should strobilurins still be used in wheat? danish and foreign experience
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Should strobilurins still be used in wheat?
Danish and foreign experience
Lise Nistrup Jørgensen
Karin ThygesenDanish Institute of Agricultural Sciences.
Flakkebjerg
2Danish Institute of Agricultural Sciences Flakkebjerg
Agenda
• 2 years’ trial after strobe resistant septoria have become widespread
• Experiences from abroad
• Experiences with strobilurins for tan spot (DTR) control
• Next years recommendations
3Danish Institute of Agricultural Sciences Flakkebjerg
Distribution of strobilurin resistance septoria 2004
• Strobilurin resistant septoria in DK
2,5
33
22
81
0
10
20
30
40
50
60
70
80
90
2003 2004
%st
robi
lurin
resi
sten
s
spring
Summer
>75%
<75%
4Danish Institute of Agricultural Sciences Flakkebjerg
Septoria control with and without strobilurins –
5 trials 2004-2005 -split-ear treatment
50
55
60
65
70
75
80
85
90
2x 0,3 Opus + 2 x 0.2 Amistar + 2 x 0,1 Amistar +2 x 0.2 Comet +2 x 0,1 Comet
% control
5Danish Institute of Agricultural Sciences Flakkebjerg
Yield increases with/without strobilurins - 5 trials 2004-2005 –split-ear treatments
-202468
1012141618
2x 0,3 Opus + 2 x 0.2Amistar
+ 2 x 0,1Amistar
+ 2 x 0.2Comet
+ 2 x 0,1Comet
grossmargin
Hkg/ha
LSD=3.4
6Danish Institute of Agricultural Sciences Flakkebjerg
-2
0
2
4
6
8
10
0,5 Opus 0,25 Opus +0,25 Amistar
0,25 Opus +0,25 Comet
0,4 Opus +0,1 Amistar
0,4 Opus +0,1 Comet
grossmargin
Yield increase with/without strobilurins –3 LC trials – single ear-treatments
Hkg/ha
LSD95 = 2.1
Source: Landsforsøgene 2005
7
% control of septoria plus/minus strobilurins 3 trials 2004-2005 – split-ear treatments
0
10
20
30
40
50
60
70
80
90
2x 0,4 Opus 2 x 0,2 Opus + 2 x 0,2 Amistar +2 x 0.2 Comet 2x0,2 Juwel
Danish Institute of Agricultural Sciences Flakkebjerg
8Danish Institute of Agricultural Sciences Flakkebjerg
Yield increase plus/minus different strobilurins 3 trials 2004-2005 split-ear treatment
-2
0
2
4
6
8
10
12
14
2x 0,4 Opus 2 x 0,2 Opus + 2 x 0,2Amistar
+2 x 0.2Comet
0,2 Juwel
grossmargin
LSD = 2.9
Hkg/ha
9Danish Institute of Agricultural Sciences Flakkebjerg
Conclusions on Danish trials
• On average little positive effect of adding strobilurins in 2 years trials
• Gain similar to increasing dose of Opus
• Little or no greening effect observed
• Positive effects not dependent on cultivar or nitrogen
10
52 forsøg med høj resistens til strobiluriner QoI(>30%)
3.2
3.9
-2
0
2
4
6
8
10
12
89
18
28
95 2
61
91
10
91
80
86
89
55
76
10
14
76
91
77
10
41
27
80
22
14
50
q/ha
Gain STROBILURINES 100 g/haGain OPUS + 50 g/ha
moyenne gain strobmoyenne gain dose OPUS
French trials with 0.2 strobilurin or 0.2 Opus added to Opus treatments at T1 and T2
Kilde: Claude Maumene Arvalis, Frankrig
+ 0,2 strobilurin
+ 0,2 Opus
11Danish Institute of Agricultural Sciences Flakkebjerg
French data from strobilurin trials
T1 and T2 Yield increase from adding strobe or Opus hkg/ha
+ 2 x 0.2 strobi
+ 2 x 0.2 Opus
+ 2 x 0.2 Comet
3.3
3.0
-
3.2
3.9
4.0
3.4
1.5
5.4No of trials 82 52 30
Resistant level High >30% Low <30%
Kilde: Claude Maumene Arvalis
Basic treatments with 2 x (0.2-0.6 l Opus)
12Danish Institute of Agricultural Sciences Flakkebjerg
Conclusions on French trials• 82 trials with +/- strobilurins
– 3.3 hkg/ha from adding 0.2 l strobilurins to Opus (Margin by 0.8 hkg/ha)
• At high resistant levels Opus alone has been best– 80% of trials have given best yield after increase in
