11 27 33 45 19,000 34
Dyna-Gro XH81H52CP HO Clearfield 1140 - 11 28 33 46 19,100 33
Dyna-Gro H49NS14CL NS Clearfield 1110 922 11 27 30 48 18,100 33
S&W Seed Company SF440 HO/CL HO Clearfield 1080 885 11 27 25 48 16,000 33
Nuseed N4H521 CL HO Clearfield, DMR 1020 803 11 27 31 50 16,900 33
CROPLAN by Winfield UnitedCP455E HO ExpressSun 990 859 11 26 28 46 18,000 31
Dyna-Gro H49HO19CL HO Clearfield 990 847 11 26 35 49 18,300 32
Nuseed N4H422 CL HO Clearfield, DMR 990 824 11 27 40 53 16,400 33
Nuseed N4H470 CL Plus HO Clearfield Plus, DMR 960 800 11 27 30 47 19,800 34
S&W Seed Company NSW21460 HO Clearfield Plus 780 - 11 27 50 44 17,000 32
S&W Seed Company SW1H81CLP HO Clearfield 600 - 11 25 40 43 14,800 31
S&W Seed Company SF1H63CL HO Clearfield 570 - 11 25 35 50 11,200 30
Nuseed Falcon NS ExpressSun 540 - 11 26 53 47 20,200 32
Average 940 860 11 27 35 47 17,300 32
d
LSD (PWhite Mold of Sunflower
White Mold of Sunflower
Olivia LoGrasso and Dr. Robyn Roberts
White mold disease and symptoms
White mold, caused by the Sclerotinia sclerotium fungus, is a highly destructive disease of
sunflower in Colorado. The white mold fungus causes disease in over 370 plant species, including dry
beans, soybean, and many legumes; aster species, which include sunflowers, are particularly
susceptible. In sunflower, the fungus causes three separate white mold diseases: basal stalk rot and wilt,
mid-stalk rot, and head rot. Each of these white mold diseases develop differently in sunflowers,
depending on the mechanism and location of the initial fungal infection, but are all caused by the same
pathogen.
Basal rot and wilt
Basal stem rot symptoms typically
appear near the flowering stage, but may A
occur earlier depending on the environmental
conditions and inoculum level. The pathogen
infects the roots and causes drooping or
wilting of the plant without any visible spots
or fungal growth on the leaves (Figure 1A). At
the base of the stem, tan to brown
discoloration, rot, and water-soaked lesions
form large, pitted wounds (called cankers),
which lead to stem girdling. If moist
B
conditions persist (which perpetuate fungal
growth), white, cottony-appearing mold
(mycelia) may appear (Figure 1B). The disease
will progress up the stem, with the fungus
consuming the internal parts of the stem
(called the pith) and causing a dry, shredded
appearance of the basal end of the stem,
along with stem bleaching. The best
diagnostic sign of white mold infection is a
Figure 1. Symptoms of basal rot and wilt. A) Wilting
hollowed stem filled with black, irregularly- symptoms, and B) fungal mycelia growth (red arrow) and
shaped and darkly-colored fungal structures basal stalk rot, indicative of white mold disease. Photos:
called sclerotia (Figure 2). Once the plant Howard F. Schwartz, 2008a & 2008b.
begins to wilt, it typically dies within one
week. Less severe infections may not cause wilt or death; however, symptoms will appear as lesions
with fluffy white mycelia on the stalk, which will be weakened and more likely to lodge in high winds.
12Mid-stalk rot
Mid-stalk rot symptoms typically aren’t observed
until later in the season (around the flowering period) and
look similar to basal rot. However, unlike basal stalk rot
which appears at the base of the stem, symptoms for mid-
stalk rot instead develop around the middle of the stalk,
typically near a leaf node. Symptoms can occasionally
begin on a leaf and move to the petiole (the slender
segment that connects the leaf to the stem) and then from
the petiole to the stem. Browning and water-soaked
lesions, similar to those seen in basal rot, appear in the
infected area. A canker forms around the stem, and tissue
Figure 2. Stalk rot symptoms due to white mold
around the canker will appear and feel wet and rotted. The disease. Shown are a degraded stalk, white fungal
weakened stalk will often fall over at or above the canker growth (mycelia), and fungal fruiting structures
(sclerotia). Red arrows indicate sclerotia. Photo:
site. Typically, white, cottony mold grows and covers the Gerald Holmes, 2009a.
rotting tissue, and sclerotia form on and in the affected
area. Eventually the infection will take on a bleached and shredded appearance like that of basal rot.
Head rot
Usually seen near the end of flowering, A
head rot often causes the most severe disease. The
early symptoms include dark and water-soaked
lesions on the back of the flower head, or white
mycelial fungal growth that progresses over the
seeds in the flower (Figure 3A). The fungus grows
prolifically inside the flower head, beneath the
seeds. It produces large numbers of sclerotia both
beneath and around the seeds; eventually, the
entire flower head disintegrates, dropping many
large sclerotia (Figure 3B). The disintegrated flower B
head appears dry and shredded, often compared to
a straw broom.
Infection and pathogen survival
The pathogen is highly dependent on
moisture from weather and irrigation practices.
Infections become more severe in cool (68°F–77°F)
and moist conditions; typically in early spring or
fall, when there is more rainfall and temperatures Figure 3. Head rot symptoms caused by white mold.
