Common bacterial diseases on plants and how to fight them

Last time we talked about the most common fungi your plants could suffer from. Now, we’ll enlist the famous bacterial diseases, their symptoms and treatment you could apply to fight them.

All plants, regardless of whether cultivated or not, are susceptible to plant diseases. They can cause harm to a plant’s leaves, fruit, or stem. To be able to fight bacterial plant disease, it is important to recognize it in its early stage to be able to treat it and prevent it from spreading to other plants. If not treated, some diseases can overwinter and infect the plants in the following year too.

We put together a short list of the most common bacterial plant diseases of what causes them,  how to recognize and treat them.


Black rot

Cause: Black rot can be caused by wet and warm weather conditions. The bacteria can enter the plant through natural openings or wounds of the leaf. Once the bacteria is in the plant, it can infect the entire plant traveling through its water conducting system.

Symptoms: Yellow to dark brown discoloration appears on the margins of the leaves. As the disease spreads it infects the whole leaf which turns dark brown. Later stages of black rot can take over the plant’s fruits or vegetables which decay and dry out.

Treatment: Prune the dead branches of trees, pluck the dried out fruit/vegetables, weed regularly to prevent the spread of the disease to other plants. Use bactericides to treat the infected plants but beware that most of them may impose harm on the plant and its fruit/vegetables. One method of prevention is to use disease-free seeds or to wash them before planting them.


Bacterial blight

Cause: The bacteria are spread by rain and wind so the disease can occur after long cool wet periods entering the plant through damaged leaves. Warm dry weather proves to stop the spread of bacterial blight.

Symptoms: Small brown spots on the upper leaves which eventually grow bigger as they encompass the whole leaf. In some cases, the infected leaves can turn brown and watery.

Treatment: Cut out the infected parts of the crop – leaves, stems, branches; make sure to disinfect the pruning tools that you use. Avoid overhead irrigation to avoid further spreading. When applicable, practice crop rotation to avoid overwintering of the bacterial blight. Use disease free seeds and practice antibiotic seed treatment.

Leaf spot

Cause: Wet and cool conditions help the bacteria spread. Once it has infected the plant, the leaf spot bacteria can multiply very quickly.

Symptoms: Dark spots on the plant’s leaves and leaf discoloration. In some extreme cases, these dark necrotic sports can spread to the whole leaf and kill it.

Treatment: Make sure to cut all infected leaves of the plant in order to prevent further spread of the leaf spot. Use a copper-based bactericide in the early stage of the disease. Make sure that you remove all debris from infected plants in the garden and then you don’t plant new ones in the very same place.


Cause: The wilt bacteria can be transmitted by insects. When insects bite off of a leaf the bacteria start multiplying at the wound and then begin to spread. Dry hot weather conditions help the bacteria spread and induce wilting.

Symptoms: When a part of the stem or the branch is cut, white slimy ooze extends from one cut to the other. Yellowing of the leaves can occur but not in every case. Sometimes the infected plant can wilt rapidly without any yellowing of the leaves.

Treatment: The most effective way to prevent the spread of bacterial wilt is to control over the insects spreading it. Once wilt has infected the plant there is no way to cure it. However, it is essential not to use the diseased plants for compost and to make sure to remove any remains of the infected plants from the soil.


All bacterial diseases in plants have one trait in common – their prevention and early diagnosis are essential to taking control of the diseases. Using bacteria-free seeds and then monitoring the plants in all their stages of growth can ensure better control over any bacterial disease that might spread. Such control can help gardeners and farmers grow better, healthier plants.

So now you know what to do to prevent some of the most common diseases, so happy farming and gardening!

* This article contains only general information and can’t be used as a disease treatment prescription. If your crops are suffering any, please consult with a specialist before taking further action.

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