Peter Leendertse

Azole fungicides, aspergillosis and
preliminary ‘hot spots’
Peter Leendertse
CLM (Centre for Agriculture and Environment)
IATP webinar 5 March 2015
Erna van der Wal (CLM) Wouter van der Weijden (CLM) en Paul Verweij
(Radboud UMC)
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Resistant fungi: new risk for humans
•  In NL lots of attention on human health and
antibiotic resistance, including measures
•  Little attention on human health and fungicide
resistance
Verweij: Doden door agressieve infecties
met resistente schimmels, NOS, 17-06-2010
Van der Wal: Resistente schimmels zijn tijdbom,
Nieuwe Oogst 7 maart 2012
Aspergillus fumigatus
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Human problem
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Where do these azole-resistant strains
originate?
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Where do these azole-resistant strains
originate?
1.  Where do we find Aspergillus?
2.  Where are azoles used?
3.  What azole amounts are used?
4.  Where are optimal conditions for development
of restistance in Aspergillus?
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1. Where do we find Aspergillus?
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Air
Animals
Compost
Farms
Humans
Houses
Hospitals
Nursery
Plants
Soil
Water
Everywhere!
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2.Where are azoles used?
Everywhere!
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Human and animal protection (medicines)
Animal protection (biocides)
Crop protection (pesticides)
Fruit conservation (pesticides)
Wood conservation (biocides)
House protection (wall paper paste, sealants)
Film conservation (biocides)
Many other protection or conservation
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3. What azole amounts are used?
Total Agriculture NL: >130.000 kg yearly
in > 50 crops
Fungicides
Use (kg)
Area(ha) Crops with highest use
Prothioconazool
40.000
152.000
Winter wheat, tulip, lily, onion
Epoxiconazool
25.000
100.000
Winter wheat, sugar beet
Tebuconazool
35.000
125.000
Winter wheat, tulip, lily, grass seed
Cyproconazool
3.600
26.000
Sugar beet, winter wheat,
Difenoconazool
8.500
40.000
sugar beet, cabbage, apple & pear
800
14.000
Winter wheat
1.700
3.200
Metconazool
Propiconazool
Pot plants, trees, flowers
(CLM estimates based on CBS 2012 and expert judgement), Official numbers still secret
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3. What azole amounts are used?
Total other uses NL:
•  In Dutch healthcare: 400 kg
of azoles annually
•  Other uses: unknown
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Remarkable observations
Promotion of azoles in maize
Quilt® Xcel (propiconazole/azoxystrobin) effectief tegen
schimmelziekten
Maïs langer groen en gezond
Het nieuwe fungicide Quilt Xcel houdt maïs langer
gezond en vitaal. Quilt Xcel biedt telers daarom meer
zekerheid en rust.
!promotion for azole even
without fungus problems
in maize
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4. Where are optimal conditions for
resistance development?
Not everywhere!
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Presence of Aspergillus
Azole pressure
High moisture
High temperature
Presence of oxygen
Let’s search for “Hot spots”
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Preliminary results in search of ‘hot spots’
Composting material
a-sexual
sexual
resistant
a-sexual
resistant sexual
1. No azole resistant strains
left after composting process
2. Sexual strain not
reproducible
Compost
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Peel waste of bulbs
Preliminary results in search of ‘hot spots’
a-sexual
Conventional farming
(prothioconazool 10mg/kg)
sexual
resistant a-sexual
Resistant sexual
Ecological farming (no
fungicides)
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Indications of the preliminary exploration
Few samples & few replications!
•  Aspergillus in different predicted locations
(compost, peel waste of bulbs)
•  Both sensitive and resistant strains
•  Sometimes only resistant strains
•  Sometimes hardly Aspergillus (dry straw of
wheat, ecological farming)
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How to reduce the risk of fungicide
resistance?
Focus in four steps!
1.  Identify “hot spots”
2.  Analyse mechanisms
3.  Eliminate “hot spots”
-change methods for plant waste material
-reduce azole use
-stimulate alternatives, preferably methods
with less or no induction of resistance.
4.  Cooperate internationally and advise
registration authorities
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Findings conference KNAW (Royal Dutch
Academy of Sciences) 2-4 March 2015
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Findings conference KNAW
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Findings conference KNAW
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Findings conference KNAW
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Sustainable farming –
Healthy food – A living countryside
Thank you very much
for your attention!
Any questions?