Pseudomonas carotovorum subsp. carotovorum (ex Erwinia carotovorum subsp. carotovorum ) first attacks the stem and develops inside it. Thus, moist, brown lesions extend into the marrow ; this liquefies fairly quickly, and a longitudinal or transverse cut in the rod shows that it is hollow. You can also tell by pinching it. This bacteria can spread to the outer layers of the stem and degrade them (Figures 1 and 2). Thus, dark brown to black longitudinal lesions cover and surround the stem for several centimeters. Decomposing tissues are moist and soft.

The internal deterioration of the stem is not without consequences on the functioning of plants and in particular on the transport of water and mineral elements. These are limited, which leads to wilting and yellowing of the leaves, especially during milder climatic periods and / or from the harvest of the first fruits. If conditions are right, the disease progresses and plants can die . When the latter are weakly affected and conditions become milder, they will be able to bear fruit normally.

These symptoms on the stem, accompanied by wilting, should not be confused with those caused by Pseudomonas corrugata responsible for black pith.

When it invades the fruits , this bacterium is at the origin of a moist rot , viscous and soft , which will lead to the total liquefaction of the latter. Ultimately, only the epidermis and some remnants of shriveled tissue will remain.