Exploring the Antifungal Activity of Moroccan Bacterial and Fungal Isolates and a Strobilurin Fungicide in the Control of
Cladosporium fulvum,

the Causal Agent of Tomato Leaf Mold Disease

Advantages of Bacillus subtilis Y1336 (Biobac):

1. High Inhibition Rates: In vitro tests showed that Bacillus subtilis Y1336 (Biobac) exhibited high inhibitory rates against Cladosporium fulvum. After 5 days of incubation, it achieved a 54.4% inhibition rate, which increased to 65% after 12 days​(2024 Exploring the Anti…).
2. Superior Spore Germination Inhibition: Biobac significantly suppressed the spore germination of C. fulvum, with an inhibition rate of 44.18%. This is competitive with other commercially available biocontrol agents and highlights Biobac’s effectiveness in stopping the spread of the fungus at its reproductive stage​(2024 Exploring the Anti…).
3. In Vivo Effectiveness: In greenhouse trials, Biobac significantly reduced the disease severity of tomato leaf mold, showing a 99.5% reduction in disease severity. This places it close to chemical fungicides like azoxystrobin, which demonstrated a 99.8% reduction. Biobac’s high effectiveness in reducing disease severity in plants makes it a strong candidate for integrated pest management programs​(2024 Exploring the Anti…).
4. VOC Production: Biobac produces volatile organic compounds (VOCs) that inhibit fungal growth even at a distance. In in vitro tests, Biobac’s VOCs achieved a 65% inhibition rate, suggesting that it can be effective even when not in direct contact with the pathogen​(2024 Exploring the Anti…).

Comparative Analysis:

1. Compared to Azoxystrobin: While azoxystrobin, a synthetic fungicide, demonstrated nearly complete control over the pathogen (95.9% inhibition after 12 days), Biobac was close behind with a 65% inhibition rate. Although azoxystrobin is slightly more effective, Biobac offers an environmentally friendly alternative with fewer side effects on soil health and ecosystems​(2024 Exploring the Anti…).
2. Compared to Other Biological Control Agents: When compared to other bacterial isolates like Pantoea agglomerans, Biobac consistently outperformed them, especially in longer incubation periods and in its ability to reduce disease incidence and severity. For instance, Pantoea agglomerans ACBC2 achieved a 60.4% inhibition rate at 12 days, slightly below that of Biobac​(2024 Exploring the Anti…).
3. Compared to Fungal Biocontrol Agents: While fungal biocontrol agents like Trichoderma spp. achieved 100% inhibition in vitro, Biobac still stood out in practical greenhouse conditions, showing a nearly perfect reduction of disease severity (99.5%). This makes it a strong contender for commercial use​(2024 Exploring the Anti…).

Conclusion

:

Bacillus subtilis Y1336 (Biobac) stands out due to its ability to inhibit both the mycelial growth and spore germination of Cladosporium fulvum, its high effectiveness in real-world greenhouse conditions, and its production of VOCs. Although chemical fungicides like azoxystrobin might be slightly more potent in specific conditions, Biobac offers a sustainable and effective biocontrol solution with comparable results, making it a valuable tool in integrated pest management strategies.