| 2.1. Review of sensitivity monitoring
2.1.1. Cereal
diseases
Powdery mildew (Erysiphe graminis f.sp. tritici),
wheat
No further monitoring has been done in 2003 in North
Western Europe. Already in 2002 high levels of resistance
were found in the main wheat growing countries in Europe.
Bayer CropScience
No resistance was detected in Austria, Hungary and
the Czech Republic.
Powdery mildew (Erysiphe graminis f.sp hordei), barley
BASF, Bayer CropScience, Syngenta
In general the frequency of resistant isolates increased
in 2003 compared to 2002, however the spread of resistant
barley powdery mildew isolates is slower than that
observed previously for wheat powdery mildew. Some
resistant strains were detected in Denmark and Sweden.
Moderate frequencies of resistance were detected in
UK and Ireland. The picture in Germany is still heterogeneous
with higher values found in the northern regions. Higher
frequencies of resistance were found in Northern France
and in Belgium. No resistance was detected in Austria
and Italy. Field performance was good when QoI products
were applied in mixtures as recommended by the QoI
FRAC guidelines.
Septoria leaf spot (Septoria tritici), wheat
BASF, Bayer CropScience, Syngenta
Extensive monitoring programmes were carried out throughout
the wheat growing areas of Europe in 2003. Due to the
first detection of resistant strains late in the 2002
season monitoring programmes were carried out to determine
the geographical distribution of resistance in Europe.
Therefore samples have been taken in winter, early
spring and during summer.
Disease pressure in 2003 was low to moderate due to
predominantly dry weather conditions. High disease
levels were observed in Ireland where rainfall was
higher.
In contrast to what was expected at the beginning
of 2003 the spread of resistance is quite fast. In
the monitoring programmes resistance was detected in
all major wheat growing countries in Western Europe
(as detailed hereafter). Generally in-season monitoring
data show increased resistance levels compared to pre-season
samplings, as well as further geographical distribution.
Different analysis methods (detached leaf assay, microtiter
plate assays, PCR, q-PCR, Pyrosequencing) with more
than 10.000 data points in 2003 resulted in comparable
data across companies. Status at the end of the season
2003 is as follows:
| Ireland |
widespread all over the
country at high levels |
| UK |
widespread at moderate to high levels
in Southern regions,but low to moderate in the
rest of the UK and Scotland |
| France |
heterogenous populations with low
to high levels in the North of France (Pas-de-Calais
and Picardie), low or no resistance elsewhere |
| Germany |
heterogeneous picture in the North
(Schleswig-Holstein, Mecklenburg-Vorpommern, Niedersachsen,
Nordrhein-Westfalen) ranging from low to high levels,
low or no resistance elsewhere |
| Belgium,
The Netherlands |
heterogeneous picture, areas without
resistance and locations with high levels |
| Denmark |
low to moderate levels |
| Sweden,
Poland, Czech Republic |
low or no resistance |
Field performance
of spray programmes with QoI containing products was
good in 2003 when FRAC guidelines have been followed.
Brown rust (Puccinia recondita), wheat
BASF, Bayer CropScience, Syngenta
Performance of QoI fungicides against brown rust was
good. No resistant isolates were detected from widespread
monitoring studies in Europe in 2003, confirming the
fully sensitive picture already established.
Leaf scald (Rhynchosporium secalis), barley
Syngenta
Performance of QoI fungicides against leaf scald
was good. Preliminary monitoring data from 2003 showed
a fully sensitive picture for the UK and Ireland. More
data will be available before the end of 2003.
2.1.2. Vine diseases
Downy mildew (Plasmopara
viticola)
BASF, Bayer CropScience, DuPont, Syngenta
In 2003, disease pressure was low in the main grape
growing areas of Europe. Infestation only occurred
towards the end of the season.
All companies carried out major monitoring programmes
in 2003 in France, Italy, Germany, Austria, Switzerland,
Spain and Portugal. Both semi-quantitative bioassay
and PCR techniques were used to generate data. A frequency
of 1-2% G143A identified through PCR diagnosis was
usually reflected as a resistant phenotype in bioassay
tests.
