Fomoz Of Beet

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

Phomosis, or zonal spotting of beets, manifests itself mainly in the second half of the growing season. With severe lesions of phomaosis, seed germination decreases by about 39.7%, their weight - by 11, 7 - 19, 1%, the yield of root crops - by 29%, and sugar content - by 1, 17 - 1.58%. Most often, phomosis attacks beet leaves, which have been noticeably weakened by some other physiological or fungal disease. To preserve the beet crop, this scourge must be fought

A few words about the disease

On the lower beet leaves affected by the phomosis, rounded necrotic specks are formed, reaching from 3 to 5 mm in diameter. Their color can be either light brown or yellow. All specks grow slowly, often merging into more solid formations, and necrotic tissue begins to fall out of their centers. As a result of such processes, the leaves dry out. Some time later, pycnidia, tiny black dots, begin to form on the specks.

On the stalks of the testes, leaf petioles and flower-bearing shoots, necrosis can be seen, manifested in the form of longitudinal brownish specks, gradually becoming covered with pycnidia. Often, a harmful fungus infects the glomeruli of seeds and affects the petals of the perianth. On peduncles with glomeruli, spots are usually absent, but dots can be observed on them. If infected seeds are subsequently sown, this can lead to massive damage to the beet seedlings.

When storing beets, the symptoms of phomosis can be detected about a month or two after laying root crops in storage, and the massive development of the disease almost always occurs in the spring. If you cut diseased roots, then on their cuts you can observe a hard blackened tissue, in which sometimes voids are formed with walls covered with a loose light gray bloom. Usually, the affected areas are located in the upper parts of the root crops.

Phomosis is a serious danger not only in storage facilities, but also on the testes. If infected root crops are planted, the testes are often damaged with their subsequent death.

The causative agent of such an unpleasant and destructive ailment is the marsupial mushroom Phoma betae A. B. Frank. His mycelium is usually highly branched and colorless, sometimes with a grayish tinge. The pathogen overwinters on plant remains in the upper soil layer (the depth of its occurrence can be from five to fifteen centimeters). Sometimes it also overwinters in the form of mycelium and pycnidia in roots and seeds. In addition to phomosis, this mushroom is also capable of causing clump rot and dry rot of beet roots.

The most favorable conditions for the development of the pathogen are considered to be the neutral acidity of the soil, pH 7, the temperature from fifteen to thirty degrees (ideally, twenty-five degrees) and the relative humidity of the air in the range from 60 to 70 percent. Phomosis is especially widespread on table beets in the first and second years of life.

How to fight

Beets in the crop rotation must be placed in such a way that they return to their previous plots no earlier than after three to four years. It is best to plant it on medium loamy soils, which are characterized by a neutral reaction. Infected plants must be eliminated from the plots: on the testes, this is usually done before the start of stem formation, and on uterine plantations - throughout the growing season.

On beet crops affected by fomoz, it will be good to spray once or twice with Alto Super. And if early symptoms of the disease are detected, spraying with one percent Bordeaux liquid will serve well.

You need to try to harvest root crops before the onset of the first frost, because if they are damaged by frost, they will lose their resistance to various diseases. And only healthy roots should be laid for storage. Moreover, their leaves must be cut off, leaving only centimeter petioles. It is best to store beets in small boxes, sprinkling it with a mixture of lime-fluff and sand.