19. Other strawberry viruses?
Revisited strawberry virus-like diseases.
Chlorotic fleck Leafroll
Goal: Identify unknown viruses that may contribute to the
decline.
20. Identification, characterization and development
of detection techniques for strawberry viruses
*
*
*
*
*
*
*
*
*
Tobacco streak virus
* Strawberry crinivirus 3
* Strawberry crinivirus 4
23. Blackberry yellow vein disease
First observed in 2000 in the Carolinas.
Tested for known viruses (RBDV, TRSV etc) – Several viruses
were found but none consistently associated with symptoms.
24. Tobacco ringspot virus and BYVD
BYVD is very similar to what people thought as being TRSV
symptoms
TRSV textbook symptoms Single TRSV-infection
Are symptoms cv. dependent? The majority of plants
infected with TRSV are symptomless
25. New viruses in Rubus in the last 7 yrs
16 viruses & virus-like agents were known to infect Rubus
before we started looking into Rubus complexes – We now
have over 40…
New Rubus viruses
Blackberry yellow vein associated virus
Blackberry virus E
Blackberry virus X
Blackberry virus Y
Blackberry virus Z
Beet pseudo yellows virus
Blackberry yellow mottle virus
Blackberry chlorotic ringspot virus
Strawberry necrotic shock virus
Black raspberry necrosis virus
Raspberry leaf mottle virus
Rubus canadensis virus -1
Impatiens necrotic spot virus
Raspberry latent virus
etc…..
26. New viruses in Rubus in the last 8 yrs
16 viruses & virus-like agents were known to infect Rubus
before we started looking into Rubus complexes – We now
have over 40…
New Rubus viruses
Blackberry yellow vein associated virus
Blackberry virus E Tests are available for all the new viruses
Blackberry virus X
Blackberry virus Y
Blackberry virus Z
Beet pseudo yellows virus
Blackberry yellow mottle virus
Blackberry chlorotic ringspot virus
Strawberry necrotic shock virus
Black raspberry necrosis virus
Raspberry leaf mottle virus
Rubus canadensis virus -1
Impatiens necrotic spot virus
Raspberry latent virus
etc…..
31. How do we tackle BYVD?
After identification of all (or almost all) viruses that are involved in
the disease we need to:
A. Make sure that mother plants are being tested for the new
viruses before they are propagated.
B. Identify virus combinations that can cause BYVD.
C. Identify virus vectors.
D. Find alternative hosts of the viruses in the field.
E. Minimize or eliminate BYVD by eliminating the weakest link, the
virus vector(s) that is the easiest to control.
32. What are the viruses present in your area?
The importance of detection
• BYVaV - Multistate sample
collection - 35 isolates
• i
33. What are the viruses present in your area?
The importance of detection
• BYVaV - Multistate sample
collection - 35 isolates
• i
1 2 3 4 5 6 7 8 9
• Detection
100%
identity
34. Virus interactions: The BYVaV/BVY story
BVY did not cause symptoms in single
infections but together with BYVaV they
cause BYVD.
In mixed infections, BVY knocks down
concentration of BYVaV to about 0.1%
compared to titer in single infections.
In mixed infections, they can cause death
of fruiting canes.
Susaimuthu et al.,2008. Plant Disease 92:1288-1292
35. Transmission
Experiment Trialeurodes abutilonea Trialeurodes vaporariorum
Experiment 1 4/7 3/9
Experiment 2 5/8 1/8
Experiment 3 3/10 3/10
Total 12/25 7/27
• Both whitefly species transmitted the virus at a rate >30%
37. Vector elimination
The BRNV paradigm
New field monitoring Time of transmission
Permanent tagged plants High incidence of virus
Potted plants
Rotated every month
P L H D
O K G C
N J F B
M I E A
38.