No resistant strains were detected in Austria. For
the first time resistant strains could be found in
Portugal (Peninsula de Setubal) at low levels. In general,
compared to 2002 a slight increase in the frequency
of detection of the resistant strains was observed
in France whereas the situation in the other countries
was unchanged. Heterogeneous results have been reported
in Italy indicating both increase and decrease in the
frequency of resistance which might be explained by
differences in the methods employed and the late occurrence
of the disease in 2003.
The occurrence of the second target site mutation
F129L was confirmed for France and identified in Spain
(1 sample) at very low frequencies. Resistance factors
of approx. 10 were recorded and emphasize the low practical
relevance of this mutation. As a consequence no further
analyses on this mutation will be done in 2004.
Where FRAC guidelines were followed field performance
of QoI containing spray programmes was good across
Europe and frequently provided better disease control
compared to non-QoI containing programmes.
Powdery mildew (Uncinula necator)
Disease pressure was low across Europe.
No 2003 data available yet
One case of reduced field performance to QoI in USA
(NY) is under investigation.No complaints are recorded
elsewhere.
2.1.3. Pome fruit diseases
Apple scab (Venturia inaequalis)
BASF, Bayer CropScience
Disease pressure was low across Europe. Infestation
only occurred towards the end of the season.
Monitoring was carried out in Germany, France, Italy,
UK, Netherlands, Belgium, Switzerland, the Czech Republic,
Poland, Hungary, Spain and USA. Employed methods included
QPCR and DHPLC.
Target site mutants (G143A) were found for the first
time in France, Belgium, Netherlands, Czech Republic
and Hungary. Levels of resistance were generally low
except for two sites in France (Montauban, Nîmes).
Performance of QoI fungicide programmes under both
trial and commercial conditions was generally good.
Despite the detection of resistance in European apple
growing regions since several years the spread of resistant
populations remains limited. A clear lack of correlation
between detection of target site mutants and disease
control is evident.
2.1.4. Cucurbit diseases
Powdery mildew (Sphaerotheca fuliginea)
No data was generated in 2003.
High frequencies of resistant isolates have previously
been detected in Japan, Taiwan, Spain, Israel and Southern
France, and in these countries field performance was
affected. Resistance has also been previously detected
at several locations in the UK, Netherlands, North
West France, Italy and Korea.
Downy mildew (Pseudoperonospora cubensis)
No data was generated in 2003.
Resistance have previously been detected in Japan
and Taiwan and field performance in these countries
has been reduced.
2.1.5. Potato/tomato diseases
Late blight (Phytophthora infestans)
Bayer CropScience, DuPont
No resistance was detected in all isolates collected
from potato crops in France, Germany, Netherlands,
UK, Eire, Belgium, Scandinavia, Portugal and Poland.
Performance remains good.
Early blight (Alternaria solani)
Syngenta
Cases of reduced sensitivity, found in 2002 in the
USA, were followed up regarding frequency and practical
relevance of the F129L mutation.
Isolates carrying the F129L mutation were detected
in 2003 in Nebraska, North Dakota and Wisconsin. Resistance
factors were confirmed to be low.
Field performance was good.
2.2. Review of guidelines
2.2.1. Strategies and Guidelines for the 2004 season
Strategies for the management of QoI fungicide resistance,
in all crops, are based on the statements listed below.
These statements serve as a fundamental guide for the
development of local resistance management programs.
Resistance management strategies have been further
enhanced in order to be proactive and to prevent the
occurrence of resistance to QoI fungicides developing
in other areas and pathogens. Specific guidelines by
crop follow the general guidelines given here.
A fundamental principle that must be adhered to when
applying resistance management strategies for QoI fungicides
is that:
The QoI fungicides (azoxystrobin, famoxadone, fenamidone,
kresoxim-methyl, picoxystrobin, pyraclostrobin, trifloxystrobin,
fluoxastrobin, dimoxystrobin, metominostrobin and oryzastrobin)
are in the same cross-resistance group.
| |
Fungicide programs must deliver effective
disease management. Apply QoI fungicide based products
at effective rates and intervals according to manufacturer's
recommendations. Effective disease management is
a critical component to delay the build-up of resistant
pathogen populations.
