Bacterial soft rot

The bacteria mainly attack the fleshy storage organs of their hosts (tubers, corms, bulbs, and rhizomes), but they also affect succulent buds, stems, and petiole tissues.

Sweet potatoes show clear lesions that grow rapidly leaving a recognizable watery and soft, oozy tissue where only the peel remains intact.

[2][3][4][5] Soft rots are characterized by their distinct maceration of hosts' cell walls with pectolytic enzymes, and subsequent digestion of the intracellular fluid as the bacteria grows.

They can be host to the bacteria either by being infected as seed, or from direct inoculation into wounds or natural openings (stomata or lenticels) in mature plants, which is most common.

But, when a plant is infected and the conditions are favorable, the bacteria immediately begin feeding on liquids released from injured cells and start replicating.

As they gorge on intracellular fluid, the bacteria continue to multiply and move into the intercellular spaces, with their cell-wall-degrading enzymes ahead of them preparing the plant tissues for digestion.

Higher temperatures and high humidity are ideal growing conditions for the bacteria making ventilation a big priority when trying to combat this disease.

There are very few things that can be done to control the spread of bacterial soft rots, and the most effective of them have to do with simply keeping sanitary growing practices.

Injury to plant tissues should be avoided as much as possible, and the humidity and temperature of the storage facility should be kept low using an adequate ventilation system.

Few varieties are resistant to the disease and none are immune, so rotating susceptible plants with non-susceptible ones like cereals is a practice positive to limiting soft rot infection.

Due to its wide range of hosts, bacterial soft rot devastates many significant crops both in the field and in storage all over the world.

But, it is not just the vegetables that are susceptible; in the tropics, soft rot develops on important crops like corn, cassava, and banana even while still in the field.