Detail Guide on How to Prevent Powdery Mildew of Grapes

Powdery mildew of grapes is prevalent in areas with high humidity and moderate temperatures, especially during the growing season. The fungus can spread rapidly, particularly in high humidity, and infect young shoots, leaves, flowers, and fruit. The disease can weaken the vines and reduce grape yield. This can negatively affect the quality of the fruit, causing significant economic losses for growers.

 Image of powdery mildew on grape vines.

Symptom of Powdery Mildew of Grapes

Powdery mildew of grapes can cause significant damage to grapevines. Grape powdery mildew symptoms might show up on the leaves, stems, fruit, and other sections of the plant. Here are the common symptoms of powdery mildew of grapes caused by:

Leaves: The fungus initially appears as small, white or grayish spots on the upper surface of the leaves. As the disease progresses, these spots enlarge and merge, forming a powdery coating on the leaves. The leaves may also curl, become distorted, and turn yellow or brown.

Stems: This coating has a white or grayish appearance and is powdery in texture. Infected stems may also show signs of twisting or cracking.

Fruit: It can damage the fruit clusters, causing them to become covered with a white or grayish powdery coating. Infected fruit may also become misshapen, cracked, and discolored.

Overall, it generally weakens plants, lowers yields, and degrades fruit quality. Suspect powdery mildew in your grapevine? Take action promptly. The spread of the disease will be decreased as a result.

Image of biological treatment of powdery mildew on grapes using Trianum V.

Powdery Mildew Grapes Treatment

Managing the disease involves a combination of cultural, chemical, and biological methods such as organic fungicide for grapes. Here, we’ll mainly talk about culture and biological methods as there are some unproven chemical powdery mildew grape treatment .

Cultural Practices on Powdery Mildew of Grapes

Monitor and Remove Infected Plant Material

Monitoring grape plants for early signs of the disease and promptly removing infected plant material can help prevent the spread of the disease. This method of illness management is efficient and kind to the environment.


Pruning grapevines helps create an open canopy structure that promotes better air circulation and sunlight penetration. This reduces humidity levels, making the environment less favorable for fungus growth and spread.

Proper Irrigation

Overhead irrigation or excessive watering should be avoided as it can create a moist environment that favors disease growth. Instead, adopting drip irrigation or other targeted watering methods can minimize leaf wetness and reduce the risk of infection.

Biological Controls on Powdery Mildew of Grapes

Choose Resistant Grape Varieties

One way to prevent grape disease is to choose resistant grape varieties. This can help reduce the spread of powdery mildew of grapes, which is caused by the causal organism Erysiphe necator.

Image of Trianum V, a biofungicide for powdery mildew on grape vines.

Apply Trichoderma Harzianum

Trichoderma harzianum, found in Trianum-V, can reduce the fungus on plants by outcompeting and inhibiting the growth of the fungus responsible for the disease. Trianum-V is a biofungicide that contains T. harzianum and is used to promote plant growth and control plant diseases.

Advantages of Trichoderma Harzianum as powdery mildew fungicide

Effective Disease Control

The organic fungicide for grapes has been proven to effectively control powdery mildew, a common and destructive fungal disease in plants. Its colonization of the grapevine’s root system and its production of antifungal compounds help suppress the growth and development of the pathogens.

Reduction of Chemical Inputs

By incorporating the powdery mildew fungicide into the disease management program, grape growers can reduce their reliance on chemical fungicides. This not only minimizes the risks associated with chemical residues but also aligns with sustainable and environmentally friendly agricultural practices.

Compatibility with Organic Farming

It is non-toxic to humans, beneficial insects, and wildlife, making it an ideal choice for organic grape production. Integrating this organic fungicide for grapes into an organic viticulture system helps maintain the integrity of the ecosystem and supports the sustainability of the vineyard.

Long-Term Effects

The powdery mildew fungicide establishes a symbiotic relationship with the grapevine’s root system, persisting in the soil even after application. This long-term presence can contribute to the biocontrol agent’s continuous suppression of powdery mildew and other soil-borne pathogens, providing ongoing protection to the grapevine.

Resistance Management

By utilizing different modes of action, biofungicides like Trichoderma Harzianum reduce the selective pressure on the pathogens, helping to mitigate the development of resistance to chemical treatments.

Biodegradability and Safety

It is biodegradable, leaves no toxic leftovers in the environment, and does not cause long-term ecological harm. This ensures the safety of workers, consumers, and the overall ecosystem.

In conclusion, Trianum-V is a natural microorganism that is not harmful to humans, animals, or the environment, making it a safe and sustainable option for powdery mildew grape treatment. By incorporating the best fungicide for powdery mildew on grapes into their disease management practices, grape growers can improve their crops’ overall health and productivity.


1.Perazzolli M, Moretto M, Fontana P, Ferrarini A, Velasco R, Moser C, Delledonne M, Pertot I. Downy mildew resistance induced by Trichoderma harzianum T39 in susceptible grapevines partially mimics transcriptional changes of resistant genotypes. BMC Genomics. 2012 Nov 22;13:660.

2.Milan V. Kamble, Shreya M. Joshi, Shiva Hadimani, Sudisha Jogaiah, Biopriming with rhizosphere Trichoderma harzianum elicit protection against grapevine downy mildew disease by triggering histopathological and biochemical defense responses. Rhizosphere, Volume 19, 2021, 100398, ISSN 2452-2198.

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