The number of applications of QoI fungicide
based products within a total disease management
program must be limited whether applied straight
or in mixtures with other fungicides. This limitation
is inclusive to all QoI fungicides. Limitation
of QoI fungicides within a spray programme provides
time and space when the pathogen population is
not influenced by QoI fungicide selection pressure.
A consequence of limitation of QoI
fungicide based products is the need to alternate
them with effective fungicides from different
cross-resistance groups.
QoI fungicides, containing only the
solo product, should be used in single or block
applications in alternation with fungicides from
a different cross-resistance group. Specific
recommendation on size of blocks is given for
specific crops.
QoI fungicides, applied as tank mix
or as a co-formulated mixture with an effective
mixture partner, should be used in single or
block applications in alternation with fungicides
from a different cross-resistance group. Specific
recommendations on size of blocks are given for
specific crops.
Mixture partners for QoI fungicides
should be chosen carefully to contribute to effective
control of the targeted pathogen(s). The mixture
partner must have a different mode of action,
and in addition it may increase spectrum of activity
or provide needed curative activity. Use of mixtures
containing only QoI fungicides must not be considered
as an anti-resistance measure.
An effective partner for a QoI fungicide
is one that provides satisfactory disease control
when used alone on the target disease.
QoI fungicides are very effective at
preventing spore germination and should therefore
be used at the early stages of disease development
(preventive treatment). |
2.2.2. Specific Crop/Pathogen
guidelines
2.2.2.1. Cereal diseases
The field performance of QoI containing spray programmes
was good in 2003, but the build up and further spread
of resistance of Septoria tritici could not be prevented.
Therefore it is essential to strengthen the role of
non-crossresistant mixture partners (e.g. SBIs, multisites)
to ensure robust disease management. This will also
help to delay the evolution of Septoria resistance
especially in regions with no resistance or where resistance
is at low levels.
Guidelines for using QoI fungicides on cereal crops
1. |
Apply QoI fungicides
always in mixtures with non-cross resistant fungicides
to control cereal pathogens. At the rate chosen
the respective partner(s) on its/ their own has/
have to provide effective disease control. Refer
to manufacturers recommendations for rates.
|
2. |
Apply a maximum of 2 QoI fungicide containing
sprays per cereal crop. Limiting the number of
sprays is an important factor in delaying the build-up
of resistant pathogen populations. |
3. |
Apply QoI fungicides according to manufacturers
recommendations for the target disease (or complex)
at the specific crop growth stage indicated. |
4. |
Apply the QoI fungicide preventively or as early
as possible in the disease cycle. Do not rely only
on the curative potential of QoI fungicides. |
5. |
Split / reduced rate programmes, using repeated
applications, which provide continuous selection
pressure accelerate the development of resistant
populations and therefore must not be used. |
2.2.2.2. Vine diseases
Guidelines for using QoI fungicides on vines
Powdery mildew (Uncinula necator)
1.
|
Apply QoI fungicides
according to manufacturer's recommendations for
the target disease at the specific crop growth
stage indicated. Effective disease management
is a critical parameter in delaying the build-up
of resistant pathogen populations.
|
2.
|
Apply a maximum of 3 QoI fungicide containing
sprays per vine crop, solo or in mixture with effective
mixture partners from different cross-resistance
groups. |
3.
|
For table grapes, a maximum of 4 QoI fungicide
containing sprays per crop may be used when 12
or more fungicide applications are made. |
4.
|
Apply QoI fungicides preventively. |
5.
|
Apply QoI fungicides in single or block application
in alternation with fungicides from a different
cross-resistance group. |
Downy mildew (Plasmopara
viticola)
1.
|
Apply QoI fungicides
according to manufacturer's recommendations for
the target disease at the specific crop growth
stage indicated. Effective disease management
is a critical parameter in delaying the build-up
of resistant pathogen populations.
|
2.
|
Apply QoI fungicides preventively. |
3.