Opus dose (+0.2 l) compared with adding 0.2 l Strobilurins
• Comet + Opus solutions equally good as Opus solutions
• Best effect from adding strobilurins at the early application
13Danish Institute of Agricultural Sciences Flakkebjerg
Experiences from abroad
• Still low septoria resistance in some parts of Europe• Still some effect on septoria – typically around 30%
in fields with high levels of resistance• Still yield increases around 3-4 hkg/ha. Big variation
difficult to explain• Possible explanations:
– Occurrences of intermediate resistant isolates (10-15%)– Preventive effects still significant on resistant isolates– Direct physiological effects, diminishes stress/antioxidants– Comet has been seen to give induced resistance
14
Control of different septoria isolates with varying degrees of strobilurin resistance
Danish Institute of Agricultural Sciences Flakkebjerg
010
2030
405060
7080
90100
0,125 0,25 0,5 1
dosering l/ha
% c
on
tro
l
DG 60 res
UK 35 inter
UK 121 inter
D63 inter
UK19 inter
IR 121 inter
s27 sen
Sensitive isolate
Inter-mediateisolates
Resistant isolate
15Danish Institute of Agricultural Sciences Flakkebjerg
Preventive or curative effects on septoria
Isolates Preventive treatments
Curative treatments
Sensitive
Resistant 1
Resistant 2
Resistant 3
84
65
27
56
68
18
16
2
Source: Bill Clark, 2005
16Danish Institute of Agricultural Sciences Flakkebjerg
Recommendations abroad
• Opus/Proline/Daconil main elements in septoria control strategies in our neighbouring countries
• Effect of strobilurins on septoria is seen as secondary• Strobilurins still recommended at late applications
(T3) for control of– Alternaria, Claudisporium etc
– Fusarium/Michodochium
– Brown rust and yellow rust
17Danish Institute of Agricultural Sciences Flakkebjerg
% control of DTR on 2nd leaf, GS 73-75 - 2005 trials
Treatments at GS 39
Høve Flakkebjerg
Untreated
Bumper 0.25
Proline 0.4
Acanto 0.5
(45%)
78
69
49
(75%)
75
76
80
18
Monitoring DTR sensitivity to strobes
Agar + fungicide
Spore suspension of pure-cultured isolates
Microtitreplate with various fungicide concentrations mixed with agar
0,1
0
1,0
10
1
10
25
ppm/L
Strobilurin
Propiconazole
50
19Danish Institute of Agricultural Sciences Flakkebjerg
DTR resistant monitoring - DKLocalities Number of
isolatesAmistar
EC50
% Strobi-resistance*
Bjærup (Flak)
Ålborg
Sjælland
Nykøbing F
Skive
Odder
Høve
Flakkebjerg
10
10
13
2
2
10
6
10
0.5
0.1
8
20
>25
>10
8
8
0
0
46
100
100
60
50
20
TotaleTotale 6363 0.1-200.1-20 33 (>10 33 (>10 ppm)ppm)
* Probably G143 resistance
20
Conclusions on strobilurins resistance to DTR
• Strobilurins have shown reduced effects in field trials in Denmark as well as in Sweden
• 8 LC trials have on average given lower effects and yields from strobilurins compared with triazols
• Both F129 and G143 resistance-mechanisms found in Denmark. G143 gives low field performance
• Few isolates tested from 2003-2004. These showed, however common resistance.
• Sensitivity tests from 2005 have shown wide spread resistance, but also variation between localities
21Danish Institute of Agricultural Sciences Flakkebjerg
Danish recommendations
• Septoria control– Opus alone or Opus + low Strobilurin dose– E.g.: 0.5 l Opus or 0.4 l Opus + 0.1 l Comet/Amistar
• DTR control– Bumper + Opus – E.g.: 0.15-25 Bumper + 0.15- 0.2 Opus– Proline (if and when registration comes in 2006)
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