Erwinia is a bacterial disease that can cause damage in a range of crops. It often produces watery looking, rotten patches on the leaves, fruit, flower or stalk. The bacterium is quite common and can develop rapidly in the greenhouse, spreading from plant to plant through crop handling and splash dispersal. Hygiene measures are crucial for keeping an infection under control.

The rotten patch gives off a very specific odour similar to rotten eggs. The bacterium breaks down the cell walls of the plant with the aid of enzymes, enabling the infection to develop rapidly. Wilting and rotten patches cause the plant to die or damage the product to such an extent that it is unsaleable.

The general type is referred to as Erwinia spp. A crop can be affected by certain species that are particularly harmful to that particular plant. The species often found in pot plants include E. cypripedii, E. carotovora subsp. carotovora, E. carotovora subsp. atroseptica and E. chrysanthemi.
A new species which can cause a lot of damage in strawberries has recently been identified: Erwinia pyrifoliae. The symptoms are blackened fruits and bacterial slime.

Text and images: Groen Agro Control.