Bacterial Blight Control: How to Identify and Get Rid of Bacterial Blights

When it comes to diseases in the vegetable garden, bacterial blight is perhaps one of the most popular. Pseudomonas savastonoi or bacterial blight is common in plants from the family of soybeans, as well as other vegetables. There is also a strain of bacteria that affects flowers, specifically geranium. It destroys mostly the lower parts of the host, making it not result in significant losses in crop yield. Still, it is a common concern for most home gardeners and even for commercial growers.

What is Bacterial Blight?

This is a plant disease that is most common early in the season or when the weather is generally wet and cool. To be specific, it is a typical problem amongst gardeners when the temperature ranges from 70 to 80 degrees Fahrenheit. It starts in the plant through the leaves, specifically on its wounds and stomata. When the bacteria enter in the plant, it begins its effects by inhibiting the production of chlorophyll. In turn, this will trigger the growth of bacterial cells and the host plant will start showing visible damages. In the case of seedlings, on the other hand, the disease can start once the seed has an infection. When the temperature rises, this also inhibits the activity of the bacteria.

Splashing water and wind are some of the most common carriers of the disease, making it spread from one plant to another. To add, the disease will also spread when the leaves of one plant touch another because of wind and cultivation, among other external factors. Plants will also be more susceptible to the disease once it is already weak and if it is suffering from other problems. Using knife or pruning shears that you have previously used in an affected plant will also be a carrier of the disease. The lack of nutrients in the soil is another condition that can be favorable for bacterial blight.

Bacterial Blight

Bacterial Blight Starts in the Plant through the Leaves

Identifying Bacterial Blight’s Damage

Host Plants

While soybeans and geranium are some of the most common plants that experience the signs and symptoms of bacterial blight, it is important to note that the disease has a wide array of hosts. Cotton, rice, pepper, tomato, cassava, and plantain are other plants that may experience this disease.


The signs and symptoms of the disease may vary from one plant to another. In a nutshell, the following are some that you may see in your plants or crops:

  • In the case of soybeans, infections will cause wrinkling, discoloration, and reduction of germination rate. The growing tips from young plants will also show signs of injury. Angular spots will be evident on the leaves, which will also turn yellow or brown. The pods, on the other hand, will have reddish-brown spots on the edges. Other parts of the plant will show burns.
  • In the case of geranium, wilting of the leaves is a more common indication of suffering from bacterial blight as against discoloration. This can happen even if the root does not rot.
  • In the case of tomato, on the other hand, the same symptoms as above can happen in the leaf. For the fruit, there will be black spots. They will sink and turn brown as the infection worsens. Also, the leaves may fall. This will cause the fruit to suffer from direct exposure to sunlight and can affect its growth.

Results of Infestation

The disease begins as brown spots and when you fail to pay attention to the problem as soon as possible, it will inevitably get worse. It is common for the host plants to suffer from cosmetic damage, especially through holes and discoloration in the leaves. When the infection is too severe for the plants to handle, the foliage will fall off the ground. Also, because it inhibits the production of the plant’s nutrients, it will make the host unhealthy.

Cabbage Infected

Cabbages Infected by Bacterial Blight Disease

How to Get Rid of Bacterial Blights

Natural and Organic Solutions

To effectively prevent and control bacterial blight without the need to resort to toxic solutions, the following are some of the methods that can prove to be promising:

  • Preventive measures should be on the top of the list. One of the first things that you need to do is to purchase plants that are resistant to the disease. In addition, crop rotation will also be a big help. Especially for beans, rotate crops at least once every three years. Also, when purchasing seeds, make sure that they are healthy as this can signal the start of the infection. See to it that the seeds are free from pathogens.
  • Sanitation, care, and maintenance of the garden will also be instrumental in the prevention of this disease. Once a plant starts showing visible signs of damage, take it out of the garden. If not, windy conditions will speed up the spread of the disease to your healthier plants.
  • When pruning or cutting your plants, see to it that you are using clean shears or scissors. The latter can also be carriers of the disease. Sanitizing your cutting equipment will inhibit the spread of bacteria that are carriers of bacterial blight.
  • Proper watering of the plants is also necessary. Because the disease can spread through irrigation, you need to water in such a way that you will directly hit the plant and while preventing splashes.
  • Spacing of the plants will also be a good way to prevent bacterial blight. If they are too near each other, it is probable that the disease will easily spread, even with light wind. This will also trigger proper air circulation.
  • Keep the soil dry and have a proper irrigation system. Moist environments are favorable for bacterial blight, which is why you need to prevent the soil from being wet for a long time.
  • Rather than using chemicals for the treatment of bacterial blight, a better alternative would be natural sprays. There are basic ingredients in the kitchen that can prove to be helpful. One would be a combination of 50 grams of ground lemongrass and two liters of water. It will work best as a spray for tomatoes, lettuce, and carrots.

Chemical Solutions

Chemicals are amongst the most common choices for controlling bacterial blight. It has a negative reputation because of being toxic, which may make it do more harm than good. With proper application, through following the instructions from the manufacturer, adverse effects will be less likely to happen.

Copper fungicides are amongst the most common for the treatment of bacterial blight. To be effective, it needs to have at least 50% copper oxychloride and applications need to be done early in the season before the disease develops. It prevents the presence of fungi and bacteria, and hence, strengthening the plant and lessening its susceptibility to damage. Liquid Copper Fungicide Spray is one product that you might want to consider.

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