|
Apply a maximum of 3 QoI fungicide containing
sprays per vine crop, only in mixture with effective
partners from different cross-resistance groups. |
4.
|
Apply QoI fungicides in single or block application
in alternation with fungicides from a different
cross-resistance group. |
2.2.2.3. Pome fruit
diseases
Guidelines for using QoI fungicides on pomefruit
Apple scab (Venturia inaequalis)
1.
|
Apply QoI fungicides
according to manufacturer’s recommendations
for the target disease (or complex) at the specific
crop growth stage indicated and adapted to size
of trees. Effective disease management is a critical
parameter in delaying the build-up of resistant
pathogen populations.
|
2.
|
QoI fungicides must be applied only in mixture
with partners contributing to the effective control
of the target pathogens. |
3.
|
Apply QoI fungicides preventatively. Under high
disease pressure the spray interval should not
exceed 7-10 days. |
4.
|
Apply a maximum of 3 QoI containing sprays per
crop. A maximum of 4 QoI fungicide applications
may be used where 12 or more applications are made
per crop. |
5.
|
A maximum of 2 consecutive QoI fungicide sprays
is preferred. Where field performance was adversely
affected apply QoI containing fungicides in strict
alternation with fungicides from a different cross-resistant
group. |
2.2.2.4. Potato and
tomato diseases
Guidelines for using QoI fungicides on potatoes and
tomatoes
Late blight (Phytophthora infestans)
1.
|
Apply QoI fungicides
according to manufacturer's recommendations for
the target disease
(or complex) at the specific crop growth stage
indicated. Effective disease management is a critical
parameter in delaying the build-up of resistant
pathogen populations.
|
2.
|
Where QoI fungicide products are applied alone
do not exceed 1 spray out of 3 with a maximum of
3 sprays per crop. Do not use more than 2 consecutive
applications. |
3.
|
Where QoI fungicide products are applied in
mixtures (co-formulations or tank mixes) do not
exceed 50% of the total number of sprays or a maximum
6 QoI fungicide applications whichever is the lower.
Do not use more than 3 consecutive Qo fungicide
containing sprays. |
Early blight (Alternaria
solani)
1.
|
Where QoI fungicide
products are applied solo do not exceed 33% of
the total number of sprays or a maximum of 4.
Where mixtures (co-formulations or tank mixes)
are used do not exceed 50% of the total number
of sprays or a maximum of 6 QoI fungicide applications,
whichever is the lower.
|
2.2.2.5. Guidelines
for using QoI fungicides on soybean diseases
QoI fungicides effectively control soybean diseases
including rust which is a new emerging disease of major
importance in Latin America. There is limited experience
at this point in time in terms of rust epidemiology,
disease management (including maximum number of QoI
applications) and resistance risk.
In order to ensure sustainable use of QoIs the Working
Group recommends:
1.
|
Apply QoI fungicides
according to manufacturer's recommendations for
the target disease (or complex) at the specific
crop growth stage indicated. Effective disease
management is a critical parameter in delaying
the build-up of resistant pathogen populations.
|
2.
|
Use QoIs preventatively or as early as possible
in the disease cycle. |
3.
|
Use QoIs preferably in mixtures with fungicides
from a different cross-resistance group. At the
rate chosen each partner on its own has to provide
effective disease control. Refer to manucaturers’ recommendations
for rates. |
2.2.2.6. Cucurbit
diseases
Guidelines for using QoI fungicides on Cucurbit Vegetables
1.
|
Apply QoI fungicides
according to manufacturer's recommendations for
the target disease (or complex) at the specific
crop growth stage indicated. Effective disease
management
is a critical parameter in delaying the build-up of resistant pathogen populations.
|
2.
|
Apply a maximum of 3 QoI fungicide sprays per
crop. |
3.
|
Use a maximum of 1 QoI fungicide spray out of
every three fungicide applications. |
4.
|
Do not use consecutive applications of QoI fungicides. |
5. |
Apply QoI fungicides in alternation with fungicides
from a different cross-resistance group with satisfactory
efficacy against the targeted pathogen(s). |
6.
