Bacterial Spots (Leaf Spots)

Bacterial Spots (Leaf Spots) Information

By Josie Borlongan, Garden Guides Contributor Various bacteria may cause leaf spots. The common causing pathogens are Pseudomonas and Xanthomonas. Bacterial spots are usually spread by rain or watering splash from leaf to leaf or sometimes from stem lesion to leaves.

Prevention and Control

To prevent or control the spread of bacterial spot, promptly remove the infected leaves. Young planting may be uprooted and thrown in the compost pile. Avoiding use of overhead irrigation may also help in the prevention and control.

Affected Plants

Bacterial spots can be seen in assorted plants, with some more susceptible than others.


Bacterial spots can cause necrotic patches usually angular in the outline of the leaves. They are also characterized by a bright yellow halo.

Natural Insecticides

Copper is a natural mineral that can be applied as dust or foliar spray. It is the strongest type of organic bactericide and fungicide available. Apply copper sprays when there is a high risk of bacterial spots that are starting to develop. Repeat every 7 to 10 days and respray if the rain washes it off.

Other Methods of Control

* Garden Cleanup: Remove infected leaves and plantings. Discard any noticeably diseased materials.
* Crop Rotation: Rotate crops every 2 years.
* Clean Tools: Avoid using tools on healthy plants that were used on infected plants. Sterilize tools in warm water or by rubbing disinfectant before using.
* Soil Solarizing: Heat can be very effective in killing bacterial spores that may be present in soil and compost.

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