Plan the perfect garden with our interactive tool →

How to Make a Homemade Fungicide for Mildew on Begonias

Powdery mildew, or Oidium begoniae, appears on begonia leaves as a white powder or powdery looking spots. It tends to occur most commonly when conditions are more humid in late summer and early fall, and it‘s encouraged by warm days followed by cool nights. Although mildew is ugly and can disfigure your begonia, the chances are good that the plant won’t die. Most fungus infestations cannot be treated with homemade products, requiring chemical applications instead. The good news is that mildew is the exception to that rule. You can easily and effectively remedy the condition with your own harmless fungicidal homebrew. Begin treating as soon as you detect the presence of mildew.

  • Powdery mildew, or Oidium begoniae, appears on begonia leaves as a white powder or powdery looking spots.
  • Although mildew is ugly and can disfigure your begonia, the chances are good that the plant won’t die.

Pick any heavily infested leaves from the begonia and destroy them. Don’t add them to your compost because the mildew spores they carry can easily spread to healthy plants

Dissolve 4 tbsp. baking soda in a gallon of warm water. Add 1 tbsp. horticultural oil and mix well. Fill a plastic spray bottle with the fungicidal solution.

  • Pick any heavily infested leaves from the begonia and destroy them.

Spray all surfaces of the entire plant, and pay particular attention to the undersides of leaves. These areas often go unnoticed and mildew will typically flourish there. Repeat applications weekly until all signs of the infection have subsided. It’s best to continue treating as long as atmospheric conditions are most humid. You probably won’t need to do this during dry weather.

Thin and prune excessively full areas of begonias to help provide excellent air circulation. Dense crowded foliage facilitates growth of powdery mildew.

  • Spray all surfaces of the entire plant, and pay particular attention to the undersides of leaves.
  • Thin and prune excessively full areas of begonias to help provide excellent air circulation.

Remove and destroy severely infected plants to prevent the fungus from spreading to healthy plants.

Related Articles

Phlox Disease
Phlox Disease
Why Are My Vinca Flowers Wilting?
Why Are My Vinca Flowers Wilting?
Black Spots on Geraniums
Black Spots on Geraniums
Fungus on a Zoysia Lawn
Fungus on a Zoysia Lawn
How to Treat Mildew on Honeysuckle
How to Treat Mildew on Honeysuckle
Coneflower Disease
Coneflower Disease
Problems With Vinca
Problems With Vinca
How to Test Soil for Fungus
How to Test Soil for Fungus
Trumpet Vine Diseases
Trumpet Vine Diseases
Cleaning Mildew Out of a Wading Pool
Cleaning Mildew Out of a Wading Pool
Diseases of St. Augustine Grass
Diseases of St. Augustine Grass
What Is White Fuzz Growing in an Herb Garden?
What Is White Fuzz Growing in an Herb Garden?
Orange Fungus on a Plant
Orange Fungus on a Plant
Garden Guides
×