Below is the evaluation of the fungicides against oomycetes and fungal infections like Downy Mildew, Blight, Cocoa Black Pod disease and other fungal diseases.
1. Foseta (Fosetyl-Al)
Mode of Action: Systemic phosphonate (FRAC 33). It stimulates plant defenses and disrupts oomycete phosphorus metabolism, inhibiting spore germination and mycelial growth.
Effectiveness Against Oomycetes:
- Cucumber Downy Mildew: Highly effective. Studies (2005–2010, Czech Republic) showed all Pseudoperonospora cubensis isolates were sensitive to fosetyl-Al at recommended rates, with no field resistance.
- Late Blight: Effective against Phytophthora infestans in potatoes and tomatoes, providing preventative and curative control via systemic action. Widely used in IPM programs.
- Cocoa Black Pod Disease: Foseta fungicide is effective against Phytophthora species (P. megakarya, P. palmivora). Systemic uptake makes it suitable for foliar sprays or trunk injections in cocoa, though copper-based fungicides are more common.
- Other Fungal Diseases: Limited activity against true fungi (Alternaria, Botrytis), as it’s oomycete-specific. May suppress some bacterial diseases in ornamentals.
- Resistance Risk: Low. No reported resistance in field populations of Pseudoperonospora or Phytophthora despite extensive use since 1978.
- Rating: High (1st). Systemic, no resistance, and consistent efficacy across oomycete diseases make fosetyl-Al the top choice.
2. Goro (Propamocarb 722 g/L SL)
Mode of Action: Systemic carbamate (FRAC 28). It inhibits lipid biosynthesis, disrupting mycelial growth and sporulation.
Effectiveness Against Oomycetes:
- Cucumber Downy Mildew: Highly effective. 2020 trials showed propamocarb reduced disease progress (low AUDPC) and protected yields in slicing cucumbers, though some isolates showed moderate resistance.
- Late Blight: Effective against Phytophthora infestans, with 90% control at 1081–2012 ppm, enhanced by mancozeb mixtures.
- Cocoa Black Pod Disease: Limited data, but systemic action suggests moderate to good control of Phytophthora species. Less common than fosetyl-Al or fluazinam in cocoa.
- Other Fungal Diseases: Minimal activity against true fungi.
- Resistance Risk: Moderate. Resistance reported in Pythium, with some Pseudoperonospora isolates showing reduced sensitivity (2006, 2008–2010).
- Rating: High (2nd). Strong systemic control for cucumber downy mildew and late blight, but slight resistance risk places it below fosetyl-Al.
3. Frost (Fluazinam 500 g/L)
Mode of Action: Non-systemic dinitroaniline (FRAC 29). It uncouples oxidative phosphorylation, disrupting energy production.
Effectiveness Against Oomycetes:
- Cucumber Downy Mildew: Effective. 2025 studies showed 52% lesion inhibition with fluazinam nanocapsules, requiring thorough coverage as a protectant.
- Late Blight: Effective against Phytophthora infestans, but reduced efficacy reported in the Netherlands (2015) due to EU_33_A2 lineage resistance.
- Cocoa Black Pod Disease: Highly effective against Phytophthora megakarya and P. palmivora, a staple in cocoa disease management.
- Other Fungal Diseases: Broad-spectrum, controlling Alternaria, Botrytis, and Sclerotinia.
- Resistance Risk: Low historically, but emerging resistance in Phytophthora infestans requires monitoring.
- Rating: Moderate to High (3rd). Excellent for cocoa black pod and broad-spectrum, but non-systemic nature and resistance concerns rank it below systemic options.
4. Smoke (Chlorothalonil 75% WP)
Mode of Action: Non-systemic, multi-site contact fungicide (FRAC M5). It disrupts multiple enzymatic processes.
Effectiveness Against Oomycetes:
- Cucumber Downy Mildew: Moderately effective as a protectant. 2020 trials showed reduced disease progress when alternated with systemic fungicides, less effective than propamocarb.
- Late Blight: Good protectant control of Phytophthora infestans when applied preventatively, often mixed with cymoxanil. No curative action.
- Cocoa Black Pod Disease: Moderate efficacy likely as a protectant, but less used than fluazinam or copper.
- Other Fungal Diseases: Highly effective against Alternaria, Anthracnose, Cercospora, and Septoria.
- Resistance Risk: Low due to multi-site action.
- Rating: Moderate (4th). Broad-spectrum protectant, but non-systemic and moderate oomycete control rank it lower.
5. Blaze (Cymoxanil 33 g/L SL)
Mode of Action: Locally systemic (FRAC 27). It inhibits spore germination with curative and antisporulant effects.
Effectiveness Against Oomycetes:
- Cucumber Downy Mildew: Limited efficacy. 2005–2010 Czech studies showed high resistance, with only 68% of Pseudoperonospora cubensis isolates controlled in 2009.
- Late Blight: Limited against phenylamide-resistant Phytophthora infestans, effective only in mixtures (9–11 days >90% control with mancozeb).
- Cocoa Black Pod Disease: Moderate efficacy possible in mixtures, not a primary choice.
- Other Fungal Diseases: Minimal activity against true fungi.
- Resistance Risk: High. Resistance documented in Pseudoperonospora cubensis and Plasmopara viticola, emerging in Phytophthora infestans.
- Rating: Low (5th). High resistance and variable efficacy limit its standalone use.
Final Ranking
- Foseta (Fosetyl-Al): Systemic, no resistance, highly effective for all listed oomycete diseases. High
- Goro (Propamocarb): Systemic, strong for cucumber downy mildew and late blight, moderate resistance risk. High
- Frost (Fluazinam): Broad-spectrum, excellent for cocoa black pod, but emerging resistance. Moderate to High
- Smoke (Chlorothalonil): Broad-spectrum protectant, moderate oomycete control, low resistance risk. Moderate
- Blaze (Cymoxanil): Limited by resistance, requires mixtures. Low
Should you want to buy any of Foseta Fungicide, Goro Fungicide, Smoke Fungicide, Blaze Fungicide, Forst Fungicide and Raiden (Sporicide), please call us on 08066437109.
