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Solatenol - the second generation benzonorbornene SDHI carboxamide with outstanding performance against key crop diseases

  • Syngenta Crop Protecton AG

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Solatenol (common name benzovindiflupyr) is a new broad spectrum foliar fungicide discovered and developed by Syngenta. It is the third Syngenta succinate dehydrogenase inhibitor (SDHI), and the second in the benzonorbornene amide subclass. The focus of the Solatenol project was on finding compounds with high intrinsic activity against soybean and cereal diseases, in particular Asian Soybean Rust (Phakopsora pachyrhizi) and Septoria leaf blotch (Zymoseptoria tritici). Solatenol is highly active on other major pathogens, e.g. Rhizoctonia spp. and Botrytis cinerea. The very high affinity to succinate dehydrogenase results in its high intrinsic activity. This, together with strong binding to the plant's wax layer, provides long lasting disease control. Solatenol is safe to the crop, also when applied in mixture with DMI and QoI compounds.
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Solatenol - The Second Generation
Benzonorbornene SDHI Carboxamide with
Outstanding Performance against Key Crop
Guicherit E., Bartlett D, Dale SM, Haas H-U., Scalliet G, Walter H.
Syngenta Crop Protection AG, Schwarzwaldallee 215, CH-4002, Basel, Switzerland;
Solatenol (common name benzovindiflupyr) is a new broad spectrum foliar fungicide
discovered and developed by Syngenta. It is the third Syngenta succinate dehydrogenase
inhibitor (SDHI), and the second in the benzonorbornene amide subclass. The focus of the
Solatenol project was on finding compounds with high intrinsic activity against soybean and
cereal diseases, in particular Asian Soybean Rust (Phakopsora pachyrhizi) and Septoria leaf
blotch (Zymoseptoria tritici). Solatenol is highly active on other major pathogens, e.g.
Rhizoctonia spp and Botrytis cinerea. The very high affinity to succinate dehydrogenase
results in its high intrinsic activity. This, together with strong binding to the plant’s wax
layer, provides long lasting disease control. Solatenol is safe to the crop, also when applied
in mixture with DMI and QoI compounds.
Researchers within Syngenta started working in the SDHI area in 1999. The first
breakthrough in this area was the discovery of the benzonorbornene amide class, which
revealed a large number of good chemical leads with the potential to cover the foliar cereals
segment. Isopyrazam was the result of a first optimization of this class and was introduced to
the market in 2010, mainly tailored for foliar use in the cereals segment (Harp et al. 2013)
(Figure 1).
Figure 1. Structures of isopyrazam and Solatenol
(syn/anti mixture)
Solatenol is the result of an optimization program mainly looking at the efficacy against
Asian Soybean Rust (ASR), caused by Phakopsora pachyrhizi. Solatenol’s structure is
closely related to isopyrazam. In addition to the outstanding efficacy against ASR, Solatenol
delivers broad spectrum fungal control including control of major diseases in the cereals
SDH enzyme inhibition tests
SDH enzyme inhibition was tested in vitro on Zymoseptoria graminicola, Botrytis cinerea
and Rhizoctonia solani using purified mitochondrial suspensions. Mitochondrial
purifications and test conditions were performed following already described procedures
(Scalliet et al. 2012). These assays enable comparison of the intrinsic potency displayed by
carboxamides of different structures at the level of the SDH enzyme. The inhibition of
ubiquinone reduction was monitored in the presence of succinate and of a terminal electron
acceptor (DCPIP) whose reduction was monitored spectrophotometrically at 595 nm. The
slopes of DCPIP reduction were used for calculation of the half inhibitory concentrations
(IC50) as described in Zeun et al. (2013).
