Beet Ramularia

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

Ramulariasis is most often observed in the second half of the beet growing season. It mainly affects the outer leaves, but from time to time it can also be observed on the inner leaves. And at a later stage, a malicious attack can also cover the petioles. The most susceptible to attacks of ramulariasis is considered to be fodder beets. The development of this ailment is largely facilitated by the moderately warm weather established in the summer months (from fifteen to seventeen degrees), as well as high humidity (about 95%). And the development of the disease is enhanced by sulfur deficiency and thickened plantings

A few words about the disease

Beet ramulariosis manifests itself mainly in the form of spotted beet leaves. Most often, old leaves suffer from it. From about the middle of summer, a lot of angular or rounded specks, painted in grayish-white tones and framed by rather wide red borders, begin to appear on them. The diameter of such spots is very decent - often it reaches one or even one and a half centimeters. On the surfaces of the formed spots, the development of powdery white sporulation (plaque consisting of numerous conidia and conidia) is observed, and necrotic tissues begin to fall out over time, leaving angular and rather large holes on the damaged leaves. And before the loss of necrotic areas begins, the centers of the spots crack and gradually collapse.

If the beet leaves are too badly affected by a harmful disease, then they die off entirely, thereby contributing to a decrease in the sugar content of root crops and a decrease in their mass.

In general, the spotting that appears with ramulariasis on beet leaves is somewhat reminiscent of cercospora. From the latter, ramulariosis differs only in the color of the specks and their size. With ramulariasis, the specks formed on the leaf blades are lighter in color, and their average size is from 4 to 7 mm. In addition, ramularia spots are less regular in shape, and the bordering along their circumferences is less distinct and characterized by a brownish color. Initially, they are grayish-greenish, and some time later these spots turn brown and often merge. The color of the plaque also differs - if with ramulariosis the plaque is usually white, then with cercosporosis it is always grayish and dotted with many black dots. In addition, for cercosporous spots, loss is not typical.

Typically, infection persists on infected seeds and plant debris. If the seed is infected, ramulariasis will manifest itself already at the beginning of the growing season, which in turn will contribute to a sharp decrease in root crop yields and greatly weaken the plants.

The causative agent of ramulariasis is the pathogenic fungus Ramularia, which requires lower temperatures for its development than the causative agent of cercosporosis - its development is usually favored by a temperature of seventeen to twenty degrees. This mushroom is most common in the colder northern regions of beet growing - losses will be especially great in years accompanied by heavy rainfall.

The spread of the pathogen occurs throughout the growing season with conidia, and the harmful fungus overwinters in the form of mycelium.

How to fight

The main preventive measures against ramulariasis are considered to be the timely collection of all post-harvest residues and compliance with crop rotation. Autumn deep tillage will also serve well.

As soon as the first symptoms of the ill-fated misfortune are found on the beets, they are sprayed with drugs such as "Abiga-Peak" and "Kartotsid". Copper oxychloride and Bordeaux mixture also help in the fight against ramulariasis.

A drug called "Alto Super" has proven itself excellently in the fight against this scourge - it is quite enough to process the growing beets with it once or twice.