39. Average Aphids/Trap
0
2
4
6
8
10
12
14
4-May
11-May
18-May
25-May
Field 1
1-Jun
8-Jun
15-Jun
22-Jun
Date
29-Jun
Field 2 6-Jul
13-Jul
20-Jul
Average Aphids/Trap: 2004
27-Jul
3-Aug
10-Aug
17-Aug
40
50
60
70
80
90
100
110
o
Max Daily Temp ( F)
Field 3
Field 3
Field 2
Field 1
M ax D aily T emp
40. Average Aphids/Trap: 2005
6 100
5 90
Average Aphids/Trap
Max Daily Temp ( F)
o
4 80
Field 1
Field 2
3 70
Field 3
Maximum Daily Temp
2 60
1 50
0 40
5-Jul
19-Jul
1-Mar
15-Mar
29-Mar
12-Apr
26-Apr
7-Jun
21-Jun
2-Aug
16-Aug
30-Aug
13-Sep
27-Sep
10-May
24-May
11-Oct
25-Oct
Date
Field 1 Field 2 Field 3
Nearly 100% transmission in three years!
41. Average Aphids/Trap
0
1
2
3
4
5
6
7
10-May
17-May
24-May
31-May
2-Jun
7-Jun
14-Jun
21-Jun
17-Jun
28-Jun
5-Jul
12-Jul 6-Jul
19-Jul
20-Jul
26-Jul
2-Aug
9-Aug
16-Aug
Date
3-Aug 18-Aug
23-Aug
30-Aug
2-Sep
6-Sep
13-Sep
20-Sep
16-Sep
27-Sep
Average Aphids/Trap vs. Positives: 2004
4-Oct
30-Sep
11-Oct
18-Oct
25-Oct
1-Nov
14-Oct 28-Oct
0
2
4
6
8
10
12
14
16
Time of Transmission
# of BRDaV Positives
# of positives
Average Aphids: 2004
42. Raspberry crumbly fruit and decline
• The Pacific Northwest (PNW) is a primary producer of red
raspberries
43. Raspberry crumbly fruit and decline
• ‘Several cultivars are susceptible to
crumbly fruit disease (drupelets
abortion)
• Raspberry bushy dwarf virus (RBDV),
a pollen-borne idaeovirus was
considered the causal agent of
crumbly fruit
• Still, in many cases RBDV single infections did not cause
symptoms
44. Another virus complex?
Important observations suggested that crumbly fruit
symptoms may be increased by additional viruses:
1. The disorder is more severe in cool areas with high
populations of the large raspberry aphid
Amphorophora agathonica
2. Two additional viruses found in severely affected fields,
Raspberry leaf mottle (RLMV) and Raspberry latent
(RpLV)
49. RBDV titer enhanced in co-infections with RLMV
RBDV titer increase verified by conventional methods
ELISA RT-PCR (20 cycles)
50. Mixed virus infections affect on plant growth
and fruit crumbliness
• H Control Raspberry virus .... what...?
