Beet Rhizomania

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

Beet rhizomania, also called beard (literally the name of the disease is translated as "crazy roots"), occurs quite often. This viral ailment leads to necrotic yellowing of beet veins. The first symptoms of a destructive misfortune can be noticed already in June, when young plants, when hot weather sets in, begin to turn brown and slowly wither. Root crops in infected plants are small. As a rule, they look underdeveloped and are characterized by an impressive number of roots intertwined with each other. And after some time, they harden, become fibrous and begin to rot

A few words about the disease

Beet leaves attacked by rhizomania acquire a yellowish or pale green color. As the disease develops, necrosis or yellowing of leaf veins may also be observed. And closer to the end of the growing season, the central leaves are characterized by narrowed leaf blades and elongated cuttings. Beets that have lost their turgor begin to noticeably lag behind in growth.

As for the root crops, they are rather small in size, and the so-called "beard" appears on their tail parts - a rather solid number of tiny lateral roots, intricately intertwined with each other. The severity of such symptoms depends on the phase of beet development, on the frequency of precipitation and on their amount, as well as on temperature. Therefore, sometimes the symptoms can vary greatly.

If rhizomania has affected the beet plantings quite strongly, then the yield may decrease by half or even more, and the sugar content of the beet at the same time falls from 16 - 18% to 10%. The growth of infected crops is greatly slowed down, sugar in beets also accumulates extremely slowly, and the water content in it decreases markedly. Also, root crops are characterized by a decrease in the content of alpha-amine and total nitrogen and various dry substances. And the amount of calcium, potassium and sodium in them increases significantly. Beets attacked by the ill-fated misfortune are characterized by woodiness and often begin to rot from the tail.

The causative agent of this scourge is a virus, the main carriers of which are considered to be cytospores and zoospores. By the way, this pathogen is present in almost all areas of beet growing. The spread of the harmful virus occurs through the mediation of a soil fungus called Polymyxa betae during the transport of beets, as well as with equipment, plant debris and water.

Rhizomania is most pronounced in case of waterlogging of the soil and at high temperatures. And if the soil is dry enough, then the disease will manifest itself much less often. Also, an increase in the development of rhizomania can be observed on soils with a slightly alkaline and neutral reaction.

How to fight

The main measures to combat beet rhizomania are collection of plant residues, culling of infected crops with their subsequent destruction and timely regular weeding of weeds. But compliance with crop rotation in most cases does not give the desired effect, since the causative agent of the infection can persist in the soil for ten years. Powerless in the fight against this ill-fated disease and all kinds of pesticides.

To some extent, it is possible to influence the reduction of the harmfulness of rhizomania by increasing soil biological activity by maintaining its optimal structure and applying high-quality organic fertilizers. And yet, these measures are able to reduce the harmfulness of the disease only to an insignificant extent.

Perhaps the only truly effective protective method is the cultivation of varieties with genes for resistance to destructive rhizomania. As a rule, hybrids have a high degree of resistance - and it is on them that you should pay attention.