| 2.1. Review of sensitivity monitoring
2.1.1. Cereal diseases
Powdery mildew (Erysiphe graminis f.sp. tritici) wheat
BASF, Bayer, Syngenta.
In 2001, high levels of resistant isolates were found
throughout Northern Europe. Resistance continues to
spread further south. The G143A mutation was found
consistently. Product performance was adversely affected
throughout Northern Europe Powdery
mildew (Erysiphe graminis f.sp hordei), barley
BASF, Bayer, Syngenta.
Compared to 2000 increased numbers of resistant
isolates were detected in Northeast and eastern France
into Belgium and in North Germany. Low to medium
levels of resistance were detected in England, Scotland
similar to those seen in the previous year. The G143A
mutation was found consistently. Product performance
remained good throughout Europe with the exception
of North eastern France. Septoria
leaf spot (Septoria tritici), wheat
BASF, Bayer, Syngenta.
Extensive monitoring programmes were carried out
throughout the wheat growing areas of Europe in
2001 using both regional monitoring approaches
and targeting isolation of strains from high risk
trial sites.
In vitro tests on over 1500 isolates showed a
broad range of responses in natural populations.
This has been a consistent finding using in vitro
testing methodology. The G143A mutation was not
found in isolates that were less sensitive in vitro.
No isolates were identified with reduced sensitivity
in in vivo tests. This confirmed the absence of
resistance. After 3 years of extensive monitoring
no QoI fungicide resistant strains of Septoria
tritici have been identified in North European
and USA populations Brown
rust (Puccinia recondita), wheat
BASF, Bayer, Syngenta.
No resistant isolates were detected in more
than 900 isolates from widespread monitoring
in Europe in 2001, confirming the fully sensitive
picture established in 2000 Net
blotch (Pyrenophora teres) barley
BASF, Syngenta.
Monitoring data was not available at the time
of the meeting. Data from 2001 survey work
will be reported as it becomes available in
early 2002. Performance of QoI fungicides against
net blotch was good. Leaf
scald (Rhynchosporium secalis) barley
BASF.
No resistant isolates were detected in a
survey of ca. 200 isolates from the UK, France
and Germany.
2.1.2. Vine diseases
Downy mildew (Plasmopara viticola)
Aventis, BASF, Bayer, Du Pont, Syngenta.
All companies carried out major monitoring
and strategy trial programmes in 2001. Both
semi-quantitative bioassay and PCR techniques
were used to generate data. Determining quantitatively
the QoI fungicide sensitivity structure of
populations of Plasmopara viticola is technically
difficult and the summary of the current
sensitivity status given below should be
interpreted accordingly. The data from surveys
of European vineyards can give only an estimate
of the real population structure.
However good progress was made in developing
Q-PCR technology to aid our understanding
of the populations and the precise relationship
between gene frequency data (G143A) and bioassay
data was established independently by separate
companies. A frequency of 1-2% G143A identified
through PCR diagnosis was usually reflected
as a resistant phenotype in bioassay tests
High levels of resistant strains continued
to be detected in the Emilia Romagna region
of Italy. A variable picture of sensitivity
was found in other regions of northern Italy.
Field performance of QoI fungicide containing
programmes recommended by the individual
companies was good throughout Italy, even
where analysis indicated the G143A allele
to be present at high frequencies.
Monitoring was conducted in all of the major
vine growing regions of France revealing
a heterogeneous picture. For example, no
resistant strains were detected in Alsace
and only very low levels of resistance were
detected in Bourgogne. Other regions showed
a variable response. There is insufficient
comparative data to enable us to judge accurately
if any significant changes in sensitivity
took place on a regional basis between 2000
and 2001 in France.
In France, as in Italy, field performance
of QoI fungicide containing programmes recommended
by the individual companies was good irrespective
of the level of G143A or levels of resistance
indicated by bioassay measured at individual
vineyards.
Resistant strains were not detected in Germany,
Spain, Portugal or Greece. Resistance was
detected in the Vaud region of Switzerland
but not in other areas of Switzerland.
In general the field performance of recommended
QoI fungicide programmes was very good in
Europe in 2001. Where a few field performance
failures were observed in Italy, France and
Switzerland they occurred where company recommendations
were not followed. Powdery
mildew (Uncinula necator)
Bayer, BASF
No resistant isolates were detected in
265 isolates collected from vineyards in
France, Italy, and Portugal. Further data
for 2001 will be published when available,
detailing monitoring in Germany, Austria
and Switzerland. 2.1.3.
