Cercosporosis Of Onions And Garlic

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

Cercosporosis is an extremely unpleasant fungal disease of garlic and onions. Especially often you can encounter him in the Far East. The harmfulness of cercosporosis primarily lies in the fact that the leaves of onion and garlic begin to die off prematurely, thereby reducing both the quality and the volume of the crop. Therefore, it is imperative to fight against cercospora

A few words about the disease

Cercosporosis manifests itself mainly on the leaves. Chlorotic spots appear on onions when infected with this ailment, the size of which ranges from 3 to 5 mm. Such spots are located mainly on the tops of the leaves. And on garlic, cercosporosis has the appearance of sharply outlined grayish-brown specks of irregular or round shape. Moreover, all of them are framed with well-visible yellow edges and reach 0.5 - 5 mm in size. When wet weather is established, infected tissues are often covered with a very unpleasant olive bloom.

The causative agent of cercospora is considered to be an imperfect mushroom called Cercospora duddiae Welles. The pathogen overwinters in infected plant debris and seeds in the form of conidia and mycelium. Conidiophores of this fungus are collected in diverging bundles, equipped with septa and colored in light brown shades. Sometimes they can be branched. And colorless conidia can be either slightly curved or straight. Each of them contains three to fifteen septa and tapers towards the top.

The spread of infection during the growing season occurs by raindrops and wind. However, the ill-fated ailment can also be tolerated with the help of tools designed to care for plants.

How to fight

When growing onions and garlic, it is very important to follow the rules of crop rotation, returning these crops to their former areas only three to four years later. And they need to be planted in well-ventilated places, while avoiding thickening of the plantings. Periodically, they should be fed with nitrogen fertilizers and superphosphate, but the use of manure as fertilizer must be excluded. As a rule, the previous crops are fed with manure, and mainly mineral fertilizers are applied directly under the onions. It is also necessary to promptly remove all post-harvest residues from the areas.

Throughout the growing season, the soil should be systematically loosened and weeds should be removed. And the affected cultures must be removed from the sites and destroyed.

It is recommended to warm up the planting material for eight hours at a temperature of forty degrees. As a rule, this procedure is carried out one and a half to two months before planting. And on the testes of onions for preventive purposes, it is recommended to carry out chemical spraying. It is equally important to observe spatial isolation from food plantings when planting testes. By the way, seeds for planting should be collected exclusively from healthy plants.

Excellent helpers in the fight against onion and garlic cercosporosis will be such drugs as "Fito-plus" or "Fitosporin". By the way, already two days after the treatment of growing crops with these preparations, the bulbs can be safely eaten. And at the stage of shooting, treatments are carried out with such means as "Immunocytofit", "Ecost" and "Novosil".

Good help to overcome cerocosporosis and spraying with copper-containing preparations: copper oxychloride, Bordeaux liquid or copper sulfate. It is quite acceptable to use "Polycarbacin" as well. However, after using these remedies, onions should not be used for food for at least three weeks. Fungicides of contact and systemic action, such as Abiga-Peak, Acrobat and Ridomil Gold, have also proven themselves in the fight against the ill-fated misfortune. And for better adhesion of fungicides as surfactants, you can use "Triton" (0.05%), "Agral" (0.05%) or a 1% solution of condensed milk.