Biological Activity on Asian Soybean Rust (ASR)
SDH enzyme inhibition was determined in situ using a whole plant-leaf disk assay. The
shoot of 24-days old soybean plants was removed just after the first trifoliate leaf one day
before application. The plants were sprayed with the test compounds at equivalent of 50 l/ha
spray volume. The compounds were sprayed at 12 rates, adapted to the known potency of the
compounds on ASR (Table 1). One day after application, 6 leaf discs per treatment were
taken from the first trifoliate leaf and placed into 24-multiwell plates. The leaf discs were
inoculated with rust spores one day after application. After dark incubation for 48 h, the
plates were further incubated under light at 22°C for another 10 days. As a reference, 6 leaf
discs of untreated plants were placed on each of the plates. Disease severity was determined
visually and activity calculated in comparison to the infestation on leaf discs of the untreated
Table 1: Compound rates applied on whole soybean plants to determine the in situ activity of 3
different SDHI against soybean rust
g/ha in 50 l/ha spray volume
Corn plants cv. Avenir were grown under glasshouse conditions to the 6-7 leaf stage and
sprayed with Solatenol 100g/l EC or 100g/l EC + 0.3% v/v NIS adjuvant in a tracksprayer at
a rate of 30g ai/ha in a spray volume of 150l/ha. Immediately after spraying, the youngest
fully expanded leaves from ten replicate plants were removed and the Solatenol retained on
the foliar surface removed to allow quantification of foliar spray retention. Six hours and 1,
3 and 7 days after spraying, unabsorbed Solatenol was recovered and quantified from leaf
surfaces, epicuticular waxes and plant tissue.
SDH enzyme inhibition tests
The results show that Solatenol is a highly potent SDH inhibitor on a range of pathogens
(Figure 2). In many cases the intrinsic activity of Solatenol was superior to other SDHI’s.
Bioavailability; a major factor influencing biological efficacy, may explain some
discrepancies when in vitro results for SDH inhibition are compared to in vivo activity within
pathogens. The outstanding performance of Solatenol on rusts, and in particular on soybean
rust (Figure 7), is most likely the result of a combination of its superior potency on the
targeted SDH rust enzyme, and a good fit of physico-chemical properties and bioavailability
required for optimal activity.
Figure 2: In vitro inhibition of the succinate ubiquinone oxidoreductase activity by
carboxamide inhibitors. IC50 values are the concentrations required for each
inhibitor to half-inhibit DCPIP reduction on M.graminicola, B.cinerea and
R.solani mitochondrial suspensions. Presented values are based on triplicate
determinations ±SD.
Biological Activity on soybean rust, Phakopsora pachyrhizi
10 days after inoculation the disease severity on untreated, infected checks was up to 85 %;
on average 80 %. Infestation on treated leaves ranged depending on rate from 0 to 80 %.
Rate for rate, Solatenol showed best activity on soybean rust, clearly more active when
compared to fluxapyroxad and penthiopyrad. (Figure 3)
Figure 3: Leaf discs in multiwell plates of comparable treatments, 5.5g/ha for Solatenol, 5.2 g
/ha for fluxapyroxad and 5.1 g/ha for penthiopyrad, showing infestation levels of
the leaf discs with Phakopsora pachyrhizi.
Data was analyzed statistically and did not benefit from transformation. Dose-response
relationships (Figure 4) were calculated using the Log-logistic model with lower (0) and
upper (100) asymptotes constrained, by calculating the data in MS Excel using the
Bioassay97 MS-Excel macro (Onofri 2005).
Figure 4: Dose response relationships of 3 different SDHI on Phakopsora pachyrhizi on
soybean leaves, based on 12 different rates adapted to each of the compounds.
The dose response curves differed, showing different dose dependent activity of each of the
compounds on soybean rust. Solatenol was more active compared to fluxapyroxad and
penthiopyrad. Based on the dose-response relationships effective concentrations at distinct
control levels could be derived (Table 2). Since the fitted dose-response curves were not
parallel, relative potencies of the compounds varied, dependent on the different control
levels. However a clear result would be that one would need at least 3 times more ai. of
either fluxapyroxad or penthiopyrad compared to Solatenol to get comparable control of
soybean rust (Table 2).
Table 2: Dose estimates (g/ha) of SDHI compounds against soybean rust for response at
distinct percent control scale
50 % control
70 % control
90 % control
Solatenol, 5.5g /ha fluxapyroxad, 5.2g /ha penthiopyrad, 5.1g /ha
The distribution over time of Solatenol between the foliar surface, epicuticular wax and
within the leaf tissue was significantly influenced by the presence of adjuvant, with adjuvant
significantly decreasing recoveries from within the wax layer and increasing in the foliar
tissue itself as shown in Figure 5. When Solatenol EC was applied alone, the wax layer
acted as a major reservoir for the absorbed compound with approximately 63% (4.03
ug/gFW) of recovered Solatenol being quantified in the wax when sampled 3 days after
application. In contrast, the addition of adjuvant decreased the wax residence time such that
only 31% (2.02 ug/gFW) remained in the wax layer with a consequent increase in Solatenol
in the leaf tissue to 53% (3.44 ug/gFW) from the 7% (0.43 ug/gFW) recovered without
adjuvant (Figure 5).