Pome fruit diseases
Apple scab (Venturia inaequalis)
BASF, Bayer.
Monitoring was carried out in Germany,
France, Italy, UK, Netherlands, Belgium,
Hungary, Switzerland, the Czech Republic,
Slovakia, and Poland. Decreased sensitivity
was found throughout Europe in bioassays
and was linked to 3 different types of
resistance mechanism; metabolism, target
site mutation (G143A) and a third unknown
mechanism that is currently under investigation.
Only resistance determined by the target
site mutation was stable in further studies.
Target site mutants (G143A) were found
in Northern Italy (2 trial sites) and
West Poland (2 trial sites). In Northern
Germany 5 sites were identified with
target mutants. All of them were trial
sites in 2001 or in earlier years. Performance
of QoI fungicide programmes under both
trial and commercial conditions was generally
good. A clear lack of correlation between
detection of target site mutants and
disease control was evident. No performance
complaints linked to target site resistance
were recorded in 2001.
All affected trial sites will be carefully
monitored in 2002. Strategy trials will
be carried out to determine optimal spray
programmes and clarify the link between
target site mutation and disease control. 2.1.4.
Cucurbit diseases
Powdery mildew (Sphaerotheca fuliginea)
BASF, Syngenta.
High levels of resistant isolates
were detected in Japan, Taiwan, Spain,
Israel and Southern France where field
performance was affected. Resistance
was also detected at several locations
in the UK, Netherlands, North West
France, Italy and Korea. No resistant
isolates were detected in Mexico or
the USA where performance remains good. Downy
mildew (Pseudoperonospora cubensis)
BASF, Syngenta.
Resistance remains widespread in
Japan and Taiwan, where field performance
has been reduced. 2.1.5.
Potato/tomato diseases
Late blight (Phytophthora infestans)
Aventis, DuPont.
No resistance was detected in
a total of 130 isolates collected
from potato crops in France, Germany,
Netherlands, UK, Belgium and Poland.
Performance remains good.
Early blight (Alternaria solani)
Syngenta.
No resistance was found. 2.2.
Review of guidelines
Strategies and Guidelines for
the 2002 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
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 or 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,
pic- oxystrobin, pyraclostrobin,
and trifloxystrobin) are in the
same cross-resistance group.
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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. |
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The number of applications
of QoI fungicide based products
within a total disease management
program must be limited.
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. |
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A consequence of limitation
of QoI fungicide based products
is the need to alternate
them with effective fungicides
from different cross-resistance
groups. |
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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.. |
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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. |
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Mixture partners for QoI
fungicides should be chosen
carefully to contribute to
effective control of the
targeted pathogen(s). The
mixture partner may increase
spectrum of activity or provide
needed curative activity.
Use of mixtures containing
only QoI fungicides should
not be considered as an anti-resistance
measure. |
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An effective partner for
a QoI fungicide is one that
provides satisfactory disease
control when used alone on
the target disease. |
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QoI fungicides are very
effective at preventing spore
germination and should therefore
be used at the early stages
of disease development (preventive
treatment). |
Specific
Crop/Pathogen guidelines
2.2.1. Cereal diseases
Guidelines for using QoI fungicides
on cereal crops
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. |
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2.
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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. |
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3.
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Preferably apply QoI fungicides
in mixtures to control cereal
pathogens other than wheat
mildew which should not be
controlled with Qo inhibitors. |
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. |
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2.
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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. |
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3.
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For table grapes, a maximum
of 4 QoI fungicide containing
sprays per crop may be used
when 12 or more fungicide
applications are made. |
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4.
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Apply QoI fungicides preventively. |
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5.
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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. |
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2.
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Apply QoI fungicides
preventively. |
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3.
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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. |
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4.
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Apply QoI fungicides
in single or block application
in alternation with fungicides
from a different cross-resistance
group.
Individual companies will
continue to carry out strategy
trials in the major vine
regions of Europe to explore
in house programme options
based around these basic
guidelines.
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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.
Effective disease management
is a critical parameter in
delaying the build-up of
resistant pathogen populations. |
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2.
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Apply QoI fungicides preventatively.
Under high disease pressure
the spray interval should
not exceed 7-10 days. |
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3.
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Apply a maximum of 3 QoI
fungicide containing sprays
per crop. A maximum of 4
QoI fungicide applications
may be used where 12 or more
applications are made per
crop. |
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4.
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QoI fungicides should preferably
be applied in mixture with
partners contributing to
the effective control of
the target pathogens. |
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5.
