Homemade Fungicide for Grapes

Baking Soda

• In a German study evaluating the effectiveness of baking soda as a treatment for powdery mildew on grape crops, a 1 percent solution applied at the onset of symptoms effectively controlled mildew without harming the grapes. Add 1 percent baking soda to 99 percent water. Solutions mixed above 2 percent are harmful for grape culture. Boost baking soda's effectiveness by adding 1 tsp. of dish soap or insecticidal soap per 1 gallon mix. This helps the mix spread evenly over the leaf and extends the length of protection. Possible harmful effects of baking soda are the accumulation of sodium and bicarbonate in the soil, along with the drying effects of the soda. For best results, irrigate the plants well two to three days before applying the mix and alternate the treatment with other fungicides. Reapply this mix after rain or irrigation washes the leaves.

Milk

• Some recent studies from Brazil found milk is an effective fungicide for grapes. Mix one part milk to nine parts water and spray. Applications with mixes stronger than a 1:5 ratio can harm the plant and lead to mold and mildew. The enzyme lactoperoxidase is believed responsible for milk's antifungal actions, preventing the inoculation of spores and acting as an antibacterial for the leaves. Lactobacilli, also naturally occurring in milk, provide additional support for the plant by feeding beneficial bacteria in the soil. Apply the solution every three to seven days.

Canola and Other Oils

• Research on petroleum-based mineral oils and plant-based oils, such as canola, safflower and soybean, shows both diminish the severity of infection by suffocating of mildew spores. Mineral oil achieved better control. Consider oils a preventative rather than a treatment, although it can play a role in an integrated fungal management program. Apply the oil at full strength every seven to 10 days.

Recommendations and Guidelines

• Integrating treatments prevents harmful effects, such as the build up of oils, sodium and other detrimental elements in the soil. Begin with a preventative, such as mineral oil, as soon as the leaves appear and harden before any symptoms occur. After the beginning signs of fungal infection, switch to baking soda mix through out the remainder of spring. As temperatures rise and rains ease, changing to milk avoids the excessive drying effect of baking soda. Never apply any fungicide mix during the heat of the day or on new leaves.