Figure 5: Distribution over time of Solatenol between the foliar surface, epicuticular wax and
within the leaf tissue of corn
In numerous field trials Solatenol applied at 75g/ha in mixture with a triazole for resistance
management has shown excellent efficacy on Zymoseptoria tritici which positively reflects
on yield (Figure 6). The trials also showed Solatenol’s excellent crop tolerance, being safe to
Figure 6: Control of Zymoseptoria tritici in wheat.
Figure 7: Control of Phakopsora pachyrhizi in soybean.
Solatenol is Syngenta’s second generation benzonorbornene amide fungicide belonging to
the group of succinate dehydrogenese inhibitors (SDHI) with high intrinsic activity on a
broad range of plant fungal diseases. Solatenol binds strongly to the plant’s wax layer where
it forms a reservoir from which it slowly translocates into the tissue. Movement with the
sapstream is very limited. Adding an NIS adjuvant, either built-in or in tank mix, greatly
enhances uptake which can positively reflect on efficacy, spectrum and duration of control.
Solatenol is highly active on key pathogens at rates between 30 to 75g/ha when applied
preventative or early curative. The performance on Asian soybean Rust sets new standards.
In wheat Solatenol mixed with a triazole provides Zymoseptoria tritici control similar to the
best commercial standard.
Zeun R; Scalliet G; Oostendorp M (2013). Biological activity of sedaxane a novel broad-
spectrum fungicide for seed treatment. Pest Management Science, 69 (4), 527-34.
FRAC Code List ©*2013: Fungicides sorted by mode of action (including FRAC Code
numbering). (date of access 01.08.2013).
Scalliet G; Bowler J; Torsten, L; Kirchhofer A; Steinhauer D; Ward K; Niklaus M; Verras A;
Csukai M; Daina A; Fonné-Pfister R (2012). Mutagenesis and Functional Studies
with Succinate Dehydrogenase Inhibitors in the Wheat Pathogen Mycosphaerella
graminicola. PLOS ONE. (date of access
Harp, T. L.; Godwin JR; Scalliet G; Walter H; Stalker AD.; Bartlett DW.; Ranner DJ (2011).
Isopyrazam, a new generation cereal fungicide. Aspects of Applied Biology 106,
Sezione Scientifica Onofri A (2005). Rivista Italiana di Agrometeorologia. (3), 40-45.
... In our study, treatments that included benzovindiflupyr in Trt 4 and Trt 7 showed obviously better yield and RLS control than bixafen in Trt 3 and Trt 6. The performance of benzovindiflupyr might have been better, as this compound is a highly potent SDHI, and secondly, the intrinsic activity is superior to other active ingredients within the same FRAC group (Guicherit et al. 2014). In addition, this greater performance could also be linked to a faster selection for sdh mutations within the R. collo-cygni population. ...
... This leads to a continuous and controlled release of the active ingredient in the plant. Additionally, the greater bioavailability of benzovindiflupyr is responsible for an optimal activity and superior performance when compared to other SDHIs (Guicherit et al. 2014). Avenot and Michailides (2010) also reported for Alternaria alternata that an SDHI within the same cross-resistance group is more potent than other SDHI's when the intrinsic activity is higher. ...
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Ramularia collo-cygni B. Sutton and J.M. Waller is a major disease in Austrian barley-growing regions. To date, fungicide application is the most effective method to manage the disease; however, fungicide resistance to demethylation and succinate dehydrogenase inhibitors has developed over the last few years. In the growing seasons 2016/2017 and 2017/2018, field trials were carried out to analyze the efficiency of fungicide strategies based on different fungicide classes. Disease development, growth parameters and monitoring of CYP51 and sdh mutations were determined. Fungicide treatments resulted in higher disease control, green leaf area and grain yield. In Austrian R. collo-cygni field populations, the frequency of the mutations CYP51 -I325T and CYP51 -I328L was low to moderate. Frequency of mutations sdhC -H146R and sdhC -H153R was low. Frequencies of CYP51 -I325T and -I328L were similar and increased following DMI application. Frequency of sdhC -H146R was higher compared to sdhC -H153R. The SDHI benzovindiflupyr showed a higher selection rate for sdh mutations compared to bixafen. These sdh mutations were not selected if chlorothalonil was used as mixing partner, leading to a stable composition of sdh resistance alleles over the last two years. Chlorothalonil was proven to be an effective tool for anti-resistance strategies. Currently, SDHIs and DMIs are the backbone of Ramularia leaf spot control in Austria; however, the level of resistance is likely to increase in absence of suitable anti-resistance strategies and following the ban of chlorothalonil.
