Based on chito-oligosaccharides and oligogalacturonides—natural substances found in fungi and plants Gowan Ibisco Vit combats powdery mildew in vines by stimulating the plants’ endogenous defenses
In addition to downy mildew and botrytis, vines can also suffer severe attacks from powdery mildew. This pathogen can affect both leaves and grape clusters, but it is on the latter that “white mold” causes the most severe damage, generating unpleasant aromas in the berries and, in the worst cases, causing deep cracks that allow other harmful microorganisms to penetrate. The pressure of this pathogen varies depending on geographic area and vineyard management practices, but the timeframe in which powdery mildew finds favorable conditions is always quite prolonged.
Its control, therefore, requires well-structured and rational programs that employ solutions with different mechanisms of action. In addition to synthetic anti-mildew products and sulfur—an element that acts against powdery mildew in the same way that copper does against downy mildew—there are also natural solutions available that help combat the disease by triggering the plant’s natural defense responses. These substances, known as elicitors, act preventively by mimicking a pathogen attack.
When a fungal attack occurs, the plant produces substances called chitosaccharides and galacturonides. The former originate from the degradation of chitosan present in the pathogen’s cell wall, while the latter result from the breakdown of pectins in the plant’s own cell walls, a process triggered by fungal hyphae attack. Both substances serve as alarm signals—chitosaccharides being exogenous and galacturonides endogenous—stimulating the crop’s natural self-defense mechanisms.
The problem, however, is that once the attack has begun, endogenous defenses take time to activate, only partially limiting pathogen spread without fully stopping it. The situation changes if the plant’s defenses are already active before powdery mildew attacks. In this case, the plant is better prepared to fight off the infection, making its defense mechanisms far more effective.
Ibisco vit di Gowan
To achieve this, Gowan has launched “Ibisco Vit”, a liquid formulation based on chito-oligosaccharides and oligogalacturonides (COS-OGA). Approved for use on both wine and table grapes at a dose of three liters per hectare, with a maximum of eight applications per year, “Ibisco Vit” maintains the crop’s natural defenses over time, significantly hindering powdery mildew attacks.
This leads to multiple benefits:
- Protection of grape clusters from pathogen attacks.
- Reduction of resistance phenomena against synthetic substances.
- Improvement of grape residue profiles, an increasingly important factor in the supply chain. Notably, “Ibisco Vit” has no mandatory pre-harvest interval.
- Enhanced grape quality, thanks to a biostimulant effect that supports plant biochemical processes, improving resistance to abiotic stress. Field trials have shown that this effect helps plants maximize their potential, including increasing sugar content in grapes.
Title: Ibisco Vit by Gowan: vine warned, infection blocked
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