|
Continue QoI fungicide alternation between successive
crops. |
2.2.2.7. Guidelines for using QoI fungicides on greenhouse
grown non-cucurbit vegetables
1.
|
Apply QoI fungicides
according to manufacturer's recommendations for
the target disease (or complex) at the specific
crop growth stage indicated. Effective disease
management is a critical parameter in delaying
the build-up of resistant pathogen populations.
|
2.
|
Use a maximum of 1 QoI fungicide spray out
of every 3 fungicide applications. |
3.
|
Do not use consecutive applications of QoI fungicides. |
4.
|
Apply QoI fungicides in alternation with fungicides
from a different cross-resistance group with satisfactory
efficacy against the targeted pathogen(s). |
5.
|
Continue QoI fungicide alternation between successive
crops. |
2.2.2.8 Guidelines
for using QoI fungicides on other multiple spray crops
(non-cucurbit field vegetables and ornamentals)
1.
|
Apply QoI fungicides
according to manufacturers recommendations for
the target disease (or complex) at the specific
crop growth stage indicated. Effective disease
management is a critical parameter in delaying
the build up of resistant pathogen populations.
|
2.
|
Observe spray limitations in the spray guideline
table shown below. |
Spray guideline table:
Total
number of spray applications per crop |
4 |
5 |
6 |
7 |
8 |
9 |
10 |
11 |
12 |
>12 |
Maximum
recommended
Solo QoI fungicide sprays |
2
|
2 |
2 |
2 |
3 |
3 |
3 |
3 |
4 |
* |
Max.
recommended QoI fungicide sprays in mixture |
2 |
2 |
3 |
3 |
4 |
4 |
5 |
5 |
6 |
* |
* Where more than 12 fungicide applications are
made, do not use more than one third of all fungicide
applications with QoI fungicides solo or 50% where
used in mixture.
When using a QoI fungicide as a solo product,
the number of applications should be no more than
1/3 (33%) of the total number of fungicide applications
per season.
For QoI mixes in programs in which tank mixes
or pre mixes of QoI with mixing partners of a different
mode of action are utilized, the number of QoI
containing applications should be no more than ½ (50%)
of the total number of fungicide application per
season.
In programs in which applications of QoI are made
with both solo products and mixtures, the number
of QoI containing applications should be no more
than ½ (50%) of the total number of fungicide
applied per season. 2.2.2.9
Banana
Guidelines for using QoI fungicides on banana
The next meeting of the FRAC banana Working Group
is scheduled for 11/12 February 2004. Guidelines
will be updated accordingly.
Black Sigatoka (Mycosphaerella fijiensis)
The following guidelines were updated following
a FRAC meeting held in San Jose, Costa Rica on
August 8th, 2000. This meeting was called specifically
to discuss what changes to the guidelines should
be recommended by FRAC in response to the detection
of strains of Mycosphaerella fijiensis resistant
to the strobilurin fungicides in multiple locations
in Costa Rica. Revised guidelines for strobilurins
(Qo inhibitors) are listed under items 16 to 23.
Where guidelines have been modified from those
agreed at the FRAC meeting in Miami (February,
2000) they are shown in bold type. Guidelines for
other fungicides remain unaltered.
1. |
Field experience
in bananas in Central America has shown that
M. fijiensis can develop resistance to the
DMI fungicides. The DMIs are and will continue
to be very key tools for the efficient control
of Black Sigatoka in bananas. An effective
anti-resistance strategy must be followed
when using these materials, in order to protect
their fungicidal performance over the long
term.