... In contrast to multisite fungicides (e.g., mancozeb) with comparatively low performance, the DMI and the QoI classes of fungicide are prime chemicals for fighting P. pachyrhizi. Since 2013, fungicides of the highly active SDHI class are available for SBR control (Guicherit et al., 2014). Because this new fungicide class performs extraordinarily well, the number of available SDHI fungicides and the intensity of their use is likely to steadily increase over the next couple of years (Godoy et al., 2015). ...
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Phakopsora pachyrhizi is a biotrophic fungus provoking SBR disease. SBR poses a major threat to global soybean production. Though several R genes provided soybean immunity to certain P. pachyrhizi races, the pathogen swiftly overcame this resistance. Therefore, fungicides are the only current means to control SBR. However, insensitivity to fungicides is soaring in P. pachyrhizi and, therefore, alternative measures are needed for SBR control. In this article, we discuss the different approaches for fighting SBR and their potential, disadvantages, and advantages over other measures. These encompass conventional breeding for SBR resistance, transgenic approaches, exploitation of transcription factors, secondary metabolites, and antimicrobial peptides, RNAi/HIGS, and biocontrol strategies. It seems that an integrating approach exploiting different measures is likely to provide the best possible means for the effective control of SBR.
Colletotrichum species cause diseases on many plants and are among the ‘top 10’ fungal plant pathogens. Species of the C. gloeosporioides and C. acutatum complexes are particularly important because they infect temperate fruit crops, but their control relies largely on chemical fungicides. In this study, differences in intrinsic fungicide sensitivity were determined in vitro using isolates of the C. gloeosporioides sp. complex (C. fructicola, C. siamense, and C. tropicale) and the C. acutatum sp. complex (C. fioriniae and C. nymphaeae), which had never been exposed to fungicides. Mycelial growth of all isolates was sensitive to the QoI azoxystrobin, the SDHI benzovindiflupyr, and the new DMI fungicide mefentrifluconazole. The isolates of C. nymphaeae were highly sensitive to the phenylpyrrole fungicide fludioxonil. The isolates of C. gloeosporioides sp. complex were sensitive to the bis-guanidine fungicide iminoctadine-albesilate, whereas those of C. acutatum sp. complex were inherently insensitive. These results are valuable when sensitivity of field populations is monitored in resistance management. Although SDHI fungicides are largely not effective against diseases caused by Colletotrichum species, benzovindiflupyr controlled anthracnose disease of various crops such as kidney bean, garland chrysanthemum, and strawberry, caused by C. lindemuthianum, C. chrysanthemi, and C. siamense, respectively, demonstrating this fungicide to be unique among SDHIs and having a broad control spectrum against anthracnose. To help understanding the reason for differential activity of benzovindiflupyr and boscalid, sdhB gene sequences were analyzed but those of C. lindemuthianum, C. chrysanthemi, and C. scovillei revealed no known mutations reported to be responsible for SDHI resistance in other fungi, indicating that other mechanism(s) than target-site modification may be involved in differential sensitivity to benzovindiflupyr and boscalid, found in Colletotrichum species.
