Begonia Diseases – Powdery Mildew

April 04 2014 | Posted in Begonia Diseases, News

Begonia Diseases – Powdery Mildew

White powdery spots on both sides of leaves and greasy spots on the undersides are signs of powdery mildew. Powdery mildew is likely to infect tuberous begonias when environmental factors permit it. Crowded, shady conditions and poor air flow are conducive to mildew. Uneven day and night temperatures paired with dramatic changes in relative humidity can favor the development of the disease.

Placing plants at least a foot apart in an area where there is good air circulation will help prevent the outbreak of mildew. Stabilizing temperatures and humidity levels may be difficult to do depending on your location. Humidity can be reduced by not watering directly over the top of the plant and watering earlier on in the day.

Fungicide application can provide mildew control. Application of fungicides to susceptible plants before or in ??earlier stages of the disease is key. Too early of an application on young plants may cause stunted growth and will result in fewer flowers on some varieties. If mildew growth is mild to moderate it is generally too late for effective control with protectant fungicides. In this case the use of horticultural and plant-base oils is needed.

A more natural, organic application can be applied. Mix 1 tablespoon of baking soda in a gallon of water or 2 parts water to 1 part milk. Spray plants every 7-10 days. Neem Tree Oil can be used as directed.