|
|
|
2. |
In general terms, the use of fungicides with
a different mode of action applied in tank
mixtures or in alternated sprays are both suitable
approaches to diminish the risk of resistance
development. These use strategies are particularly
valuable in the case of site specific systemic
fungicides and in situations when there is
a need to cope with a shift towards decreased
sensitivity. The anti-resistance strategies
only allow a limited number of sprays with
the systemic fungicides (see items 9-10). Therefore,
the use of these materials in alternation with
fungicides belonging to other classes seems
to be the best approach in order to allow the
necessary total number of sprays which are
required with the systemic fungicides, for
efficient Black Sigatoka control over the whole
high pressure period. |
|
|
3. |
The use of the full recommended label rate
of DMIs is strongly urged (straight DMI use). |
|
|
4. |
The DMIs must be used at least ¾ of
their full recommended label rates when they
are applied in tank mix with other systemic
fungicides. When tridemorph is the partner
compound, it must be added at least at 2/3
its commercially recommended label rate . In
the case of tank mixtures with benzimidazoles,
these fungicides must be used at their full
recommended label rates. Finally, when mancozeb
is used as the partner material for site specific
systemic fungicides, these DMIs must be applied
at their full recommended label rates. |
|
|
5. |
Single alternation of DMIs with other systemic
fungicides is recommended. Repeated (sequential)
applications of DMIs (either alone or in tank
mixtures with other systemics) must be limited
to no more than 2 consecutive sprays (i.e.
block of 2 sprays). The same recommendation
is also applicable to tridemorph. |
|
|
6. |
All the fungicides belonging to the DMI’s
class are considered to be a single product
group, amongst which there is in general some
degree of cross-resistance. Therefore, alternation
or mixtures of DMIs must not be recommended
for the purpose of resistance management. |
|
|
7. |
The benzimidazole fungicides must not be
applied in consecutive sprays. The applications
of benzimidazole fungicides should not exceed
a total of 6 sprays in a period of 12 months.
It is also recommended that this class of fungicides
must be always used in mixtures with mancozeb. |
|
|
8. |
In the case of straight applications of
the DMIs, the number of sprays against Black
Sigatoka must not exceed a total of 8 cycles
during any 12 month period (a maximum of 6
total sprays in the case of Yellow Sigatoka). |
|
|
9. |
The maximum number of DMI's sprays for controlling
Black Sigatoka might be increased to a total
of 10 applications in a 12 month period, if
the DMIs are always applied in mixtures with
other systemics (7 maximum sprays in the case
of Yellow Sigatoka ). |
|
|
10. |
The number of tridemorph sprays with this
fungicide used either alone, in mixture with
the DMIs or other classes of fungicides must
not exceed a total of 12 applications within
a 12 month period. |
|
|
11. |
Protective (preventative) fungicides are
considered to be a very valuable and necessary
tool for the banana Sigatoka control programs. |
|
|
12. |
The systemic fungicides must only be applied
in oil or oil-water emulsions |
|
|
13. |
A DMI-free period of at least 2 (and if possible
3-4) consecutive months, during the periods
of lower disease pressure is recommended. |
|
|
14. |
DMIs should be applied to achieve as early
a curative control as possible. |
|
|
15. |
Eradicative use of DMIs should be avoided. |
|
|
16. |
A maximum of 4 cycles of strobilurin fungicides
(QoI fungicides) should be used during a 12
month period. |
|
|
17. |
Strobilurin applications (QoI fungicides)
should be limited to a maximum of 3 exposure
periods per calendar year. |
|
|
18. |
Strobilurins (QoI fungicides) should only
be applied in April, August and December in
Costa Rica. In other countries, exposure periods
should be defined locally, with 3 months between
exposure periods as a working guideline.
In regions where high levels of strobilurin
(QoI)resistance have been detected, strobilurin
sprays should be discontinued until there
is evidence of a significant increase in
the frequency of sensitive strains. |
|
|
19. |
Do not exceed recommended label spray intervals. |
|
|
20. |
Do not apply strobilurins (QoI fungicides)
in successive sprays |
|
|
21. |
Apply full recommended label rates of the
strobilurins (QoI fungicides) alone or in mixtures.
Mixtures with fungicides with different modes
of action are valuable for disease control
and resistance management. |
|
|
22. |
Strobilurins (QoI fungicides) should be applied
to give as early a curative control as possible. |
|
|
23. |
The eradicative use of strobilurins (QoI
fungicides) should be avoided. |
2.3.
Communication plans
The above WebPages will serve as the main communication
vehicle for the group.
Details of sensitivity monitoring methodology
for various diseases are currently being collected
and will be made accessible on the web by the end
of Q2 2004.
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