Fungicide resistance and increasingly stringent regulations are major threats to the commercial longevity of the majority of fungicide active ingredients.
This unique new report is based on an in-depth assessment of accessible literature and comprehensively explains what these threats are, how they arise, the science behind them, and how companies can challenge these threats in various crop varieties across the world.
Major themes explored in this report include:
- The complexities of the evolution of resistance to Demethylation Inhibitors (DMIs), especially in cereal pathogens.
- The first cases of resistance to newer Succinate Dehydro-genase Inhibitors (SDHI) fungicides, also mainly in cereal diseases.
- Multi-drug resistance primarily in Botrytis cinerea (and also in Zymoseptoria tritici), both via efflux pump mechanisms and the simultaneous acquisition of multiple target site mutations.
The risk of resistance to new and forthcoming fungicides, including biocontrol agents and ribonucleic acids (RNAs), is also discussed.
Resistance to fungicides has become a major preoccupation across the global crop protection industry and combatting resistance has taken centre stage in considering the development of new fungicides and the management of existing compounds.
1.2 EC50 and resistance factor (RF)
1.3 Cross resistance (CR)
1.4 Fitness penalty
1.5 Mode of resistance (MOR)
1.6 Resistance risk
1.7 Genotypic descriptions of resistant strains
2. Importance of fungicides in crop protection
3. Impact of resistance on current crop protection.
4. Resistance in the field and laboratory.
4.1 Baited samples versus random sampling.
4.2 Detection of resistance when fungicide mixtures are in use.
4.3 Monosporic isolations methods.
4.4 High-throughput phenotyping.
4.5 Genotypic monitoring
4.5.1 Methods for pathogen detection and identification
4.5.2 Methods for pathogen differentiation and enumeration
4.5.3 Limitations and advantages of genotypic monitoring.
5. Evolutionary perspective on resistance.
5.2 Number of applications.
5.3 Mixtures and alternations.
5.4 Fitness penalties.
5.5 Resistance risk related to pathogen life history parameters.
6. New cases of fungicide resistance since 2013
6.1 A1 Phenylamides
6.2 A2 Pyrimidines
6.3 A3 Hymexazole and octhilinone
6.4 B1/2/3 MBCs, N-phenylcarbamates, benzamides and thiazole carbamates.
6.5 B4 Pencycuron
6.6 B5 Fluopicolide
6.7 B6 Phenamacril
6.8 C1 complex 1
6.9 C2 SDHI
6.9.1 Barley net-blotch Pyrenophora teres
6.9.2 Potato early blight Alternaria solani
6.9.3 Vine powdery mildew Erysiphe necator
6.9.4 Apple scab Venturia inaequalis
6.9.5 Wheat septoria tritici blotch Zymoseptoria tritici
6.9.6 Prospects for resistance to SDHI fungicides.
6.10 C3 QoI
6.10.1 Asian soybean rust P. pachyrhizi
6.10.2 Wheat blast Magnaporthe grisea
6.10.3 Cercospora leaf blight of soybean Cercospora kikuchii
6.10.4 Anthracnose leaf spot of Peach Colletotrichum siamense
6.10.5 New fungicides active at the QoI site.
6.11 C4 QiI
6.12 C5 Uncouplers
6.13 C6 Fentin
6.14 C7 Silthiofam
6.15 C8 QoSI Ametoctradin
6.16 D1 Anilino-pyrimidine (AP)
6.17 D2, D3, D4, D5 Amino acid biosynthesis
6.18 E1 Azanapthalene
6.19 E2 Phenylpyrroles
6.20 E3 Dicarboximides
6.21 F1/2/3/4 Lipid synthesis and membrane integrity
6.22 G1 Demethylation inhibitors.
6.22.1 Molecular basis for resistance
6.22.2 Asian soybean rust Phakopsora pachyrhizi
6.22.3 Barley powdery mildew Blumeria graminis f. sp hordei
6.22.4 Rice false smut Villosiclava virens
6.22.5 Oilseed rape light leaf spot pathogen Pyrenopeziza brassicae
6.22.6 Barley net-blotch Pyrenophora teres
6.22.8 Multiple drug resistance
6.23 G2 ?14 reductase and ?8-?7isomerase inhibitors
6.24 G3 3-ketoreductase inhibitors
6.25 H4 Polyoxin
6.26 H5 - CesA3 CAA
6.27 I 1/2/3 Melanin biosynthesis
6.29 U6 Cyflufenamid
6.30 U8 Metrafenone
6.31 U27 Cymoxanil
6.32 U33 Fosetyl-al
7. Multidrug resistance
7.1 Reports of MDR, species, fungicides and genes
7.2 Impact of MDR and resistance on resistance management.
8. Risk-assessment of pathogens.
9. Geographic spread of resistance
10. New fungicide groups and resistance. Can we predict risk of resistance?
10.1 New fungicide classes
11. Impact of the potential withdrawal of actives on resistance management
13. Pathogen synonym table
Figures & Tables:
Table 1. Percentage loss of farmgate value resulting from withdrawal of category 1 2 or 3 fungicides
Table 2. Fungicide resistance by class of fungicide
Table 3. ß-Tubulin - archetype ASPENI
Table 4. Myosin-5 archetype GIBBZE
Table 5. SDH-B archetype PYRNTE
Table 6. SDH-C archetype PYRNTE
Table 7. SDH-D archetype PYRNTE
Table 8. Cyt-B archetype SEPPTR
Table 9. OS-1 archetype BOTRCI
Table 10. Cyp51A archetype ASPEFU
Table 11. Cyp51B archetype SEPPTR
Table 12. CesA3 archetype PHYTIN
Table 13. Oxysterol-binding protein (OSBP)-Related Proteins (ORP) archetype PHYTIN
Table 14. Reports of MDR, species, fungicides and genes.
Table 15. High Risk Pathogens 1
Table 16. High Risk Pathogens 2
Table 17. Geographic spread of resistance of major pathogens
Table 18. Fungicides at risk of withdrawn registrations; impact on resistance