Fusarium Carrot Rot

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

Fusarium rot of carrots is a very harmful disease: its pathogen attacks planted seed plants, shoots and roots, provoking their rapid wilt. This ailment can manifest itself both in the form of dry and in the form of wet rot. As for the volume of crop losses, it depends on the time of appearance of fusarium. If the disease struck the growing carrots early enough (approximately in the middle of summer), then it often dies, and with a late defeat (approximately at the beginning of autumn), not only the yield decreases, but also the quality and duration of storage of root crops

A few words about the disease

Manifestations of fusarium rot can be found on the entire surface of root crops - depressed and fairly light dry sores begin to form on them. Expanding, they form concentric folding, which is noticeable to the eye. Severely affected root crops are noticeably compacted and gradually mummified. However, the rot that forms on them is often wet - in this case, infected tissues are characterized by a brown color and pronounced moisture, and the boundaries with healthy pulp are vague. Similar signs are caused by increased air humidity and its elevated temperature during storage of carrots. It is noteworthy that simultaneously with the development of fusarium, the development of other pathogenic microflora can also be observed.

The causative agents of the ill-fated misfortune are fungi of the genus Fusarium. They are especially dangerous because even in the presence of several viable conidia in the soil, these fungi are able to form huge colonies, and without interference from any other microorganisms. The soil in such areas becomes unsuitable for growing any plants, and in order to bring it back to normal, it is necessary to disinfect it and introduce various biological products. And the sources of infection are usually infected plant debris and soil, in which the pathogen leads a saprotrophic lifestyle. Most often, it affects severely weakened plants.

It should also be mentioned that the presence of infection in plants does not always lead to their wilting and subsequent death. For example, if carrot plantings are well cared for, the pathogen will infect three times fewer plants than the number of seeds initially infected. But if the cultivation technology is violated, then the percentage of wilted carrot plantings will increase significantly.

To a large extent, the spread of a destructive disease is influenced by weather and growing conditions. Fusarium rot is especially harmful if the process of harvesting root crops is accompanied by an elevated temperature (from eighteen to twenty-three degrees), and also if mechanically damaged root crops remain in the beds.

How to fight

In order to prevent fusarium rot, it is necessary to deal with weeds and observe the rules of crop rotation - it is better not to return the carrots to the previous plots earlier than three or four years later. The best precursors for carrots will be cereal crops, as they retain more moisture and cleanse the soil from pathogenic microflora. And the soil should have good water permeability and aeration. Also, between the carrots of the first and second years, it is necessary to withstand spatial isolation.

Carrot seeds are treated with TMTD before planting. You can also disinfect seeds thermally - for half an hour at a temperature of 45 to 50 degrees.

Plants of the second year, when the first signs of an illness are detected, are sprayed with one percent Bordeaux liquid. And before you send uterine roots for storage, they are treated with fungicides.

As for the storage of bright root crops, it should be carried out at an air humidity of 80 - 85% and a temperature of one to two degrees.