Although benzovindiflupyr (BZF), which is a novel succinate dehydrogenase inhibitor fungicide, has considerable application potential worldwide, its extensive use is toxic to non-targeted soil organisms. Therefore, this study aimed to evaluate the acute and subchronic toxicity of BZF to earthworms (Eisenia fetida). The acute toxicity of BZF to adult and larval earthworms was measured, as indicated by the following LC50 values obtained after 14 days of exposure: 416 mg/kg for adult earthworms and 341 mg/kg for juveniles. Subchronic toxicity tests were conducted using only adult earthworms. The earthworms’ weight gain was slower on days 14 and 28 after commencing the BZF T100 treatment (50mg/kg of soil). Following 14 days of BZF exposure, enzymes and gene expressions associated with the mitochondrial respiratory chain and energy metabolism were activated to some extent, and the reactive oxygen species level and malondialdehyde content also increased. Antioxidant and detoxifying enzymes and metallothionein gene, Heat shock protein 70 gene associated with resistance to oxidative damage were also activated to varying degrees. Increased BZF concentrations corresponded to increased genotoxicity. Integrated biological response (IBR) values were calculated at the biochemical and molecular levels to show increased toxicity with increased BZF concentration. Although a series of biomarkers changes occurred after initiating BZF treatment, these changes were all likely to have been resisted by the earthworms’ own antioxidant defense system and only showed phenotypic (weight-related) changes with treatments of 50 mg/kg. In conclusion, reasonable levels of BZF application may have little impact on earthworms. Our findings provide insights on the toxic effects of BZF on earthworms and may prove useful for risk assessments relating to BZF’s impacts on soil ecosystems.
Azoxystrobin, azoxystrobin plus benzovindiflupyr, kresoxim-methyl, propiconazole, pyraclostrobin, pyraclostrobin plus fluxapyroxad, tebuconazole, tetraconazole, thiophanate-methyl, and triflumizole fungicides were evaluated for curative and anti-sporulant activity against boxwood blight caused by Calonectria pseudonaviculata on detached leaves and whole boxwood plants (Buxus spp.). Pretreating detached leaves with 30 or 300 ppm a.i. 24 h prior to inoculation reduced disease compared to the untreated control for all fungicides. Fungicides were also applied 24 to 96 h post-inoculation. Only propiconazole reduced diseased leaf incidence to at least half of the control. When leaves were treated post-infection with 300 ppm propiconazole, tetraconazole, tebuconazole, or triflumizole, the pathogen did not sporulate over 2 wks. Propiconazole also reduced the percent of leaf area diseased; lesions were nearly 80% smaller with 300 ppm applied 48 h after inoculation. ‘True Dwarf' boxwood plants treated with 450 ppm thiophanate-methyl, 120 ppm pyraclostrobin or 150 ppm propiconazole 48 h after inoculation demonstrated that only propiconazole reduced the number of diseased leaves, blight lesions and the frequency of pathogen re-isolation. Experiments with ‘Green Mound' and ‘Green Mountain' boxwood cultivars and additional fungicides applied 48 h after inoculation demonstrated that propiconazole at 300 ppm, pyraclostrobin plus fluxapyroxad (150 ppm each) and azoxystrobin (135 ppm) plus benzovindiflupyr (67.5 ppm) reduced disease. Index words: fungicide management, Buxus, chemical disease management Chemicals used in this study: azoxystrobin (Heritage 50 WG), azoxystrobin plus benzovindiflupyr (Mural 30, 50 WG), kresoxim-methyl (Cygnus 50 WG), propiconazole (ProCon-Z 14.3 L), pyraclostrobin (Insignia 20 WG), pyraclostrobin plus fluxapyroxad (Orkestra Intrinsic 21.26 SC), tebuconazole (Torque 38.7 SC), tetraconazole (Minerva 11.6 SC), thiophanate-methyl (3336 50% WP), triflumizole (Procure 480 SC). Species used in this study: boxwood (Buxus L.), boxwood blight (Calonectria pseudonaviculata (Crous, J.Z. Groenew. & C.F. Hill) L. Lombard, M. J. Wingf. & Crous.
