Ring Rot Of Potatoes

2024 Author: Gavin MacAdam | [email protected]. Last modified: 2023-12-16 13:38

Ring rot of potatoes is a common attack. This ailment affects not only aboveground, but also underground parts of growing crops, and in any phase of their development. And the ill-fated disease manifests itself mainly in the form of wilting of potato tops and gradual decay of nodules. These symptoms can be observed both during storage and directly on potato beds. Warm and humid weather is especially favorable for the development of harmful misfortune. Ring rot is very harmful - in some seasons, you can lose about 40% of the crop

A few words about the disease

The development of ring rot is rather slow. Usually, its first symptoms can be noticed only in the second half of the growing season. Harmful bacteria that move into potato stalks from infected mother tubers provoke vascular occlusion, as a result of which the upper parts of the stalks begin to fade, since water access to them is noticeably limited. Sometimes only individual stems wither on potato bushes. The leaves in the areas attacked by the disease lose chlorophyll and turn white. And if you put slices of infected stalks into the water, then mucus of an unpleasant milky consistency will begin to ooze from them.

Weakly affected nodules practically do not differ from healthy ones. However, when cut open, you can observe a softening and pronounced yellowing of tissue throughout the vascular ring. And at later stages, the vascular system disintegrates completely, turning into a disgusting mucous mass, which is easy to squeeze out of the cut tubers with the usual pressure. Such nodules give rise to outwardly full-fledged plants, however, by the end of the growing season, under conditions favorable for the development of the pathogen, the first symptoms of the ill-fated disease begin to appear on them. If favorable conditions do not come, the infection in a latent form will be transmitted to the daughter nodules.

As for the nodules severely affected by the disease, they often rot after planting. Only in rare cases do they survive and give rise to underdeveloped and undersized plants. This type of infection is usually called dwarfism. And tubers of such plants usually do not form at all.

The causative agent of the devastating disease is a pathogen called Corynebacterium sepedonicum, which most often hibernates in infected nodules. And although it does not hibernate in the soil, it is easily preserved in unharvested nodules and plant debris. Ring rot is easily transmitted when cutting potatoes with knives, as well as through potato planters and other agricultural equipment. Sometimes infection is possible when the affected foliage comes into contact with the nodules. It is noteworthy that in seasons characterized by rather cool weather, this ailment often occurs in a latent form.

How to fight

The main preventive measures against ring rot of potatoes are considered to be the cultivation of resistant varieties and adherence to the basic rules of crop rotation. It is strongly discouraged to plant potatoes in infected areas. All infected plants that are found on the site must be removed without fail. Also, in order to minimize the risk of infection of the nodules with ring rot, it is necessary to mow and eliminate the tops in a timely manner.

Seed material should be warmed up at a temperature of fourteen to eighteen degrees for two to three weeks before storing tubers or at the end of storage - this measure will help identify infected nodules, and at the same time will contribute to the further use of only healthy planting material.

Before sending the harvested potato crop for storage, it is recommended to dry the tubers in the light. Seed material is etched with "Maxim" before storage, and the storage facilities themselves must be treated with a solution of copper sulphate and lime solution.