A) Mycelial growth around sunflower seeds. B)
are lower. It overwinters in the soil or crop debris Disintegration of heads. Sclerotia are indicated with
in fungal long-term ‘survival structures’ called red arrows. Photos: Gerald Holmes, 2009b & 2009c.
sclerotia, which are darkly colored, pigmented
13structures composed of compacted thread-like fungal filaments (hyphae). The fungus can remain
dormant and infectious for long periods of time through sclerotia. For S. sclerotiorum, they remain
infectious for 3 to 7 years.
There are two ways that the fungus can infect sunflower. In the early summer when
temperatures are cooler and soil moisture is higher, the sclerotia will germinate in the soil and infect the
plant through the roots. Chemicals emitted by the roots stimulate the sclerotia to germinate mycelial
strands that penetrate plant roots and begin moving up through the plant. This mode of infection leads
to basal stem rot and wilt. Unlike other crops, sunflower is especially susceptible to root infection by S.
sclerotiorum.
The fungus can also infect the plant through mushroom-like fruiting bodies (called apothecia)
that develop from the sclerotia. Around the time of flowering, sclerotia germinate apothecia after
periods of cooler temperatures, high soil moisture, and high humidity. The apothecia produce spores
(ascospores) that are puffed out into the air. Upon landing on the plant, they germinate and infect the
plant. This infection process causes mid-stalk rot and head rot, which typically remains localized within
the field; however, wind can sometimes carry spores further distances, allowing infections to spread
more broadly.
Management
Integrated pest management approaches have shown to be the most effective methods in white
mold management. Because sclerotia can persist and remain infectious in fields for at least 3 years,
three- to five-year crop rotations (or longer with severe infections) with non-hosts (such as corn) should
be used. Do not rotate fields with other host species (such as soybeans), and if possible, avoid planting
sunflowers on or near fields that were known to be infected in recent years. In fields with less severe
infections, no-till practices in combination with non-host crop rotation can help control disease in
subsequent years. Since sclerotia can remain infectious in the soil for up to 7 years, crop rotation alone
is not sufficient at controlling disease so other management practices should also be implemented.
Management of white mold host weeds (such as Canada thistle, pigweed, or wild sunflowers)
prevents the pathogen from ‘hiding out’ in other plants, which can serve as a pathogen inoculum source.
Making the environment around sunflowers less favorable to the pathogen can also help control the
fungus. Since the fungus thrives under cool, moist conditions, effectively managing irrigation to prevent
water-logged soil and using wide row spacing to help promote air flow in the field will make the
environment less favorable for the fungus. Avoid over-fertilization as it will promote a dense canopy
that inhibits air flow.
Head rot disease results in the formation of sclerotia on seed (and sometimes within seeds), so
choosing certified disease-free seed will help minimize the risk of introducing the fungus into fields.
Currently, no sunflower varieties are completely resistant to white mold diseases, but tolerant varieties
are commercially available. The use of resistant or tolerant crop varieties in combination with other
management practices will help reduce disease impact. There are potential biological controls, including
the fungal parasite Coniothryium minitans Campbell, which attacks sclerotia produced by S.
sclerotiorum. While this control method has been shown to reduce levels of sclerotia in the field, its
reliability is not thoroughly understood. While fungicides may help control white mold infections in
soybean, they are not typically recommended for sunflowers because the fungus commonly infects
14through roots, making above-ground fungicide applications ineffective. Seed coating with fungicide
resistance action committee (FRAC) group 11 active ingredients may help protect plants from basal stalk
rot during the seedling stage. There are fungicides labelled for Sclerotinia mid-stalk rot and head rot, but
the efficacy trials of these fungicides are inconsistent and other management methods are more
reliable.
Additional resources
Colorado Sunflower trial results to aid in variety selection:
https://agsci.colostate.edu/csucrops/sunflower/
Lesson on S. sclerotiorum diseases on sunflower, with in-depth control methods:
https://www.apsnet.org/edcenter/disandpath/fungalasco/pdlessons/Pages/SclerotiniaSunflow
er.aspx
FRAC (Fungicide Resistance Action Committee, https://www.frac.info/ and https://plant-pest-
advisory.rutgers.edu/understanding-the-strobilurin-fungicides-frac-group-11-2015-2/)
Photos (used with permission):
Schwartz, H. F., Colorado State University and Bugwood.org. 2008a. Sclerotinia timber rot (Sclerotinia
sclerotiorum). IPM Images. https://www.ipmimages.org/browse/detail.cfm?imgnum=5357373.
Schwartz, H. F., Colorado State University and Bugwood.org. 2008b. Sclerotinia timber rot (Sclerotinia
sclerotiorum). IPM Images. https://www.ipmimages.org/browse/detail.cfm?imgnum=5357376.
Holmes, G., Strawberry Center, Cal Poly San Luis Obispo, and Bugwood.org. 2009a. Sclerotinia timber rot
(Sclerotinia sclerotiorum). IPM Images.
https://www.ipmimages.org/browse/detail.cfm?imgnum=5610168.
Holmes, G., Strawberry Center, Cal Poly San Luis Obispo, and Bugwood.org. 2009b. Sclerotinia timber rot
(Sclerotinia sclerotiorum). IPM Images.
https://www.ipmimages.org/browse/detail.cfm?imgnum=5610169.
Holmes, G., Strawberry Center, Cal Poly San Luis Obispo, and Bugwood.org. 2009c. Sclerotinia timber rot
(Sclerotinia sclerotiorum). IPM Images.
https://www.ipmimages.org/browse/detail.cfm?imgnum=5610153.
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