Evaluation of Fungicides to
Manage Blackleg of Canola
Kurtt Lindbeck/Audrey
K
Li db k/A d Leo
L – NSW Department
D
t
t off Primary
Pi
Industries,
I d t i Wagga
W
Wagga
W
Steve Marcroft/Vicki Elliot – Marcroft Grains Pathology, Horsham
Angela van de Wouw – University of Melbourne, Parkville
National Canola Pathology Project (UM0051)
Introduction
 Southern NSW traditionally a profitable canola
producing region
– Since early 1990’s (Oscar, Rainbow, Dunkeld,
Karoo and Pinnacle)
Pinnacle).
– Mid/late 1990’s
1990 s, area increased dramatically
• wheat/canola/wheat/canola
• disease
di
concerns
• rotation was profitable
Area sown to Canola in NSW 1993 - 2015
800,000
Area sow
wn to Canola (ha)
700,000
600,000
500,000
400,000
300,000
200,000
100,000
-
Year
Introduction
 Late 1990’s
– Canola yield decline observed
– Level of disease observed in crops suggested
increasing disease could be responsible
– Kirkegaard et al.
al (2001 – 2003)
• High rainfall districts (Galong/Wallendbeen)
• Blackleg (1% lodging = 5% yield loss)
• Sclerotinia ((1% stem rot = 1.3% yyield loss))
 Blackleg was having an impact
Why is
Wh
i bl
blackleg
kl
such
ha
severe disease ?
5
Leptosphaeria maculans in Australia
stubble
sexual fruiting bodies
windborne sexual spores
AUTUMN
SUMMER
lodged plants
SPRING
root rot
stem canker
WINTER
cotyledon infection
Regional
g
effect on blackleg
g
High canola intensity = blackleg every year
7
Regional effect on blackleg
L
Low
canola
l intensity
i t
it = low
l
blackleg
bl kl regardless
dl
off season
Summary
y
 Sexually reproducing
– diverse populations that can evolve and
overcome resistance
 Survives on stubble
– lots of inoculum in southern NSW
 Blackleg
g severity
y is determined by
y canola intensity
y
and environment
Blackleg Management
10
Blackleg Management
 Current Recommended Strategies
– Cultivar resistance
• Select varieties with adequate resistance
– Separation from st
stubble
bble
• Separate crops from old stubble by 500m
– Seed and fertiliser dressings and foliar
fungicides
• Select appropriate level of fungicide protection
– Rotation groups
g p
• Rotate ‘resistance groups’ every 2 – 3 years
Evaluation of fungicides to manage blackleg
 Trials conducted at Wagga Wagga (Graham Centre) and
Cowra
– Evaluate current registered fungicide options
• Jockeyy – seed dressing
g
• Impact – fungicide treated fertiliser
• Prosaro – foliar fungicide (4 – 6 leaf)
– Applied to a range of canola cultivars
• 2013 - Jardee (MS), Crusher (MR/MS), Thumper (R)
• 2014 - Crusher (MR/MS) Stingray (MR)
Effect of fungicide treatment on
blackleg internal infection - 2013
100.0
e
90.0
de
80.0
d
Nil
% stem
m Infection
70 0
70.0
d
60.0
d
c
Jockey
Impact
d
bc
Prosaro
50.0
Jockey + Impact
ab
Jockey + Prosaro
40.0
a
30.0
a
c
Impact + Prosaro
bc
Jockey + Impact + Prosaro
bc
ab
20.0
a
10.0
a
a
a
a
a
a
0.0
Jardee
5% LSD = 1.16
Crusher
5% LSD = 1.22
Thumper
5% LSD = 0.90
a
Effect of fungicide treatment on
canola yield - 2013
2.0
d
1.8
b
1.6
bc
bc
ab
e de
1.4
Yield ((t/ha)
d
cd
a
Nil
cde
cd
1.2
b
Jockey
bc
Impact
b
b
10
1.0
b
ab
b
b
ab
a
a
Prosaro
Jockey + Impact
ab
0.8
b
Jockey + Prosaro
Impact + Prosaro
0.6
Jockey + Impact + Prosaro
0.4
5% LSD = 0.16 (t/ha)
0.2
0.0
Jardee
Crusher
Thumper
Effect of fungicide treatment on
Crusher (% internal infection) - 2014
100.0
90.0
80 0
80.0
f
70.0
e
60.0
50 0
50.0
40.0
d
30.0
cd
bcd
20 0
20.0
ab
abc
10.0
a
pa
ct
+J
oc
ke
y+
Im
on
ly
+P
ro
sa
ro
nl
y
pa
ct
o
+J
oc
ke
y+
Pr
os
ar
o
+I
m
pa
ct
+P
ro
+I
sa
m
pa
ro
ct
+J
oc
ke
y+
Pr
os
ar
o
5% LSD = 10.1
+I
m
+J
oc
ke
y
Ni
l
on
ly
0.0
Effect of fungicide treatment on
Stingray (% internal infection) - 2014
100.0
90.0
80.0
70.0
d
60.0
d
50.0
40.0
30.0
c
bc
20 0
20.0
bc
a
10.0
ab
pa
ct
+J
oc
ke
y+
Im
on
ly
+P
ro
sa
ro
nl
y
pa
ct
o
+J
oc
ke
y+
Pr
os
ar
o
+I
m
pa
ct
+P
ro
+I
sa
m
pa
ro
ct
+J
oc
ke
y+
Pr
os
ar
o
5% LSD = 9.8
+I
m
on
ly
+J
oc
ke
y
Ni
l
0.0
a
Fungicide tolerance….
 All available fungicides from the one active group –
Ti
Triazoles
l (DMI
(DMIs, G
Group 3)
– Strong selection pressure for fungicide resistance to
evolve
 Isolates of Letosphaeria maculans identified with tolerance
to fluquinconazole
 Develop lesions on Jockey treated seedlings
Identified five isolates with increased
tolerance to fluqinconazole
8.0
Avera
age pathogen
nicity score
7.0
6.0
5.0
Westar - Nil
4.0
Westar - Full rate
3.0
2.0
1.0
0.0
7225-1
7225-2
7229-1
7229-2
7235-2
D13
D9
Fungicide tolerance….
 Isolates identified appear to have increased tolerance
rather than resistance
– Lesions that develop are not completely virulent
– Lesions develop slower on jockey treated plants
compared to nil control
 Large scale stubble survey Australia wide – early 2015
– Collection and screening
g of isolates
– 200 paddocks sampled
– 20% currently being retested
Conclusions
 Fungicides are a valuable tool in providing
protection from infection
– Seed and fertiliser treatment most effective
– Foliar fungicides effective under high disease pressure
– Over reliance on fungicides…??
 Always remember IDM
– Consider the level of cultivar resistance and group
– Consider the ‘background’ disease pressure
– Select the appropriate combination
• Cultivar and fungicide
22
23
24