The development of plant protection product (PPPs)-resistant populations of plant pathogens, pests, and weeds, represents a major challenge that the crop protection sector is facing. Focusing on plant pathogenic fungi, the increased efflux of the active ingredients (a.i.) from the cytoplasm is highly correlated to elevated resistance levels to the applied fungicides. Such mechanism is regulated by ATP-binding cassette transporters (ABC transporters), and although it has been investigated for the past two decades, the latest developments in “omics” technologies could provide new insights with potential applications in crop protection. Within this context, and based on results from preliminary experiments, we have undertaken the task of mining the involvement of the ABC transporter YCF1, which is located in the vacuole membrane, in the fungicide resistance development, applying a functional genomics approach and using yeast (Saccharomyces cerevisiae) as the model organism. Among the fungicides being assessed, flusilazole, which belongs to the azole group of dimethylation inhibitors (DMIs), was discovered as a possible substrate of the YCF1. GC/EI/MS metabolomics analysis revealed the effect of the fungicide's toxicity and that of genotype on yeast's metabolism, confirming the role of this transporter. Fluctuations in the activity of various yeast biosynthetic pathways associated with stress responses were recorded, and corresponding metabolites-biomarkers of flusilazole toxicity were discovered. The metabolites α,α-trehalose, glycerol, myo-inositol-1-phosphate, GABA, l-glutamine, l-tryptophan, l-phenylalanine, l-tyrosine, and phosphate, were the major identified biomarkers of toxicity. Among these, are metabolites that play important roles in fungal metabolism (e.g., cell responses to osmotic stress) or serve as signaling molecules. To the best of our knowledge, this is the first report on the implication of YCF1 in fungal resistance to PPPs. Additionally, the results of GC/EI/MS yeast metabolomics confirmed the robustness of the method and its applicability in the high-throughput study of fungal resistance to fungicides.
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A range of novel carboxamide fungicides, inhibitors of the succinate dehydrogenase enzyme (SDH, EC is currently being introduced to the crop protection market. The aim of this study was to explore the impact of structurally distinct carboxamides on target site resistance development and to assess possible impact on fitness. We used a UV mutagenesis approach in Mycosphaerella graminicola, a key pathogen of wheat to compare the nature, frequencies and impact of target mutations towards five subclasses of carboxamides. From this screen we identified 27 amino acid substitutions occurring at 18 different positions on the 3 subunits constituting the ubiquinone binding (Qp) site of the enzyme. The nature of substitutions and cross resistance profiles indicated significant differences in the binding interaction to the enzyme across the different inhibitors. Pharmacophore elucidation followed by docking studies in a tridimensional SDH model allowed us to propose rational hypotheses explaining some of the differential behaviors for the first time. Interestingly all the characterized substitutions had a negative impact on enzyme efficiency, however very low levels of enzyme activity appeared to be sufficient for cell survival. In order to explore the impact of mutations on pathogen fitness in vivo and in planta, homologous recombinants were generated for a selection of mutation types. In vivo, in contrast to previous studies performed in yeast and other organisms, SDH mutations did not result in a major increase of reactive oxygen species levels and did not display any significant fitness penalty. However, a number of Qp site mutations affecting enzyme efficiency were shown to have a biological impact in planta. Using the combined approaches described here, we have significantly improved our understanding of possible resistance mechanisms to carboxamides and performed preliminary fitness penalty assessment in an economically important plant pathogen years ahead of possible resistance development in the field.
Background: Sedaxane is a new broad-spectrum seed treatment fungicide developed by Syngenta Crop Protection for control of seed- and soil-borne diseases in a broad range of crops. Its physicochemical properties and activity spectrum have been optimised for use as a seed treatment providing both local and systemic protection of the seed and roots of target crops. Results: Sedaxane inhibits respiration by binding to the succinate dehydrogenase complex in the fungal mitochondrium. Its activity spectrum covers seed-borne fungi such as Ustilago nuda, Tilletia caries, Monographella nivalis and Pyrenophora graminea, as well as the soil-borne fungi Rhizoctonia solani, R. cerealis and Typhula incarnata. Under greenhouse conditions, sedaxane showed high levels and consistent protection against U. nuda, P. graminea and Rhizoctonia spp. Under field conditions, efficacy against Rhizoctonia spp. resulted in increased yield compared with the untreated check. Efficacy against snow mould has been shown under very high disease pressure conditions. The combination of sedaxane plus fludioxonil against snow mould can provide resistance management for sustainable use. Conclusions: The broad spectrum and high level of activity in combination with excellent crop tolerance allow the use of sedaxane as a seed treatment in a wide variety of crops. It is a potential tool for precautionary resistance management when combined with other fungicides, especially against pathogens showing a potential for resistance development, such as M. nivalis.
  • T L Harp
  • Jr Godwin
  • G Scalliet
  • H Walter
  • Ad Stalker
Harp, T. L.; Godwin JR; Scalliet G; Walter H; Stalker AD.; Bartlett DW.; Ranner DJ (2011).
Rivista Italiana di Agrometeorologia
Sezione Scientifica Onofri A (2005). Rivista Italiana di Agrometeorologia. (3), 40-45.