Bean Anthracnose

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

Bean anthracnose affects all parts of plants located above the ground - beans with seeds are no exception. Occasionally, this dangerous ailment can also affect the roots. The infection develops especially strongly in rainy and humid weather, massively affecting growing crops. And in a rainy, cold spring, the disease actively attacks tiny seedlings. Harvest losses from bean anthracnose are usually quite large, so you need to deal with this problem quite actively

A few words about the disease

On the cotyledons of beans affected by anthracnose, reddish-brown small specks are formed, the center of which is usually several tones lighter. And on the leaves, the veins from the lower sides are mainly affected. As a rule, they almost always turn black. Some time later, the pathogen spreads to the adjacent areas. The yellowed flesh of the leaves is slowly dying off, and the leaves themselves are perforating.

On the stalks and stalks with stalks affected by anthracnose, you can notice an impressive number of small brownish specks or stripes.

The most characteristic of anthracnose is the defeat of the beans. At first, small rusty-reddish or brownish specks are formed on them, gradually growing and merging. A little later, the tissues at the sites of the lesions deepen and ulcers begin to appear on them, the surfaces of which are densely covered with reddish pads. Drying, these pads take on the appearance of brownish crusts.

Often, bean seeds are also attacked by anthracnose. Grayish-brownish spots are gradually formed on them. And when wet weather is established, the seeds shrivel, rot and greatly lose weight.

The causative agent of this destructive scourge is the imperfect mushroom Colletotrichum lindemuthiar. Its development occurs in the conidial stage, which manifests itself on infected tissues in the form of brightly colored mucous pads. These pads are essentially clusters of colorless unicellular spores and conidiophores. During the summer season, several generations of the pathogen have time to develop at once.

The infection persists in the form of mycelium, mainly in the infected post-harvest residues and in the seeds. Diseased seeds usually rot or give very weak shoots, the cotyledons of which are initially infected.

How to fight

When growing beans, it is best to give preference to resistant, early maturing varieties. The rules of crop rotation must be followed with special care, returning the beans to their former areas at least two or three years later.

Seeds to be sown must be carefully selected, sorted and cleaned. Lightweight seeds should be parted with no regrets - they are almost always contaminated. And if they are eliminated in time, the quality of the seed material improves markedly.

It is also recommended to pickle seeds before sowing with Fentiuram or TMTD (60%). Warming them up in water with a temperature of up to 60 degrees gives a good effect - the seeds are kept in it for six hours, after which the water cooled to twenty-five degrees is drained, and the heated seeds are thoroughly dried.

It is necessary to sow seeds in carefully warmed up soil, while avoiding excessive thickening of crops. Bean areas must be open and well ventilated. And all work on the care of this crop is carried out only when the tops dry out from rain moisture and dew.

As soon as young shoots begin to hatch, as well as at the stage of beans formation, prophylactic treatments are carried out with one-percent Bordeaux liquid or with preparations replacing it like "Cineba", etc.

Plants heavily affected by anthracnose must be cut and burned during the growing season. And after harvesting, plant residues should be eliminated from the plots and deep autumn plowing should be carried out on them.