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A maximum of
2 consecutive QoI fungicide
sprays is preferred. |
Guidelines
for using QoI fungicides on pomefruit
where target site mutants (G143A)
of apple scab (Venturia inaequalis)
have been detected and simultaneously
performance was adversely affected
( see section 2.1.3 )for details
1.
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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. |
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2.
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Apply QoI fungicides preventively
at spray intervals not exceeding
7-10 days. |
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3.
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Apply a maximum of 2 QoI
fungicide containing sprays
per crop. A maximum of 3
QoI fungicide applications
may be used where 12 or more
applications are made per
crop. |
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4.
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Do not apply consecutive
QoI fungicide sprays. |
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5.
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Always apply
QoI fungicides in mixture
with partners contributing
to effective control of the
target pathogens. |
2.2.4.
Potato diseases
Guidelines for using QoI fungicides
on potatoes
Potato late blight (Phytophthora
infestans)
1.
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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. |
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2.
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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. |
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3.
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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.
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Where QoI fungicide
products are applied solo
or mixtures (co-formulations
or tank mixes) do not exceed
50% of the total number of
sprays or a maximum of 6
QoI fungicide applications,
whichever is the lower |
Note:
The maximum number of QoI fungicide
sprays on a potato/tomato crop
is 6.
2.2.5. Cucurbit diseases
Guidelines for using QoI fungicides
on Cucurbit Vegetables
1.
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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. |
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2.
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Apply a maximum of 3 QoI
fungicide sprays per crop |
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3.
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Use a maximum of 1 QoI
fungicide spray out of every
three fungicide applications. |
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4.
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Do not use consecutive
applications of QoI fungicides. |
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5. |
Apply QoI fungicides in
alternation with fungicides
from a different cross-resistance
group with satisfactory efficacy
against the targeted pathogen(s). |
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6.
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Continue QoI
fungicide alternation between
successive crops. |
2.2.6.
Guidelines for using QoI fungicides
on greenhouse grown non-cucurbit
vegetables
1.
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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. |
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2.
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Use a maximum of 1 QoI
fungicide spray out of every
3 fungicide applications. |
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3.
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Do not use consecutive
applications of QoI fungicides. |
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4.
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Apply QoI fungicides in
alternation with fungicides
from a different cross-resistance
group with satisfactory efficacy
against the targeted pathogen(s). |
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5.
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Continue QoI
fungicide alternation between
successive crops. |
2.2.7
Guidelines for using QoI fungicides
on other multiple spray crops
(non-cucurbit field vegetables
and ornamentals)
1.
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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. |
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2.
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Observe spray limitations
in the spray guideline table
shown below. |
Spray
guideline table:
Total
number of spray applications
per crop
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4 |
5 |
6 |
7 |
8 |
9 |
10 |
11 |
12 |
>12 |
Maximum
recommended Solo QoI fungicide
sprays
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2
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2 |
2 |
2 |
3 |
3 |
3 |
3 |
4 |
* |
Max.
recommended QoI fungicide
sprays in mixture
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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.
2.2.8 Banana
Guidelines for using QoI fungicides
on banana
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.
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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.
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2.
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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. |
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3.
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The use of the full recommended
label rate of DMIs is strongly
urged (straight DMI use). |
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4.
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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. |
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5.
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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. |
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6.
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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. |
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7.
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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. |
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8.
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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). |
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9.
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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 ). |
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10.
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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. |
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11.
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Protective (preventative)
fungicides are considered to
be a very valuable and necessary
tool for the banana Sigatoka
control programs. |
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12.
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The systemic fungicides must
only be applied in oil or oil-water
emulsions. |
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13.
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A DMI-free period of at least
2 (and if possible 3-4) consecutive
months, during the periods
of lower disease pressure is
recommended. |
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14.
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DMIs should be applied to
achieve as early a curative
control as possible. |
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15.
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Eradicative use of DMIs should
be avoided. |
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16.
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A maximum of 4 cycles of
strobilurin fungicides (QoI
fungicides) should be used
during a 12 month period. |
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17.
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Strobilurin applications
(QoI fungicides) should be
limited to a maximum of 3 exposure
periods per calendar year |
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18.
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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.
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19.
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Do not exceed recommended
label spray intervals. |
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20.
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DDo not apply strobilurins
(QoI fungicides) in successive
sprays |
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21.
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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. |
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22.
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Strobilurins (QoI fungicides)
should be applied to give as
early a curative control as
possible. |
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23.
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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 vine diseases (Plasmopara
viticola and Uncinula necator)
will be edited to a common template
and be available on the web by
the end of February 2002.
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