About bacterial soft rot
These bacteria can cause disease in onions, eucalyptus, tomatoes, melons, maize, and other plants. There are different strains of the bacteria. Some can be helpful, some harmful, and some harmless. Scientists are still learning about the benefits and risks of the different strains of bacteria.
Global distribution of bacterial soft rot
Why this is a problem for New Zealand
The bacteria have caused serious crop losses overseas. They can cause diseases such as:
- stalk rot, bacterial wilt, and leaf blight in maize
- bacterial leaf blight and shoot tip dieback in 2 types of eucalyptus
- centre rot in onions
- grey wall in tomatoes
- internal rot in melons.
How it could get here
Infected plant material, seeds, or soil are the most likely pathways for the bacteria to enter New Zealand.
There are 2 species of thrips that could transmit the bacteria between plants. Thrips are tiny insects that feed on plants. The thrips eat infected material and pass it on to otherwise healthy plants.
Biosecurity New Zealand has strict measures in place to limit the chances of Pantoea ananatis making it through the border in plants or thrips.
How to identify infection
The signs of a Pantoea ananatis infection can be similar to other diseases. Diagnosis requires an expert. The severity of these diseases can vary depending on conditions, like humidity and temperature.
Right: Onion cut open to show damage from bacterial blight. Image: CC 3.0 Howard F. Schwartz, Bugwood.org
If you find signs of the diseases
If you're an experienced grower of the host plants and have found an unusual disease in your plants:
- photograph it
- call 0800 80 99 66
Note: This information is a summary of this disease's global distribution and potential impacts on New Zealand.