Michigan State Experts Offer Tips on Managing Xanthomonas in Begonias

Michigan State Experts Offer Tips on Managing Xanthomonas in Begonias


Spots, splotches, and blight from Xanthomonas on Reiger begonia leaves. Photo by Jeremy Jubenville, MSU Extension.

In recent weeks, plant diagnostic experts at Michigan State University (MSU) have received numerous samples of begonias with Xanthomonas axonopodis pv. begonia. As a result, many greenhouse growers are asking questions about the biology of the bacteria, how it spreads, how to minimize losses, and how to sanitize after finding plants with the bacterial leaf spot.


Xanthomonas is the name of a group of bacterial species, some of which cause diseases in plants. These species are often further separated into strains that indicate the specific group of plants each one attacks. Each type of Xanthomonas has a specific host, or group of related hosts, that it can infect. As the name suggests, Xanthomonas axonopodis pv. begonia is the pathovar that infects begonias. Therefore, this bacterial pathogen cannot be spread to other crops prone to Xanthomonas, such as geraniums.

In response to the above concerns, from both growers in the state and elsewhere who may be concerned, the team of Heidi Lindberg and Jeremy Jubenville of MSU Extension, and Jan Byrne of MSU Diagnostic Services, have put together a three-part series of articles online.

The first part of the series covers how infections develop, the potential impacts they can have, and quick diagnostic tips.

The second article in the series covers the cultural practices that reduce disease pressure (scouting, moisture management, isolation, and sanitation), and chemical treatments to prevent the spread of the pathogen.

The third part of the series addresses commonly asked questions about how growers should approach plant disposal in order to minimize losses in the crop.

For even more information, check out this e-gro alert with tips on identification of bacterial leaf spot and blight on begonia.