• D RBDV - Dwarf
• M RLMV - Mottle
• L RpLV - Latent
• DM RBDV + RLMV
• DL RBDV + RpLV
• ML RLMV + RpLV
• DML RBDV + RLMV + RpLV
51. Plant Growth
Establishment (2010)
Oct. Height
140.00
120.00 109.03
100.00
80.00 65.43 63.83
60.00 44.90 48.93
cm
33.49 32.00
40.00 26.09
20.00
a cd b b d bc cd cd
0.00
H D M L DM DL LM DML
Treatments
Oct. Cane diameter
12.00
10.07
10.00
8.18
8.00 7.02
6.30 5.94
5.74 5.73
mm
6.00 5.41
4.00
2.00 a bc d cd d cd
d b
0.00
H D M L DM DL LM DML
Treatments
52. Plant Growth (2011)
July
Height Cane diameter
70.00 9.00 8.06 7.81 7.72
55.57 8.00 7.34 7.18 7.34 6.99
60.00
51.27 51.03 50.73
48.50 7.00 6.05
50.00 44.60 42.13 6.00
mm
40.00
cm
5.00
30.20
30.00 4.00
3.00
20.00
2.00
10.00
a b b b d b c c 1.00 a a a b c b b b
0.00 0.00
H D M L DM DL LM DML H D M L DM DL LM DML
Treatments Treatments
53. Plant Growth (2011)
October
Height Cane diameter
3 14 12.79
2.60 11.79 11.52 11.83
2.25 2.25 12 10.77 10.82 10.21 10.03
2.5 2.17 2.12
1.97 1.93 1.89 10
2
8
m 1.5 mm 6
1
4
0.5
a b b b cd bc cd d 2
a b b b c bc c c
0 0
H D M L DM DL ML DML H D M L DM DL ML DML
Treatments Treatments
54. Crumbly Fruit
No. Drupelets Weight
120 4.000
94 95 3.35
100 89
75 76 3.000 2.74 2.87 2.57
80 2.43 2.33
64 59 66 2.08 2.05
60 g 2.000
40
1.000
20
a c a a b c b c a c b b bc cd cd d
0 0.000
H D M L DM DL LM DML H D M L DM DL LM DML
Treatments Treatments
55. Crumbly fruit
Firmness
D
90.000
80.000 73.54
65.58
70.000
58.54 61.38 61.83 61.46
60.000
46.38 49.15
50.000
g 40.000
30.000
20.000
10.000
a c bc b bc d bc d
0.000
H D M L DM DL LM DML
Treatments
H DML DML
57. Crumbly Fruit Scouting
Crumbly fruit and virus incidence in Washington
Field Crumbliness Virus incidence
Age 0: normal %
3: severe
0 1 2 3 RBDV RLMV RpLV
4 1 44 25 0
4 2 100 100 0
4 3 93 100 7
5 3 100 100 40
6 3 92 96 40
Crumbliness Crumbliness Crumbliness
rate 1 rate 2 rate 3
58. Insects in Traps (2011)
Empoasca fabae was sporadic
Raspberry aphid A. agathonica
predominant insect
Average # aphids / 10 8
Few numbers of 7 Harvest clean-up
Macropsis fuscula 6 sprays applied
5
leaves
4
3
2
1
0
1-Apr 16-May 30-Jun 14-Aug 28-Sep
Lightle, unpublished data
59. RLMV spread in the field
Four fields being monitored for virus spread
Field 4 26 % (24 %) 50 %
4% (40 %) 44 %
Field 3
21 % (12 %) 33 %
Field 2
16 % (16 %) 32 %
Field 1
year 0 year 1 year 2 year 3
Age of Field
60. Control Strategies
1. Think long term, identify potential risks of a site
2. Start with clean plants
3. Identify and diagnose problems early
4. Implement control strategies ASAP
5. If a virus complex is involved - identify viruses present
and which are the easiest to control
63. The importance of clean plants
• Better establishment
• Longer life of plantings
64.
65. The importance of clean plants
• Better establishment
• Longer life of plantings
• Fewer disease problems/Reduce risk of introducing
new viruses to a region or field
66.
67.
68. National Clean Plant Network
A federally-coordinated effort to secure high quality virus-
tested plants for clonally propagated crops.
NCPN Mission
The NCPN provides high quality asexually propagated
plant material free of targeted plant pathogens and
pests that cause economic loss to protect the
environment and ensure the global competitiveness of
specialty crop producers in the United States.
69. NCPN Supported Clean Plant Centers
WSU
USDA at OSU
Cornell
UC-Davis
MO State U.
NCSU
UCR
UAZ UAF Clemson
Auburn
LSU
FAMU
UHM FL-Dept. Ag.
TAMU
72. The story:
Propagation from an existing plot
10 ton/acre =$30,000/year
Latent infections with Blueberry scorch
The result?
Removal of infected material
Cumulative loss: ~ 100,000/acre
76. The team
The berry virus consortium:
16 individuals from UA, NCSU, USDA-ARS, MSU, UGA
Bindu Poudel, Diego Quito, Danielle Lightle, Anne Halgren,
James Susaimuthu
